JPH10158729A - Induction heating coil and induction heating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an induction heating coil for efficiently induction-heating the inner wall of a metallic parts having a through-hole whose narrowest part is formed at the inner side from both ends of the opening, such as a bearing outer ring having a concave type hollow part. SOLUTION: A first separated induction heating coil 20 having almost truncated conical outer shape along the inner wall 12a of a first part hole 14d in the section from the opening hole 14a of the outer ring 12 to the narrowest part 14c, is inserted from the opening hole 14a into the first part hole 14d. Further, a second separated induction heating coil 40 having a truncated conical outer shape along the inner wall of a second part hole 14e in the section from the opening hole 14b to the narrowest part 14c, is inserted from the opening hole 14b into the second part hole 14e, and the first and the second separated induction heating coils are mutually connected to supply electric power.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an induction heating method for heating a metal component using induction heating, and an induction heating coil used for induction heating.

[0002]

2. Description of the Related Art Conventionally, induction heat treatment for performing heat treatment on various metal parts using induction heating has been widely known. For example, in order to harden the surface layer of the metal component by the induction heat treatment, the surface layer is induction-heated using an induction heating coil having a shape along the surface layer, and then rapidly cooled.
As one of the metal parts whose surface layer is hardened in this way, a bearing is known. As is well known, a bearing generally includes an inner ring through which a shaft that performs a rotating motion, a reciprocating motion, and the like penetrates, and an outer ring in which the inner ring is fitted via balls and rollers. High pressure is applied by pressing the rollers and rollers.
For this reason, the surface layer of the inner wall of the outer ring is hardened in order to enhance wear resistance.

There are various types of bearings. The hollow portion of the outer ring (the portion surrounded by the inner wall of the outer ring) has a cylindrical shape, or a drum-shaped hollow portion having a central portion narrower than both ends. Some have parts.

When the shape of the hollow portion of the outer ring is cylindrical, the outer shape of the induction heating coil used for induction heating the inner wall of the outer ring is cylindrical. On the other hand, if the shape of the hollow part of the outer ring is a drum shape, if a cylindrical induction heating coil is used,
A cylindrical induction heating coil having a diameter slightly smaller than the diameter of the central portion of the hollow portion (the narrowest portion of the hollow portion) is inserted into the hollow portion of the outer ring to induction heat the inner wall of the outer ring. In this case, the inner wall corresponding to the center of the hollow portion (the center portion of the inner wall) is closer to the induction heating coil than the inner walls corresponding to the both ends of the hollow portion (both ends of the inner wall). Is heated to a predetermined quenching temperature to a position deeper than the surface layer at both ends of the inner wall. As a result, the surface layer at the center of the inner wall is hardened to a position deeper than the surface layers at both ends of the inner wall, and a difference occurs in the hardened layer depth. In the above-mentioned bearing, since the maximum load is usually applied to the center portion of the inner wall and both end portions of the inner wall, it is desired that the hardened layer depth is the same at these two positions.

[0005] As a technique for equalizing the depth of the hardened layer at the center of the inner wall of the outer ring and at both ends of the inner wall as described above, a shape from one end to the center of both ends of the hollow portion of the outer ring is used. A technique for inductively heating the inner wall of the outer ring by using an induction heating coil having a truncated conical shape along it is conceivable. In this technique, a frusto-conical induction heating coil is inserted from one end to the center of a hollow portion, and first, a half of an inner wall of an outer ring is heated and rapidly cooled to be hardened. After the curing process is completed, a frustoconical induction heating coil is inserted from the other end to the center of the hollow portion, and the other half of the inner wall of the outer ring is heated and rapidly cooled to be cured.

[0006]

In the above-mentioned technique, since the inner wall of the outer ring is hardened by half, the step of hardening the half of the inner wall of the outer ring and disposing the outer ring in the opposite direction after the completion of this step, or by performing induction heating. A step of hardening the remaining half of the inner wall of the outer ring by inserting the coil from the opposite side of the hollow portion of the outer ring, and hardening the entire surface of the inner wall of the outer ring to substantially the same depth.

As described above, in the technique of heating the inner wall of the outer ring by half from the top and bottom, in order to harden the entire surface of the outer ring inner wall to almost the same depth, after hardening the half of the outer ring inner wall, the other half is hardened. However, there is a problem that the operation is complicated and the productivity is reduced. In addition, the temperature near the center of the outer ring becomes high due to the influence of heat when the other half of the inner wall is heated, and the first hardened portion may be softened.
In such a case, the entire surface of the inner wall of the outer ring cannot be hardened to almost the same depth.

In view of the above circumstances, the present invention efficiently improves the inner wall of a metal component having a through-hole having a narrowest portion inside the openings at both ends, such as a bearing outer ring having a drum-shaped hollow portion. An object of the present invention is to provide an induction heating coil and an induction heating method for induction heating.

