Heating coil for high frequency heating device

Abstract

To provide a heating coil that can efficiently harden a workpiece in a short time and can control the depth of a hardened layer formed by hardening a workpiece for each height position in accordance with the shape of the workpiece.SOLUTION: A heating coil 1 includes grounding portions 2a, 2b for contacting the electrodes, a pair of support portions 3a, 3b arranged perpendicularly to the grounding portions 2a, 2b, respectively and parallel to each other, with their tips branched upward and downward, a circumferential upper heating portion 4α provided to connect the upper tips of the support portions 3a, 3b, and a circumferential lower heating portion 4β provided to connect the lower tips of the support portions 3a, 3b. In addition, a heat dissipation portion R is formed at the upper branch portion of the left support portion 3a so as to protrude outward, and high-frequency current from the grounding portions 2a, 2b is supplied to the upper heating portion 4α via the heat dissipation portion R.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a heating coil used in a high-frequency heating device for heating a workpiece by utilizing electromagnetic induction caused by a high-frequency current. [Background technology]

[0002] To increase the hardness of the surface of a metal workpiece (workpiece), the surface of the workpiece is heated to a temperature equal to or higher than the metal's transformation point (austenite transformation point) and then rapidly cooled (a process known as quenching). A widely used method for quenching involves using a high-frequency heating device to heat the workpiece by bringing a metal member (heating coil) through which a high-frequency current flows close to the surface of the workpiece. A known heating coil for use in quenching is one described in Patent Document 1, which has an annular coil made of a metal pipe fitted around the workpiece and connected to a conductive plate (copper plate) for supplying high-frequency power. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-115428 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the heating coils for the conventional high-frequency heating devices described above, current always flows in one direction inside the annular coil. Therefore, if a large amount of current flows inside the coil, the workpiece is overheated, the crystal grains of the hardened structure of the workpiece become coarse, and the toughness of the workpiece decreases, resulting in a decrease in mechanical strength. Conversely, if only a small amount of current flows inside the coil, the hardened layer depth of the workpiece becomes shallow, resulting in insufficient hardening. Therefore, with the heating coils for conventional high-frequency heating devices, it is difficult to control the depth of the hardened layer caused by hardening the workpiece.

[0005] The object of the present invention is to provide a practical heating coil that solves the problems of the heating coils for conventional high-frequency heating devices described above, that can efficiently harden a workpiece in a short time, that can effectively prevent the workpiece from being overheated due to its shape, that can prevent a decrease in the mechanical strength of the workpiece, and that can easily control the depth of the hardened layer formed by hardening the workpiece. [Means for solving the problem]

[0006] Of the present inventions, the invention described in claim 1 is a heating coil used in a high-frequency heating device for heating a workpiece by utilizing electromagnetic induction caused by high-frequency current, and is characterized in that it has a pair of plate-shaped grounding portions for contacting electrodes through which high-frequency current is passed, a pair of support portions each perpendicular to the grounding portions and arranged parallel to each other, with their tip portions branching into multiple parts, and a series of multiple circular heating portions arranged to connect the tips of each branched portion of the pair of support portions, and a U-shaped heat dissipation portion (bypass current path forming portion) formed so as to protrude outward in one of the branched portions formed on one side of the pair of support portions.

[0007] The invention described in claim 2 is characterized in that, in the invention described in claim 1, the heat dissipation part is provided with a current path length adjustment means for adjusting the length of the path of the current flowing inside.

[0008] The invention described in claim 3 is characterized in that, in the invention described in claim 1, the current path length adjustment means comprises two protruding pieces formed to protrude outward from the main body of the support part, and a connecting member that can connect those protruding pieces at different positions in the protruding direction.

