JP2814059B2 - Heating device for small diameter holes - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating device for a small-diameter hole for heating an inner peripheral surface of a small-diameter hole formed in a work.

[0002]

2. Description of the Related Art An inner peripheral surface 811 of a small-diameter hole 810 of a work 800 is heated by a heating coil as shown in FIGS. First, a so-called multi-turn type shown in FIG.
The heating coil 510 shown in (A) includes a heating conductor 511 wound spirally and a power supply conductor 512 connected to the heating conductor 511 and provided inside.

Further, a heating coil 5 shown in FIG.
Reference numeral 20 denotes a so-called hairpin type, which has a heating conductor 520 bent substantially in a hairpin type.
The heating coil 530 shown in FIG. 6C is a modified type of the hairpin-shaped heating coil 520, and has a cross shape.

On the other hand, the heating coil 700 shown in FIG. 7 is not the inner peripheral surface 811 of the small diameter hole 810 but the small diameter hole 810.
And a first and second power supply conductor portions 711A and 711B of the conductor portion 710 to which the first and second power supply conductor portions 711A and 711B are attached. Mounting plate portions 720A and 710B and conductor portion 7
An insulating plate portion for preventing a short circuit at 10 (however, this insulating plate portion is omitted in FIG. 7 to show the conductor portion 710).

The conductor 710 includes a first loop portion 71 in addition to the first and second power supply conductor portions 711A and 711B.
2A and the second loop portion 712B, and the first and second loop portions 712B.
Loop portions 712A and 712B and a power supply conductor portion 711A,
711B and a connecting conductor portion 713, and is formed in a U-shape as a whole.

The first loop portion 712A has a small-diameter hole 81
The second loop portion 712B faces an opening on the back surface side of the small-diameter hole portion 810. The first loop portion 712A and the second loop portion 712B are both formed outward as shown in FIG.

The first and second openings are formed in both openings of the small-diameter hole 810.
The opening is heated by causing a high-frequency current to flow by bringing the loop portions 712A and 712B close to each other.

[0008]

The conventional heating coil as described above has the following problems. That is, in the multi-turn type heating coil, since the power supply conductor needs to be provided inside the heating conductor, it cannot be used in a small-diameter hole having a diameter of 15 mm or less. this is,
The same applies to hairpin-shaped and cross-shaped heating coils.

In the case of a multi-turn type heating coil, it is not necessary to relatively rotate the work and the heating coil (however, if the rotation is performed, more uniform heating is possible). In the case of a cross-shaped heating coil, it is necessary to relatively rotate the work and the heating coil in order to ensure uniform heating.

Further, in the heating coil shown in FIG. 7, since the opening of the small-diameter hole is heated, the inner peripheral surface of the small-diameter hole cannot be heated. For example, even if the core is inserted into the small-diameter hole, the current flowing through the pair of loops is reversed, so that no lines of magnetic force penetrate the core, so that the inner peripheral surface of the small-diameter hole is effectively heated. It is not possible.

The present invention has been made in view of the above circumstances, and can also heat the inner peripheral surface of a smaller-diameter hole, and does not require relative rotation between the work and the heating coil. It is an object of the present invention to provide a heating device for a small-diameter hole.

[0012]

A heating device for a small-diameter hole according to the present invention is a heating device for a small-diameter hole that heats the inner peripheral surface of the small-diameter hole formed in a work. A heating coil having a pair of loop portions facing the openings on both front and back surfaces, and a magnetic core inserted into the small-diameter hole portion through the loop portions, so that current flows in the same direction in the loop portions. Is configured.

[0013]

1 is a schematic perspective view of a heating device for a small-diameter hole according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view showing the relationship between the small-diameter hole, a heating coil, and a magnetic core. FIG. 3 is a schematic sectional view for explaining the principle of the heating device for the small-diameter hole, and FIG.
Is a schematic sectional view of a heating device for a small diameter hole showing another embodiment, and FIG. 5 is a schematic perspective view of a heating device for a small diameter hole showing another embodiment.

The apparatus for heating a small-diameter hole according to the present embodiment includes an inner peripheral surface 811 of a small-diameter hole 810 formed in a work 800.
A small diameter hole heating device for heating
A heating coil 100 having a pair of first and second loop portions 111A and 111B facing the openings on both front and back surfaces of the heating coil 100;
A magnetic core 200 inserted into the small-diameter hole portion 810 via the first and second loop portions 111A and 111B, and the first and second loop portions 111A and 11B.
1B is configured so that current flows in the same direction.

As shown in FIG. 1, the heating coil 100 includes a conductor 110 formed by bending a hollow pipe, and first and second power supply conductors 112A and 112A of the conductor 110.
First and second mounting plate portions 120 to which 2B is mounted
A, 120B, and an insulating plate portion for preventing a short circuit in the conductor portion 110 (however, this insulating plate portion is omitted in FIG. 1 to show the conductor portion 110).

The conductor 110 is formed of a hollow pipe to cool the conductor 110 itself which is being heated by flowing cooling water.

The conductor section 110 includes a first loop section 11 in addition to the first and second power supply conductor sections 112A and 112B.
1A and the second loop portion 111B, and the first and second loop portions 111B.
Loop portions 111A and 111B and a power supply conductor portion 112A,
And a connection conductor portion 113 for connecting the second conductor 112B to the second conductor 112B.

The first loop portion 111A faces the opening on the surface side of the small-diameter hole portion 810 of the work 800, and the second loop portion 111B faces the small-diameter hole portion 810 of the work 800.
Facing the opening on the back surface side.

The first loop portion 111A and the second loop portion 111B are reversed as shown in FIG. That is, the first loop portion 111A faces outward, while the second loop portion 111B faces inward.

