Induction heating coil and high-frequency quenching device

Abstract

To improve power efficiency in a lead portion and provide a power-saving induction heating coil.SOLUTION: An induction heating coil according to the present disclosure includes a coil portion that is brought close to a workpiece and excites an induced current in the workpiece, and a lead portion that supplies a current to the coil portion, the lead portion includes a first lead portion and a second lead portion facing each other with an insulator in between, and two opposing surfaces of the first lead portion and the second lead portion are curved surfaces or inclined surfaces, and the two opposing surfaces are parallel.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to an induction heating coil and a high-frequency quenching device with improved power efficiency.

Background Art

[0002] A high-frequency quenching device performs quenching on a workpiece to increase the strength of the workpiece. When the heat capacity of the workpiece is large, a high-frequency quenching device requires a large amount of power. FIG. 7(a) is a perspective view schematically showing the overall structure of the high-frequency quenching device 1 of Patent Document 1. As shown in FIG. 7(a), the high-frequency quenching device 1 includes an induction heating coil 10 and a high-frequency oscillator 20. The induction heating coil 10 has a first lead portion 3, a second lead portion 4, a coil portion 2, a first power supply lead portion 7, a second power supply lead portion 8, a coolant supply port 5, and a coolant discharge port 6. The high-frequency oscillator 20 is supplied with power (alternating current power such as 100 V or 200 V, 50 or 60 Hz) from a commercial power supply 52, and converts the power into power with a frequency and amplitude appropriate for quenching.

[0003] FIG. 9 is a circuit diagram schematically showing the high-frequency quenching device 1. As shown in FIG. 9, the high-frequency oscillator 20 has a high-frequency oscillator 53, a transformer 54, and a connection line 21. High-frequency power is supplied to the coil portion 2 from the high-frequency oscillator 20 side. The high-frequency oscillator 53 is connected to the commercial power supply 52 and generates power with an arbitrary frequency. The high-frequency oscillator 53 generates power with a high-frequency, but may also generate power with a low-frequency. The primary side of the transformer 54 is connected to the high-frequency oscillator 53. In addition, the secondary side of the transformer 54 is connected to the first power supply lead portion 7 and the second power supply lead portion 8 via the connection line 21, and supplies power with an arbitrary amplitude to the first power supply lead portion 7 and the second power supply lead portion 8. That is, the high-frequency oscillation device 20 is connected to the first power supply lead portion 7 and the second power supply lead portion 8 via the connection line 21, and supplies power with an arbitrary frequency and an arbitrary amplitude to the first power supply lead portion 7 and the second power supply lead portion 8.

[0004] As shown in FIG. 7(a), the first power supply lead portion 7 and the second power supply lead portion 8 are respectively connected to the first lead portion 3 and the second lead portion 4. The first lead portion 3 and the second lead portion 4 face each other via the insulator 9 and each extend linearly. The insulator 9 electrically insulates the first lead portion 3 and the second lead portion 4 and is an inorganic material, an organic material, air, or the like.

[0005] The coil portion 2 is disposed between the first lead portion 3 and the second lead portion 4 and is electrically connected to the first lead portion 3 and the second lead portion 4. As shown in FIG. 7(a), the coil portion 2 is a coil for inductively heating a workpiece (not shown) disposed inside the coil portion 2 and is a good conductor such as copper or a copper alloy. The cross section of the coil portion 2 has a rectangular hollow structure. Inside the coil portion 2, a coolant (such as water or air) that suppresses the temperature rise of itself during inductive heating passes through.