[0009] The heating coil for a high-frequency heating device according to the present invention can be integrally formed using a molding method that repeatedly lays, melts, solidifies, and layers conductive powder based on three-dimensional data (hereinafter referred to as a partial deposition method for conductive powder layers), or a molding method that layers molten conductive material based on three-dimensional data (hereinafter referred to as a melt extrusion deposition method for conductive material). By using the partial deposition method for conductive powder layers or the melt extrusion deposition method for conductive material, the heating coil for a high-frequency heating device according to the present invention can be manufactured inexpensively and very easily. Furthermore, heating coils (products) for high-frequency heating devices with the same shape and characteristics can be manufactured efficiently and with good reproducibility, regardless of the skill of the manufacturing worker. Furthermore, because the heating coil for a high-frequency heating device manufactured by the partial deposition method for conductive powder layers or the melt extrusion deposition method for conductive material does not have any silver brazing adhesives like conventional heating coils, it does not deform even when the temperature rises during continuous use, and can be subjected to standard heating treatments (hardening treatments) for a long period of time.

[0010] The conductive material used as a raw material for shaping in the above-mentioned partial deposition method for conductive material powder layers and melt extrusion deposition method for conductive materials refers to a material that is substantially non-magnetic and has good electrical conductivity. Examples of such conductive materials include copper, brass, and silver. Among these conductive materials, copper is preferred because it reduces material costs, enables inexpensive and easy manufacturing of heating coils using a three-dimensional printer, and provides excellent electrical conductivity and high heat generation efficiency through electromagnetic induction. Furthermore, while pure copper can be used as the conductive material, it is preferable to use an alloy (high-copper alloy) containing copper and iron, tin, nickel, titanium, beryllium, zirconium, chromium, silicon, or other elements in smaller proportions than copper, as this enhances laser absorption and promotes temperature rise.

[0011] Furthermore, when forming the heating coil of the present invention using the method for partially fusing and laminating conductive material powder layers, it is necessary to melt the laid raw material for the formation (i.e., powder made of conductive material) by irradiating it with a laser or electron beam. As the laser, a semiconductor laser, a carbon dioxide laser, an excimer laser, a YAG laser, a fiber laser, etc. can be suitably used, but the use of a fiber laser (i.e., a laser that uses an optical fiber doped with a rare earth element such as Yb as a laser medium) is preferable because it makes it possible to obtain high-output laser light with a stable optical axis using a small device, and it becomes possible to very efficiently manufacture heating coils with high dimensional accuracy. [Effects of the Invention]

[0012] The heating coil for the high-frequency heating device described in claim 1 (hereinafter simply referred to as the heating coil) has a heat dissipation section formed in the flow path that supplies current to the upper heating section or the flow path that supplies current to the lower heating section.Therefore, the heat generation amount of the heating section on the side where the heat dissipation section is formed (upper heating section or lower heating section) can be made smaller than that of the heating section on the side where the heat dissipation section is not formed (lower heating section or upper heating section).As a result, the depth of the hardened layer caused by quenching the workpiece can be easily controlled for each height position to match the shape of the workpiece.

[0013] The heating coil described in claim 2 is provided with a current path length adjustment means for adjusting the length of the current flowing inside the heat dissipation part R, and by changing the length of the current flowing inside the heat dissipation part, the amount of magnetic flux generated in the heat dissipation part can be changed, and therefore the amount of heat generated in the upper heating part to which current is supplied via the heat dissipation part can be changed. Therefore, with the heating coil described in claim 2, it is very easy to control the depth of the hardened layer caused by quenching for each height position of the workpiece.