[0009]

According to a first aspect of the present invention, there is provided a first induction heating coil comprising: a metal part having a through-hole having a narrowest narrowest portion inside openings at both ends; An induction heating coil for induction heating an inner wall of the through hole, wherein: (1) the first portion inserted into a first partial hole between one of the openings at both ends and the narrowest portion; A first individual induction heating coil for induction heating an inner wall of the hole; (2) a first individual induction heating coil which is inserted into a second partial hole between the other opening opposite to the one opening and the narrowest portion and is inserted into the second partial hole; A second individual induction heating coil connected to the individual induction heating coil for induction heating the inner wall of the second partial hole is provided.

In order to achieve the above object, a second induction heating coil of the present invention narrows inward from openings at both ends or the vicinity thereof and forms a narrowest narrowest portion inside the openings at both ends. An induction heating coil for induction-heating an inner wall of the through-hole of the metal component having the through-hole having: (3) a shape of the inner wall from one of the openings at both ends to the narrowest portion. A first individual induction heating coil inserted from the one opening; and (4) a shape along the shape of the inner wall from the other opening opposite to the one opening to the narrowest portion. And a second individual induction heating coil inserted from the other opening and connected to the first individual induction heating coil.

Here, the first and second individual induction heating coils are preferably (5) for generating an eddy current flowing in the same direction on the inner wall of the through hole.

Further, according to a first induction heating method of the present invention for achieving the above object, the present invention provides a method for producing a metal part having a through hole having a narrowest narrowest portion inside the openings at both ends. In the induction heating method for induction heating the inner wall, (6) a second individual induction heating for induction heating the inner wall of the second partial hole between one of the openings at the both ends and the uppermost narrow portion. A first step of inserting a coil into the second partial hole (7) a first step for inductively heating the inner wall of the first partial hole from the other opening opposite to the one opening to the narrowest portion; A second step of inserting one individual induction heating coil into the first partial hole and connecting to the second individual induction heating coil; (8) energizing the first and second individual induction heating coils to allow the penetration; 3rd induction heating of the inner wall of the hole
It is characterized by including a step.

According to a second induction heating method of the present invention for achieving the above object, the narrowest portion narrows inward from or near the openings at both ends and narrowest inside the openings at both ends. An induction heating method for induction heating an inner wall of the through-hole of the metal component having the through-hole formed therein. (9) A shape along the shape of the inner wall from one of the openings at both ends to the narrowest portion. A first step of inserting a second individual induction heating coil having the shape from the one opening (10) a second step having a shape along the shape of the inner wall from the other opening opposite to the one opening to the narrowest portion; A second step of inserting one individual induction heating coil from the other opening and connecting to the second individual induction heating coil; (11) energizing the first and second individual induction heating coils to allow the penetration; It is characterized in that a third step of the inner wall induction heating.

Here, the third step is: (12) energizing the first and second individual induction heating coils so as to generate an eddy current flowing in the same direction on the inner wall of the through hole. Is preferred.

According to a third induction heating coil of the present invention for achieving the above object, there is provided a metal part having a through hole having a narrowest narrowest portion inside the openings at both ends. In an induction heating coil for induction heating an inner wall, (13) the inner wall of the first partial hole is inserted into a first partial hole between one of the openings at the both ends and the narrowest portion. First individual induction heating coil for induction heating (14) Inserted into a second partial hole between the other opening opposite to the one opening and the narrowest portion, and an inner wall of the second partial hole (15) Outside the first and second individual induction heating coils for electrically opening and closing the first individual induction heating coil and the second individual induction heating coil. (16) One end of the switch A first conductor connected to the first individual induction heating coil and the other end connected to the switch. (17) One end is connected to the second individual induction heating coil, and the other end is connected to the switch. A second conductor is provided.

[0016]

Embodiments of the present invention will be described below.

Referring to FIGS. 1 and 2, a schematic configuration of an induction heating apparatus incorporating an induction heating coil according to an embodiment of the present invention will be described.

FIG. 1 is a schematic diagram showing a schematic configuration of an induction heating device incorporating an induction heating coil. FIG. 2 (a)
FIG. 3 is a perspective view illustrating a schematic configuration of a first individual induction heating coil, and FIG. 3B is a perspective view illustrating a schematic configuration of a second individual induction heating coil.

In the induction heating device 10, for example, an inner wall 12a of a metal part such as a bearing outer ring 12 in which a drum-shaped hollow portion (an example of a through hole according to the present invention) 14 is formed is hardened by induction heating. It is for. The hollow portion 14 of the outer ring 12 becomes narrower from the vicinity of the openings 14a and 14b at both ends toward the inside, and a narrowest portion (narrowest portion) 14c is formed at a substantially central portion of the hollow portion 14.

