Induction heating coil

Abstract

To provide an induction heating coil which suppresses the occurrence of cracks due to thermal stress.SOLUTION: In the induction heating coil of the present disclosure, a square pipe having a refrigerant passage through which a refrigerant flows is formed in an annular shape, a treatment target 40 is disposed at a center portion and induction heating is performed, the inner wall portion 31, the first connection wall portion 33, and the second connection wall portion 34 are formed to have a thickness smaller than a thickness of the outer wall portion 32, ribs 37, 38 protruding toward the refrigerant path are respectively formed on a first side 1R shaped part 35 formed at a boundary part between the internal 2R part 31 and the first connecting wall part 33 and a second side wall shaped part 36 formed at a boundary part between the internal wall part 31 and the second connecting wall part 34.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to induction heating coils. [Background technology]

[0002] Patent Document 1 discloses an induction heating coil that includes a coil section that inductively heats the workpiece, a power supply section that supplies power to the coil section, and a refrigerant passage arranged within the power supply section and the coil section, and that by continuously changing the cross-sectional shape of the refrigerant passage at the connection between the power supply section and the coil section, uneven thermal stress at the connection section is suppressed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-41730 A Summary of the Invention [Problem to be solved by the invention]

[0004] The induction heating coil has an inner wall portion facing the workpiece, and both axial ends thereof become hot, which makes them prone to cracking due to thermal stress. The present disclosure is intended to solve such problems and provides an induction heating coil that suppresses the occurrence of cracks due to thermal stress. [Means for solving the problem]

[0005] The induction heating coil of the present disclosure comprises a circularly shaped square pipe having a refrigerant passage through which a refrigerant flows, and a workpiece placed in the center for induction heating. The coil has an inner wall formed radially inward and facing the workpiece, an outer wall formed radially outward and facing the inner wall through the refrigerant passage, a first connecting wall connecting one end of the inner wall and the outer wall, and a second connecting wall connecting the other end of the inner wall and the outer wall, the inner wall, the first connecting wall, and the second connecting wall being thinner than the outer wall, and a first R-shaped portion formed at the boundary between the inner wall and the first connecting wall, and a second R-shaped portion formed at the boundary between the inner wall and the second connecting wall, each having a rib protruding toward the refrigerant passage. This configuration suppresses the occurrence of cracks due to thermal stress.

[0006] The ribs are formed at the center of the first R-shaped portion and the second R-shaped portion, respectively. With this configuration, the ribs improve the cooling performance of both axial end portions of the inner wall portion facing the workpiece, thereby suppressing cracks due to thermal stress.

[0007] The ribs are formed on both ends of the first R-shaped portion and the second R-shaped portion, respectively. With this configuration, the ribs improve the cooling performance of both axial end portions of the inner wall portion facing the workpiece, thereby suppressing cracks due to thermal stress.

[0008] The induction heating coil of the present disclosure is a circularly shaped square pipe having a refrigerant passage through which a refrigerant flows, and a workpiece is placed in the center for induction heating. The induction heating coil has an inner wall portion formed radially inward and facing the workpiece, an outer wall portion formed radially outward and facing the inner wall portion via the refrigerant passage, a first connecting wall portion connecting one ends of the inner wall portion and the outer wall portion, and a second connecting wall portion connecting the other ends of the inner wall portion and the outer wall portion, and the outer wall portion, the first connecting wall portion, and the second connecting wall portion are formed to be thinner than the thickness of the inner wall portion. This configuration suppresses the occurrence of cracks due to thermal stress.