[0014] The heating coil described in claim 3 has a current path length adjustment means consisting of two protruding pieces formed to protrude outward from the main body of the support part, and a connecting member that can connect these protruding pieces at different positions in the protruding direction.By simply changing the connecting position of the two protruding pieces, the length of the current flow path flowing inside the heat dissipation part can be changed, and the amount of heat generated in the heat dissipation part can be changed.Since the amount of heat generated in the upper heating part or the lower heating part can be changed, it is extremely easy to control the depth of the hardened layer caused by hardening for each height position of the workpiece. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 2 is a perspective view of a heating coil (coil body). [Figure 2] FIG. 2 is a perspective view of a heating coil (coil body). [Figure 3]FIG. 2 is a front view of the heating coil (coil body). [Figure 4] FIG. 2 is a rear view of the heating coil (coil body). [Figure 5] FIG. 2 is a plan view of the heating coil (coil body). [Figure 6] FIG. 2 is a left side view (partially see-through) of the heating coil (coil body). [Figure 7] FIG. 2 is a right side view (partially see-through right side view) of the heating coil (coil body). [Figure 8] 5A and 5B are cross-sectional views of the heating coil (coil body) (a is a cross-sectional view taken along line AA in FIG. 5, b is a cross-sectional view taken along line BB in FIG. 5, c is a cross-sectional view taken along line CC in FIG. 5, d is a cross-sectional view taken along line DD in FIG. 5, and e is a cross-sectional view taken along line EE in FIG. 5). [Figure 9] FIG. 1 is an explanatory diagram (plan view) showing how to use the heating coil (coil body). (A vertical cross-sectional view) [Figure 10] FIG. 10 is an explanatory diagram (left side view) showing a modified example of the heat dissipation portion. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, an embodiment of a heating coil according to the present invention will be described in detail with reference to the drawings. <Heating coil structure> 1 to 8 show a heating coil, and the heating coil 1 is composed of a metal coil body C, an insulating plate (not shown) formed in a sheet shape from a synthetic resin (such as a fluororesin) having insulating and heat-resistant properties, screw members (not shown) such as bolts and nuts, a metal connecting member 13, and a fixing member (screw member) for fixing the connecting member 13 to the coil body C.

[0017] The coil body C was integrally formed using a three-dimensional printer by a molding method that repeatedly lays, melts, solidifies, and layers powder made of a conductive material (copper alloy (high-copper alloy)) based on three-dimensional data (i.e., a method for partially fusing and laminating conductive material powder layers), and has dimensions of length (front-to-back) x width (width) x height = 300 mm x 150 mm x 100 mm (lengths of the maximum portion of length, width, and height). The coil body C also has grounding portions 2a and 2b for contact with the electrodes of a high-frequency power supply, heating portions 4 (i.e., a series of circumferential upper and lower heating portions 4α and 4β) for heating the workpiece (workpiece) by induction heating, and supports 3a and 3b for supporting the upper and lower heating portions 4α and 4β at positions spaced from the grounding portions 2a and 2b.

[0018] Each grounding portion 2a, 2b is formed as a pair of flat rectangular parallelepipeds (plates) and is arranged adjacent to the left and right with their inner sides facing each other and a predetermined distance (approximately 2.0 mm) between them. Left and right support portions 3a, 3b are connected to the inner edges of each grounding portion 2a, 2b, respectively, with the plate surfaces of the support portions 3a, 3b perpendicular to the plate surfaces of the grounding portions 2a, 2b. Each grounding portion 2a, 2b has a hollow cooling medium flow path 5a, 5b for allowing a cooling medium to flow downward. Inlet ports 25, 24 provided at the upper ends of each grounding portion 2a, 2b are connected to the cooling medium flow path 5a, 5b (see FIGS. 6, 7, and 8(a)).

[0019] The right support portion 3b is formed in a plate shape with a constant thickness, and the base end portion (base end portion 3b b On the other hand, the upper branch portion 3b is formed in a band shape with a constant width. d1 and the lower branch 3b d2 The upper branch 3b d1 The right support portion 3b has a downwardly inclined front. Two hollow cooling medium channels 6b1 and 6b2 for allowing the cooling medium to flow downward are arranged side by side, one above the other, inside the right support portion 3b. The tip end of the upper cooling medium channel 6b1 is connected to the upper branch portion 3a. d1through the inside of the upper branch portion 3a d1 The tip end of the lower coolant flow field 6b2 is the lower branch portion 3b d2 through the inside of the lower branch 3b d2 The base ends of the coolant channels 6b1 and 6b2 inside the support part 3b are connected to the coolant channels 5b inside the ground part 2b (see FIGS. 6 and 8(b)).

