JP4243556B2 - Induction heating apparatus and metal member heating method using the same - Google Patents

Description

  The present invention relates to an induction heating device used when a metal metal member is heated by induction heating, and a method of heating a metal member using the induction heating device.

  As a method of heating a metal member, a method using induction heating is widely used. In induction heating, a metal member is placed close to a work coil such as a solenoid, and a magnetic field is generated by flowing a high-frequency current through the work coil, and an eddy current is generated so that a magnetic field is generated in the metal member to cancel it. Thus, Joule heat is generated by the current and the electric resistance of the metal member to raise the temperature of the metal member.

  For example, in Patent Document 1, an outer cylinder member having a predetermined length, an inner cylinder member inserted coaxially with a certain space toward the inside of the outer cylinder member, and an upper surface fixed to the outer peripheral surface of the inner cylinder member For induction heating arranged along the outer wall surface of the outer cylinder member of the propeller shaft, which is composed of an elastic member pressed against the inner peripheral surface of the outer cylinder member and an adhesive interposed between the outer cylinder and the elastic member In the propeller shaft manufacturing apparatus in which the outer cylinder member and the elastic member are firmly bonded to each other, the shape of the induction heating coil arranged along the outer wall surface of the outer cylinder member is changed to the outer cylinder. A configuration is disclosed in which a shape that covers substantially half of the outer surface along the longitudinal direction of the member is provided, and a rotation mechanism that integrally rotates the outer cylinder member and the inner cylinder member when the coil is energized is disclosed. And according to this, the outer cylinder member and the elastic member vulcanized and bonded in the inner cylinder member can be firmly bonded over the entire circumference of the outer cylinder member, and the process can be simplified. Furthermore, it is described that the cost required for the power cost and the equipment cost is reduced.

  Patent Document 2 has a metal inner cylinder, a metal outer cylinder, and a rubber elastic body interposed between the inner cylinder and the outer cylinder, and is formed inside the rubber elastic body. In a method for manufacturing a fluid-filled vibration isolator in which an incompressible fluid is sealed in a plurality of liquid chambers, a rubber elastic body is vulcanized and bonded to the outer surface of the inner cylinder, and the inner surface of the outer cylinder or the rubber elasticity After the adhesive is applied to the outer surface of the body, a rubber elastic body is press-fitted into the outer cylinder in the fluid so that the rubber elastic body has a squeezing ratio of 10 to 40%, and then the outer cylinder is 160 to 250 ° C. It is disclosed that the outer cylinder and the rubber elastic body are bonded by induction heating in the range of. And it is described that according to this, a process can be simplified and the number of parts of apparatus itself can be reduced.

  In Patent Document 3, a lamination process of alternately laminating metal plates and raw rubber layers to form an unvulcanized laminated rubber bearing, and a raw rubber layer of the unvulcanized laminated rubber bearing by an electromagnetic induction heating means. A laminated rubber bearing comprising a preheating step of preheating through the metal plate by induction heating of the metal plate, and a vulcanization forming step of mounting the preheated laminated rubber bearing in a mold and further heating. The manufacturing method is disclosed. And according to this, by preheating by induction heating, the temperature of the central portion of the laminated rubber bearing, which has conventionally been difficult to receive heat, can be raised to the same or higher temperature than the ambient temperature, thereby suppressing overvulcanization. However, it is described that the vulcanization time can be greatly shortened.

  In Patent Document 4, in an induction heating apparatus of a vending machine that heats a beverage can, the heating coil has a plurality of turns and is formed in a cylindrical shape having a gap at a predetermined position in the axial direction. It is disclosed. And according to this, it is described that the local heat in the vicinity of the heating coil is eliminated, the number of mechanical parts when the beverage can is mounted in the heating coil is reduced, and the inductance can be adjusted by the heating coil itself.