[0006] The first lead portion 3 and the second lead portion 4 are hollow and linear. Inside the first lead portion 3 and the second lead portion 4 made of hollow linear members, a coolant (such as water or air) that suppresses the temperature rise of itself during inductive heating passes through. Specifically, the coolant is supplied from the coolant supply port 5 into the inside of the first lead portion 3, the coolant passes through the inside of the coil portion 2, the coolant is supplied into the inside of the second lead portion 4, and the coolant is discharged from the coolant discharge port 6.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] FIG. 7(b) is a cross-sectional view schematically showing a cross-section perpendicular to the longitudinal direction of the first lead portion 3 and the second lead portion 4 of Patent Document 1. As shown in FIG. 7(b), the cross-section perpendicular to the longitudinal direction of the first lead portion 3 and the second lead portion 4 is formed of a rectangular hollow structure. The first lead portion 3 and the second lead portion 4 are hollow rectangular pipes, which are easy to manufacture. In particular, the above cross-section is preferably square from the viewpoint of ease of manufacture. The first lead portion 3 and the second lead portion 4 are arranged close to each other and in parallel. And an insulator 9 such as an inorganic material, an organic material, air, etc. is arranged between the first lead portion 3 and the second lead portion 4. In the case of FIG. 7(b), the insulator 9 is air.

[0009] The two-dot chain line on the left side of FIG. 7(b) is the center line between the outer ring and the inner ring of each side of the cross-section of the first lead portion 3. That is, the two-dot chain line on the left side of FIG. 7(b) eliminates the concept of the width of each side of the cross-section of the first lead portion 3 and is a line schematically representing each side of the cross-section of the first lead portion 3. The two-dot chain line of the first lead portion 3 forms a square and is composed of four sides. Here, in FIG. 7(b), let the upper right vertex of the square of the first lead portion 3 be Q1, and the intersection points of the other sides be Q2, Q3, Q4 in a clockwise direction, and the four sides be defined as side Q1Q2, side Q2Q3, side Q3Q4, and side Q4Q1. Similarly, the two-dot chain line of the second lead portion 4 on the right side of FIG. 7(b) forms a square and is composed of four sides. Let the upper left vertex of the second lead portion 4 be Q5, and the intersection points of the other sides be Q6, Q7, Q8 in a counterclockwise direction, and the four sides be defined as side Q5Q6, side Q6Q7, side Q7Q8, and side Q8Q5. Side Q4Q1 and side Q2Q3 are parallel. Side Q1Q2 and side Q4Q1 are perpendicular. Therefore, the length of side Q1Q2 is such that the distance between side Q4Q1 and side Q2Q3 is the shortest distance. Side Q8Q5 and side Q6Q7 are parallel. The side Q5Q6 and the side Q8Q5 are perpendicular. Therefore, the length of the side Q5Q6 is the shortest distance between the side Q8Q5 and the side Q6Q7. The side Q1Q2 and the side Q5Q6 are parallel and are opposed to each other with the insulator 9 therebetween in proximity. In FIG. 7(b), the right side Q1Q2 of the first lead portion 3 and the left side Q5Q6 of the second lead portion 4 are opposed to each other in proximity. The direction of the current flowing through the first lead portion 3 and the direction of the current flowing through the second lead portion 4 are opposite to each other. As a result, the higher the frequency of the power supplied to the first lead portion 3 and the second lead portion 4, and the greater the power, the higher the current density becomes on the surface where the first lead portion 3 and the second lead portion 4 face each other due to the proximity effect, as shown in the hatched portion of FIG. 7(b). Then, heat generation occurs on the surface where the first lead portion 3 and the second lead portion 4 face each other, and there is room for improvement in that the power efficiency cannot be increased in the first lead portion 3 and the second lead portion 4. The present disclosure improves power efficiency in the first lead portion 3 and the second lead portion 4 and provides a power-saving induction heating coil.