[0020] On the other hand, the left support portion 3a also has a base end portion (base end portion 3a b The shape of the base end 3a and the portion on the front side is the same as that of the support portion 3b on the right side. b The part on the side of the first application is in the form of a strip of a certain width, and the part on the side of the first application is in the form of an upper branch part 3a d1 and the lower branch 3a d2 The upper branch portion 3a d1 However, the upper part of the left support part 3a is inclined downwards toward the front. b and upper branch 3a d1 are not continuously connected (separated), but are connected via a heat dissipation portion (a bypass current path forming portion) R formed so as to protrude laterally.

[0021] In addition, the base end 3a of the left support portion 3a b Two hollow cooling medium flow paths 6a1 and 6a2 for allowing a cooling medium to flow downward are arranged side by side in the interior of the base end 3a. b The lower branch portion 3a d2 through the inside of the lower branch part 3a d2 The base ends of the coolant flow channels 6a1 and 6a2 inside the support portion 3a are connected to the coolant flow channels 5a inside the ground portion 2a (see FIGS. 7 and 8(b)). d1 A coolant flow field 6a3 is formed in the interior of the heat exchanger 6a1 in a hollow shape, separate from the coolant flow field 6a1 (see FIGS. 7 and 8(c)).

[0022] The heat release section R is composed of a first protruding piece 11, a second protruding piece 12, a connecting member 13, and fixing members (screw members) consisting of a bolt B, a nut N, and a washer W for fixing (screwing) the connecting member 13 to the first protruding piece 11 and the second protruding piece 12. The first protruding piece 11 is formed in a wide (horizontally elongated) rectangular shape with a constant thickness. A horizontally elongated slit 15 with a constant width is formed in the center in the height and width directions. Inside the first protruding piece 11, a cooling medium flow path 7 for allowing the cooling medium to flow downward is formed in a circumferential shape surrounding the slit 15 (see FIG. 8(d)). Furthermore, on the rear surface near the tip of the first protruding piece 11, a discharge pipe 16 is provided that protrudes rearward and bends upward to discharge the cooling medium that has flowed down the internal cooling medium flow path 7 to the outside. Furthermore, the base end of the coolant flow field 7 inside the first protruding piece 11 is connected to the upper coolant flow field 6a1 inside the left support part 3a (see FIG. 7). b At the tip end of the base end 3a, the plate surface is oriented vertically. b The plate surface is integrally formed so as to be perpendicular to the plate surface.

[0023] Similarly to the first protruding piece 11, the second protruding piece 12 is also formed in a wide (horizontally elongated) rectangular shape with a constant thickness. A horizontally elongated slit 17 with a constant width is formed in the center in the front-rear and width directions. A cooling medium flow path 8 for causing a cooling medium to flow downward is formed in the interior of the second protruding piece 12 in a circumferential shape surrounding the slit 17 (see FIG. 8(d)). Furthermore, a discharge pipe 18 for discharging the cooling medium that has flowed downward through the internal cooling medium flow path 8 to the outside is provided at the tip end of the upper surface of the second protruding piece 12 so as to protrude upward. Furthermore, the base end of the cooling medium flow path 8 inside the second protruding piece 12 is connected to the upper branch part 3a of the left support part 3a. d1 The second protruding piece 12 is connected to the coolant flow field 6a3 inside the upper branch portion 3a of the support portion 3a (see FIG. 7). d1 At the lower end edge of the base end of the upper branch part 3a, the plate surface is oriented horizontally. d1The plate surface is integrally formed so as to be perpendicular to the plate surface.

[0024] On the other hand, the connecting member 13 is formed from metal (such as iron) separately from the coil main body C and has a shape obtained by bending a strip of a constant width into an L-shape (orthogonal to the longitudinal direction) in a direction perpendicular to the longitudinal direction. Furthermore, a screw insertion hole (not shown) is drilled at each of both longitudinal ends of the connecting member 13. The connecting member 13 is fixed (screwed) across the first protruding piece 11 and the second protruding piece 12 using the screw insertion holes at both ends, the slit 15 in the first protruding piece 11, and the slit 17 in the second protruding piece 12, with a fixing member (screwed member) composed of a bolt B, a nut N, and a washer W. The fixed connecting member 13 can be slid along the longitudinal direction (the direction in which it protrudes to the left) of the first protruding piece 11 and the second protruding piece 12 by loosening (or releasing) the screwed state of the fixing member.