[0009] The inner wall portion has a first protruding portion that protrudes further toward one axial end than the first connecting wall portion and a second protruding portion that protrudes further toward the other axial end than the second connecting wall portion, thereby suppressing cracks caused by thermal stress. [Effects of the Invention]

[0010] The present disclosure provides an induction heating coil that suppresses the occurrence of cracks due to thermal stress. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a plan view of an induction heating device according to a first embodiment. [Figure 2] 2 is a cross-sectional view of a first induction heating coil taken along line II in FIG. 1. FIG. [Figure 3] 3 is a cross-sectional view of the first induction heating coil corresponding to FIG. 2, showing a modified example of the rib. FIG. [Figure 4] 3 is a cross-sectional view of a first induction heating coil corresponding to FIG. 2 in an induction heating device according to a second embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present disclosure will be described with reference to Figs. 1 to 4. Fig. 1 is a plan view of an induction heating device according to a first embodiment. Fig. 2 is a cross-sectional view of a first induction heating coil, taken along line II in Fig. 1. Fig. 3 is a cross-sectional view of a first induction heating coil corresponding to Fig. 2, showing a modified example of the rib. Fig. 4 is a cross-sectional view of a first induction heating coil corresponding to Fig. 2, in an induction heating device according to a second embodiment.

[0013] Naturally, the right-handed XYZ Cartesian coordinate system shown in Figures 1 to 4 is for the sake of convenience in explaining the positional relationships of the components. In Figure 1 and other figures, for example, the positive direction of the Z axis is vertically upward, and the XY plane is the horizontal plane, which is common among the figures.

[0014] Embodiment 1 As shown in FIG. 1, the induction heating device 1 has lead portions 11 and 12, pipes 15 and 16, and an induction heating coil 20.

[0015] As shown in Fig. 1, lead portions 11 and 12 are arranged opposite each other with sheet-like insulator 13 sandwiched therebetween. Lead portions 11 and 12 are made of a metal material such as copper. Lead portion 11 has a flat plate portion 11a and a vertical plate portion 11b. Lead portion 12 has a flat plate portion 12a and a vertical plate portion 12b.

[0016] 1, flat plate portions 11a and 12a are formed in a flat plate shape with their planes facing the Z-axis direction. Vertical plate portion 11b is formed to extend in the X-axis direction, with its end on the X-axis positive side protruding in the Y-axis negative side. Vertical plate portion 12b is formed to extend in the X-axis direction, with its end on the X-axis positive side protruding in the Y-axis positive side.

[0017] 1, the pipe 15 is formed in an L-shape when viewed from the side, and has a first pipe 15a on one side and a second pipe 15b on the other side. The pipe 15 is arranged so that the first pipe 15a extends in the Y-axis direction and the second pipe 15b extends in the X-axis direction. The second pipe 15b is arranged below the vertical plate portion 11b.

[0018] 1, the pipe 16 is formed in an L-shape when viewed from the side, and has a third pipe 16a on one side and a fourth pipe 16b on the other side. The pipe 16 is arranged so that the third pipe 16a extends in the Y-axis direction and the fourth pipe 16b extends in the X-axis direction. The fourth pipe 16b is arranged below the vertical plate portion 12b.

[0019] 1, the induction heating coil 20 has a first induction heating coil 21 arranged relatively on the upper side (positive Z-axis direction side) and a second induction heating coil 22 arranged relatively on the lower side (negative Z-axis direction side). The first induction heating coil 21 and the second induction heating coil 22 are arranged overlapping in the vertical direction (X-axis direction) so that their central axes coincide. The first induction heating coil 21 and the second induction heating coil 22 are connected by a connection part 23.

[0020] 1, the first induction heating coil 21 and the second induction heating coil 22 are formed in a substantially circular ring shape and induction heat the workpiece 40 placed in the center. The first induction heating coil 21 and the second induction heating coil 22 are manufactured by a metal additive manufacturing method using a metal material such as copper.

[0021] 1, a first connection portion 21a that protrudes radially outward is formed at one circumferential end of the first induction heating coil 21. The first connection portion 21a is disposed below the vertical plate portion 11b, and its upper surface (the surface on the positive Z-axis direction side) is connected to the lower surface (the surface on the negative Z-axis direction side) of the vertical plate portion 11b. Furthermore, the end of the first connection portion 21a on the negative X-axis direction side is connected to the end of the second pipe 15b on the positive X-axis direction side.

