JP2020129443A - Induction heating coil and method of manufacturing the same - Google Patents

Abstract

To provide an induction heating coil and a method of manufacturing the same capable of reducing a flow channel resistance of a coolant flow channel to increase a coolant flow rate and cool the entire coil down to a lower temperature compared with the conventional art, and thereby, effectively reducing accumulation of thermal fatigue, melting of a brazing part and rise in electric resistance.SOLUTION: An induction heating coil comprises: a coil part 10 for induction-heating an object to be processed 1; and a power supply part 50 for supplying a power to the coil part 10. The coil part 10 has a coolant flow channel 20, a quenching agent flow channel 22 and a plurality of injection flow channels 24. The coolant flow channel 20 has an annular shape, is arranged at a radially inner side of the coil part 10 and is configured to circulate coolant 3 around the object to be processed 1. The quenching agent flow channel 22 has an annular shape, is arranged at a radially outer side in the coil part, and is configured to circulate a quenching agent 4 around the coolant flow channel 20. The plurality of injection flow channels 24 penetrate through the coolant flow channel 20 in a radial direction to communicate between the quenching agent flow channel 22 and an inner surface 10a of the coil part 10.SELECTED DRAWING: Figure 3

Description

The present invention relates to an induction heating coil, and more particularly to an induction heating coil for stationary one-shot quenching and a method for manufacturing the same.

Induction heating coils are used to induction harden metal parts by the electromagnetic induction principle.
In addition, "stationary one-shot quenching" means that the object (metal part) for induction hardening is fixed at a predetermined position, the object is heated at a fixed position, and the object is rapidly cooled and quenched at the same position. It is a metal hardening method.
The induction heating coil for stationary one-shot quenching is a multi-functional component that can perform continuous high-frequency heating and quenching by injection of quenching agent at a fixed position. However, such an induction heating coil has a complicated structure and is difficult to manufacture.
Therefore, an induction heating coil using a metal additive manufacturing method and a manufacturing method thereof have been proposed (for example, Patent Document 1).

The "induction heating coil" of Patent Document 1 includes a coil portion for inductively heating an object to be processed, a power supply portion for supplying electric power to the coil portion, a power supply portion, and a coil portion arranged in the coil portion. A coolant channel for supplying a coolant. The coil part, the power supply part, and the coolant flow path are formed by using the metal additive manufacturing method. Further, the refrigerant flow path includes a coil portion side passage formed in the coil portion, the coil portion side passage has an undulation portion, and the undulation portion advances in the circumferential direction of the coil portion, and thus, in the thickness direction of the coil portion. It extends up and down.

Patent No. 6219228

Induction hardening using an induction heating coil (hereinafter, coil) for stationary one-shot quenching generally repeats a heating/cooling cycle of several seconds to several tens of seconds. Due to this heating/cooling cycle, the coil causes the following problems due to repeated thermal expansion and thermal contraction.
(1) Accumulation of thermal fatigue due to repeated thermal expansion and thermal contraction (2) Damage due to melting of brazed part (3) Efficiency decrease due to increase in electrical resistance

The above-described induction heating coil of Patent Document 1 is entirely formed by metal additive manufacturing in order to prevent damage due to melting of the brazing portion. However, since the undulations of the refrigerant channel formed in the coil portion extend along the circumferential direction of the coil portion so as to undulate in the thickness direction, the cross-sectional area of the undulation channel is small and the flow of the refrigerant channel is small. The road resistance is large and the flow rate of the refrigerant is insufficient.
Therefore, cooling of the coil portion is insufficient and the coil portion is overheated to, for example, 70° C. or more, and it is difficult to avoid accumulation of thermal fatigue and reduction in efficiency due to increase in electric resistance.

The present invention was created to solve the above-mentioned problems. That is, an object of the present invention is to provide an induction heating coil capable of cooling the entire coil at a lower temperature (for example, 50° C. or lower) than conventional ones by reducing the flow resistance of the coolant flow passage to increase the flow rate of the coolant, and a manufacturing method thereof. To do.

According to the present invention, a coil portion for inductively heating an object to be processed,
A power supply unit for supplying power to the coil unit,
The coil portion is arranged on the inner side in the radial direction thereof, and has an annular refrigerant flow path that surrounds the object to be treated and causes a refrigerant to flow.
A ring-shaped quenching agent flow path that is arranged radially outside in the coil portion and that flows the quenching agent around the refrigerant flow path,
An induction heating coil is provided, which has a plurality of injection channels that penetrate the coolant channel in the radial direction and communicate between the quenching agent channel and the inner surface of the coil portion.

