JP7362061B2 - Induction heating method and induction heating device - Google Patents

Description

The present invention relates to a cylindrical member, a ring-shaped member, etc. made of a material such as a metal that can be heated by induction, and which has a shaft hole at its center. The present invention relates to an induction heating coil method and an induction heating device used when simultaneously induction heating a radial surface.

Conventionally, this type of induction heating coil is disclosed in, for example, Patent Document 1. This induction heating coil (induction heating device for cylindrical objects) is provided with an inner coil and an outer coil that are adjacent to the inner and outer circumferential surfaces of the object to be heated, respectively, and the inner and outer coils have the same current of the same phase. The coil is connected in series to one high-frequency power source so that the current flows in the same direction, and the number of turns of the inner coil is at least one more turn than the number of turns of the outer coil.

Patent No. 4098076

However, in such an induction heating coil, both the inner coil and the outer coil are formed by winding a round pipe with a circular cross section a predetermined number of times, and these coils are wrapped around the inner circumferential surface or outer circumferential surface of the object to be heated in a predetermined manner. Because they are arranged close to each other with a gap, and the winding state of the outer coil is uniform in the axial direction of the object to be heated, the heating efficiency of the object to be heated by the inner and outer coils is poor, and the axial This method has the disadvantage that it is difficult to uniformly heat the entire object to be heated, such as the inner peripheral surface of the hole, the outer peripheral surface, and the upper and lower surfaces.

In other words, an inner coil made by winding a round pipe a predetermined number of times is simply inserted into the shaft hole of the object to be heated, and when a high-frequency current is applied to the coil, cooling water is circulated and supplied within the round pipe, causing the coil to generate heat. Because of the structure that suppresses heat generation, the inner coil can only be cooled from the inner surface of the round pipe, making it difficult to sufficiently suppress the heat generated by the inner coil itself when energized. As a result, when induction heating the inner peripheral surface of the shaft hole of the object to be heated, it is difficult to uniformly heat the entire area, and the heating efficiency of the inner coil is also poor, for example, the heating time becomes longer, etc. It is also difficult to sufficiently increase efficiency.

In addition, the outer coil with a small number of turns is arranged on the outer peripheral surface of the object to be heated, and is evenly wound over the entire axial direction of the outer peripheral surface of the object to be heated. The inner coil, which has a large number of turns inserted in the Although the upper and lower surfaces are more heated, the magnetic flux does not pass through the upper and lower surfaces, making them difficult to heat compared to the outer circumferential surface, etc., and the magnetic flux also tends to concentrate on the edges of the inner and outer circumferential surfaces of the object to be heated, causing these edge portions to reach high temperatures. The other inner and outer circumferential surfaces and upper and lower surfaces are heated to a low temperature, and as a result, it becomes more difficult to heat the entire object to be heated at a uniform temperature.

The present invention has been made in view of the above circumstances, and its purpose is to promote cooling of the heating coil , efficiently heat the entire inner circumferential surface of the shaft hole of the object to be heated, and to An object of the present invention is to provide an induction heating method and an induction heating device that can uniformly inductively heat the entire object to be heated while sufficiently increasing the heating efficiency of the inner peripheral surface of the hole. In addition to the above-mentioned objectives, another purpose is induction heating, which can satisfactorily heat the upper and lower surfaces of the object to be heated and the edge portions of the inner and outer circumferential surfaces of the object to be heated, and can heat the entire object to be heated at a more uniform temperature. An object of the present invention is to provide a method and an induction heating device.

In order to achieve this object, the invention according to claim 1 of the present invention supplies a high frequency current of a predetermined frequency from a high frequency power source to a cylindrical heating coil disposed in the shaft hole of the object to be heated. The entire area of the inner peripheral surface of the shaft hole of the object to be heated is heated by induction, and the heating temperature of the inner peripheral surface of the shaft hole during the induction heating is directed in the direction of the shaft hole of the object to be heated, and the emitted light inside the shaft hole is heated. is measured with a radiation thermometer set to receive light , and when the measured temperature reaches a predetermined temperature , a control device stops supplying the high frequency current from the high frequency power source to the heating coil. shall be.