[0010] FIG. 8(a) is a perspective view schematically showing the overall structure of another prior art high-frequency quenching apparatus 1. In FIG. 8(a), it is the same as FIG. 7(a) except that the first lead portion 3, the second lead portion 4, and the coil portion 2 are cylindrical pipes. The cylindrical pipe is easy to manufacture and is inexpensive. FIG. 8(b) is a cross-sectional view schematically showing a cross-section perpendicular to the longitudinal direction of the first lead portion 3 and the second lead portion 4 of FIG. 8(a). The two-dot chain line on the left side of FIG. 8(b) is the center line of the outer ring and the inner ring of the cross-section of the first lead portion 3. That is, the two-dot chain line of the first lead portion 3 eliminates the concept of the width of the cross-section of the first lead portion 3 and is a line schematically representing the cross-section of the first lead portion 3. The two-dot chain line of the first lead portion 3 forms a circular shape. The two-dot chain line of the second lead portion 4 is the same as the two-dot chain line of the first lead portion 3. In Fig. 8(b), define the upper vertex of the circular shape indicated by the dashed two-dot line of the first lead portion 3 as D1, the lower vertex of the circular shape as D2, the upper vertex of the circular shape indicated by the dashed two-dot line of the second lead portion 4 as D4, and the lower vertex of the circular shape as D5.

[0011] In Fig. 8(b), the arc-shaped right side D1D2 of the first lead portion 3 and the arc-shaped left side D4D5 of the second lead portion 4 are close to and face each other. And the direction of the current flowing through the first lead portion 3 and the direction of the current flowing through the second lead portion 4 are opposite. As a result, the higher the frequency of the power supplied to the first lead portion 3 and the second lead portion 4, and the greater the power, the higher the current density becomes on the surface where the first lead portion 3 and the second lead portion 4 face each other due to the proximity effect, as shown in the hatched portion of Fig. 8(b). And on the surface where the first lead portion 3 and the second lead portion 4 face each other, heat generation occurs, and there was room for improvement in that the power efficiency could not be increased in the first lead portion 3 and the second lead portion 4. The present disclosure improves the power efficiency in the first lead portion 3 and the second lead portion 4 and provides an induction heating coil with power saving.

Means for Solving the Problem

[0012] An induction heating coil according to an aspect of the present disclosure is In an induction heating coil having a coil portion that excites an induced current in a workpiece by being close to the workpiece and a lead portion that supplies current to the coil portion, the lead portion has a first lead portion and a second lead portion that face each other via an insulator, two opposing surfaces of the first lead portion and the second lead portion are curved surfaces or inclined surfaces, the two opposing surfaces are parallel. According to the above aspect, by making the area of the surface where the first lead portion 3 and the second lead portion 4 face each other a curved surface or an inclined surface, an induction heating coil with improved power efficiency can be provided.

[0013] A preferred aspect is that the curved surface is in a waveform shape. According to the above aspect, by making the area of the surface where the first lead portion 3 and the second lead portion 4 face each other be the area of the waveform shape, it is possible to provide an induction heating coil with increased power efficiency. A more preferable aspect is that the inclined surface has a waveform shape. According to the above aspect, by making the area of the surface where the first lead portion 3 and the second lead portion 4 face each other be the area of the waveform shape of the inclined surface, it is possible to provide an induction heating coil with increased power efficiency. A more preferable aspect is that the combined structure of the curved surface and the inclined surface has a waveform shape. According to the above aspect, by making the area of the surface where the first lead portion 3 and the second lead portion 4 face each other be the area of the waveform shape, it is possible to provide an induction heating coil with increased power efficiency. A more preferable aspect can provide a high-frequency quenching device having the induction heating coil described above and a high-frequency oscillation device. According to the above aspect, by increasing the area of the surface where the first lead portion 3 and the second lead portion 4 face each other, it is possible to provide a power-saving high-frequency quenching device with improved power efficiency in the lead portion. Another induction heating coil according to an aspect of the present disclosure has a coil portion that is brought close to a workpiece to excite an induced current in the workpiece, and a lead portion that supplies current to the coil. The lead portion has a first lead portion and a second lead portion that face each other via an insulator. On two opposing surfaces of the first lead portion and the second lead portion, a cross section perpendicular to the longitudinal direction of the two opposing surfaces is an arc shape, and a part of the arc shape of the opposing surfaces is parallel. According to the above aspect, by making a part of the arc shape of the opposing surfaces parallel, it is possible to provide an induction heating coil with improved power efficiency and power saving in the lead portion. A preferable aspect is a high-frequency quenching device having the induction heating coil described above and a high-frequency oscillation device. According to the above aspect, by making a part of the arc shape of the opposing surfaces parallel, it is possible to provide a power-saving high-frequency quenching device with improved power efficiency in the lead portion.