The induction heating apparatus 10 includes a first individual induction heating coil 20 made of copper and a second individual induction heating coil 40 also made of copper. The first individual induction heating coil 20
The first portion between the opening 14a of the outer ring 12 and the narrowest portion 14c
It has a substantially frustoconical outer shape along the inner wall 12a corresponding to the partial hole 14d, and is inserted into the first partial hole 14d from the opening 14a. On the other hand, the second individual induction heating coil 40
It has a truncated conical outer shape along the inner wall 12a corresponding to the second partial hole 14e between 4b and the narrowest portion 14c, and is inserted into the second partial hole 14e from the opening 14b.

The first individual induction heating coil 20 has a substantially frustoconical umbrella portion 22 and a conductive shaft 24 extending in the direction of the umbrella axis at the center of the umbrella portion 22.
“a” is electrically connected to the umbrella unit 22. A large number of holes 26 are formed on the outer surface of the umbrella portion 22, and cooling water for cooling the outer ring 12 is ejected from the large number of holes 26.

As shown in FIG. 2A, the umbrella 22 includes
A cut 22a in a direction substantially perpendicular to the outer circumferential direction of the umbrella portion 22;
Are formed, and an insulating bakelite plate 28 made of a urea-based resin is sandwiched between the cuts 22a. For this reason, the umbrella part 22 is insulated at the part of the cut 22a, and forms a one-turn (one-turn) coil. Instead of the umbrella portion 22, a multi-turn coil may be used. A bakelite plate 27 is attached to a contact surface of the umbrella portion 22 that contacts the umbrella portion 42. A part of the bakelite plate 27 is stripped off, and a copper contact plate 29 is attached to the stripped portion. The contact plate 29 contacts the contact surface 49 of the umbrella portion 42. Also, at the lower end 24b of the conductive shaft 24,
The projection 24c is formed. FIG. 2 shows the convex portion 24c.
The conductive shaft 44 of the second individual induction heating coil 40 shown in FIG.
The conductive shaft 24 and the conductive shaft 44 are electrically connected to each other by being fitted into the concave portion 44c formed at the upper end 44a.

As shown in FIG. 2 (b), the bakelite plate 4
7 is pasted. A part of the bakelite plate 47 is stripped off, and the stripped portion forms a contact surface 49 with the contact plate 29. By electrically connecting the contact plate 29 and the contact surface 49, the umbrella portion 22 and the umbrella portion 42 are electrically connected. Note that a polyester plate may be used instead of the bakelite plates 27, 28, 47, and 50.

As shown in FIG. 1, the first individual induction heating coil 20 has a lower end portion 30 of two shafts 30 on an upper portion thereof.
a is fixed. Upper end 30b of two shafts 30
Is fixed to a plate 32, which has a piston rod 34 disposed substantially parallel to the two shafts 30.
Is fixed at one end 34a. Piston rod 34
Is moved up and down in the direction of arrow A by an air cylinder 38 fixed to the frame 36, and the two shafts 30 and the first individual induction heating coil 20 are also moved up and down in the direction of arrow A with this up and down movement. The frame 36 is installed on a fixed base 41 to which the second individual induction heating coil 40 is fixed. Further, a guide 37 for guiding one of the two shafts 30 in the direction of arrow A is fixed to the frame 36. Note that a hydraulic cylinder may be used instead of the air cylinder 38.

On the other hand, the second individual induction heating coil 40 is fixed to a fixed base 41 and has a substantially truncated cone-shaped umbrella part 42 and a conductive shaft 44 extending in the center of the umbrella part 42 in the umbrella axis direction. ing. The conductive shaft 44 and the head 42 are electrically insulated. The lower end 44b of the conductive shaft 44 is
Is connected to a high-frequency power supply 80 (see FIG. 8). A large number of holes 48 are formed on the outer surface of the umbrella portion 42, similarly to the umbrella portion 22 of the first individual induction heating coil 20. Cooling water for cooling 12a is jetted. As shown in FIG. 2B, a cut 42a is formed in the umbrella portion 42 in a direction substantially orthogonal to the outer peripheral direction of the umbrella portion 42. The cut 42a has a bakelite plate made of a urea-based resin. 5
0 is inserted. For this reason, the umbrella part 42 is insulated at the part of the cut 42a, and one turn (one turn)
It is a coil. The umbrella unit 42 is connected to the high-frequency power supply 80 described above. The umbrella unit 42 may be a multi-turn coil.

By arranging the outer ring 12 on the outer ring fixing table 52 from above so that the second individual induction heating coil 40 is inserted into the hollow portion 14 of the outer ring 12, the second individual induction heating coil 40 is inserted into the second partial hole 14e. Is inserted into. Further, a gear is formed on the outer peripheral surface 52a of the outer ring fixing base 52, and the outer ring 12 can be rotated during induction heating by rotating a gear (not shown) that meshes with the gear by a motor or the like. .