[0025] The support portions 3a and 3b are arranged adjacent to each other on the left and right sides with a predetermined distance (approximately 2.0 mm) between them, with their inner surfaces facing each other. d1 and the upper branch 3b of the support 3b d1 The upper heating section 4α is provided to connect the lower branch section 3b of the support section 3a. d2 and the lower branch 3b of the support 3b d2 An upper heating section 4β is provided to connect the above.

[0026] The upper heating section 4α and the upper heating section 4β are used to heat a workpiece inserted into the heating section (or placed close to the workpiece). The upper heating section 4α is a series of rings (annular) with its base end separated into left and right halves, while the upper heating section 4β is a series of rings (annular) that is slightly larger (larger in diameter) than the upper heating section 4α. The inner circumferential surfaces of the upper heating section 4α and the upper heating section 4β are inclined so that the diameter gradually decreases from top to bottom. The upper heating section 4α and the upper heating section 4β are arranged concentrically above and below the heating section 4α at a predetermined distance (so that the difference in height between the bottom surfaces is approximately 5.0 mm).

[0027] A cooling medium flow path 9 for allowing a cooling medium to flow downward is formed in the upper heating section 4α, and a cooling medium flow path 10 for allowing a cooling medium to flow downward is formed in the upper heating section 4β (see FIG. 8(e)). Furthermore, two discharge pipes 22, 23 for discharging the cooling medium from the internal cooling medium flow path 10 are integrally provided on the front side of the upper heating section 4β, protruding forward and bending upward. Furthermore, the cooling medium flow path 9 in the upper heating section 4α is connected to the upper branch part 3b of the right support part 3b. d1 the tip of the coolant flow path 6b1 inside the left support portion 3a and the upper branch portion 3a d1 On the other hand, the coolant flow path 10 inside the lower heating part 4β is connected to the end of the lower branch part 3a of the left support part 3a. d2 the tip of the coolant flow path 6a2 inside the right support portion 3b, and the lower branch portion 3b d2 The cooling medium flow path 6b2 is connected to the tip of the cooling medium flow path 6b2 inside the cooling medium flow path 6b (see FIGS. 6, 7, and 8(c)).

[0028] Furthermore, although not shown, sheet-like insulating plates of a predetermined thickness (approximately 2.0 mm) are sandwiched between the left and right grounding portions 2a, 2b of the coil body C, between the left and right support portions 3a, 3b, between the left and right base end portions of the upper heating portion 4α, and between the left and right base end portions of the lower heating portion 4β, and in this state, the left and right support portions 3a, 3b and the insulating plates are screwed together with screw members (bolts and nuts, not shown) inserted through screw holes (not shown) formed through them. Note that these screw members screw together the supports 3a, 3b and the insulating plates via bushings made of insulating and heat-resistant synthetic resin (glass epoxy resin), so that the supports 3a, 3b are not electrically connected to each other via the bolts.

[0029] <How to use the heating coil and how it works> The heating coil 1 configured as described above has the left and right grounding portions 2a, 2b grounded to the electrodes, and with the workpiece inserted inside the series of circumferential heating portions 4a, 4b, an external power source (high-frequency power source) is turned on via the electrodes, and the workpiece can be heated (hardened) using the electromagnetic induction phenomenon.

