Heating coil for high frequency heating device

Abstract

To provide a heating coil for high frequency heating apparatus which, even when there is an outward convex angular portion in a workpiece, effectively prevents the overheating of only that portion and prevents the mechanical strength of the workpiece from decreasing.SOLUTION: A heating coil 1 includes: a pair of plate-like grounding parts 2a, 2b that is formed in an integrated manner using a molding method that repeats laying, melting, solidifying, and laminating of powder made of conductive materials on the basis of three-dimensional data and are attached to electrodes that generate high-frequency currents; a pair of plate-like support parts 3a, 3b which is arranged so as to be orthogonal to each of grounding parts 2a, 2b; and a circumferential heating part 4 which is provided so as to connect the tips of the support parts 3a, 3b. In the heating part 4, gas injection holes 25, 25... for injecting the gas for cooling to the workpiece are formed.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] In order to increase the hardness of the surface of a metal workpiece, the surface of the workpiece is heated to a temperature equal to or higher than the transformation point of the metal (austenite transformation point) and then rapidly cooled (so-called quenching).A widely used method for quenching is to use a high-frequency heating device to bring a metal ring-shaped member (heating coil) through which a high-frequency current flows close to the surface of the workpiece, and to heat the workpiece with heat generated by electromagnetic induction (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-115428 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, when a workpiece is quenched using a metal, annular heating coil as in Patent Document 1, if the workpiece has an outwardly convex, angular part, only that part is excessively heated, and the grain size of that part increases, which induces a situation in which mechanical strength such as impact resistance decreases. In addition, since a conventional heating coil as in Patent Document 1 must be formed by bonding multiple parts with silver solder or the like, it is likely to break and leak cooling medium if it is used continuously under high output conditions (processing conditions in which a high-voltage high-frequency power source is applied). Furthermore, since a conventional heating coil as in Patent Document 1 must be formed by soldering multiple parts, it is difficult to reproducibly manufacture the same characteristics during manufacturing, which causes a problem of variation in the quality of the heated workpiece.

[0005] The object of the present invention is to provide a heating coil for a high-frequency heating device which solves the above-mentioned problems of conventional heating coils for high-frequency heating treatment, which effectively prevents a situation in which only an outwardly convex angular portion is heated excessively even if the workpiece has such an angular portion, thereby preventing a decrease in the mechanical strength of the workpiece, which is less likely to break even when the output of the high-frequency power source is increased, and which can be easily and cheaply manufactured to have the same characteristics with good reproducibility during manufacturing. [Means for solving the problem]

[0006] The present invention, as set forth in claim 1, is a heating coil for use in a high-frequency heating device for heating a workpiece by utilizing electromagnetic induction caused by a high-frequency current, the heating coil having a pair of plate-shaped grounding parts for contacting electrodes to which a high-frequency current is applied, a pair of plate-shaped supporting parts disposed so as to be perpendicular to the grounding parts, and a circumferential heating part provided so as to connect the tips of the supporting parts together, The heating section has a shape in which an upper circumferential body and a lower circumferential body are arranged side by side with a predetermined gap between them and aligned on their central axes, the upper circumferential body is provided with a cooling medium flow path for flowing water down, and the lower circumferential body is provided with a gas flow path for flowing gas down, and the gas flow path is provided with a plurality of gas injection holes for injecting gas onto the workpiece, the gas injection holes being inclined at a predetermined angle with respect to the central axis of the lower circumferential body. It is characterized by the above.

[0007] The invention described in claim 2 is the invention described in claim 1, wherein the gas flow path is: formed within the lower peripheryThe cooling medium flow passage is characterized in that it is formed in a double pipe shape.