Effect of the Invention

[0014] According to one aspect of the present disclosure, by increasing the area of the surfaces where the first lead portion and the second lead portion face each other, it is possible to improve the power efficiency in the first lead portion and the second lead portion and provide a power-saving induction heating coil.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Modes for Carrying Out the Invention

[0016] Hereinafter, more specific embodiments of the present disclosure will be described. However, detailed descriptions that are more than necessary may be omitted. For example, detailed descriptions of well-known matters and redundant descriptions of substantially the same configurations may be omitted. This is to avoid making the following description unnecessarily redundant and to facilitate the understanding of those skilled in the art. Note that the inventors provide the accompanying drawings and the following description so that those skilled in the art can fully understand the present disclosure, and do not intend to limit the subject matter described in the claims thereby. In the following description, the same or similar components are denoted by the same reference numerals.

[0017] (Embodiment 1) Hereinafter, the first lead portion 3 and the second lead portion 4 of the high-frequency quenching device 1 according to Embodiment 1 showing one aspect of the present disclosure will be described with reference to the drawings. Since the schematic overall configuration of the high-frequency quenching device 1 according to Embodiment 1 is substantially the same as that of FIGS. 7, 8, and 9 of the prior art, the description of the schematic overall configuration of the high-frequency quenching device 1 according to Embodiment 1 is omitted. In Embodiment 1, the cross-sectional shape perpendicular to the longitudinal direction of the first lead portion 3 and the second lead portion 4 according to Embodiment 1 is different from the cross-sectional shape perpendicular to the longitudinal direction of the first lead portion 3 and the second lead portion 4 of the prior art.

[0018] FIG. 1 is a perspective view schematically showing the first lead portion 3 and the second lead portion 4 in Embodiment 1. The first lead portion 3 and the second lead portion 4 have a hollow shape and extend linearly. A coolant passes through the inside of the first lead portion 3 and the second lead portion 4, and the first lead portion 3 and the second lead portion 4 are cooled by the coolant. An insulator 9 such as an inorganic material, an organic material, or air is interposed between the first lead portion 3 and the second lead portion 4. In FIG. 1, a coil portion 2 is connected to the front side of the first lead portion 3 and the second lead portion 4 (not shown). On the back side of the first lead portion 3 and the second lead portion 4, a first power supply lead portion 7 and a second power supply lead portion 8 are electrically connected respectively (not shown).

[0019] Figure 2 is a cross-sectional view schematically showing the cross-section of the first lead portion 3 and the second lead portion 4 in Embodiment 1. Two opposing surfaces of the first lead portion 3 and the second lead portion 4 are composed of a curved surface and an inclined surface. The dashed-dotted line in Figure 2 is the center line between the outer ring and the inner ring of the cross-section. The present disclosure will be described in detail with reference to Figure 2. Here, in Figure 2, the upper right vertex of the first lead portion 3 is defined as P1, and the other inflection points are defined as P1', P1'', P2, P3, P4 in a clockwise direction. Also, the upper left vertex of the second lead portion 4 is defined as P5, and the other inflection points are defined as P5', P5'', P6, P7, P8 in a counterclockwise direction.