Patent Document 5 discloses an anti-vibration method in which an anti-vibration material body formed of an elastic material is bonded and fixed to a metal base material covered with a baking coating film made of a thermosetting resin paint with a thermosetting resin adhesive. As a structure manufacturing method, a work coil for electromagnetic induction heating is brought close to the adherend surface of a metal substrate, and then the adherend surface is gelled by the electromagnetic induction heating so that the thermosetting resin adhesive is in a gel state. After that, a thermosetting resin adhesive is attached to the vibration isolator body, and the temperature is raised to the gel-like temperature range of the metal substrate and the thermosetting adhesion of the vibration isolator body Disclosed is a technology for pressure-contacting the adhesive. Then, according to this, even if the metal substrate, such as those covered by baked coating film of a thermosetting resin coating material, a metal substrate by electromagnetic induction heating while minimizing the deterioration of the baked coating film It is described that it is possible to achieve adhesion and integration with the anti-vibration rubber body.
Japanese Patent Publication No. 6-9873 JP 10-89411 A Japanese Patent Laid-Open No. 11-218183 Japanese Patent Laid-Open No. 2002-8125 JP 2001-271859 A

By the way, the bush type vibration isolator comprises an inner cylinder and an outer cylinder arranged coaxially, and a vibration isolating rubber interposed therebetween. Such vibration damping device, the inner cylinder and anti-vibration rubber vulcanization integrally molded is manufactured by press-fitting a material obtained by applying an adhesive to the outer periphery thereof to the outer cylinder was heated by induction heating. At this time, heating of the outer cylinder, induction heating apparatus having a work coil for heating induction is used, is performed with a working coil inside or outside of the outer cylinder.

  In addition, there are various sizes of outer cylinders. At this time, in order to efficiently heat the outer cylinder according to the size of the outer cylinder, the work coil is changed for each size of the outer cylinder to be processed. .

  However, the work coil has a structure in which cooling water is circulated and has a complicated structure. It takes a long time to change the work coil, and thus there is a problem that productivity is lowered.

The present invention has been made in view of the above points, and the object of the present invention is to provide a metal member without changing the work coil even when the metal members having different shapes are heated by induction heating. and to provide a method of heating a metallic member using the the induction heating device and it can perform a suitable induction heating corresponds to.

The induction heating device of the present invention that achieves the above object is an induction heating device used when raising the temperature of a cylindrical metal member by induction heating,
A work coil for induction heating;
A cylindrical core made of a magnetic body that is externally or detachably fitted and fixed so that the work coil can be replaced corresponding to a metal member;
Equipped with a,
At the time of induction heating, the metal member is arranged so that the metal member is put on the outside of the cylindrical core that is externally fitted to the work coil, or the cylindrical metal member is inside the cylindrical core that is internally fitted to the work coil. Is arranged to be inserted .

And the heating method of the metal member of the present invention is to raise the temperature of the cylindrical metal member by induction heating using the induction heating device of the present invention ,
A core selection step of selecting a cylindrical core made of a magnetic material corresponding to the metal member;
A core attachment step of attaching and fixing the core selected in the core selection step so as to be detachably fitted to the work coil;
The cylindrical core member is arranged so that the cylindrical metal member is placed on the outer side of the cylindrical core that is externally fitted and fixed to the work coil in the core attaching step, or the cylindrical core that is fixedly fitted and fixed to the work coil. A work set step for placing the cylindrical metal member on the inside ; and
A heating step of raising the temperature of the metal member arranged in the work setting step by induction heating using the work coil;
It is provided with.

When various metal members are to be heated by induction heating with a single work coil, if the distance between the work coil and the metal member is small, it can be heated efficiently, but if the distance is large, the magnetic flux density in the metal member Becomes small and cannot be efficiently heated. Moreover, when the space | interval of each part of a metal member and a work coil is non-uniform | heterogenous, temperature distribution will arise in a metal member. However, according to the above configuration, since the core made of a magnetic body that suppresses the decrease in magnetic flux density is detachably attached to the work coil, even if the gap between the work coil and the metal member is large or small, If the core is selected and replaced so that the distance between the core and the metal member is the same in both cases, induction heating can be performed under the same conditions regardless of the size of the metal member. In addition, if a core is selected and replaced so that the distance between each part of the metal member and the core is uniform, the metal member can be heated uniformly without causing a temperature distribution. If the core is selected and replaced so that only the distance between the core and the core becomes small, the heating temperature can be locally increased. Therefore, by preparing a core made of a magnetic material having a shape suitable for heating for each shape such as the size of the metal member, even when each of the metal members having different shapes is heated by induction heating, the work coil without a stage replacement, it is possible to perform a suitable induction heating corresponding to the metal member.