Further, according to the present invention, there is provided a method for manufacturing the above induction heating coil,
A hollow cylindrical internal structure portion having the refrigerant flow path and the injection flow path, integrally molded using a metal additive manufacturing method,
A hollow cylindrical outer peripheral member is joined to the outer peripheral surface of the internal structure portion to form the quenching agent flow path therebetween,
A method for manufacturing an induction heating coil is provided, in which a side plate is joined to the internal structure portion and the refrigerant flow path is formed therebetween.

According to the present invention, since the annular refrigerant flow path that is disposed inside the coil portion in the radial direction and that allows the refrigerant to flow around the object to be processed is provided, the cross-sectional area of the refrigerant flow path is set large and the flow of the refrigerant flow path is set. Road resistance can be reduced significantly.

In addition, since the plurality of injection flow paths radially penetrate the annular coolant flow path and communicate between the quenching agent flow path arranged on the radially outer side and the inner surface of the coil portion, With this refrigerant, the injection flow path can always be cooled to a temperature close to that of the refrigerant.

Therefore, with the configuration of the present invention, the refrigerant flow rate can be increased and the entire coil can be cooled to a temperature lower than the conventional one (for example, 50° C. or lower), whereby thermal fatigue is accumulated, the brazing portion is melted, and the electric resistance is increased. Can be effectively reduced.

1 is an overall perspective view of an induction heating coil according to the present invention. It is a top view (A) and its BB arrow line view (B) of an induction heating coil. It is CC sectional drawing (A) and DOD sectional drawing (B) of FIG. It is a figure which shows another embodiment of FIG.3(B).

A preferred embodiment of the present invention will be described with reference to the drawings. In addition, in each figure, the common part is denoted by the same reference numeral, and the duplicated description will be omitted.

FIG. 1 is an overall perspective view of an induction heating coil 100 according to the present invention.
In this figure, the induction heating coil 100 includes a coil unit 10 for induction heating the workpiece 1, and a power supply unit 50 for supplying electric power to the coil unit 10.

The object 1 to be processed is preferably a cylindrical metal member located substantially concentrically with respect to the central axis of the coil portion 10 in this example, but may have another shape (for example, a polygonal shape).

The coil portion 10 is a hollow cylindrical member (a hollow cylindrical member in this example) having a slit groove 11 extending in the radial direction (X direction orthogonal to the Z axis) in a part thereof. The coil portion 10 in this example has a cylindrical inner surface 10a, a cylindrical outer surface 10b, and axial side surfaces 10c and 10d.
The inner surface 10a and the outer surface 10b are preferably concentric. The side surfaces 10c and 10d are preferably orthogonal to the Z axis and are parallel to each other.

The coil portion 10 further includes a pair of power introduction portions 12 extending in the X direction with the slit groove 11 interposed therebetween. The X-direction outer ends of the power introducing units 12 are connected to the pair of power supply units 50, respectively. The connecting portion 2 between the power introducing portion 12 and the power supplying portion 50 is firmly connected by a connecting member (for example, bolt and nut) or brazing, and the electric resistance therebetween is substantially equal to that of the base material. It's getting low.

A bolt hole 51 is provided in each of the pair of power supply units 50. The bolt holes 51 are used to connect with a pair of terminals of a high frequency power source (not shown).

With the above-described configuration, the high frequency current I can be caused to flow from the high frequency power supply to the coil unit 10 through the pair of power supply units 50 as shown by an arrow 5 in FIG.

FIG. 2 is a plan view (A) of the induction heating coil 100 and a BB arrow view (B) thereof.

In this figure, a pair of electric power introducing portions 12 of the coil portion 10 are provided with a refrigerant inlet 12a and a refrigerant outlet 12b, respectively. The refrigerant inflow port 12a and the refrigerant outflow port 12b communicate with each other inside the power introducing unit 12 and the coil unit 10.
With this configuration, it is possible to supply the refrigerant 3 from the refrigerant inlet 12a, cool the power introduction unit 12 and the coil unit 10, and heat the refrigerant 3 to the outside through the refrigerant outlet 12b. The coolant 3 is, for example, cooling water, but may be another liquid.

1 and 2, the outer surface 10b of the coil portion 10 is provided with a plurality of quenching agent supply ports 13. In this example, a pair of quenching agent supply ports 13 are provided so as to face each other in the Y direction, but one or more quenching agent supply ports 13 may be provided.