[0008] The invention described in claim 3 is as follows: A method for manufacturing a heating coil for a high-frequency heating device according to claim 1, characterized in that the heating coil for the high-frequency heating device is integrally formed using a molding method in which powder made of a conductive material is repeatedly laid, melted, solidified, and laminated based on three-dimensional data (hereinafter referred to as a partial deposition lamination method of conductive material powder layers), or a molding method in which a molten conductive material is laminated based on three-dimensional data (hereinafter referred to as a melt extrusion lamination method of conductive material). It is something. Effect of the Invention

[0009] The heating coil for a high-frequency heating device according to claim 1 (hereinafter simply referred to as the heating coil) has a gas injection hole formed in the heating section for injecting gas to the workpiece, so that by injecting gas (such as nitrogen) from a gas injection pipe and injecting the gas from the gas injection hole to the workpiece, it is possible to rapidly cool a specific part of the workpiece (for example, an outwardly convex angular part) and avoid excessive heating. Therefore, according to the heating coil according to claim 1, it is possible to effectively prevent a situation in which the crystal grain size of a specific part of the workpiece becomes large and mechanical strength such as impact resistance decreases.

[0010] Also, Produced by the production method according to claim 3 The heating coil is formed by a method of partial deposition lamination of conductive powder layers based on three-dimensional data or a method of melt extrusion lamination of conductive materials. Therefore, even though the circumferential heating portion has a complex shape with gas injection holes, it can be manufactured cheaply and very easily, and products having the same shape and characteristics can be manufactured efficiently with good reproducibility regardless of the skill of the manufacturing worker. Furthermore, Produced by the production method according to claim 3 The heating coil is formed by a partial welding lamination method of conductive material powder layers based on three-dimensional data or a conductive material melt extrusion lamination method. Therefore, unlike conventional heating coils, there are no adhesive parts bonded with silver solder, so the coil 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.

[0011] In the heating coil described in claim 2, the gas downflow passage for guiding gas to the gas injection hole is formed in a double-tube shape inside the cooling medium downflow passage formed in the heating section, so that the gas in the gas downflow passage can be kept at a low temperature by the cooling medium in the cooling medium downflow passage and injected onto the workpiece, thereby making it possible to cool a specific portion of the workpiece more efficiently.

[0012] Heating coil The gas jetted from the gas jet hole is directed toward the convex ridge of the workpiece. If configured Since it is possible to very effectively cool the convex angular portions of the workpiece, it is possible to extremely effectively prevent the crystal grain size in a particular portion of the workpiece from becoming large, which would result in a decrease in mechanical strength. [Brief description of the drawings]

[0013] [Figure 1] FIG. [Diagram 2] FIG. [Diagram 3] FIG. [Figure 4] FIG. [Diagram 5] FIG. [Figure 6] 3 is a vertical cross-sectional view of the heating coil (a cross-sectional view taken along line AA in FIG. 2). [Figure 7] 3 is a vertical cross-sectional view of the heating coil (cross-sectional view taken along line BB in FIG. 2). [Figure 8] 3 is a vertical cross-sectional view of a grounding portion of the heating coil (a cross-sectional view taken along line CC in FIG. 2). [Figure 9] 3A and 3B are vertical sectional views of a heating part of a heating coil (a is a sectional view taken along line DD in FIG. 2, and b is an enlarged view of part E in a). [Figure 10] 6 is a horizontal cross-sectional view of the heating part (cross-sectional view taken along line FF in FIG. 5). [Figure 11] FIG. 2 is an explanatory diagram showing a process for manufacturing a heating coil (a is a plan view, and b is a vertical cross-sectional view). [Figure 12] FIG. 2 is an explanatory diagram (vertical cross-sectional view of the heating part) showing a state in which a heating coil is used. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The heating coil according to the present invention must be integrally formed by a modeling method based on three-dimensional data using a three-dimensional printer. As such a modeling method, a modeling method in which powder made of a conductive material is repeatedly laid, melted, solidified, and layered based on three-dimensional data (a method for partially fusing and laminating a conductive material powder layer), or a modeling method in which a molten conductive material is layered based on three-dimensional data (a method for melt extrusion lamination of a conductive material) can be adopted. Note that the partial fusing and lamination method for conductive material powder layers is preferably used as a modeling method for the heating coil, since it makes it possible to easily manufacture a heating coil having a complex shape and structure.

[0015] The conductive material used as the raw material for shaping in the present invention 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 preferable because it can reduce costs such as material costs, makes it possible to inexpensively and easily manufacture the heating coil using a three-dimensional printer, and has very good electrical conductivity, resulting in high heat generation efficiency by electromagnetic induction.