[0020] Two sides of the first lead portion 3 and the second lead portion 4 that face each other are composed of side P1P1', side P1'P1'', and side P1''P2 in the first lead portion 3, and side P5P5', side P5'P5'', and side P5''P6 in the second lead portion 4. Side P1P1' is an arc-shaped curve convex to the left, side P1'P1'' is a straight line, and side P1''P2 is an arc-shaped curve convex to the right. Side P5P5' is an arc-shaped curve convex to the left, side P5'P5'' is a straight line, and side P5''P5 is an arc-shaped curve convex to the right. The left side P1P1'P1''P2 and the right side P5P5'P5''P6 are parallel. And an insulator 9 is disposed between the left side P1P1'P1''P2 and the right side P5P5'P5''P6. Side P4P1 and side P2P3 are parallel, and side P8P5 and side P6P7 are parallel. Side P3P4 and side P7P8 are curves.

[0021] In Figure 2, the length of the line segment Q1Q2 passing through P4 and perpendicular to side P4P1 is the same as the length of side Q1Q2 in Figure 7 of the prior art. Since the length of the left side P1P1'P1''P2 consists of a combination of curves and straight lines, it is longer than the length of the line segment Q1Q2. In FIG. 2, the length of the line segment Q5Q6 passing through P8 and perpendicular to the side P8P5 is the same as the length of the side Q5Q6 in FIG. 7 of the prior art. The length of the right side P5P5’P5’’P6 consists of a combination of curves and straight lines, so it is longer than the length of the line segment Q5Q6.

[0022] Since the two opposing surfaces of the first lead portion 3 and the second lead portion 4 are composed of a combination of a curved surface and an inclined surface, the surface area of the two opposing surfaces can be made larger than the surface area of the two opposing surfaces in FIG. 7 of the prior art. As a result, the current density of the two opposing surfaces can be reduced, and the power-saving first lead portion 3 and second lead portion 4 can be realized.

[0023] The shape of the combination of the above-mentioned curved surface and inclined surface can be manufactured by a metal 3D lamination manufacturing technique. The metal 3D lamination manufacturing technique includes a powder bed method, a deposition method, a binder jetting method, etc., and can manufacture a complex three-dimensional shape of metal. In addition, the meaning of the above-mentioned curved surface includes the meaning that a part of the two opposing surfaces is a curved surface, and includes the cases of a combination of a curved surface and an inclined surface, and a combination of a curved surface and a vertical surface (plane). In addition, the shape of the left side P1P1’P1’’P2 and the shape of the right side P5P5’P5’’P6 may be shapes that are reversed left and right. In addition, the curve P1P1’P1’’P2 of the left cross-section and the curve P5P5’P5’’P6 of the right cross-section are parallel, and the curve P5P5’P5’’P6 is a parallel curve of the curve P1P1’P1’’P2. A parallel curve is a curve that is a certain distance away in a direction perpendicular to the tangent at each point. "The two opposing surfaces of the first lead portion and the second lead portion are a curved surface or an inclined surface, and the two opposing surfaces are parallel" means that "in the two opposing sides of the cross-section perpendicular to the longitudinal direction of the first lead portion and the second lead portion, the two opposing sides are parallel curves or inclined parallel lines". Hereinafter, when it is said that curves are parallel, it means parallel curves. (Embodiment 2)

[0024] Next, the first lead portion 3 and the second lead portion 4 showing another aspect of the present disclosure will be described with reference to FIG. 3. The cross-sections of the first lead portion 3 and the second lead portion 4 in FIG. 2 of Embodiment 1 are different in shape from the cross-sections of the first lead portion 3 and the second lead portion 4 in FIG. 3 of Embodiment 2. All the surfaces of the first lead portion 3 and the second lead portion 4 in FIG. 3 that face each other are curved surfaces.

[0025] FIG. 3 is a diagram schematically showing the cross-sections of the first lead portion 3 and the second lead portion 4 represented by the center lines. The first lead portion 3 and the second lead portion 4 are composed of four sides. In FIG. 3, the upper right vertex of the first lead portion 3 is defined as P1, the intersection points of the other sides are defined as P2, P3, and P4 in the clockwise direction, and the four sides are defined as side P1P2, side P2P3, side P3P4, and side P4P1. Also, the upper left vertex of the second lead portion 4 is defined as P5, the intersection points of the other sides are defined as P6, P7, and P8 in the counterclockwise direction, and the four sides are defined as side P5P6, side P6P7, side P7P8, and side P8P5.