Further, a plurality of injection ports 14 are provided on the inner surface 10 a of the coil portion 10.
Further, the quenching agent supply port 13 and the injection port 14 communicate with each other inside the coil portion 10 and are separated from the refrigerant 3 by a partition wall (not shown).
With this configuration, the quenching agent 4 is supplied from the quenching agent supply port 13 and the quenching agent 4 is injected inward from the injection port 14 toward the outer surface of the object 1 to be treated, which is induction-heated. Item 1 can be quenched. The quenching agent 4 is, for example, water, emulsion water, or oil, but may be another liquid.

FIG. 3 is a sectional view (A) and a sectional view (B) taken along line CC of FIG.
In this figure, the coil portion 10 has a coolant channel 20, a quenching agent channel 22, and a plurality of injection channels 24.

The coolant flow path 20 is annular (annular in this example), is arranged inside the coil portion 10 in the radial direction, and surrounds the object to be processed 1 to flow the coolant 3.
In this example, the ring of the refrigerant flow path 20 is circumferentially separated at the slit groove 11, and the separated circumferential ends are a pair of ends provided inside the power introduction unit 12. It communicates with the refrigerant inflow port 12a and the refrigerant outflow port 12b via the flow path 21.
With this configuration, it is possible to supply the refrigerant 3 from the refrigerant inlet 12a, cool the power introduction unit 12 and the coil unit 10 and heat the heated refrigerant 3 to the outside from the refrigerant outlet 12b.

The cross-sectional shapes of the refrigerant flow path 20 and the end flow path 21 are substantially single rectangles, and are set large so as to reduce the flow path resistance. With this configuration, the flow passage resistance of the coolant flow passage 20 can be significantly reduced.

The quenching agent flow path 22 has an annular shape (annular shape in this example), is arranged radially outside in the coil portion, and surrounds the refrigerant flow path 20 to flow the quenching agent 4.
In this example, the ring of the quenching agent channel 22 is circumferentially separated at the slit groove 11. Further, the quenching agent flow passage 22 communicates with a plurality (one pair in this example) of quenching agent supply ports 13.
With this configuration, the quenching agent passage 22 substantially evenly surrounds the entire outer side in the radial direction of the refrigerant passage 20 except the slit groove 11, and the quenching agent passage 22 is substantially covered with the quenching agent passage 22. It is possible to supply the quenching agent 4 having a dynamic pressure.

The plurality of injection flow paths 24 penetrate the refrigerant flow path 20 in the radial direction, and connect the quenching agent flow path 22 and the inner surface 10 a of the coil portion 10 to each other. The injection port 14 is an opening in the inner surface 10a of the injection flow path 24.
In this example, the plurality of injection ports 14 are substantially evenly arranged on the inner surface 10 a of the coil portion 10.
With the configuration described above, the quenching agent 4 is supplied from the quenching agent supply port 13, and the quenching agent is supplied from the inner end of the injection flow path 24 (that is, the injection port 14) toward the outer surface of the induction-heated object 1. 4 can be injected inward.

In FIG. 3, the coil portion 10 includes an internal structure portion 30, an outer peripheral member 32, and a pair of side plates 34.

The internal structure 30 has a hollow cylindrical shape (hollow cylindrical shape in this example), and has a refrigerant flow path 20 and an injection flow path 24. Details of the internal structure unit 30 will be described later.

The outer peripheral member 32 has a hollow cylindrical shape (hollow cylindrical shape in this example), is joined to the outer peripheral surface of the internal structure portion 30, and forms the quenching agent flow path 22 with the internal structure portion 30.
The pair of side plates 34 are joined to the internal structure portion 30 and form the refrigerant flow path 20 therebetween.
The outer peripheral member 32 and the internal structure portion 30 and the side plate 34 and the internal structure portion 30 are preferably joined by brazing. In this case, the brazing material has a heat resistance of preferably 50°C or higher, more preferably 100°C or higher.

In this example, the internal structure portion 30 has an inner ring portion 30a, an outer ring portion 30b, and a plurality of spoke portions 30c.
The inner ring portion 30a has a hollow cylindrical shape (hollow cylindrical shape in this example), and its inner surface faces the object to be processed 1 and surrounds it.
The outer ring portion 30b has a hollow cylindrical shape (hollow cylindrical shape in this example), and its outer peripheral surface is joined to the inner surface of the outer peripheral member 32 to form the quenching agent flow channel 22 with the outer peripheral member 32.
The plurality of spoke portions 30c connect the inner ring portion 30a and the outer ring portion 30b at a circumferential interval with each other, and have the injection channel 24 inside thereof. The spokes 30c penetrate the inside of the coolant in the coolant flow path 20 in the radial direction.