Moreover, the invention according to claim 2 is characterized in that the radiation thermometer is disposed on a support block that supports the heating coil . In addition, the invention according to claim 3 provides that the heating coil is inserted into the shaft hole of the heated object, and the heating coil is inserted into the shaft hole of the heated object, and the heating coil is inserted between the outer peripheral surface of the heating coil and the inner peripheral surface of the shaft hole of the heated object. The heating temperature is measured by the radiation thermometer based on the emitted radiation light. Furthermore, the invention according to claim 4 is characterized in that the heating coil has a coil conductor wound in a coil shape a predetermined number of times, and a coil cover that covers the outer peripheral side and the tip side of the coil conductor.

Further, the invention according to claim 5 has a coil conductor wound in a coil shape a predetermined number of times, and a coil cover that covers the outer peripheral side and the tip side of the coil conductor, and is arranged in the shaft hole of the object to be heated. A cylindrical heating coil that is supplied with a high-frequency current of a predetermined frequency from a high-frequency power source to inductively heat the entire inner peripheral surface of the shaft hole of the object to be heated; a radiation thermometer that is set to receive radiation light inside the hole and measures the heating temperature of the inner peripheral surface of the shaft hole during induction heating by the heating coil; The heating coil is characterized by comprising a control device that stops supplying high-frequency current from the high-frequency power source to the heating coil .

According to the invention described in claims 1 to 5 of the present invention, the radiation thermometer is integrally disposed on the support block of the heating coil, and the pointing direction of the radiation thermometer is aligned with the outer peripheral side of the heating coil. Since it is set so that it is directed between the inner peripheral surface (inside) of the shaft hole of the object to be heated and the radiation inside the shaft hole can be accurately received, the induction heating coil can be left in place (while it is being heated). The heating temperature at a desired position inside the shaft hole (for example, a position near the center in the axial direction) can be measured successively with high accuracy, and as a result, almost the entire inner peripheral surface of the shaft hole can be heated almost uniformly at the desired temperature. can.

A perspective view showing an embodiment of an induction heating coil according to the present invention Same side view Perspective view of the inner coil Vertical sectional view of the same (a) is a front view showing the coil conductor of the inner coil, and (b) is its longitudinal cross-sectional view. (a) is an enlarged view of part A in Fig. 5(b), (b) is an enlarged view of part B in Fig. 5(b), and (c) is a view taken along the line CC in Fig. 5(a). An explanatory diagram of the same usage condition

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail based on the drawings.
1 and 2 show one embodiment of an induction heating coil according to the present invention. As shown in FIGS. 1 and 2, an induction heating coil 1 (referred to as heating coil 1) includes an inner coil 2, an outer coil 3, and a holder 4 that supports them.

The holder 4 has a pair of long copper plates 4a having a predetermined width and a predetermined length, and the copper plates 4a are pressed together via an insulating plate 4b, and these are connected to the inner coil 2 and the outer coil 3. A pair of support plates 4c and 4d supporting both ends and bolts 4e are used to press and fix them.

The inner coil 2 is inserted into a shaft hole Wa of a rotor W as an object to be heated, and includes a coil cover 2a2 into which a coil conductor 2a1, which will be described later, is inserted, and a base end portion of this coil cover 2a2. Round copper pipes 2c1 and 2c2 as a first pipe and a second pipe, which have a disk-shaped support block 2b, etc. to support, and protrude by a predetermined dimension from the coil cover 2a2 to the upper surface side of the support block 2b, are connected to the copper plate of the holder 4. It is fixedly supported on the outer surface (surface) of 4a by a support plate 4c and bolts 4e.

Further, the outer coil 3 has a coil portion 3a disposed close to the outside of the outer circumferential surface Wb of the rotor W, and a base end portion 3b extending above both ends thereof on the outer surface of the copper plate 4a of the holder 4. It is fixedly supported by a support plate 4d and bolts 4e. Incidentally, on the outer surface of each copper plate 4a, between the support plates 4c and 4d for the inner coil 2 and outer coil 3, cooling pipes 5 made of square copper pipes and having a U-shape in side view are fixed by brazing. From both ends of the pair of cooling pipes 5 (only one shown) projecting upward, from the pair of ends projecting upward from the support plate 4c of the inner coil 2, and from the support plate 4d of the outer coil 3. Hose joints 6 (eight in total) are fixed to each of the pair of upwardly protruding ends.