[0030] After the workpiece is heated, the cooling medium (water) is injected from the injection pipe 24 of the right grounding portion 2b, passes through the cooling medium flow path 5b inside the grounding portion 2b, passes through the upper cooling medium flow path 6b1 inside the right support portion 3b, passes through the cooling medium flow path 9 inside the upper heating portion 4α, and then passes through the upper branch portion 3a of the left support portion 3a. d1The cooling medium injected from the injection pipe 24 of the grounding portion 2b passes through the cooling medium flow path 5b inside the grounding portion 2b, the lower cooling medium flow path 6b2 inside the support portion 3b, and the cooling medium flow path 10 inside the lower heating portion 4β, and then is discharged from the exhaust pipe 22. At the same time, cooling medium is injected from injection pipe 25 of the left grounding portion 2a, passes through cooling medium flow path 5a inside the grounding portion 2a, passes through upper cooling medium flow path 6a1 inside the left support portion 3a and cooling medium flow path 7 inside the first protruding piece 11, and is then discharged from discharge pipe 16.The cooling medium injected from injection pipe 25 of the grounding portion 2a passes through cooling medium flow path 5b inside the grounding portion 2a, passes through lower cooling medium flow path 6a2 inside the support portion 3a and cooling medium flow path 10 inside the lower heating portion 4β, and is then discharged from discharge pipe 23.

[0031] As described above, by injecting the cooling medium through the injection pipes 24 and 25, allowing it to flow thoroughly inside the coil body C, and then discharging it through the discharge pipes 16 and 18 and the discharge pipes 22 and 23, damage caused by melting the insulating plate (not shown) can be accurately prevented. Furthermore, by allowing the cooling medium to flow down into the upper heating section 4α and the lower heating section 4β in this manner, the workpiece can be rapidly cooled. Then, by rapidly cooling the workpiece after being heated in this manner, the workpiece is hardened.

[0032] Furthermore, as described above, when hardening a workpiece, when power is supplied to the grounding portions 2a and 2b, current (AC) flows through the inside and near the surface of the left and right support portions 3a and 3b, and through the inside and near the surface of the upper heating portion 4α and the lower heating portion 4β. When current flows through the inside and near the surface of the upper heating portion 4α and the lower heating portion 4β in this manner, magnetic flux is generated around the upper heating portion 4α and the lower heating portion 4β, and the workpiece is heated by electromagnetic induction.

[0033] At this time, at the lower parts of the support parts 3a and 3b, the AC current supplied from the ground parts 2a and 2b flows through the interior and surface of the support parts 3a and 3b and is guided linearly over the shortest distance to the lower heating part 4β. Meanwhile, at the upper part of the support part 3a, the current applied from the ground parts 2a and 2b is guided to the upper heating part 4α through the heat dissipation part (detour current path forming part) R (i.e., the first protruding piece 7, the connecting member 13, and the second protruding piece 8), and is also guided to the heat dissipation part R through the upper heating part 4α. When the current applied from the ground parts 2a and 2b passes through the heat dissipation part R in this way, a magnetic flux is also generated in the heat dissipation part R, and the magnetic flux generated in the upper heating part 4α is reduced. Therefore, the amount of heat generated in the workpiece due to electromagnetic induction is smaller at the upper heating part 4α than at the lower heating part 4β. Therefore, even when a large amount of alternating current is passed through the grounding portions 2a, 2b (when a high voltage is applied), the portion of the workpiece located inside the upper heating portion 4α is not excessively heated, and it is possible to adjust the depth of the hardened layer formed by quenching to a thin layer.

[0034] 9, the loop (current path length) of the heat release portion R can be changed by loosening (or releasing) the screwed state of the fixing member that fixes the connecting member 13 to the first protruding piece 11 and the second protruding piece 12 and sliding the connecting member 13 along the longitudinal direction (the direction in which it protrudes to the left) of the first protruding piece 11 and the second protruding piece 12. When the current path length of the heat release portion R is increased (i.e., when the fixing position of the connecting member 13 is moved outward as shown in FIG. 9(a)), the magnetic flux generated in the heat release portion R increases, and the amount of reduction in the magnetic flux generated in the upper heating portion 4α increases. As a result, the amount of heat generated in the workpiece due to electromagnetic induction in the upper heating portion 4α is further reduced.

[0035] On the other hand, when the loop length of the heat dissipation part R is shortened (i.e., when the fixing position of the connecting member 13 is moved inward as shown in FIG. 9(b)), the magnetic flux generated in the heat dissipation part R decreases, and the amount of reduction in the magnetic flux generated in the upper heating part 4α decreases. Therefore, in the upper heating part 4α, the amount of heat generated in the workpiece due to electromagnetic induction is smaller than when there is no heat dissipation part R, but the difference is small.