The outer ring 1 fixed to the outer ring fixing base 52
A cooling jacket 54 is provided so as to surround the cooling jacket 2.
A number of holes (not shown) are formed on the inner peripheral surface of the cooling jacket 54, and the cooling water supplied through the cooling pipe 54a gushes out of the holes, so that the outer wall of the outer ring 12 mainly Cooled.

The schematic structure of the first and second individual induction heating coils will be described with reference to FIGS.

FIG. 3A is a side view showing a first individual induction heating coil, and FIG. 3B is a side view showing a second individual induction heating coil. FIG. 4 is a bottom view showing the second individual induction heating coil. FIG. 5 is a sectional view taken along line BB of FIG. 4, and FIG. 6 is a sectional view taken along line CC of FIG. FIG.
FIG. 4 is an enlarged view showing a connection portion between the conductive shafts 24 and 44. In these figures, the same components as those in FIGS. 1 and 2 are denoted by the same reference numerals.

As shown in FIG. 3, the first individual induction heating coil 20 has a height H1 of about 50 mm and an upper outer diameter D1.
Is 119 mm, the lower outer diameter d1 is 90 mm, and has an outer shape along the inner wall of the first partial hole 14d of the outer ring 12 (see FIG. 1). On the other hand, the second individual induction heating coil 40
Its height H2 is about 50mm and upper outer diameter D2 is 90m
m, the outer diameter d2 of the lower part is 114 mm, and has an outer shape along the inner wall of the second partial hole 14 e of the outer ring 12.

The conductive shaft 44 of the second individual induction heating coil 40
Is made of copper and hollow. As shown in FIGS. 6 and 7, the conductive shaft 44 has an inner pipe 60 in which a cooling water inlet 60 a for cooling a connection portion with the conductive shaft 24 is formed, and a cooling water outlet 61 a. And an outer tube 61. The cooling water injected from the inlet 60a goes around the inside of the conductive shaft 44 and is discharged from the outlet 61a. Also,
The conductive shaft 44 is connected to a high-frequency power supply 80 via a copper lead 46.
(See FIG. 8). The lead 46 is hollow, and as shown in FIGS. 4 and 5, a pipe 62 having a cooling water inlet 62a and a discharge port 62b for cooling the lead 46 is connected to the lead 46. 46
Is configured to be cooled. The second individual induction heating coil 40 is supported by a bakelite round bar 74.

The conductive shaft 24 of the first individual induction heating coil 20
Is also made of copper and hollow, as shown in FIG. 5 and FIG.
The upper end 24 a of the conductive shaft 24 is electrically connected to the umbrella 22 via a copper pipe 64. Further, a copper pipe 66 in which a cooling water inlet 66 a for cooling a connection portion between the conductive shafts 24 and 44 is formed is connected to an upper end of the conductive shaft 24. Further, one end of the copper pipe 64 is connected to a copper pipe 68 having an outlet 68a for discharging the cooling water injected from the inlet 66a.

As shown in FIG. 6, a pipe 70 for cooling the umbrella section 42 is connected to the umbrella section 42 of the second individual induction heating coil 40. An inlet 70a and an outlet 70b are formed.
A similar cooling pipe is connected to the first individual induction heating coil 20, but is not shown here.

As described above, the first and second individual induction heating coils 20 and 40 are formed with a number of holes 26 and 48 through which cooling water for cooling the outer race 12 is jetted. As shown in FIGS. 5 and 6, the holes 4 of the second individual induction heating coil 40 are provided.
8, a pipe 72 having a cooling water inlet 72a formed therein.
Cooling water is supplied through the. Cooling water is similarly supplied to the hole 26 of the first individual induction heating coil 20.

Referring to FIG. 8, a description will be given of a current when the inner wall 12a of the outer ring 12 (see FIG. 1) is induction-heated.

FIG. 8 is a schematic diagram showing the first and second individual induction heating coils and the current flowing therethrough.

The first individual induction heating coil 20 and the second individual induction heating coil 40 are electrically connected to each other to form the outer ring 1.
In the induction heating of the inner wall 12a of the first induction heating coil 2, the piston rod 34 is lowered.
0 is moved downward to open the first partial hole 14d from the opening 14a.
Insert completely. As a result, the protrusion 24c of the conductive shaft 24 of the first individual induction heating coil 20 and the recess 44c of the conductive shaft 44 of the second individual induction heating coil 40 are electrically connected, and the contact plate of the head 22 29 and the contact surface 49 of the head 42 of the second individual induction heating coil 40 are electrically connected, and the two coils 20 and 40 are electrically connected.