Next, the specific structure of the inner coil 2 will be explained based on FIGS. 3 to 6. As shown in FIG. 3, the inner coil 2 includes a coil portion 2a and the support block 2b that supports the base end side (upper side in FIG. 4) of the coil portion 2a. As shown in FIG. 4, the coil portion 2a includes a coil conductor 2a1 formed by winding a flat pipe into a coil shape a predetermined number of times at an even pitch in the axial direction, and a baking material that covers the outer circumferential side and the tip side of the coil conductor 2a1. The coil cover 2a2 has a cylindrical shape with a bottom and is made of an insulator such as the like.

At this time, the coil conductor 2a1 is a crushed copper pipe having a flat space 9 (see FIG. 6) inside by crushing a round copper pipe of a predetermined diameter as a conductor in the diametrical (cross-sectional) direction. It is formed into a coil shape by winding a copper pipe a predetermined number of times at a constant pitch along a linear axis. Note that a straight portion 2a3 is provided on the base end side of the coil conductor 2a1, and is not wound but integrally extends upward for a predetermined length.

In addition, a pair of straight round copper pipes 2c1 are provided at the distal end (lower end in FIG. 4) that is one end of the coil conductor 2a1 and the base end of the straight portion 2a3 that is the other end. The distal ends of the round copper pipes 2c2 are fixed by brazing, respectively, and the base end of the round copper pipe 2c1 extends upward a predetermined length while passing through the axial center position of the coil conductor 2a1. Further, the length of the other round copper pipe 2c2 is set to be short so that its upper end position is the same as that of the round copper pipe 2c1, and its tip is connected to the base end of the straight portion 2a3 of the coil conductor 2a1. It is attached and fixed.

As shown in FIG. 6(b), a communication hole 7a is formed at the tip of one of the round copper pipes 2c1 and communicates with the flat space 9 at the tip of the coil conductor 2a1. As shown in FIG. 6(a), a communication hole 7b is also formed at the tip of the copper pipe 2c2, communicating with the flat space 9 of the base end (straight portion 2a3) of the coil conductor 2a1. Note that the tips (lower ends) of the round copper pipe 2c1 and the round copper pipe 2c2 are opened and communicated with the inside of the coil cover 2a2. Further, the upper end of the coil cover 2a2, which is the opening thereof, is supported by a support block 2b, which will be described later, so that the inner space thereof is airtight.

As a result, for example, cooling water as a cooling medium supplied from the base end of one of the round copper pipes 2c1 flows inside the round copper pipe 2c1 and is ejected at a predetermined pressure from the opening at its tip into the bottom of the coil cover 2a2. The cooling water that is supplied and bounced off the inner surface of the bottom flows upward inside the coil cover 2a2, and flows into the flat space 9 from the tip of the coil conductor 2a1 through the communication hole 7a, and flows inside the flat space 9. It flows upward and flows into the other round copper pipe 2c2 from its base end.

At the same time, the cooling water that has flowed up to the top inside the coil cover 2a2 also flows into the tip of the other round copper pipe 2c2. In other words, the cooling water supplied from one round copper pipe 2c1 to the bottom of the coil cover 2a2 flows through two channels: one through the coil cover 2a2, and the other through the flat space 9 of the coil conductor 2a1. As a result, the coil conductor 2a1 is simultaneously cooled from the outside (outer surface side) and the inside (inner surface side).

As shown in FIGS. 3 and 4, the support block 2b of the inner coil 2 includes a cover fixing nut 2b1, a sensor support plate 2b2, a divided coil clamp 2b3, etc., each made of an insulating material, and the whole The coil cover 2a has a disk shape and supports the upper end of the coil cover 2a in an airtight manner.

Note that the sensor support plate 2b2 (and cover fixing nut 2b1) is provided with a sensor mounting hole 8 (sensor mounting portion) penetrating in the vertical direction, and a radiation temperature sensor (not shown) is installed in this sensor mounting hole 8. It is mounted so as to be oriented downward (in the direction of the shaft hole Wa of the rotor W), so that the temperature at a predetermined position in the height (depth) direction of the inner surface of the shaft hole Wa of the rotor W can be detected. The inner coil 2 is supported by the holder 4, with the base end of the coil portion 2a supported by the support block 2b via the round copper pipes 2c1, 2c2, etc., using a cover fixing nut 2b1.