[0016] In addition, when copper is used as the conductive material, it is possible to use pure copper, but it is preferable to use an alloy (high copper alloy) in which copper contains iron, tin, nickel, titanium, beryllium, zirconium, chromium, silicon, etc. in a smaller proportion than copper, since it is possible to increase the absorption of the laser and promote the temperature rise. Furthermore, among these copper alloys, it is more preferable to use a copper-chromium alloy in which copper contains chromium, since it is possible to effectively increase the strength of the heating coil while maintaining high manufacturing efficiency by the three-dimensional printer, and it is particularly preferable to use an alloy in which copper contains chromium and zirconium in a predetermined proportion (for example, one containing 98.71 to 99.45 mass% copper, 0.50 to 1.00 mass% chromium, and 0.05 to 0.25 mass% zirconium (high copper alloy), etc.).

[0017] 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 an electron beam. As the laser, a semiconductor laser, a carbon dioxide gas laser, an excimer laser, a YAG laser, a fiber laser, etc. can be suitably used, but if a fiber laser (i.e., a laser using an optical fiber doped with a rare earth element such as Yb as a laser medium) is used, it is possible to obtain a laser beam with high output and no deviation in the optical axis using a small device, and it is therefore possible to very efficiently manufacture a heating coil with high dimensional accuracy, which is preferable.

[0018] In addition, the output and wavelength of the fiber laser when forming a heating coil by the partial deposition lamination method of conductive material powder layers are not particularly limited, but it is preferable to adjust the output to within the range of 400 to 1,000 W and the wavelength to within the range of 1,000 to 1,100 nm, since this enables efficient forming in a short time. In addition, when copper (pure copper) is used as the conductive material, it is also possible to add an absorbent made of a mixed powder of graphite and inorganic oxide to the copper powder in order to improve the laser absorptivity of the copper powder and increase the manufacturing efficiency of the heating coil.

[0019] In addition, the heating coil according to the present invention is required to have a pair of plate-shaped grounding parts for contacting the electrodes through which high-frequency current is passed, a pair of plate-shaped supporting parts arranged so as to be perpendicular to each of the grounding parts, and a circumferential heating part provided so as to connect the tips of the supporting parts. The shape of each supporting part is not particularly limited as long as it is a pair of plate-shaped (or rod-shaped) parts arranged so as to be perpendicular to each of the grounding parts, but it is preferable that the corners are chamfered so that no discharge phenomenon occurs when power is applied.

[0020] On the other hand, the heating section needs to be formed in a continuous circumferential shape, but is not limited to a circular shape, and may be a non-circular shape (for example, a rectangular ring shape in a plan view), a shape that forms a part of a ring (i.e., an arc shape), a shape that forms a part of a rectangular or polygonal ring, etc. In addition, it may be a shape in which a plurality of circular bodies, non-circular bodies (such as a rectangular ring shape in a plan view), arc bodies, and bodies that form a part of a rectangular or polygonal ring arranged above and below are connected by one or more vertical columnar bodies, etc.

[0021] In the heating coil according to the present invention, it is necessary that the circumferential heating portion has a gas injection hole for injecting gas to the workpiece. The gas injected from the gas injection hole to the workpiece can be air, nitrogen gas, a mist of a quenching coolant, or the like. In this way, by forming a gas injection hole in the circumferential heating portion and injecting a cooling gas from the gas injection hole to the workpiece, it is possible to rapidly cool a specific portion of the workpiece (for example, an outwardly convex angular portion) and avoid excessive heating.

[0022] In addition, it is preferable that the circumferential heating portion is provided with a cooling medium flow passage for cooling the workpiece after heating and for cooling the heating portion itself. Furthermore, the cooling medium flow passage can be provided with a plurality of injection holes for injecting the cooling medium onto the workpiece after heating. By providing such injection holes, it is possible to further improve the cooling efficiency of the workpiece after heating.