In this state, while the first individual induction heating coil 20 is strongly pressed against the second individual induction heating coil 40 by the air cylinder 38 (see FIG. 1),
When an alternating current is supplied from 0 to the conductive shaft 44 via the lead 46, the alternating current flows from the conductive shaft 44 to the umbrella portions 22 and 42 in the same direction via the conductive shaft 24 as shown by arrows. The alternating current generates an alternating magnetic flux that penetrates the outer ring 12, and generates an eddy current in the outer ring 12 in the same direction. The Joule heat generated by the eddy current heats the inner wall 12a of the outer ring 12. When the current flowing through the umbrella portion 22 and the current flowing through the umbrella portion 42 are set in opposite directions, the outer ring 12
In the inner wall corresponding to the narrowest portion 14c of the hollow portion 14 (see FIG. 1), the alternating magnetic flux generated by the current flowing through the umbrella portion 22 and the current flowing through the umbrella portion 42 is canceled, and the eddy current becomes zero. Therefore, the inner wall corresponding to the narrowest portion 14c is not heated. Therefore, the narrowest part 14
In order to heat c, as described above, the current flowing through the umbrella 22 and the current flowing through the umbrella 42 must be in the same direction.

Referring to FIG. 9, the above-described induction heating apparatus 1
The quenching pattern of the outer ring 12 quenched using 0 will be described.

FIG. 9 is a cross-sectional view showing a quenching pattern of the inner wall of the outer ring. The quenched outer ring is cut in the longitudinal direction and the cut surface is etched.

In quenching the inner wall 12a of the outer ring 12, the hollow portion 1 of the outer ring 12 is positioned from above the second individual induction heating coil 40 fixed to the fixing table 41 (see FIG. 1).
The outer ring 12 is set such that the second individual induction heating coil 40 is inserted into the second partial hole 14e of No. 4. Then the first
The individual induction heating coil 20 is lowered and inserted into the first partial hole 14d of the hollow portion 14, and the first individual induction heating coil 20 is
These are pressed against the individual induction heating coils 40 to electrically connect them. In this state, the induction heating device 10 was set to a frequency of 8.5 kHz and an output of 270 kW, and electricity was supplied to the first individual induction heating coil 20 and the second individual induction heating coil 40 for 30 seconds. Immediately after this energization, each hole 2
6, 48 and cooling water at a rate of 200 liters / minute were jetted from the holes of the cooling jacket 54 for 15 seconds. The outer ring 12 thus quenched was cut and etched as described above. As a result, as shown in FIG.
A hardened layer 12b (mesh portion) having the same depth of 0 mm was obtained. The hardened layer 12b is a contact portion with the roller bearing 82, and the contact portion is hardened to almost the same depth, so that the durability of the bearing is improved.

As described above, according to the above-described technique, the first individual induction heating coil 20 and the second individual induction heating coil 40 along the shape of the inner wall 12a of the hollow portion 14 are connected to the hollow portion 14
And electrically connected to each other, and then heats the inner wall 12a at once by heating and rapidly cools the inner wall 12a. Therefore, the inner wall 12a of the outer ring 12 can be efficiently quenched to a substantially uniform depth, and the productivity is improved. Further, since the inner wall 12a is heated at once and rapidly cooled, the surface layer of the inner wall corresponding to the narrowest portion 14c of the hollow portion 14 is not softened.

In the above-described embodiment, the hollow portion 1
4 shows an example in which the narrowest portion 14c is substantially at the center of the hollow portion 14, but the present invention is not limited to this.
For example, the present invention can be applied to a structure in which the narrowest portion 14c is formed on the side near the opening 14a. In this case, the height H1 of the first individual induction heating coil 20 is reduced and the second individual induction heating coil 4
The height H2 of 0 may be increased.

Further, in the above-described embodiment, the induction heating coil used for efficiently heating the inner wall of the metal component having the tapered hollow portion which becomes narrower inward from the openings at both ends has been described. This induction heating coil
However, the present invention is not limited to this, and can be used for heating the inner wall of a hollow portion that is not completely tapered since the inner wall has step-like irregularities.

Referring to FIG. 10, an induction heating coil for heating a metal component having a step-like unevenness on the inner wall will be described.

FIG. 10 is a cross-sectional view schematically showing a metal part having stepped irregularities formed on the inner wall and an induction heating coil for heating the metal part.

A through hole 92 is formed in the cylindrical metal component 90, and a step-like unevenness 94 is formed on the inner wall of the through hole 92. Metal part 90 having such a shape
In order to heat the inner wall of the metal part 90, a first individual induction heating coil 100 having an umbrella portion 102 having a step-like unevenness along the unevenness 94 of the inner wall of the metal component 90, and a step-like shape similar to the umbrella portion 102 are provided. A second individual induction heating coil 110 having an umbrella portion 112 having irregularities is used. Umbrella units 102, 11
2 is a contact plate 29 and a contact surface 4 similar to those shown in FIG.
9. Bakelites 27 and 47 are provided, and a hole 48 from which cooling water is jetted out is formed.

The configuration of the induction heating device having the first individual induction heating coil 100 and the second individual induction heating coil 110 is the same as that of the induction heating device 10 shown in FIG. The procedure for heating the metal component 90 using the induction heating device including the first individual induction heating coil 100 and the second individual induction heating coil 110 is also the same as that of the induction heating device 1 shown in FIG.
This is the same procedure as when using 0, and the same effect can be obtained.