[0026] The left curve P1P2 and the right curve P5P6 in FIG. 3 are in a waveform shape combining convex portions and concave portions. The convex portion is a portion protruding outside the squares P1P2P3P4 and P5P6P7P8, and the concave portion is a portion entering inside the squares P1P2P3P4 and P5P6P7P8.

[0027] The curve P1P2 and the curve P5P6 are parallel. An insulator 9 is disposed between the curve P1P2 and the curve P5P6. The side P2P3 and the side P4P1 are parallel, and the side P6P7 and the side P8P5 are parallel. The side P3P4 and the side P7P8 are straight lines, but they may also be curves.

[0028] In FIG. 3, the length of the line segment Q1Q2 (two-dot chain line) representing the distance between the side P4P1 and the side P2P3 is the same as the length of the side Q1Q2 in FIG. 7 of the prior art. Since the length of the left curve P1P2 consists of a curve, it is longer than the length of the line segment Q1Q2. The length of the line segment Q5Q6 (two-dot chain line) representing the distance between side P8P5 and side P5P6 is the same as the length of side Q5Q6 in FIG. 8 of the prior art. Similarly, the length of the right curve P5P6 is also longer than the length of the line segment Q5Q6 (two-dot chain line) representing the distance between side P8P5 and side P6P7.

[0029] Since the two opposing surfaces of the first lead portion 3 and the second lead portion 4 are formed of curved surfaces, the surface area of the two opposing surfaces can be made larger than the surface area of the two opposing surfaces in FIG. 7 of the prior art. As a result, the current density of the two opposing surfaces can be reduced, and the power-saving first lead portion 3 and second lead portion 4 can be realized. Incidentally, the shape of the left curve P1P2 and the shape of the right curve P5P6 may be shapes that are reversed left and right. (Embodiment 3)

[0030] Hereinafter, the first lead portion 3 and the second lead portion 4 showing another aspect of the present disclosure will be described with reference to FIG. 4. The cross-sections of the first lead portion 3 and the second lead portion 4 in FIG. 2 of Embodiment 1 and the cross-sections of the first lead portion 3 and the second lead portion 4 in FIG. 4 of Embodiment 3 are different in shape. Specifically, the surfaces of the first lead portion 3 and the second lead portion 4 that face each other in FIG. 2 are a curved surface and an inclined surface, whereas the surfaces of the first lead portion 3 and the second lead portion 4 that face each other in FIG. 4 are all inclined surfaces.

[0031] FIG. 4 is a schematic diagram representing the cross-sections of the first lead portion 3 and the second lead portion 4 by a center line. Side P1P2 is not perpendicular to side P4P1, but is an inclined straight line with an acute angle P4P1P2. Side P5P6 is not perpendicular to side P8P5, but is an inclined straight line with an obtuse angle P8P5P6. Side P1P2 and side P5P6 are parallel. An insulator 9 is disposed between side P1P2 and side P5P6. Side P4P1 and side P2P3 are parallel, and side P8P5 and side P6P7 are parallel. Side P3P4 and side P7P8 may be a straight line or a curve.