On the other hand, as shown in FIGS. 1 and 2, the outer coil 3 is formed by winding a round copper pipe as a conductor pipe whose outer peripheral surface is covered with an insulating material a predetermined number of times (approximately 4 turns in the figure). The coil portion 3a has a coil portion 3a, and a pair of base end portions 3b formed by linearly extending both ends of the coil portion 3a upward (in the direction of the holder 4). At this time, in the coil portion 3a, the upper end portion 3a1 and the lower end portion 3a2, which are arranged close to the upper surface Wd and the lower surface We at both axial ends of the rotor W, are each set to approximately 1.5 turns (closely wound), for example. The number of turns between the pair of upper end portions three a1 and lower end portions three a2 is set to approximately one turn (roughly wound).

The heating coil 1 configured in this way is used by being connected to an induction heating device 10, as shown in FIG. That is, the induction heating device 10 includes a transistor inverter 11 as a high-frequency power source, and an output that is fixedly connected to the output terminal of the transistor inverter 11 with a copper plate or the like or movably connected via a flexible cable. It includes a shift converter 12, a cooling water supply device 13 as a cooling medium supply means having a cooler, a cooling water tank, etc., and a control device (not shown).

The pair of copper plates 4a of the holder 4 are directly fixedly connected to the pair of output terminals of the output transformer 12 using, for example, fixing bolts (not shown) or fixedly connected via an appropriate cable. Through this connection, the round copper pipes 2c1, 2c2 and base end 3b of the inner coil 2 and outer coil 3 are connected to the pair of copper plates 4a, so that the output terminal of the output transformer 12 (high frequency power supply) is connected to the inner coil. 2 and the outer coil 3 are connected in parallel.

In addition, the cooling water supply device 13 has its supply ports connected to the inner coil 2, outer coil 3, and one hose joint 6 of the cooling pipe 5 through hoses, and its return ports to the inner coil 2, outer coil 3, and one hose joint 6 of the cooling pipe 5. 3 and the other hose joint 6 of the cooling pipe 5 via hoses. In other words, the coil parts 2a and 3a of the inner coil 2 and the outer coil 3 and the cooling pipe 5 are connected in parallel to the cooling water supply device 13.

Note that this cooling water circulation flow path (connection form) is not limited to the parallel connection state; for example, the inner coil 2, outer coil 3, and cooling pipe 5 may all be connected in series, or two of these three may be connected in series. Of course, it is also possible to connect two in series. In addition, for example, the cooling water supply device 13 may be provided with a plurality of supply ports having different cooling water supply pressures, so that the cooling water supply pressures to the inner coil 2 and the outer coil 3 are different (the pressure to the inner coil 2 is different from the pressure to the outer coil 3). The circulating amount of cooling water may be optimally set by setting the pressure higher than that of the cooling water.

Then, in the connected state shown in FIG. 7, the heating coil 1 is lowered from the upper surface Wd side of the rotor W set on a setting table (not shown), and the coil cover 2a2 portion of the inner coil 2 is inserted into the shaft hole Wa of the rotor W. At the same time, the coil portion 3a of the outer coil 3 is placed close to the outer circumferential side of the outer circumferential surface Wb of the rotor W. At this time, the tip of the coil cover 2a2 of the inner coil 2 protrudes by a predetermined dimension from the lower surface We of the rotor W, and the outer coil 3 has an upper end portion 3a1 and a lower end portion 3a2 of the coil portion 3a on the upper surface Wd and the lower surface of the rotor W. Set so that it is approximately opposite to We.

In this state, when the transistor inverter 11 and cooling water supply device 13 of the induction heating device 10 are operated, a high frequency current is transmitted from the transistor inverter 11 to the inner coil 2 (coil conductor 2a1) via the output transformer 12 and the holder 4. At the same time, it is also supplied to the outer coil 3 (coil portion 3a). When a high frequency current is supplied to both coils 2 and 3, eddy currents are induced in the inner circumferential surface of the shaft hole Wa of the rotor W, the outer circumferential surface Wb, the upper surface Wd, the lower surface We, etc. of the rotor W, and the rotor W is heated by induction. Ru.