Another embodiment of the present invention will be described with reference to FIGS.

FIG. 11 is a schematic diagram showing a state in which an induction heating coil according to another embodiment of the present invention is inserted into a hollow portion (an example of a through hole according to the present invention) of a metal part. FIG. 3 is a schematic diagram showing a current flowing through an induction heating coil.

The induction heating device 120 includes the air cylinder 1
22 and a piston shaft 124 of the air cylinder 122.
A first individual induction heating coil 130 made of copper, which is fixed to and moves vertically (in the direction of arrow A), and a fixing stand (not shown)
Is provided with a second individual induction heating coil 140 made of copper and fixed to the coil. A cut 132 is formed in the first individual induction heating coil 130 in a direction substantially orthogonal to the outer peripheral direction, and the cut 132 has an insulating bakelite plate 13.
4 is sandwiched. For this reason, the first individual induction heating coil 130 is insulated at the cut 132, and is a one-turn (one-turn) coil. on the other hand,
A cut 142 is also formed in the second individual induction heating coil 140 in a direction substantially perpendicular to the outer peripheral direction, and an insulating bakelite plate 144 is also sandwiched between the cuts 142. For this reason, the second individual induction heating coil 140 is also insulated at the portion of the cut 142 and is a one-turn (one-turn) coil. Here, the first and second individual induction heating coils are both single-turn coils, but may be multi-turn coils.

The first individual induction heating coil 130 is connected to the conductor 1
It is connected to a high frequency power supply 150 via. A part of the conductive wire 136 is wound into a coil to form a flexible lead 136a, and the first individual induction heating coil 130
The lead 132 expands and contracts in accordance with this movement even if the lead moves up and down, so that the lead 136 is not cut. In addition, a conductor 138 is connected to the opposite side of the connecting portion 136b where the conductor 136 is connected to the first individual induction heating coil 130 with the bakelite plate 134 interposed therebetween. The conducting wire 138 is connected to the first individual induction heating coil 130 at a connection portion 138a, and a copper connection plate 139 is fixed to one end opposite to the connection portion 138a. The connection plate 139 is electrically connected to the connection plate 149 as described later.

The second individual induction heating coil 140 is connected to the conductor 1
It is connected to a high-frequency power supply 150 via. A conductor 148 is connected to a connection part 146 a where the conductor 146 is connected to the second individual induction heating coil 140, on a side opposite to the bakelite plate 144. This conductor 14
Reference numeral 8 denotes a connection portion 148a connected to the second individual induction heating coil 140, and a copper connection plate 149 is fixed to one end opposite to the connection portion 148a. Also, the second
The bakelite plate 1 is placed on the upper surface of the individual induction heating coil 140.
47 is pasted. Therefore, even if the first individual induction heating coil 130 moves downward and comes into contact with the second individual induction heating coil 140, the first individual induction heating coil 130 comes into contact with the second individual induction heating coil 140 via the bakelite plate 147. The upper surface of second individual induction heating coil 140 is not electrically connected.

The metal product 126 has openings 126 at both ends.
a and a hollow portion 128 having 126b is formed;
The opening 126a communicates with the first partial hole 128a, and the opening 12a
6b communicates with the second partial hole 128b. The first individual induction heating coil 130 is inserted into the first partial hole 126a,
The second individual induction heating coil 140 is inserted into the second partial hole 128b. First and second individual induction heating coils 130,
140 are respectively the first and second partial holes 126a, 126a.
8b, the connection plate 139 and the connection plate 14
9 are electrically connected to each other, and the first and second individual induction heating coils 130 and 140 are electrically connected to each other.

When the first and second individual induction heating coils 130 and 140 are electrically connected via the connection plates 139 and 149, as shown by arrows in FIG.
From the first individual induction heating coil 13 via a conducting wire 136
0, and further flows to the second individual induction heating coil 140 via the connection plates 139 and 149. In this case, the first and second individual induction heating coils 130, 14
0, an alternating current flows in the same direction.
6, an alternating magnetic flux is generated in the same direction through the metal part 126.
Generates an eddy current in the same direction, and the metal component 126 is heated by Joule heat due to the eddy current.

In the first and second individual induction heating coils 130 and 140 described above, the coils 130 and 140 are electrically connected to each other by the connection plates 139 and 149 separated from the coils 130 and 140. FIG.
It is not necessary to arrange the conductive shafts 24 and 44 inside the coils as in the first and second individual induction heating coils 20 and 40 shown in FIG. Therefore, the first and second individual induction heating coils 13
It is convenient when the metal part 126 is small and the hollow part 128 is narrow.