[0022] 1, a second connection portion 22a that protrudes radially outward is formed at one circumferential end of the second induction heating coil 22. The second connection portion 22a is disposed below the vertical plate portion 12b, and its upper surface (the surface on the positive Z-axis direction side) is connected to the lower surface (the surface on the negative Z-axis direction side) of the vertical plate portion 12b. Furthermore, the end of the second connection portion 22a on the negative X-axis direction side is connected to the end of the fourth pipe 16b on the positive X-axis direction side.

[0023] 1, three first mounting portions 21b that protrude radially outward are formed on the outer peripheral surface of the first induction heating coil 21. Three second mounting portions (not shown) that protrude radially outward are formed on the outer peripheral surface of the second induction heating coil 22. The induction heating coil 20 is attached to a fixing member (not shown) with bolts that pass through the first mounting portions 21b and the second mounting portions.

[0024] 2, the first induction heating coil 21 is made of a square pipe. Although not shown, the second induction heating coil 22 is also made of a square pipe.

[0025] As shown in Fig. 2, the first induction heating coil 21 has a cooling water passage 25 therein. The cooling water passage 25 is a refrigerant passage through which cooling water, which serves as a refrigerant, flows. The refrigerant may be cooling air instead of cooling water. Although not shown, the second induction heating coil 22 also has a cooling water passage therein through which cooling water flows.

[0026] The cooling water passage 25 of the first induction heating coil 21 and the cooling water passage of the second induction heating coil 22 are formed along the circumferential direction. One end of the cooling water passage 25 of the first induction heating coil 21 is connected to a passage formed inside the second piping 15b. The other end of the cooling water passage 25 of the first induction heating coil 21 is connected to one end of the cooling water passage of the second induction heating coil 22 at a connection part 23. The other end of the cooling water passage of the second induction heating coil 22 is connected to a passage formed inside the fourth piping 16b.

[0027] As shown in Fig. 2, the first induction heating coil 21 has a wall 30. The wall 30 is formed so as to surround the periphery of the cooling water passage 25. Although not shown, the second induction heating coil 22 also has a wall. The wall of the second induction heating coil 22 has a similar configuration to the wall 30 of the first induction heating coil 21, and therefore a description thereof will be omitted.

[0028] As shown in FIG. 2, the wall portion 30 has an inner wall portion 31, an outer wall portion 32, a first connecting wall portion 33, and a second connecting wall portion . The inner wall portion 31 is formed radially inward and faces the workpiece 40. The outer wall portion 32 is formed radially outward and faces the inner wall portion 31 across the cooling water passage 25. The first connecting wall portion 33 connects one end of the inner wall portion 31 and one end of the outer wall portion 32. The second connecting wall portion 34 connects the other end of the inner wall portion 31 and one end of the outer wall portion 32.

[0029] 2, the inner wall portion 31, the first connecting wall portion 33, and the second connecting wall portion 34 are formed to have a thickness smaller than that of the outer wall portion 32. Moreover, the inner wall portion 31, the first connecting wall portion 33, and the second connecting wall portion 34 are formed to have the same thickness.

[0030] As shown in FIG. 2, the wall portion 30 has a first R-shaped portion 35 and a second R-shaped portion 36. The first R-shaped portion 35 is formed at the boundary between the inner wall portion 31 and the first connecting wall portion 33, and has an R-shape (arc shape). The second R-shaped portion 36 is formed at the boundary between the inner wall portion 31 and the second connecting wall portion 34, and has an R-shape (arc shape).

[0031] 2, a rib 37 is formed in the center of the first R-shaped portion 35. The rib 37 is formed to protrude toward the coolant passage 25 and is formed along the circumferential direction of the first induction heating coil 21. The rib 37 has a substantially triangular cross section.