According to the present invention, even when heated by induction heating respectively different metal member shapes like, without the stage sort of work coil, it is possible to perform a suitable induction heating corresponding to the metal member.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
FIG. 1 shows an induction heating apparatus 100 according to Embodiment 1 of the present invention.

  The induction heating device 100 according to the first embodiment of the present invention is used in a manufacturing process of a bush type vibration isolator 300 used for an automobile suspension.

  Specifically, as shown in FIG. 2, the vibration isolator 300 is formed by vulcanizing and integrally molding an inner cylinder 311 and a vibration isolating rubber 312 and applying an adhesive 320 to the outer periphery thereof. It is manufactured by press-fitting into the cylinder 200. The induction heating device 100 is used to preheat the outer cylinder (metal member) 200.

  The induction heating apparatus 100 includes a work coil 110 for induction heating, an apparatus main body 120 connected to the work coil 110, and a core 131 that is detachably attached to the work coil 110.

  The work coil 110 is made of a metal tubular material, and is of a solenoid type formed so as to form a spiral and extend upward, and then extend downward from the upper end of the spiral so as to pass through the axial position. Is provided at the bottom. The work coil 110 is fixed to a support base (not shown) so that the spiral axis is in the vertical direction.

  The apparatus main body 120 is connected to both ends of the work coil 110 and functions as an oscillator that supplies a high-frequency current to the work coil 110. In addition to functioning as a coil cooler that circulates cooling water that flows through the work coil 110, the apparatus main body 120 It also controls the entire device such as adjustment.

  The core 131 is made of a ferromagnetic material such as ferrite, and is formed in a cap shape in which a bottomed cylinder is turned upside down. Further, the core 131 is detachably mounted and fixed by being fitted over the work coil 110 formed in a substantially cylindrical shape from the upper side. Here, the core 131 is provided so as to be in direct contact with the work coil 110. The core 131 shown in FIG. 1 is for heating the outer cylinder 200 having a small outer diameter. The outer diameter of the core 131 is slightly smaller than the inner diameter of the outer cylinder 200, and the inner wall of the outer cylinder 200 and the outer periphery of the core 131. Are formed so that the distance between them is uniform. Hereinafter, the configuration illustrated in FIG. 1 in which the core 131 for heating the outer cylinder 200 having a small outer diameter is attached and fixed to the work coil 110 is referred to as a first configuration.

  Next, the manufacturing method of the vibration isolator 300 using this induction heating apparatus 100 is demonstrated.

  First, the inner cylinder 311 and the vibration isolating rubber 312 are integrally formed by vulcanization.

  Next, a thermosetting adhesive 320 is applied to the outer periphery of the rubber of the monolith 310.

  On the other hand, the outer cylinder 200 is disposed so as to surround the core 131 of the induction heating device 100.

Next, a high-frequency current is passed from the apparatus main body 120 to the work coil 110 and the cooling water is circulated. At this time, a magnetic field is generated by the high-frequency current flowing through the work coil 110. In the outer cylinder 200, an eddy current is generated in the inner surface layer portion so as to generate a magnetic field that cancels the magnetic field generated by the work coil 110, and the outer cylinder 200 is generated by Joule heat generated by the eddy current and the electric resistance of the outer cylinder 200. Is heated up. Here, the core 131 is formed of a ferromagnetic material, and attenuation of the magnetic field between the work coil 110 and the outer cylinder 200 is suppressed, so that the core 131 can be heated efficiently and the inner wall of the outer cylinder 200 can be heated. and the spacing between the outer periphery of the core 131 is uniform, the entire outer cylinder 200 is similarly exposed to a magnetic field, it is possible to perform uniform induction heating without temperature distribution occurs inside the outer tube 200. Although heating degree of the outer cylinder 200 (temperature) is freely set by the current value of the high-frequency current supplied to the work coil 110, the outer cylinder 200 has been subjected to electrodeposition coating, the electrodeposition by induction heating The current value of the high-frequency current is set so that the coating does not deteriorate.

  Then, the integral 310 of the inner cylinder 311 and the vibration isolating rubber 312 is press-fitted coaxially into the heated outer cylinder 200. Thereby, the adhesive 320 applied to the outer periphery of the integrated object 310 is cured, and the integrated object 310 and the outer cylinder 200 are bonded. The integral object 310 is press-fitted into the outer cylinder 200 by placing the integral object 310 above the outer cylinder 200 coaxially with the heated outer cylinder 200 and moving the heated outer cylinder 200 upward. This is performed so as to be fitted on the object 310.