Also, the first and second individual induction heating coils 1
Electromagnetic switches (one example of a switch according to the present invention) for electrically opening and closing both the first and second individual induction heating coils 130 and 140 are arranged outside the first and second induction heating coils 30 and 140. 138 and 148 each have a connection plate 13
9, 149, instead of connecting conductors 138, 148
May be connected to an electromagnetic switch. In this case, when the first individual induction heating coil 130 moves downward and comes into contact with the second individual induction heating coil 140, the electromagnetic switch is turned on, and both the first and second individual induction heating coils 130 and 140 are turned on. Are electrically connected to each other. In the case where the first and second individual induction heating coils 130 and 140 are electrically connected and disconnected by using the electromagnetic switch as described above, the first and second individual induction heating coils 130 and 140 are more reliably connected than the connection plates 139 and 149 are used. 1st and 2nd individual induction heating coils 130,1
40 can be electrically connected and disconnected from each other. In addition, the electromagnetic switch includes first and second individual induction heating coils 1.
Since they are arranged outside of the first and second induction heating coils 20, 40 shown in FIG. 2, there is no need to arrange the conductive shafts 24, 44 inside the coils. Therefore, similar to the case where the connection plates 139 and 149 are used,
The first and second individual induction heating coils 130 and 140 can be reduced in size, and the metal part 126 is small and its hollow part 128 is small.
This is convenient when is small.

[0058]

As described above, according to the first induction heating coil of the present invention, the first and second individual induction heating coils are inserted into the first and second partial holes, respectively, and connected to each other. Accordingly, the inner wall of the through hole formed in the metal component can be induction-heated at one time. Therefore, the inner wall of the metal component can be efficiently heated, and the productivity is improved.

According to the second induction heating coil of the present invention, the first individual induction heating coil having a shape along the shape of the inner wall from one opening to the narrowest portion is inserted from one opening, and By inserting a second individual induction heating coil having a shape along the shape of the inner wall from the other opening to the narrowest portion from the other opening and connecting the first and second individual induction heating coils to each other, The inner wall of the through hole formed in the part can be uniformly induction-heated at one time.
Therefore, the inner wall of the metal component can be efficiently and evenly heated, and the productivity is improved.

Here, when the first and second individual induction heating coils are for generating an eddy current flowing in the same direction on the inner wall of the through hole, the first and second individual induction coils of the inner wall are used. In the part corresponding to the connection part of the heating coil,
Since the eddy current flows in the same direction without canceling the alternating magnetic flux, the portion corresponding to the connection portion is also heated.
Therefore, the inner wall can be uniformly heated and cured,
An even cured layer can be efficiently formed.

According to the first induction heating method of the present invention, the first and second individual induction heating coils are inserted into the first and second partial holes and connected to each other to form the first and second individual induction heating coils. By energizing the induction heating coil, the inner wall of the through hole formed in the metal component can be induction heated at one time. Therefore, the inner wall of the metal component can be efficiently heated, and the productivity is improved.

According to the second induction heating method of the present invention, the first individual induction heating coil having a shape along the shape of the inner wall from one opening to the narrowest portion is inserted from one opening and the other. A second individual induction heating coil having a shape along the shape of the inner wall from the opening to the narrowest portion is inserted from the other opening, the first and second individual induction heating coils are connected to each other, and the first and second individual induction heating coils are connected to each other. By energizing the individual induction heating coils, the inner wall of the through-hole formed in the metal component can be uniformly induction-heated once. Therefore, the inner wall of the metal component can be efficiently and evenly heated, and the productivity is improved.

Here, the third step is performed so as to generate eddy currents flowing in the same direction on the inner wall of the through hole.
In the case where the individual induction heating coils are energized, eddy current flows in the same direction without canceling the alternating magnetic flux in the portion of the inner wall corresponding to the connection portion of the first and second individual induction heating coils. Therefore, a portion corresponding to the connection portion is also heated. Accordingly, the inner wall can be uniformly heated and cured, and a cured layer without unevenness can be efficiently formed.

Further, according to the third induction heating coil of the present invention, since the first and second individual induction heating coils are electrically connected and disconnected using the switch, it is more reliable. In addition, the first and second individual induction heating coils can be electrically connected and disconnected from each other. Further, since the switch is arranged outside the first and second individual induction heating coils, the first and second individual induction heating coils can be reduced in size, and when the metal parts are small and the through holes thereof are narrow, etc. It is convenient.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a schematic configuration of an induction heating device incorporating an induction heating coil according to an embodiment of the present invention.

FIG. 2A is a perspective view showing a schematic configuration of a first individual induction heating coil, and FIG. 2B is a perspective view showing a schematic configuration of a second individual induction heating coil.

FIG. 3A is a side view showing a first individual induction heating coil, and FIG. 3B is a side view showing a second individual induction heating coil.

FIG. 4 is a bottom view showing a second individual induction heating coil.

FIG. 5 is a sectional view taken along line BB of FIG. 4;

FIG. 6 is a sectional view taken along line CC of FIG. 4;

FIG. 7 is an enlarged view showing a connection portion between two conductive shafts.