In this example, the internal structure portion 30 is integrally molded using a metal additive manufacturing method.

Moreover, the internal structure part 30, the outer peripheral member 32, and the side plate 34 are made of pure copper or a copper alloy integrally molded.
With this configuration, the electric resistance of the entire coil portion can be reduced.

In FIG. 3B, the spoke portion 30c is set to have a small cross-sectional area so that the refrigerant 3 flows with low resistance around the spoke passage 30c as long as it has the injection passage 24 inside.
The spokes 30c are circular tubes each having a single injection flow path 24 in this example. However, the single spoke portion 30c may have a plurality of injection flow paths 24.

FIG. 4 is a diagram showing another embodiment of FIG. 3(B).
In the example of FIG. 3, the injection flow path 24 is a linear flow path that extends in the radial direction, but as shown in FIG. 4A, it may be branched inside the spoke portion 30c.
For example, one injection flow path 24 is internally divided into two, one injection flow path 24 communicates with the quenching agent flow path 22, and two injection flow paths 24 are provided on the inner surface 10 a of the coil part 10. May communicate with each other.
Furthermore, for example, the two injection flow paths 24 are internally branched into three, the two injection flow paths 24 communicate with the quenching agent flow path 22, and the three injection flows are provided on the inner surface 10a of the coil portion 10. The passage 24 may communicate with each other.

Further, as shown in FIG. 4B, a hollow chamber 35 is provided inside the inner ring portion 30a, and a large number of injection ports 14 having a diameter smaller than that of the injection flow passage 24 are evenly provided on the inner surface 10a of the inner ring portion 30a. May be. In this case, the cross-sectional area of the jet flow path 24 of the spoke portion 30c is set relatively large to reduce the required number, and the cross-sectional area of the jet port 14 of the inner surface 10a is set relatively small so as to uniformly jet. Is good.

The method for manufacturing the induction heating coil 100 according to the present invention includes steps (processes) S1 to S3.

In step S1, the hollow cylindrical internal structure portion 30 having the refrigerant flow path 20 and the injection flow path 24 is integrally molded by using the metal additive manufacturing method. Pure copper or a copper alloy is used as the material of the internal structure portion 30.
In parallel, the outer peripheral member 32 and the side plate 34 are integrally molded using pure copper or a copper alloy. The manufacturing of the outer peripheral member 32 and the side plate 34 is not limited to the metal additive manufacturing method, and may be another processing method (for example, machining).

In step S2, the hollow cylindrical outer peripheral member 32 is joined to the outer peripheral surface of the internal structure portion 30, and the quenching agent flow path 22 is formed therebetween.
In step S3, the side plate 34 is joined to the internal structure portion 30 and the coolant flow path 20 is formed therebetween.

The joining in steps S2 and S3 is preferably performed by brazing. In this case, the brazing material has a heat resistance of preferably 50°C or higher, more preferably 100°C or higher.
The order of steps S2 and S3 may be reversed.
Further, the internal structure portion 30, the outer peripheral member 32, and the side plate 34 may be integrally processed using a metal additive manufacturing method.

The simulation was performed about the induction heating coil mentioned above.
(Simulation conditions)
Dimensions of coil part 10: inner diameter 34 mm, outer diameter 76 mm, thickness 16 mm
Material: Pure copper Emissivity of the object to be treated 0.2, ambient temperature 950°C
Heat transfer coefficient of the outer surface of the coil is 20 W/m ² K, ambient temperature is 30℃
Heat transfer coefficient inside the coil part 300 W/m ² K,

(simulation result)
In the case of the induction heating coil of Patent Document 1, the maximum temperature of the coil portion surface was 71.7°C and the minimum temperature was 71.1°C under the same conditions.
In the case of the induction heating coil 100 of the present invention, the maximum temperature of the coil surface was 36.5°C and the minimum temperature was 35.7°C under the same conditions.

In the induction heating coil of Patent Document 1, since the undulating portion of the refrigerant flow path formed in the coil portion extends so as to undulate in the thickness direction along the circumferential direction of the coil portion, the cross-sectional area of the undulating portion is small, The flow passage resistance of the coolant flow passage is large, and the flow rate of the coolant is insufficient.
Therefore, it can be determined that the coil portion is insufficiently cooled and the coil portion is overheated to, for example, 70° C. or more.