[0032] As shown in Fig. 2, a rib 38 is formed in the center of the second R-shaped portion 36. The rib 38 is formed so as to protrude toward the coolant passage 25, and is formed along the circumferential direction of the first induction heating coil 21. The rib 38 has a substantially triangular cross section. The cross section of the ribs 37 and 38 may not be substantially triangular, but may be substantially rectangular or substantially arc-shaped.

[0033] When the induction heating device 1 is in use, a current is supplied from an external power source to the induction heating coil 20 via the leads 11 and 12, and the induction heating effect of the induction heating coil 20 enables high-frequency hardening of the workpiece 40.

[0034] Furthermore, when the induction heating device 1 is in use, cooling water is supplied from one of the pipes 15 and 16, and the cooling water flows through the cooling water passage 25 of the first induction heating coil 21 and the cooling water passage of the second induction heating coil 22, and the cooling water is discharged from the other of the pipes 15 and 16.

[0035] The first induction heating coil 21 has an inner wall portion 31 facing the workpiece 40, and the first rounded portion 35 and the second rounded portion 36, which are both axial end portions, tend to become hot and generate thermal stress.

[0036] Therefore, the thickness of the inner wall 31 and the first connecting wall 33, which sandwich the first R-shaped portion 35, is made thinner than the thickness of the outer wall 32. This thinning improves the cooling performance of the inner wall 31 and the first connecting wall 33, suppressing a temperature rise, and also suppressing a temperature rise of the first R-shaped portion 35 sandwiched between the inner wall 31 and the first connecting wall 33. Furthermore, the thickness of the inner wall 31 and the second connecting wall 34, which sandwich the second R-shaped portion 36, is made thinner than the thickness of the outer wall 32. This thinning improves the cooling performance of the inner wall 31 and the second connecting wall 34, suppressing temperature rise, and also suppressing temperature rise of the second R-shaped portion 36 sandwiched between the inner wall 31 and the second connecting wall 34.

[0037] Furthermore, ribs 37 are provided on the first R-shaped portion 35, and ribs 38 are provided on the second R-shaped portion 36. The ribs 37 increase the surface area of ​​the inner periphery of the first R-shaped portion 35, improving cooling performance. The ribs 38 increase the surface area of ​​the inner periphery of the second R-shaped portion 36, improving cooling performance. Therefore, temperature increases in the first R-shaped portion 35 and the second R-shaped portion 36 are suppressed, and cracks due to thermal stress in the first induction heating coil 21 are suppressed.

[0038] The ribs 37, 38 are not limited to the configuration shown in Fig. 2 as long as they can suppress the temperature rise of the first R-shaped portion 35 and the second R-shaped portion 36. For example, as shown in Fig. 3, ribs 37 formed on both ends of the first R-shaped portion 35 and ribs 38 formed on both ends of the second R-shaped portion 36 may also be employed.

[0039] 3 also increases the surface area of ​​the inner circumferences of the first R-shaped portion 35 and the second R-shaped portion 36, improving cooling performance. Therefore, temperature increases in the first R-shaped portion 35 and the second R-shaped portion 36 are suppressed, and cracks due to thermal stress in the first induction heating coil 21 are suppressed.

[0040] Embodiment 2 Fig. 4 is a cross-sectional view of first induction heating coil 41 of the induction heating device of embodiment 2, corresponding to Fig. 2. First induction heating coil 41 of embodiment 2 has a different wall configuration compared to first induction heating coil 21 of embodiment 1. Furthermore, first induction heating coil 41 of embodiment 2 is not provided with ribs.

[0041] 4, the first induction heating coil 41 has a wall portion 50. The wall portion 50 has an inner wall portion 51, an outer wall portion 52, a first connecting wall portion 53, and a second connecting wall portion .