  As described above, the vibration isolator 300 in which the vibration isolating rubber 312 is interposed between the inner cylinder 311 and the outer cylinder 200 arranged coaxially is manufactured.

  As described above, in this induction heating apparatus 100, the core 131 is detachable and can be exchanged corresponding to the outer cylinder 200. Below, the structure for heating the outer cylinder 200 different from a 1st structure is demonstrated.

  FIG. 3 shows a main part of the induction heating apparatus 100 in which the core 132 for heating the outer cylinder 200 having a large outer diameter is attached and fixed to the work coil 110.

  The core 132 is for heating the outer cylinder 200 having an outer diameter larger than that of the first configuration. The outer diameter of the core 132 is slightly smaller than the inner diameter of the outer cylinder 200, and the inner wall of the outer cylinder 200 and the core 132 are arranged. Is formed so that the distance between the outer circumference of the first and second outer circumferences is uniform and substantially the same as that of the first configuration. In this case, the core 132 is formed of a ferromagnetic material, and the attenuation of the magnetic field between the work coil 110 and the outer cylinder 200 is suppressed. Therefore, the interval between the work coil 110 and the outer cylinder 200 is the first configuration. Although the distance between the inner wall of the outer cylinder 200 and the outer periphery of the core 132 is substantially the same as that of the first configuration, the induction heating can be performed as efficiently as the first configuration. Since the distance between the inner wall of the core and the outer periphery of the core 132 is uniform as in the first configuration, the entire outer cylinder 200 is similarly exposed to a magnetic field and heated uniformly without causing a temperature distribution in the outer cylinder 200. Can do. Hereinafter, the configuration shown in FIG. 3 in which the core 132 for heating the outer cylinder 200 having a large outer diameter is attached and fixed to the work coil 110 is referred to as a second configuration.

  FIG. 4 shows a main part of the induction heating apparatus 100 in which a core 133 for heating the outer cylinder 200 having an elliptical cross section is attached and fixed to the work coil 110.

  The core 133 is for heating the outer cylinder 200 having an elliptical cross section, and has an outer diameter that is slightly smaller than the inner diameter of the outer cylinder 200. The core 133 is formed so that the distance between the inner wall of the outer cylinder 200 and the outer periphery of the core 133 is uniform, and the distance is substantially the same as that of the first configuration. In this case, the core 133 is formed of a ferromagnetic material, and the attenuation of the magnetic field between the work coil 110 and the outer cylinder 200 is suppressed, and the interval between the inner wall of the outer cylinder 200 and the outer periphery of the core 133 is reduced. Since it is substantially the same as the first configuration, induction heating can be performed as efficiently as the first configuration, and the interval between the inner wall of the outer cylinder 200 and the outer periphery of the core 133 is uniform as in the first configuration. Therefore, the entire outer cylinder 200 is similarly exposed to a magnetic field, and can be heated uniformly without causing a temperature distribution in the outer cylinder 200.

  FIG. 5 shows a main part of the induction heating apparatus 100 in which a core 134 for heating the outer cylinder 200 having a substantially D-shaped cross section is attached and fixed to the work coil 110.

  The core 134 is for heating the outer cylinder 200 having a substantially D-shaped cross section, and has an outer diameter that is slightly smaller than the inner diameter of the outer cylinder 200. The core 134 is formed so that the interval between the inner wall of the outer cylinder 200 and the outer periphery of the core 134 is uniform, and the interval is substantially the same as in the first configuration. In this case, the core 134 is formed of a ferromagnetic material, the attenuation of the magnetic field between the work coil 110 and the outer cylinder 200 is suppressed, and the interval between the inner wall of the outer cylinder 200 and the outer periphery of the core 134 is reduced. Since it is substantially the same as the first configuration, induction heating can be performed as efficiently as the first configuration, and the interval between the inner wall of the outer cylinder 200 and the outer periphery of the core 134 is uniform as in the first configuration. Therefore, the entire outer cylinder 200 is similarly exposed to a magnetic field, and can be heated uniformly without causing a temperature distribution in the outer cylinder 200.

  FIG. 6 shows the main part of the induction heating apparatus 100 in which the core 135 for heating the welded joint portion with the rod material to a higher temperature is attached to the work coil 110 for the outer cylinder 200 having a circular cross section attached to the rod material. Indicates.