At this time, since the coil conductor 2a1 of the inner coil 2 is a flat copper pipe, its width is increased, and the surface area of the conductor facing the inner circumferential surface of the shaft hole Wa is larger than that of, for example, a simple round copper pipe. That is, the number of magnetic lines of force irradiated from the coil conductor 2a1 toward the inner peripheral surface of the shaft hole Wa can be increased, and an efficient induction heating state can be obtained.

The heating temperature of the inner circumferential surface of the shaft hole Wa due to this induction heating is successively measured by a radiation temperature sensor (not shown), and the signal thereof is input to a control device (not shown) of the induction heating device 10. Then, when the measured temperature reaches a set temperature preset in the control device, for example, the operation of the transistor inverter 11 is stopped. As a result, the inner circumferential surface of the shaft hole Wa of the rotor W is induction heated at a predetermined temperature.

Note that a radiation temperature sensor that receives radiation light is integrally disposed on the sensor support plate 2b2 of the support block 2b of the inner coil 2, and the direction of radiation light is directed between the outer peripheral side of the coil cover 2b and the rotor W. Since it is set so that it is directed between the inner circumferential surface (inside) of the shaft hole Wa and the radiation inside the shaft hole Wa can be accurately received, the heating coil 1 can be left in place (in the heating state). The heating temperature at a desired position inside the shaft hole Wa (for example, a position near the center in the axial direction) can be measured successively with high accuracy, and as a result, almost the entire inner peripheral surface of the shaft hole Wa can be heated almost uniformly at the desired temperature. Become.

On the other hand, simultaneously with the induction heating of the inner coil 2, the outer peripheral surface Wb of the rotor W is also induction heated to a predetermined temperature by induction heating by the outer coil 3. During induction heating of the outer circumferential surface Wb, the winding state of the coil portion 3a of the outer coil 3 is such that the upper surface Wd and lower surface We portions of the rotor W are set (wound) more densely than the intermediate portion. The magnetic flux of the lower surface We and the edge portion Wc can be controlled, and these can be heated substantially in the same manner as the inner and outer circumferential surfaces, that is, the entire rotor W can be uniformly heated by induction.

Note that, when the cooling water supply device 13 operates, for example, at approximately the same time as the transistor inverter 11, cooling water is circulated and supplied into the coil cover 2a2 and the coil conductor 2a1 via the pair of hose joints 6 of the inner coil 2, and the inner coil The coil conductor 2a1 of the inner coil 2 is cooled from the outer surface side and the inner surface side, that is, the coil conductor 2a1 of the inner coil 2 has a flow path through which cooling water flows and a flow path through which cooling water flows inside the coil cover 2a2. Two systems of cooling water flow paths are formed.

As a result, the cooling water flows through the coil cover 2a2 and cools the coil conductor 2a1, so that the coil conductor 2a1 is cooled while being immersed in the cooling water, and the cooling water is applied to the inner surface and surface (outer surface) of the flat space 9. are cooled while being in reliable contact with each other, and heat generation of the coil conductor 2a during energization is efficiently suppressed.

Further, the cooling water supplied from the cooling water supply device 13 is also circulated and supplied into the round copper pipe of the outer coil 3, so that the outer coil 3 is cooled from the inner surface side. At this time, since the outer coil 3 is a round copper pipe with a larger outer diameter and fewer turns than the inner coil 2, cooling water flows well through the round copper pipe and flows into the outer coil 3. A cooling state approximately the same as that of the inner coil 2 can be easily obtained.

Furthermore, since the cooling pipe 5 is fixed to the outer surface (surface) of the copper plate 4a between the support plates 4c and 4d of the inner coil 2 and outer coil 3, the heat generation of the copper plate 4a itself between the support plates 4a and 4c is suppressed. It turns out. In other words, the heat generation of the inner coil 2 and outer coil 3 themselves and the heat generation of the copper plate 4a itself that supports both coils 2 and 3 is suppressed, and a decrease in heating efficiency due to the heat generation of the energized heating coil 1 itself is prevented. become.