[0023] In addition, the heating coil according to the present invention is preferably provided with a series of cooling medium flow-down paths for flowing down the cooling medium in each support part, or each ground part and each support part, so as to be connected to the cooling medium flow-down path in the heating part. The cooling medium flow-down path may be a single one provided to connect the left and right ground parts, the left and right support parts, and the inside of the heating part, or two cooling medium flow-down paths provided on the left and right sides of the heating coil to connect the ground parts, the support parts, and the inside of the heating part, respectively. In addition, if the cooling medium flow-down path has no seams or steps of a predetermined height or more (1.0 mm or more) on the inner wall, or the bent parts and connecting parts are formed in a gentle curve (curved with a curvature radius of 5 mm or more), the cooling medium will flow down very smoothly, and the cooling efficiency of the heating part, ground part, and support part of the heating coil will be extremely good, which is preferable.

[0024] As described above, the heating coil of the present invention has gas injection holes formed in the circumferential heating portion, and although the shape of the circumferential heating portion is complex, it can be manufactured very easily because it is formed by a partial welding lamination method of a conductive material powder layer based on three-dimensional data or a melt extrusion lamination method of a conductive material. EXAMPLES

[0025] Hereinafter, an embodiment of a heating coil according to the present invention will be described in detail with reference to the drawings.

[0026] [Example 1] <Heating coil structure> 1 to 10 show the heating coil of Example 1, and the heating coil 1 is composed of a coil body 5 integrally formed from a copper alloy (high copper alloy), an insulating plate (not shown) formed in a sheet shape from a synthetic resin (fluororesin) having insulating properties and heat resistance, and a screw member (not shown). The heating coil 1 has a size of length (front to back) x width (width) x height = 300 mm x 150 mm x 100 mm (lengths of the maximum parts of length, width, and height).

[0027] The coil body 5 is formed by a modeling method using a three-dimensional printer, which will be described later, and has grounding parts 2a, 2b for contacting the electrodes of a high-frequency power source, a circumferential heating part 4 for heating a workpiece (workpiece) by induction heating, and supporting parts 3a, 3b for supporting the heating part 4 at a position away from the grounding parts 2a, 2b. The heating part 4 is divided into an upper peripheral body 15 and a lower peripheral body 16. The supporting part 3a on the left side supports the upper peripheral body 15, and the supporting part 3b on the right side supports the lower peripheral body 16. Since the coil body 5 is formed by a modeling method using a three-dimensional printer, the entire body has the same color, and the entire surface has the same roughness (surface roughness).

[0028] Each of the grounding parts 2a, 2b is formed as a pair of flat rectangular parallelepipeds (plates) on the left and right, and is arranged so that one side faces the other and is adjacent to the left and right at a predetermined distance (about 2 mm). As shown in FIG. 8, inside each of the grounding parts 2a on the left side, a cooling medium flow path 10a for causing a cooling medium (such as water) to flow down is formed, and the tip side part is divided into two parts to form an upper flow path 10α and a lower flow path 10β. Similarly, inside the grounding part 2b on the right side, a cooling medium flow path 10b for causing a cooling medium to flow down is formed, and the tip side part is divided into two parts to form an upper flow path 10γ and a lower flow path 10δ. In addition, cylindrical discharge pipes 7a, 7b are provided on the upper surfaces of the grounding parts 2a, 2b so as to protrude upward, and are connected to the cooling medium flow path 10a and the cooling medium flow path 10b, respectively.

[0029] The left support part 3a is formed in a flat rectangular parallelepiped shape at the base end, and the tip end is formed in a flat rectangular parallelepiped shape with a narrower vertical width than the base end. The left support part 3a connects the left ground part 2a and the upper circumferential body 15 of the heating part 4. Inside the left support part 3a, an upper cooling medium flow passage 11 having a vertically elongated elliptical cross section for allowing the cooling medium to flow down, and a lower cooling medium flow passage 12 having a vertically elongated elliptical cross section narrower than the upper cooling medium flow passage 11 are provided in parallel vertically. The base ends of the upper cooling medium flow passage 11 and the lower cooling medium flow passage 12 are connected to the upper flow passage 10α and the lower flow passage 10β of the ground plate 2a, respectively.