On the other hand, the induction heating coil 100 of the present invention is provided inside the coil portion 10 in the radial direction, and is provided with the annular refrigerant flow passage 20 that surrounds the object to be processed 1 and causes the refrigerant 3 to flow. Therefore, since the cross-sectional area of the refrigerant flow path 20 can be set to be large and the flow path resistance of the refrigerant flow path 20 can be significantly reduced, the refrigerant flow rate can be increased and the entire coil can be cooled to a temperature lower than the conventional temperature (for example, 50° C. or less). It can be judged that it was possible.

According to the above-described embodiment of the present invention, since the annular coolant passage 20 is disposed inside the coil portion 10 in the radial direction and the coolant 3 flows around the object 1, the cross-sectional area of the coolant passage 20 is provided. Can be set to a large value to significantly reduce the flow path resistance of the coolant flow path 20.

In addition, since the plurality of injection flow paths 24 penetrate the annular coolant flow path 20 in the radial direction and communicate between the quenching agent flow path 22 arranged on the outer side in the radial direction and the inner surface 10 a of the coil part 10. The injection channel 24 can be always cooled to a temperature close to that of the refrigerant 3 by the refrigerant 3 in the refrigerant channel.

Therefore, according to the configuration of the present invention, the refrigerant flow rate can be increased and the entire coil can be cooled to a temperature lower than the conventional one (for example, 50° C. or less), whereby thermal fatigue is accumulated, the brazing part is melted, and the electric resistance is increased. Can be effectively reduced.

The present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made without departing from the gist of the present invention.

1 to-be-processed object, 2 connection part, 3 refrigerant, 4 quenching agent, 10 coil part,
10a inner surface, 10b outer surface, 10c, 10d side surface, 11 slit groove,
12 power inlet, 12a refrigerant inlet, 12b refrigerant outlet,
13 quenching agent supply port, 14 injection port, 20 refrigerant channel, 21 end channel,
22 quenching agent flow path, 24 injection flow path, 30 internal structure part,
30a inner ring portion, 30b outer ring portion, 30c spoke portion,
32 outer peripheral member, 34 side plate, 35 hollow chamber,
50 power supply section, 51 bolt hole, 100 induction heating coil

Claims (7)

A coil portion for inductively heating the object to be processed,
A power supply unit for supplying power to the coil unit,
The coil portion is arranged on the inner side in the radial direction thereof, and has an annular refrigerant flow path that surrounds the object to be treated and causes a refrigerant to flow.
A ring-shaped quenching agent flow path that is arranged radially outside in the coil portion and that flows the quenching agent around the refrigerant flow path,
An induction heating coil, comprising: a plurality of injection channels that penetrate the coolant channel in a radial direction and communicate between the quenching agent channel and the inner surface of the coil portion. The coil portion is a hollow cylindrical internal structure portion having the refrigerant flow passage and the injection flow passage,
A hollow cylindrical outer peripheral member that is joined to the outer peripheral surface of the internal structure portion and forms the quenching agent flow path therebetween.
The side wall plate joined to the said internal structure part and forming the said refrigerant flow path between them, The induction heating coil of Claim 1. The internal structure portion is a hollow cylindrical inner ring portion that faces the object to be processed and surrounds the object.
A hollow cylindrical outer ring portion joined to the inner surface of the outer peripheral member,
The inner ring portion and the outer ring portion are connected to each other at intervals in the circumferential direction, and a plurality of spoke portions having the injection channel inside thereof are provided,
The induction heating coil according to claim 2, wherein the spoke portion radially penetrates through the coolant in the coolant flow path. The induction heating coil according to claim 2, wherein the inner structure portion, the outer peripheral member, and the side plate are made of pure copper or a copper alloy integrally molded. The induction heating coil according to claim 3, wherein the injection flow path branches inside the spoke portion. The induction heating coil according to claim 3, wherein a hollow chamber is provided inside the inner ring portion, and an injection port having a diameter smaller than that of the injection passage is provided on an inner surface of the inner ring portion. A method of manufacturing an induction heating coil according to claim 1, wherein
A hollow cylindrical internal structure portion having the refrigerant flow path and the injection flow path, integrally molded using a metal additive manufacturing method,
A hollow cylindrical outer peripheral member is joined to the outer peripheral surface of the internal structure portion to form the quenching agent flow path therebetween,
A method for manufacturing an induction heating coil, comprising joining a side plate to the internal structure portion and forming the refrigerant flow path therebetween.

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