  The core 135 is for heating the welded joint with the rod material with the most remarkable heat dissipation to a higher temperature with respect to the outer cylinder 200 having a circular cross section attached to the rod material. The cross section is slightly smaller than the inner diameter, and the cross section is formed into a shape that combines a circle and a rectangle. The core 135 is fixedly attached to the work coil 110 so that the rectangular portion corresponds to the joint portion with the rod member of the outer cylinder 200, and in particular, the rectangular corner corresponds to the welded portion. For this reason, the interval between the inner wall of the outer cylinder 200 and the outer periphery of the core 135 is uniform corresponding to the circular portion of the core 135, whereas the outer cylinder 200 is more than the circular portion corresponding to the rectangular portion. The interval between the inner wall and the outer periphery of the core 135 is small. In particular, the interval between the corner of the rectangular portion and the welded portion is the smallest. In this case, the core 135 is made of a ferromagnetic material, and the attenuation of the magnetic field between the work coil 110 and the outer cylinder 200 is suppressed, so that induction heating can be performed efficiently. Further, since the space between the inner wall of the outer cylinder 200 and the outer periphery of the core 135 is uniform corresponding to the circular part, the circular part corresponding part of the outer cylinder 200 is similarly exposed to the magnetic field, Heating can be performed uniformly without causing a temperature distribution. On the other hand, since the interval between the inner wall of the outer cylinder 200 and the outer periphery of the core 135 is smaller than the circular part corresponding to the rectangular part, it can be heated to a higher temperature than the circular part corresponding part of the outer cylinder 200. In particular, since the interval between the corner of the rectangular portion and the welded portion is the smallest, the welded portion can be heated to the highest temperature.

When various outer cylinders are to be heated by induction heating with a single work coil, if the distance between the work coil and the outer cylinder is small, it can be heated efficiently, but if the distance is large, the magnetic flux density in the outer cylinder Becomes small and cannot be efficiently heated. Moreover, when the space | interval of each part of an outer cylinder and a work coil is uneven, temperature distribution will arise in an outer cylinder. However, according to the induction heating apparatus 100 having the above-described configuration, the cores 131 to 135 made of a magnetic material that suppresses a decrease in magnetic flux density are detachably attached and fixed to the work coil 110. Even when there is a large or small gap with respect to 200 (for example, the first configuration and the second configuration), the cores 131 to 135 are selected so that the distance between the cores 131 to 135 and the outer cylinder 200 is the same in both cases. If they are exchanged, induction heating can be performed under the same conditions regardless of the size of the outer cylinder 200. Further, if the cores 131 to 135 are selected and replaced so that the distance between each part of the outer cylinder 200 and the cores 131 to 135 is uniform, the outer cylinder 200 can be heated uniformly without causing a temperature distribution. On the other hand, if the cores 131 to 135 are selected and replaced so that only the interval between a part of the outer cylinder 200 and the cores 131 to 135 is reduced, the heating temperature can be locally increased. Therefore, by preparing the cores 131 to 135 made of a magnetic material having a shape suitable for heating for each type such as the size of the outer cylinder 200, the outer cylinders 200 having different shapes and the like are heated by induction heating. even if, without a stage replacement of the work coil 110, it is possible to perform a suitable induction heating corresponding to the outer cylinder 200.

  Further, since the cores 131 to 135 are formed so as to cover the work coil 110 and the direct influence of the work coil 110 does not reach the outer cylinder 200, the setting of the local heating degree of the outer cylinder 200 and the like can be performed. This can be done only by setting the shape of ~ 135.

(Embodiment 2)
FIG. 7 shows a main part of the induction heating apparatus 100 according to Embodiment 2 of the present invention. In addition, the part of the same name as Embodiment 1 is shown with the same code | symbol.

  In this induction heating apparatus 100, a cylindrical core 136 is detachably fitted inside and fixed to a solenoid type work coil 110 formed by spiraling a metal tubular material. The core 136 has a through hole having a substantially square outline in cross section. A cylindrical metal member 200 having a substantially square cross section whose outer diameter is slightly smaller than that of the through hole is arranged in the through hole at a distance from the surface of the core 136 so that the metal member 200 is heated by induction heating. It has become.