[0030] On the other hand, the right support part 3b has a base end formed in a flat rectangular parallelepiped shape with the same vertical width as the left support part 3a, and a tip end formed in a flat rectangular parallelepiped shape with the same vertical width as the lower circumferential body 16 of the heating part 4. The right ground part 2b and the lower circumferential body 16 of the heating part 4 are connected to each other. In addition, inside the right support part 3a, an upper cooling medium flow passage 13 having a vertically elongated elliptical cross section for flowing the cooling medium down, and a lower cooling medium flow passage 14 having a vertically elongated elliptical cross section narrower than the upper cooling medium flow passage 13 are provided in parallel to each other. The base ends of the upper cooling medium flow passage 13 and the lower cooling medium flow passage 14 are connected to the upper flow passage 10γ and the lower flow passage 10δ of the ground plate 2b, respectively.

[0031] The left and right support parts 3a, 3b are arranged adjacent to each other at a predetermined distance (about 2 mm) with one plate surface facing each other. The base end edge of each support part 3a, 3b is connected to the inner end edge of the left and right grounding parts 2a, 2b, and the plate surface of each support part 3a, 3b is perpendicular to the plate surface of each grounding part 2a, 2b.

[0032] <Heating section structure> On the other hand, the heating section 4 is for heating the workpiece inserted (close to the workpiece), and has an upper circumferential body 15 and a lower circumferential body 16, which have the same outer diameter, arranged vertically with their central axes aligned. The upper circumferential body 15 is formed in a thick cylindrical shape (a cylindrical shape separated into left and right at the base end), and its inside functions as a cooling medium flow passage 17 for allowing the cooling medium to flow downward. A protrusion 18 of a predetermined vertical width is provided around the inner circumference of the upper circumferential body 15 so as to protrude inward.

[0033] Furthermore, the base end portion of the upper peripheral body 15 is divided into left and right portions, and the left portion is connected to the tip of the support portion 3a. The separated right portion is connected to a pipe support 19 formed in a rectangular parallelepiped shape with a constant vertical width. The plate surface of the pipe support 19 is parallel to the support portion 3a (i.e., flush with the support portion 3b). In addition, a cooling medium flow-down passage 20 is formed inside the pipe support 19 so as to communicate with the cooling medium flow-down passage 17. Furthermore, the pipe support 19 has an injection pipe 9b provided perpendicular to the plate surface, and communicates with the cooling medium flow-down passage 20.

[0034] The lower circumferential body 16 is formed in a flat, thick cylindrical shape, and its inside functions as a cooling medium downflow passage 21 for allowing a cooling medium to flow down. The cooling medium downflow passage 21 has a gas downflow passage 22 for allowing a gas (such as nitrogen) for cooling the workpiece to flow down. That is, the inside of the lower circumferential body 16 has a double-tube structure, and the inside of the gas downflow passage 22 is independent from the inside of the cooling medium downflow passage 21. The gas downflow passage 22 has inner and outer side walls 23a and 23b inclined at a predetermined angle (about 45°) with respect to the central axis of the lower circumferential body 16, and has a parallelogram cross section. The upper plate (top plate) of the cooling medium downflow passage 21 also serves as the upper plate of the gas downflow passage 22. Furthermore, three gas injection pipes 24, 24... are radially provided on the lower peripheral body 16 for injecting gas from the outside into the gas flow down passage 22. Each gas injection pipe 24, 24... protrudes outward from the front, left and right sides and from the lower end of the outer periphery of the lower peripheral body 16.

[0035] Further, twelve gas injection holes 25, 25... for injecting gas to the workpiece are drilled at equal intervals on the same circumference in the upper plate of the cooling medium flow down passage 21 (i.e., the upper surface of the lower circumferential body 16) (see FIG. 10). The gas injection holes 25, 25... are drilled in a cylindrical shape so as to be inclined at a predetermined angle (about 45°) with respect to the central axis of the lower circumferential body 16 (see FIG. 9). The gas injection holes 25, 25... are arranged radially with respect to the central axis of the lower circumferential body 16. The lengths from the central axis C of the gas injection holes 25, 25... to the inner and outer side walls 23a, 23b of the gas flow down passage 22 are equal.