The rotor 10, in which the inner circumferential surface of the shaft hole Wa and the outer circumferential surface Wc are heated by the heating coil 1 in this manner, has thin margins such as the end portion of the laminated silicon steel plate constituting the rotor W due to abnormal heating of the edge portion Wc. Deformation such as floating is prevented, and a high-quality rotor W can be easily obtained. As a result, operations such as shrink-fitting the rotating shaft into the shaft hole Wa of the heated rotor W can be performed easily and with high precision.

As described above, according to the heating coil 1, the inner coil 2 has the coil conductor 2a1 and the coil cover 2a2 having a bottomed cylindrical shape that covers the outer peripheral side of the coil conductor 2a1, and both ends of the coil conductor 2a1 are It is connected to the transistor inverter 11 via the output transformer 12, and cooling water is circulated and supplied into the coil cover 2a2 from the cooling water supply device 13, so that the coil conductor is 2a1 can be cooled by being immersed in cooling water, and the inner peripheral surface of the shaft hole Wa of the rotor W can be efficiently heated while the heat generation of the inner coil 2 itself is well suppressed, and the heating efficiency can be sufficiently increased. becomes possible.

In addition, since the outer coil 3 is tightly wound at both upper and lower end portions of the outer circumferential surface Wb of the rotor W, and the other portions are wound loosely, the magnetic flux on the upper and lower surfaces Wd, We and the edge portion Wc of the rotor W is can be controlled, the entire rotor W can be heated at a uniform temperature, and a high-quality rotor W can be easily obtained.

Further, the coil conductor 2a1 of the inner coil 2 is formed of a coiled flat pipe, and a round copper pipe 2c1 is inserted through the axial center position of the coil conductor 2a1, and the tip of the round copper pipe 2c1 and the coiled flat pipe are connected to each other. Since the tip portions are connected and the round copper pipes 2c1 and 2c2 are supported by the support block 2b, the coil conductor 2a1 can be reliably supported by the round copper pipe 2c1 and placed stably inside the coil cover 2a2, and the inside The coil 2 itself can be stably supported by the holder 4.

In particular, depending on the configuration of the coil conductor 2a1 of the inner coil 2, the following special effects can be obtained. That is, with the coil portion 2a inserted into the shaft hole Wa, a high frequency current is supplied from the transistor inverter 11 to the coil conductor 2a1, and the cooling water supply device 13 supplies the inside of the coil cover 2a2 and the flat space 9 of the coil conductor 2a1. In order to inductively heat the inner circumferential surface of the shaft hole Wa of the rotor W by supplying cooling water, the entire outer circumferential surface of the coil conductor 2a1 and the inner surface of the flat space 9 can be simultaneously cooled with the cooling water. Heat generation during energization can be effectively suppressed and heating efficiency can be further increased.

At the same time, since the coil conductor 2a1 is formed of a crushed copper pipe obtained by crushing a round copper pipe into a flat shape, the coiled conductor 2a1 can be easily formed by crushing and winding the round copper pipe. Therefore, it becomes possible to suppress an increase in the cost of the heating coil 1.

In addition, since the tip of the round copper pipe 2c1 communicates with the inside of the bottom of the coil cover 2a2 and communicates with the tip of the coil conductor 2a1 through the communication hole 7a, cooling water supplied from the round copper pipe 2c1 can be transferred to the coil. The cooling water can be supplied into the cover 2a2 from the bottom of the cover 2a2, and can also be supplied into the coil conductor 2a1 through the communication hole 7a, allowing the cooling water to circulate better within the coil cover 2a2 and the coil conductor 2a1. Heat generation of the inner coil 2 itself can be suppressed even better.

In particular, since the cooling water from the cooling water supply device 13 can be supplied to the flat space 9 of the coil conductor 2a1 and the inside of the coil cover 2b, the shape of the rotor W etc. The cooling system can be set accordingly, and the cooling effect of the coil conductor 2a1 can be set more optimally. At this time, if the supply of cooling water to the flat space 9 of the coil conductor 2a1 and the coil cover 2a2 is controlled based on the temperature of the cooling water inside the coil cover 2a2, the cooling state of the coil conductor 2a1 can be controlled. This makes it possible to perform cooling under more optimal conditions.