[0036] As described above, the amount of heat generated in the portion of the workpiece located inside the upper heating portion 4α can be easily adjusted by adjusting the loop length of the heat dissipation portion R. That is, the first protruding piece 11 having the slit 15 formed therein, the second protruding piece 12 having the slit 17 formed therein, and the connecting member 13 that can be fixed (screwed) at different positions using the slits 15 and 17 function as a current path length adjusting means for adjusting the length of the path of the alternating current flowing inside the coil body C.

[0037] <Effect of heating coil> As described above, the heating coil 1 has a pair of plate-shaped grounding portions 2a, 2b for contacting electrodes through which high-frequency current is passed, a pair of support portions 3a, 3b that are arranged perpendicular to the grounding portions 2a, 2b and parallel to each other, and whose tip portions are branched upward and downward, a series of circumferential upper heating portions 4α that are arranged to connect the upper tips of the pair of support portions 3a, 3b, and a series of circumferential lower heating portions 4β that are arranged to connect the lower tips of the pair of support portions 3a, 3b.A heat dissipation portion R (a first protruding piece 11, a second protruding piece 12, a connecting member 13, etc.) is formed at the upper branching portion of the left support portion 3a so as to protrude outward, and AC current from the grounding portions 2a, 2b is supplied to the upper heating portion 4α via the heat dissipation portion R.

[0038] Therefore, the heating coil 1 can reduce the heat generation amount of the upper heating portion 4α compared to the lower heating portion 4β, which is directly supplied with AC current from the ground portions 2a and 2b. Therefore, with the heating coil 1, it is possible to easily control the depth of the hardened layer formed by quenching the workpiece for each height position in accordance with the shape of the workpiece.

[0039] Furthermore, the heating coil 1 is provided with a current path length adjustment means (such as a first protruding piece 11 with a slit 15 formed therein, a second protruding piece 12 with a slit 17 formed therein, and a connecting member 13) for adjusting the length of the current flow path inside the heat dissipation part R, and by changing the length of the current flow path inside the heat dissipation part R, the amount of magnetic flux generated in the heat dissipation part R can be changed, thereby changing the amount of heat generated in the upper heating part 4α to which current is supplied via the heat dissipation part R. Therefore, the heating coil 1 makes it very easy to control the depth of the hardened layer caused by quenching at each height position of the workpiece.

[0040] In addition, the heating coil 1 has a current path length adjustment means consisting of a first protruding piece 11 and a second protruding piece 12 formed to protrude outward from the main body of the support portion 3a, and a connecting member 13 that can connect the first protruding piece 11 and the second protruding piece 12 at different positions in the protruding direction.By simply changing the connecting position of the first protruding piece 11 and the second protruding piece 12, the length of the flow path of the alternating current flowing inside the heat dissipation portion R can be changed, and the amount of magnetic flux generated in the heat dissipation portion R can be changed.This changes the amount of heat generated in the inner part of the upper heating portion 4a of the workpiece, making it extremely easy to control the depth of the hardened layer caused by quenching for each height position of the workpiece.

[0041] In addition, because the heating coil (coil body C) is formed by a modeling method using a three-dimensional printer device M (i.e., a method of partially fusing and laminating conductive material powder layers based on three-dimensional data), it can be manufactured very easily despite the complex shape of the series of circumferential heating portions 4a, 4b including the middle heating portion (first conductive portion) 14 and the lower heating portion (second conductive portion) 15. Furthermore, products having the same shape and characteristics can be manufactured efficiently and with good reproducibility, regardless of the skill of the manufacturing worker. Furthermore, because the heating coil (coil body C) is formed by a modeling method using a three-dimensional printer device M, there are no adhesive portions bonded with silver brazing like conventional heating coils, so it will not deform even if the temperature rises during continuous use, and heating treatment (hardening treatment) can be performed according to the standard over a long period of time.