[0042] 4, the inner wall portion 51 is formed radially inward and faces the workpiece 40. The outer wall portion 52 is formed radially outward and faces the inner wall portion 51 across the cooling water passage 25. The first connecting wall portion 53 connects one end of the inner wall portion 51 and one end of the outer wall portion 52. The second connecting wall portion 54 connects the other end of the inner wall portion 51 and one end of the outer wall portion 52.

[0043] 4, the outer wall portion 52, the first connecting wall portion 53, and the second connecting wall portion 54 are formed to have a thickness smaller than the thickness of the inner wall portion 51. Moreover, the outer wall portion 52, the first connecting wall portion 53, and the second connecting wall portion 54 are formed to have the same thickness.

[0044] As shown in Figure 4, the inner wall portion 51 has a first protruding portion 51a that protrudes toward one axial end (positive Z-axis direction side) beyond the first connecting wall portion 53, and a second protruding portion 51b that protrudes toward the other axial end (negative Z-axis direction side) beyond the second connecting wall portion 54.

[0045] In the second embodiment, the thicknesses of the outer wall portion 52, the first connecting wall portion 53, and the second connecting wall portion 54 are formed thinner than the thickness of the inner wall portion 51. With this configuration, the rigidity of the first induction heating coil 41 is reduced on the radially outer side (the outer wall portion 52 side), where thermal stress is less likely to occur, compared to the radially inner side (the inner wall portion 51 side), where thermal stress is more likely to occur. Due to this reduction in rigidity, the restraining force on both end portions of the inner wall portion 51 is reduced, and thermal stress generated in the inner wall portion 51 is suppressed.

[0046] The present disclosure is not limited to the above-described embodiment, and can be modified as appropriate within the scope of the present disclosure. [Explanation of symbols]

[0047] 20. Induction heating coil 25...Cooling water passage 31, 51... Inner wall 32, 52...Outer wall 33, 53... First connecting wall portion 34, 54... Second connecting wall portion 35... First R-shaped section 36...2nd R shape part 37, 38 Ribs 40...Workpiece

Claims

1. An induction heating coil in which a square pipe having a refrigerant passage through which a refrigerant flows is formed in a circular shape, and an object to be treated is placed in the center and induction heated, an inner wall portion formed radially inward and facing the object to be treated; an outer wall portion formed radially outward and facing the inner wall portion with the refrigerant passage interposed therebetween; a first connecting wall portion connecting one end of the inner wall portion and one end of the outer wall portion; a second connecting wall portion connecting the other ends of the inner wall portion and the outer wall portion, the inner wall portion, the first connecting wall portion, and the second connecting wall portion are formed to have a thickness smaller than a thickness of the outer wall portion, a first R-shaped portion formed at a boundary between the inner wall portion and the first connecting wall portion, and a second R-shaped portion formed at a boundary between the inner wall portion and the second connecting wall portion, each having a rib protruding toward the refrigerant passage; Induction heating coil.

2. The ribs are formed at the center of the first R-shaped portion and the second R-shaped portion, respectively.

2. The induction heating coil according to claim 1.

3. The ribs are formed on both end portions of the first R-shaped portion and the second R-shaped portion, respectively.

2. The induction heating coil according to claim 1.

4. An induction heating coil in which a square pipe having a refrigerant passage through which a refrigerant flows is formed in a circular shape, and an object to be treated is placed in the center and induction heated, an inner wall portion formed radially inward and facing the object to be treated; an outer wall portion formed radially outward and facing the inner wall portion with the refrigerant passage interposed therebetween; a first connecting wall portion connecting one end of the inner wall portion and one end of the outer wall portion; a second connecting wall portion connecting the other ends of the inner wall portion and the outer wall portion, The outer wall portion, the first connecting wall portion, and the second connecting wall portion are formed to have a thickness smaller than a thickness of the inner wall portion. Induction heating coil.

5. The inner wall portion is a first protruding portion protruding toward one axial end side beyond the first connecting wall portion; a second protruding portion protruding toward the other axial end side beyond the second connecting wall portion, 5. The induction heating coil according to claim 4.

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