[0036] Furthermore, the lower circumferential body 16 is divided into a left and a right part at the base end side, and the right part is connected to the tip of the support part 3b. The separated left part is connected to a pipe support 26 formed in a rectangular parallelepiped shape with the same vertical width as the lower circumferential body 16. The plate surface of the pipe support 26 is parallel to the support part 3b (i.e., it is flush with the support part 3a). In addition, a cooling medium flow-down passage 27 is formed inside the pipe support 26 so as to communicate with the cooling medium flow-down passage 21. Furthermore, an injection pipe 9a is provided in the pipe support 26 so as to be perpendicular to the plate surface, and is in a state of communication with the cooling medium flow-down passage 27.

[0037] <Cooling medium flow path structure> In the heating coil 1 described above, two series of cooling medium flow paths 6a, 6b for cooling the coil itself and the workpiece are formed inside the heating part 4, the left and right grounding parts 2a, 2b, and the support parts 3a, 3b. That is, one cooling medium flow path 6a runs from the right injection pipe 9b to the discharge pipe 7a via the cooling medium flow path 20 inside the right piping support 19, the cooling medium flow path 17 inside the upper peripheral body 15, the upper cooling medium flow path 11 inside the left support part 3a, and the cooling medium flow path 10a inside the left grounding part 2a. On the other hand, the other cooling medium flow path 6b extends from the left injection pipe 9a, via the cooling medium flow path 27 inside the left piping support 26, the cooling medium flow path 21 inside the lower peripheral body 16, the lower cooling medium flow path 14 inside the right support part 3b, and the cooling medium flow path 10b inside the right grounding part 2b, to the discharge pipe 7b.

[0038] In addition, since the heating coil 1 is integrally formed by a three-dimensional printer, all bends and connecting parts of the two cooling medium flow paths 6a, 6b are formed in gentle curves (curves with a curvature radius of 5 mm or more) and no sharp bends are formed. In addition, the two cooling medium flow paths 6a, 6b have no seams or steps of a predetermined height (1.0 mm or more) on their inner walls.

[0039] Furthermore, a sheet-like insulating plate (not shown) of a predetermined thickness (about 2.0 mm) is sandwiched between the left and right grounding parts 2a, 2b, between the left and right support parts 3a, 3b, and between the left and right base end parts of the heating part 4, and in this state, the left and right support parts 3a, 3b and the insulating plate 31 are screwed together by bolts (not shown) inserted through the screw holes 8, 8. Note that these bolts are in a state in which the support parts 3a, 3b and the insulating plate 31 are screwed together via bushes (not shown) made of synthetic resin (glass epoxy resin) having insulating and heat-resistant properties, so that the support parts 3a, 3b are not electrically connected to each other via the bolts.

[0040] <Heating coil manufacturing method> 11 shows how to form the coil body 5 of the heating coil 1, and the three-dimensional printer device M for forming the heating coil 1 has a frame F with a rectangular parallelepiped recessed portion formed in the center, a lifting member provided so as to be able to rise and fall with respect to the frame F, an irradiation means S for irradiating the laser L, a reflection means R for reflecting the laser, a driving means (not shown) for raising and lowering the lifting member, etc. The lifting member is provided with a table T having approximately the same area as the opening of the recessed portion of the frame F.

[0041] When manufacturing the heating coil 1 by the three-dimensional printer device M, first, copper alloy (high copper alloy) powder is laid to a predetermined thickness (for example, 30 μm) on the surface of the table T of the lifting member in the raised position (copper powder is laid only in the gap between the surface of the table T and the surface of the outer frame of the frame F). Then, a laser (fiber laser) L of a predetermined output is irradiated to the copper alloy powder in a predetermined shape to melt a part of the copper alloy powder, which is then cooled and solidified to form a part of the heating coil 1.

[0042] As described above, after forming a part of the heating coil 1, the table T of the lifting member is lowered by a predetermined height (e.g., 30 μm) by the driving means. Then, at that height position, the following operations are repeated: "laying copper alloy powder on the part of the heating coil 1 previously formed → irradiating the copper alloy powder with the laser L → cooling and solidifying the molten copper alloy (solidification by solidification)." Then, by repeating the above-mentioned operations of "lowering the table T of the lifting member → laying copper alloy powder → irradiating the copper alloy powder with the laser L → cooling and solidifying the molten copper alloy" a predetermined number of times (e.g., 5,000 times), the heating coil 1 made of copper alloy can be integrally formed.