[0042] <Example of changing the heating coil> The heating coil according to the present invention is not limited to the above-described embodiments, and the materials, sizes, shapes, structures, etc. of the grounding portion, support portion, heating portion (upper heating portion, lower heating portion), heat dissipation portion, cooling medium flow path, connecting member, fixing member, etc. of the coil body can be appropriately changed as needed within the scope of the present invention.

[0043] For example, the heating coil is not limited to the one in which the heating portion is annular in plan view as in the above embodiment, but can be changed to one in which the heating portion is rectangular in plan view, etc.

[0044] Furthermore, the heating coil is not limited to the above embodiment in which the tip of the support part branches into two and is connected to the upper and lower heating parts, and a heat release part is formed at the upper branch part of the support part, but may also be one in which the heat release part is formed at the lower branch part of the support part, or one in which the tip of the support part branches into three or more parts, each connected to a heating part, and a heat release part is formed at any of the branch parts of the support part.

[0045] Furthermore, the heating coil is not limited to the above embodiment in which a heat dissipation portion is formed from a protruding piece (first protruding piece) attached to the support part so that the plate surface faces vertically, a protruding piece (second protruding piece) attached to the support part so that the plate surface faces horizontally, and a connecting member, but may also be formed from a pair of protruding pieces attached to the support part so that the plate surface faces vertically, and a heat dissipation portion formed from a connecting member.

[0046] Furthermore, the heating coil is not limited to the one having a heat dissipation portion formed of a pair of protrusions and a connecting member attached to the support portion as in the above embodiment, but may be one having a heat dissipation portion formed of a protrusion that is U-shaped in plan view and suspended so as to straddle a vertical slit formed in one of the support portions, etc. In addition, the heating coil is not limited to the one having slits (long holes along the longitudinal direction) in a pair of protrusions formed on the support portion so that the current path length in the heat dissipation portion is adjustable as in the above embodiment, but may be one having a pair of protrusions formed on the support portion with a plurality of screw holes arranged along the longitudinal direction so that the current path length in the heat dissipation portion is adjustable, as in Figure 10.

[0047] In addition, the heating coil is not limited to the above-described embodiment in which the coil body is formed by a partial welding lamination method of conductive material powder layers, or the entire coil body or the coil body is formed by a partial welding lamination method of conductive material powder layers or a melt extrusion lamination method of conductive material, but the entire coil or the coil body may be formed by assembling multiple components by methods such as welding, brazing, or screwing using bolts and nuts. [Industrial Applicability]

[0048] The heating coil according to the present invention has the excellent effects as described above, and can therefore be suitably used as a member for heating a workpiece by utilizing electromagnetic induction. [Explanation of symbols]

[0049] 1. Heating coil 2a,2b...Grounding part 3a,3b··Support Department 3b b ,3a b ··Base end 3b d1 ,3a d1 ··Upper side bifurcation 3b d2 ,3a d2 ··Inferior bifurcation 4. Heating unit 4α··Upper heating element 4β··Lower heating element C··Coron body R··Heat dissipation portion (detour current path forming portion)

Claims

1. A heating coil used in a high-frequency heating device for heating a workpiece by utilizing electromagnetic induction caused by a high-frequency current, a pair of plate-shaped grounding portions to be attached to electrodes through which high-frequency current is passed; a pair of support parts, each of which is orthogonal to the grounding parts and arranged parallel to each other, and each of which has a tip part branched into multiple parts; a plurality of series of circumferential heating portions provided so as to connect the tips of the branched portions of the pair of support portions, a heating coil for a high frequency heating device, characterized in that a U-shaped heat dissipation part is formed so as to protrude outward from one of the branched parts formed on one side of the pair of support parts;

2. 2. The heating coil for a high frequency heating device according to claim 1, wherein the heat dissipating portion is provided with a current path length adjusting means for adjusting the length of a path of current flowing therethrough.

3. 2. A heating coil for a high-frequency heating device as described in claim 1, characterized in that the current path length adjustment means comprises two protruding pieces formed to protrude outward from the main body of the support part, and a connecting member that can connect the protruding pieces at different positions in the protruding direction.

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