FIG. 8 is a schematic diagram showing first and second individual induction heating coils and currents flowing through them.

FIG. 9 is a sectional view showing a quenching pattern of the inner wall of the outer ring.

FIG. 10 is a cross-sectional view schematically showing a metal component having stepped irregularities formed on an inner wall and an induction heating coil for heating the metal component.

FIG. 11 is a schematic diagram showing a state in which an induction heating coil according to another embodiment of the present invention is inserted into a hollow portion of a metal component.

FIG. 12 is a schematic diagram showing a current flowing through first and second individual induction heating coils of FIG. 11;

[Explanation of symbols]

 10, 120 Induction heating device 12 Outer ring 12a Inner wall 14, 128 Hollow portion 14a, 14b, 126a, 126b Openings at both ends 14c Narrowest portion (narrowest portion) 14d, 128a First partial hole 14e, 128b Second partial hole 20, 100, 130 First individual induction heating coil 40, 110, 140 Second individual induction heating coil 90, 126 Metal part 92 Through hole

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Eiji Muto 84-10 Jiyoda, Nishisakai-cho, Kariya-shi, Aichi Prefecture Inside the Kariya Plant, Takanami Wave Heating Co., Ltd. 84-10 Ten Takashu Namirenzu Co., Ltd.Kariya Plant

Claims (7)

[Claims] 1. An induction heating coil for induction heating an inner wall of a through-hole of a metal component having a through-hole having a narrowest narrowest portion inside the openings at both ends, wherein: A first individual induction heating coil inserted into the first partial hole between the one opening and the narrowest portion for induction heating the inner wall of the first partial hole; and a side opposite to the one opening. A second individual induction inserted into the second partial hole between the other opening and the narrowest portion and connected to the first individual induction heating coil for induction heating the inner wall of the second partial hole An induction heating coil, comprising: a heating coil. 2. Induction heating of the inner wall of the through-hole of a metal component in which a through-hole which narrows inward from or near the openings at both ends and has the narrowest narrowest portion inside the openings at both ends is formed. A first individual induction heating coil having a shape along the shape of the inner wall from one of the openings at both ends to the narrowest portion, and being inserted from the one opening; A shape that follows the shape of the inner wall from the other opening opposite to the one opening to the narrowest portion, and is inserted from the other opening and connected to the first individual induction heating coil; An induction heating coil comprising two individual induction heating coils. 3. The first and second individual induction heating coils are for generating an eddy current flowing in the same direction on an inner wall of the through-hole.
Induction heating coil as described. 4. An induction heating method for induction heating an inner wall of a through-hole of a metal part having a through-hole having a narrowest narrowest portion inside the openings at both ends, wherein one of the openings at the both ends is provided. A first step of inserting a second individual induction heating coil for induction heating the inner wall of the second partial hole between the opening and the narrowest portion into the second partial hole; For induction heating the inner wall of the first partial hole between the other opening on the side and the narrowest portion
Inserting an individual induction heating coil into the first partial hole and inserting the second
Induction comprising: a second step of connecting to an individual induction heating coil; and a third step of inductively heating the inner wall of the through hole by energizing the first and second individual induction heating coils. Heating method. 5. Induction heating of the inner wall of the through-hole of a metal component in which a through-hole which narrows inward from or near the openings at both ends and has a narrowest narrowest portion inside the openings at both ends is formed. A first step of inserting a second individual induction heating coil having a shape along the shape of the inner wall from one of the openings at both ends to the narrowest portion from the one opening, A first individual induction heating coil having a shape along the shape of the inner wall from the other opening opposite to the one opening to the narrowest portion is inserted from the other opening to the second individual induction heating coil. An induction heating method comprising: a second step of connecting; and a third step of inductively heating the inner wall of the through hole by energizing the first and second individual induction heating coils. 6. The method according to claim 6, wherein the third step is to energize the first and second individual induction heating coils so as to generate an eddy current flowing in the same direction on the inner wall of the through hole. The induction heating method according to claim 4. 7. An induction heating coil for induction heating an inner wall of a through-hole of a metal component having a through-hole having a narrowest narrowest portion inside the openings at both ends, wherein the opening at both ends is provided. A first individual induction heating coil inserted into the first partial hole between the one opening and the narrowest portion for induction heating the inner wall of the first partial hole; and a side opposite to the one opening. A second individual induction heating coil inserted into the second partial hole between the other opening and the narrowest portion for induction heating the inner wall of the second partial hole; and the first individual induction heating coil A switch arranged outside the first and second individual induction heating coils for electrically opening and closing the second individual induction heating coil; one end connected to the first individual induction heating coil, the other end Is a first conductor connected to the switch, and one end is Serial second is connected to the individual induction heating coil, the induction heating coil and the other end has a second lead connected to the switch.