[0043] <Effect of heating coil> The heating coil 1 constructed as described above has the left and right grounding portions 2a, 2b grounded to the electrodes, and a workpiece W (for example, a workpiece having a shape in which a small-diameter cylindrical portion protrudes concentrically downward from the underside of a large-diameter cylindrical portion) inserted inside the circumferential heating portion 4 as shown in FIG. 12. In this state, an external power source (high-frequency power source) is turned on via the electrodes, and the workpiece W can be heated (hardened) by utilizing the electromagnetic induction phenomenon.

[0044] In addition, the cooling medium is injected into the cooling medium flow paths 6a, 6b from the left and right injection pipes 9a, 9b, passed through the inside of the heating portion 4 (i.e., the upper peripheral body 15 and the lower peripheral body 16), and then passed through the support portions 3a, 3b and the grounding portions 2a, 2b before being discharged from the discharge pipes 7a, 7b.This efficiently cools the heating portion 4, the support portions 3a, 3b and the support portions 3a, 3b, and accurately prevents damage caused by melting of the insulating plate (not shown).

[0045] When hardening the workpiece W in this manner, gas (such as nitrogen) is injected from the gas injection pipes 24, 24... and the gas is injected from the gas injection holes 25, 25... onto the workpiece W, thereby rapidly cooling a specific portion of the workpiece W (for example, an outwardly convex angular portion, portion α in FIG. 12) and preventing excessive heating. The gas injected from the gas injection pipes 24, 24... is injected from the gas injection holes 25, 25... via the gas flow passage 22 provided circumferentially inside the upper peripheral body 15 of the heating section 4. This means that the pressure of the gas injected from the gas injection holes 25, 25... varies little, and therefore the specific portion of the workpiece W can be cooled evenly.

[0046] <Effect of heating coil> As described above, the heating coil 1 has the gas injection holes 25, 25... formed in the heating section 4 for injecting gas toward the workpiece W, and by injecting gas (such as nitrogen) introduced from outside through the gas injection holes 25, 25... toward the workpiece W, it is possible to rapidly cool a specific portion of the workpiece W (the outwardly convex angular portion α in FIG. 12) and avoid excessive heating. Therefore, the heating coil 1 can effectively prevent a situation in which the crystal grain size of a specific portion of the workpiece W becomes large, resulting in a decrease in mechanical strength such as impact resistance.

[0047] In addition, since the heating coil 1 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 even though the circumferential heating part 4 has a complex shape, and products having the same shape and characteristics can be manufactured efficiently with good reproducibility without being affected by the skill of the manufacturing worker. Furthermore, since the heating coil 1 is formed by a modeling method using a three-dimensional printer device M, there is no adhesive part using silver solder as in conventional heating coils, so it does not deform even if the temperature rises due to continuous use, and heating treatment (hardening treatment) according to the standard can be performed for a long period of time.

[0048] Furthermore, the heating coil 1 is provided with a cooling medium downflow passage 17 and a cooling medium downflow passage 21 in the heating section 4 for causing the cooling medium to flow down, and a gas downflow passage 22 for directing gas to the gas injection holes 25, 25, etc., and the gas downflow passage 22 is formed in a double-tube shape within the cooling medium downflow passage 21. Therefore, the gas in the gas downflow passage 22 can be kept at a low temperature by the cooling medium in the cooling medium downflow passage 21 and injected onto the workpiece W. Therefore, a specific portion of the workpiece W (the α portion in Figure 12) can be cooled more efficiently.

[0049] In addition, the heating coil 1 is configured so that the gas injected from the gas injection holes 25, 25... is blown toward the convex ridge of the workpiece W (i.e., the axis is inclined at a predetermined angle), so that the outwardly convex angular portion of the workpiece W (part α in Figure 12) can be cooled very effectively, thereby extremely effectively preventing the crystal grain size of the outwardly convex portion of the workpiece W from becoming large, thereby reducing the mechanical strength.

[0050] <Example of changing the heating coil> The heating coil according to the present invention is not limited to the above-described embodiment, and the materials, shapes, structures, and other configurations of the grounding portion, support portion, heating portion, injection pipe, exhaust pipe, gas injection hole, gas flow path, cooling medium flow path, etc. can be appropriately changed as necessary without departing from the spirit of the present invention.