Furthermore, since the inner coil 2 and the outer coil 3 are connected in parallel to the high frequency power supply, it is possible to use multiple high frequency power supplies, for example, and the high frequency current supplied to the inner coil 2 and the outer coil 3 can be adjusted. It becomes possible to supply high-frequency current under optimal conditions depending on the form of the rotor W, and it is possible to easily accommodate rotors W of various forms.

In the embodiment described above, a coiled flat pipe made of a crushed copper pipe having a flat space 9 inside was used as the coil conductor 2a1 of the inner coil 2. An appropriate solid conductor may be used as the coil conductor, and in this case, the cooling water supplied from the round copper pipes 2c1 and 2c2 may be configured to be circulated and supplied only within the coil cover 2a1.

In addition, in the embodiment, the number of turns and the density of the inner coil 2 and the outer coil 3, the form of the support block 2b of the inner coil 2 and the holder 4, the form of the cooling medium, the form of the induction heating device 10, etc. are merely examples. Therefore, for example, the winding form of the coil conductor 2a1 of the inner coil 2 is not set at a uniform pitch, but is made different between the upper and lower opening portions and the center portion of the shaft hole Wa, thereby achieving a more uniform heating state over the entire inner circumferential surface of the shaft hole Wa. The present invention can be modified as appropriate without departing from the gist of each invention related to the present invention, such as by making it possible to obtain the same effects as those of the embodiments described above.

The present invention is not limited to application to objects to be heated such as rotors, but can be used for all objects to be heated that require induction heating of the shaft hole at the center and the outer peripheral surface.

DESCRIPTION OF SYMBOLS 1... Induction heating coil, 2... Inner coil, 2a... Coil part, 2a1... Coil conductor, 2a2... Coil cover, 2a3... Straight line part, 2b... Support block, 2b1... Cover fixing nut, 2b2... Sensor support plate, 2b3... Coil clamp, 2c1, 2c2... Round copper pipe, 3... Outer coil, 3a... Coil part, 3b... - Base end, 4...Holder, 4a...Copper plate, 4c, 4d...Support plate, 5...Cooling pipe, 6...Hose joint, 7a, 7b...Communication hole, 9 ... flat space, 10 ... induction heating device, 11 ... transistor inverter, 12 ... output transformer, 13 ... cooling water supply device, W ... rotor, Wa ... shaft hole , Wb...outer peripheral surface, Wc...edge portion, Wd...upper surface, We...lower surface.

Claims (5)

A high-frequency current of a predetermined frequency is supplied from a high-frequency power supply to a cylindrical heating coil disposed in the shaft hole of the object to be heated to induction heat the entire inner peripheral surface of the shaft hole of the object to be heated, and during the induction heating. The heating temperature of the inner circumferential surface of the shaft hole of the object to be heated is measured with a radiation thermometer that is oriented in the direction of the shaft hole of the object to be heated and is set so that it can receive radiation light inside the shaft hole, and the measured temperature is An induction heating method, characterized in that a control device stops supplying high frequency current from the high frequency power supply to the heating coil when the temperature reaches a predetermined temperature. The induction heating method according to claim 1 , wherein the radiation thermometer is disposed on a support block that supports the heating coil . The heating coil is fitted into the shaft hole of the object to be heated, and the radiation thermometer is measured based on the radiation light emitted from between the outer peripheral surface of the heating coil and the inner peripheral surface of the shaft hole of the object to be heated. The induction heating method according to claim 1 or 2, wherein the heating temperature is measured at . The induction heating method according to any one of claims 1 to 3, wherein the heating coil has a coil conductor wound in a coil shape a predetermined number of times, and a coil cover that covers the outer peripheral side and the tip side of the coil conductor. . It has a coil conductor wound in a coil shape a predetermined number of times and a coil cover that covers the outer circumferential side and the tip side of the coil conductor, and is placed in the shaft hole of the object to be heated and is supplied with a high frequency current of a predetermined frequency from a high frequency power source. a cylindrical heating coil for inductively heating the entire area of the inner peripheral surface of the shaft hole of the object to be heated; a radiation thermometer that measures the heating temperature of the inner circumferential surface of the shaft hole during induction heating by the heating coil; and a radiation thermometer that transmits a high-frequency current from the high-frequency power source to the heating coil when the measured temperature reaches a predetermined temperature. An induction heating device characterized by comprising: a control device for stopping the supply of .