[0032] In FIG. 4, the length of line segment Q1Q2 (two-dot chain line) representing the distance between side P4P1 and side P2P3 is the same as the length of side Q1Q2 in FIG. 7 of the prior art. Since the length of the left side P1P2 is an inclined straight line, it is longer than the length of line segment Q1Q2. Similarly, the length of the right side P5P6 is also longer than the length of line segment Q5Q6 (two-dot chain line). Therefore, since the two opposing surfaces of the first lead portion 3 and the second lead portion 4 are composed of inclined surfaces, the surface area of the two opposing surfaces can be made larger than the surface area of the two opposing surfaces in FIG. 7 of the prior art. Thus, the current density of the two opposing surfaces can be reduced, and the power-saving first lead portion 3 and second lead portion 4 can be realized. Note that the shape of the left side P1P2 and the shape of the right side P5P6 may be shapes that are reversed left and right. (Embodiment 4)

[0033] Hereinafter, the first lead portion 3 and the second lead portion 4 showing another aspect of the present disclosure will be described with reference to FIG. 5. The cross-sections of the first lead portion 3 and the second lead portion 4 in FIG. 2 of Embodiment 1 are different in shape from the cross-sections of the first lead portion 3 and the second lead portion 4 in FIG. 5 of Embodiment 4. Specifically, the surfaces where the first lead portion 3 and the second lead portion 4 in FIG. 2 face each other are a curved surface and an inclined surface, while the surfaces where the first lead portion 3 and the second lead portion 4 in FIG. 5 face each other are provided with a curved surface with an inclined surface as an axis.

[0034] FIG. 5 is a diagram schematically showing the cross-sections of the first lead portion 3 and the second lead portion 4 represented by a center line. The side P1P2 (dashed line) is not perpendicular to the side P4P1, but is an inclined straight line with an acute angle P4P1P2. The side P5P6 (dashed line) is not perpendicular to the side P8P5, but is an inclined straight line with an obtuse angle P8P5P6. The curve P1P2 is an inclined shape with a combination of convex and concave parts around the side P1P2 (dashed line) as the axis. The curve P5P6 is an inclined shape with a combination of convex and concave parts around the side P5P6 (dashed line) as the axis.

[0035] The curve P1P2 and the curve P5P6 are parallel. An insulator 9 is disposed between the curve P1P2 and the curve P5P6. The side P4P1 and the side P2P3 are parallel, and the side P8P5 and the side P6P7 are parallel. The side P3P4 and the side P7P8 are straight lines, but they may also be curves.

[0036] In FIG. 5, the length of the line segment Q1Q2 (two-dot chain line) representing the distance between the side P4P1 and the side P2P3 is the same as the length of the side Q1Q2 in FIG. 7 of the prior art. Since the length of the left curve P1P2 is an inclined curve, it is longer than the length of the line segment Q1Q2. In FIG. 5, the length of the line segment Q5Q6 (two-dot chain line) representing the distance between the side P8P5 and the side P5P6 is the same as the length of the side Q5Q6 in FIG. 7 of the prior art. Similarly to the left side, the length of the right curve P5P6 is also longer than the length of the line segment Q5Q6.

[0037] Since the two opposing surfaces of the first lead portion 3 and the second lead portion 4 are composed of inclined surfaces, the surface area of the two opposing surfaces can be made larger than the surface area of the two opposing surfaces in FIG. 7 of the prior art. As a result, the current density of the two opposing surfaces can be reduced, and the power-saving first lead portion 3 and second lead portion 4 can be realized. Incidentally, the shape of the left side P1P2 and the shape of the right side P5P6 may be shapes that are reversed left and right. (Embodiment 5)

[0038] Next, the first lead portion 3 and the second lead portion 4 showing another aspect of the present disclosure will be described with reference to FIG. 6. The cross-sections of the first lead portion 3 and the second lead portion 4 in FIG. 2 of Embodiment 1 are different in shape from the cross-sections of the first lead portion 3 and the second lead portion 4 in FIG. 5 of Embodiment 4. Specifically, the surfaces where the first lead portion 3 and the second lead portion 4 in FIG. 2 face each other are a curved surface and an inclined surface, while the surfaces where the first lead portion 3 and the second lead portion 4 in FIG. 6 face each other are substantially cylindrical surfaces.