[0051] For example, the heating section of the heating coil is not limited to an upper peripheral body and a lower peripheral body arranged side by side with a predetermined gap therebetween as in the above embodiment, but can be changed to a simple annular shape, a rectangular peripheral shape when viewed from above, or a shape formed by arranging divided annular bodies or peripheral bodies horizontally above and below and connecting them with vertical cylindrical bodies (cylindrical bodies extending in the vertical direction), etc.

[0052] Furthermore, the heating section is not limited to the one having a plurality of cooling medium downflow paths in the heating section as in the above embodiment, but may be one having a single cooling medium downflow path in the heating section. In addition, when a plurality of cooling medium downflow paths are provided in the heating section as in the above embodiment, it is possible to more efficiently cool the workpiece after heating and the heating section itself. Furthermore, the heating section is not limited to the one having the gas downflow path formed in a double pipe shape in the cooling medium downflow path as in the above embodiment, but may be one having the gas downflow path formed separately from the cooling medium downflow path.

[0053] In addition, the heating coil of the present invention is not limited to the above embodiment in which the pair of grounding parts and the pair of supporting parts are insulated by an insulating plate made of fluororesin (PTFE, PFA, FEP, ETFE, PCTFE, ECTFE, PVDF), but can also be changed to one in which the pair of grounding parts and the pair of supporting parts are insulated by an insulating plate made of other synthetic resins having insulating properties and heat resistance, such as polyacetal (POM), polyphenylene sulfide (PPS), polyether ether ketone (PEEK), etc.

[0054] In addition, the overall shape and size of the heating coil of the present invention, the shape of the heating part (overall shape, the number and angle of the gas injection holes facing the workpiece, etc.), the shape and size of the grounding part, the shape and size of the support part, the type (material) and thickness of the sheet-like insulating plate, the number of bolts for clamping the insulating plate, etc. are not limited to the aspects of the above embodiment and can be changed appropriately depending on the shape of the workpiece to be hardened, etc. [Industrial Applicability]

[0055] Since the heating coil according to the present invention has the excellent effects as described above, it can be suitably used as a member for heating a workpiece by utilizing electromagnetic induction. [Explanation of symbols]

[0056] 1. Heating coil 2a,2b...Grounding part 3a,3b...Support part 4. Heating unit 6a, 6b··Cooling media flow path 7a,7b··Discharge pipe 9a,9b··Injection pipe 10a, 10b··Cooling medium flow path 11··Upper cooling medium flow path 12··Lower cooling medium flow path 13··Upper cooling medium flow path 14··Lower cooling medium flow path 15··Upper lateral periarthritis 16··Inferior periarthritis 17··Cooling media flow path 21··Cooling media flow path 22··The body flows down the road 24a,24b··ガス injection pipe 25··ガス jet hole

Claims

1. A heating coil for use 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 an electrode through which a high-frequency current is passed; A pair of plate-shaped support parts arranged perpendicular to each of the grounding parts; and a circumferential heating portion provided so as to connect the tips of the support portions, The heating unit has a shape in which an upper peripheral body and a lower peripheral body are arranged vertically with a predetermined gap therebetween and aligned along their central axes, The upper peripheral body is provided with a cooling medium flow-down passage for allowing water to flow down, and the lower peripheral body is provided with a gas flow-down passage for allowing gas to flow down, A heating coil for a high-frequency heating device, characterized in that a plurality of gas injection holes for injecting gas onto a workpiece are provided in the gas flow path so as to be inclined at a predetermined angle with respect to the central axis of the lower peripheral body.

2. 2. The heating coil for a high frequency heating device according to claim 1, wherein the gas flow passage is formed in a double tube shape within a cooling medium flow passage formed in the lower peripheral body.

3. A method for manufacturing a heating coil for a high frequency heating device according to claim 1, comprising: A manufacturing method for a heating coil for a high-frequency heating device, characterized in that the heating coil for the high-frequency heating device is integrally formed using a molding method in which powder of an electrically conductive material is repeatedly laid, melted, solidified, and layered based on three-dimensional data, or a molding method in which molten electrically conductive material is layered based on three-dimensional data.

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