Since the core 136 is detachable, by preparing the core 136 having a different shape of the through hole, the work coil 110 is replaced even when the metal member 200 having a different shape is heated by induction heating. it can be performed without a suitable induction heating corresponding to the metal member 200.

  Other configurations, operations, and configurations are the same as those of the first embodiment.

(Embodiment 3)
FIG. 8 shows a main part of the induction heating apparatus 100 according to Embodiment 3 of the present invention. In addition, the part of the same name as Embodiment 1 is shown with the same code | symbol.

  In this induction heating apparatus 100, a block-like core 137 is detachably attached and fixed to a lower portion of a pancake-type work coil 110 formed of a metal wire in a spiral shape. The core 137 has a substantially conical hole formed on the upper surface. A substantially conical metal member 200 is inserted into the substantially conical hole and spaced from the surface of the core 137, and the metal member 200 is heated by induction heating.

Since the core 137 is detachable, by preparing the core 137 having different hole shapes, the work coil 110 can be replaced even when the metal members 200 having different shapes are heated by induction heating. no, it is possible to perform a suitable induction heating corresponding to the metal member 200.

  Other configurations, operations, and configurations are the same as those of the first embodiment.

(Other embodiments)
In the first and second embodiments, the solenoid-type work coil 110 is used, and in the third embodiment, the pancake-type work coil 110 is used. However, the present invention is not particularly limited thereto, and other types of work such as a hairpin type work coil are used. A coil may be used.

  In the first embodiment, the induction heating device 100 is used for manufacturing the vibration isolator 300. However, the induction heating device 100 is not particularly limited thereto, and may be used for heating any metal member.

  INDUSTRIAL APPLICABILITY The present invention is useful for an induction heating device used when raising the temperature of a metal metal member by induction heating and a method for heating a metal member using the induction heating device.

It is a figure which shows the 1st structure of the induction heating apparatus which concerns on Embodiment 1 of this invention. It is explanatory drawing which shows the manufacturing method of a vibration isolator. It is a figure which shows the principal part of the induction heating apparatus which attached and fixed the core of the 2nd structure to the work coil. It is a figure which shows the principal part of the induction heating apparatus which attached and fixed the core for heating the outer cylinder of an elliptical cross section to the work coil. It is a figure which shows the principal part of the induction heating apparatus which attached and fixed the core for heating the outer cylinder of a cross-section substantially D shape to the work coil. It is a figure which shows the principal part of the induction heating apparatus which attached and fixed to the work coil the core for heating a welding coupling | bond part with the rod material of an outer cylinder to higher temperature. It is a figure which shows the principal part of the induction heating apparatus which concerns on Embodiment 2 of this invention. It is a figure which shows the principal part of the induction heating apparatus which concerns on Embodiment 3 of this invention.

Explanation of symbols

100 induction heating device 110 workcoils 120 apparatus main body 131 to 137 core 200 outer tube (metal member)
210 Rod material 300 Vibration isolator 310 Integrated object 311 Inner cylinder 312 Vibration isolator rubber 320 Adhesive

Claims (2)

An induction heating device used when raising the temperature of a cylindrical metal member by induction heating,
A work coil for induction heating;
A cylindrical core made of a magnetic body that is externally or detachably fitted and fixed so that the work coil can be replaced corresponding to a metal member;
Equipped with a,
At the time of induction heating, the metal member is arranged so that the metal member is put on the outside of the cylindrical core that is externally fitted to the work coil, or the cylindrical metal member is inside the cylindrical core that is internally fitted to the work coil. An induction heating device, wherein the induction heating device is arranged to be inserted . A method of heating a metal member, wherein the temperature of the cylindrical metal member is increased by induction heating using the induction heating device according to claim 1 ,
A core selection step of selecting a cylindrical core made of a magnetic material corresponding to the metal member;
A core attachment step of attaching and fixing the core selected in the core selection step so as to be detachably fitted to the work coil;
The cylindrical core member is arranged so that the cylindrical metal member is placed on the outer side of the cylindrical core that is externally fitted and fixed to the work coil in the core attaching step, or the cylindrical core that is fixedly fitted and fixed to the work coil. A work set step for placing the cylindrical metal member on the inside ; and
A heating step of raising the temperature of the metal member arranged in the work setting step by induction heating using the work coil;
A method for heating a metal member, comprising:

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