[0039] FIG. 6 is a diagram schematically showing the cross-sections of the first lead portion 3 and the second lead portion 4 represented by the center line. The cross-section of the first lead portion 3 has a convex portion C3 on the right side C1C2 of a circle surrounded by the right side C1C2 and the left side C2C1. The cross-section of the second lead portion 4 has a concave portion C6 on the left side C4C5 of a circle surrounded by the left side C4C5 and the right side C5C4. The convex portion C3 and the concave portion C6 are parallel. An insulator 9 is disposed between the right side C1C3C2 and the left side C4C6C5.

[0040] In FIG. 6, the side C1C3C2 which is the cross-section of the first lead portion 3 is longer than the length of the left semi-circle D1D2 in FIG. 8(b). Similarly, the length of the left side C4C6C5 which is the cross-section of the second lead portion 4 is also longer than the length of the right semi-circle D4D5 in FIG. 8(b).

[0041] Since the two opposing cross-sections of the first lead portion 3 and the second lead portion 4 are configured to be longer than the length of the semi-circle, they can be made larger than the length of the two opposing semi-circles in FIG. 8 which is the prior art. As a result, the current density of the two surfaces where the first lead portion 3 and the second lead portion 4 face each other can be reduced, and the power-saving first lead portion 3 and second lead portion 4 can be realized. Note that the shapes of the left side C1C3C2 and the right side C4C6C5 may be shapes that are reversed left and right.

[0042] Incidentally, in FIG. 2, the two opposing surfaces of the first lead portion 3 and the second lead portion 4 are a combination of a curved surface and an inclined surface, but they may be a combination of a curved surface and a vertical surface (plane). Incidentally, the left curve P1P2 and the right curve P5P6 in FIG. 3 are a waveform shape combining a convex portion and a concave portion, but they may be curves having simply one convex portion or one concave portion.

[0043] Incidentally, the inventions according to Embodiments 1 to 4 can be replaced or combined as long as no contradiction occurs.

Explanation of Reference Numerals

[0044] 1 High-frequency quenching device 2 Coil portion 3 First lead portion 4 Second lead portion 7 First power supply lead portion 8 Second power supply lead portion 9 Insulator 10 Induction heating coil 20 High-frequency oscillation device

Claims

1. In an induction heating coil having a coil portion that excites an induced current in a workpiece by approaching the workpiece and a lead portion that supplies current to the coil portion, the lead portion has a first lead portion and a second lead portion that face each other with an insulator therebetween, two opposing surfaces of the first lead portion and the second lead portion are curved surfaces or inclined surfaces, and the induction heating coil is characterized in that the two opposing surfaces are parallel.

2. The induction heating coil according to claim 1, wherein the curved surface has a waveform shape.

3. The induction heating coil according to claim 1, wherein the inclined surface has a waveform shape.

4. The induction heating coil according to claim 1, wherein the two opposing surfaces have a combined structure of a curved surface and an inclined surface.

5. The induction heating coil according to claim 4, wherein the combined structure of the curved surface and the inclined surface has a waveform shape.

6. The induction heating coil according to any one of claims 1 to 5, wherein the first lead portion and the second lead portion are manufactured by a metal 3D lamination modeling technique.

7. A high-frequency quenching device, characterized by comprising the induction heating coil according to any one of claims 1 to 6 and a high-frequency oscillation device.

8. In an induction heating coil having a coil portion that excites an induced current in a workpiece by approaching the workpiece and a lead portion that supplies current to the coil, the lead portion has a first lead portion and a second lead portion that face each other with an insulator therebetween, in two opposing surfaces of the first lead portion and the second lead portion, a cross section perpendicular to the longitudinal direction of the two opposing surfaces is arc-shaped, and the induction heating coil is characterized in that a part of the arc shape of the opposing surfaces is parallel.

9. The induction heating coil according to claim 8, wherein the first lead portion and the second lead portion are manufactured by a metal 3D lamination modeling technique.

10. A high-frequency quenching device, characterized by comprising the induction heating coil according to claim 8 or 9 and a high-frequency oscillation device.

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