An insulating thread 140 is wound around these loop portions 111A and 111B. This thread 140
The magnetic core 200 is directly connected to the loop portions 111A and 111A.
B for preventing contact with the magnetic core 200
If is an insulating material, there is no need to provide the thread 140 in particular.

The connection conductor 113 is a third conductor for connecting the first power supply conductor 112A and the second loop 111B.
The connecting conductor 113C, the first loop 111A and the second
Connecting conductor portion 113 for connecting to loop portion 111B
B, the first loop portion 111A and the second power supply conductor portion 11
2B and a first connection conductor 113A that connects to the first connection conductor 113B.

The first connection conductor 113A has a downwardly concave shape. Further, the second connection conductor portion 11
3B has a substantially U-shape in a horizontal direction. The second connection conductor 113B is the same as the first loop 111A in FIG.
1 is connected on the right side, and the second loop portion 111B is connected on the right side in FIG.

The second connection conductor 113B allows the first
In the loop portion 111A and the second loop portion 111B,
The current flows in the same direction. That is, when a current flows from left to right in FIG. 1 in the first loop portion 111A (when a current flows in the order of the first connection conductor portion 113A → the first loop portion 111A → the second connection conductor portion 113B). FIG. 1 illustrates the second loop unit 111B.
Since the current flows from the right side to the left side in (2), the second connection conductor portion 113B → the second loop portion 111B → the third
Since the current flows in the order of the connection conductor 113C), the direction of the current is the same in each of the loops.

The third connection conductor 113C is formed substantially identical to the first connection conductor 113A.

The first power supply conductor 112A is attached to the mounting plate 1
A hose port 112 to which a hose (not shown) for supplying cooling water is connected at the end of the hose port 112 by welding.
a is formed.

The second power supply conductor 112B has the same configuration as the first power supply conductor 112A.

The insulating plate portion, not shown, is provided between the first mounting plate portion 120A and the second mounting plate portion 120B, between the first connecting conductor portion 113A and the second connecting conductor portion 113B, and between the first connecting conductor portion 113A and the second connecting conductor portion 113B.
It is sandwiched between the connection conductor 113B and the third connection conductor 113C.

In the above-described heating coil 100, the first power supply conductor 112A → the third connection conductor 113C → the second loop 111B → the second connection conductor 113B → the first loop 111A → the first connection conductor. The high-frequency current flows in the direction from the section 113A to the second power supply conductor section 112B or in the opposite direction.

On the other hand, as shown in FIG. 1, the magnetic core 200 is formed by integrally forming a round bar-shaped insertion portion 210 and a stopper portion 220 having a diameter larger than that of the insertion portion 210. The magnetic core 200 is made of, for example, sintered ferrite or a substance having a high saturation magnetic flux density.

The diameter of the insertion portion 210 of the magnetic core 200 is such that when the insertion portion 210 is
It is set smaller than the inner diameter of the small-diameter hole portion 810 in order to leave a predetermined interval with respect to 1.

The length of the insertion portion 210 is set to be longer than the distance between the first loop portion 111A and the second loop portion 111B. This is the magnetic core 20
0 is a small-diameter hole portion 810 via the first loop portion 111A.
This is because the insertion portion 210 is made to face the entire inner peripheral surface 811 of the small-diameter hole portion 810.

The diameter of the stopper portion 220 is set to be larger than the inner diameter of the first loop portion 111A so that the stopper portion 220 does not come off even when inserted into the small-diameter hole portion 810.

For example, when the magnetic core 200 is formed by sintering ferrite, the magnetic core 200 can be formed to have a diameter of 6 mm or less, so that the inner peripheral surface 811 of the small-diameter hole 810 having a diameter of about 6 mm can be heated.

Next, the heating of the small-diameter hole 810 by the above-described small-diameter hole heating device will be described with reference to FIG. First, the work 800 is sandwiched between the first loop portion 111A and the second loop portion 111B, and the small-diameter hole portion 8 is formed.
The two loop portions 111A and 111B are made to face the ten openings 811.

The insertion portion 210 of the magnetic core 200 is inserted into the small-diameter hole portion 810 via the first loop portion 111A.
Then, as shown in FIG. 2, the stopper portion 220 is hooked on the first loop portion 111A, and the tip of the insertion portion 210 protrudes from the second loop portion 111B.

In this state, a high-frequency current is supplied to the heating coil 100 from a high-frequency power supply (not shown). This high-frequency current is transferred from the second power supply conductor 112B to the first power supply conductor 112A.
In the case where the magnetic flux flows toward the first loop portion 111A and the second loop portion 111B, a magnetic force line indicated by a solid arrow α in FIG. 3 is generated. The first loop 111A and the second
3 is configured so that current flows in the same direction, the magnetic core 200 generates magnetic lines of force indicated by solid arrows β in FIG.

Therefore, the inner peripheral surface 811 of the small-diameter hole portion 810
, An induced current is generated in a direction to cancel the magnetic field indicated by the solid arrow β, and this current heats the inner peripheral surface 811.

Conversely, when a high-frequency current flows from the first power supply conductor 112A to the second power supply conductor B, lines of magnetic force are generated in a direction opposite to that shown in FIG.

When the predetermined heating is completed, the magnetic core 20
0 from the small-diameter hole portion 810 and the work 80
0 is removed from between the two loop portions 111A and 111B, and the work 800 is immersed in cooling oil or liquid to quench the inner peripheral surface 811.

Next, a heating device for a small-diameter hole according to another embodiment will be described with reference to FIG. In the heating device having the small diameter hole, the heating coil 100 is the same as that described above, but the magnetic core 300 is different. That is, as shown in FIG. 4, the magnetic material core 300 is a closed circuit. If the magnetic resistance is reduced by using the magnetic core 300 as a closed circuit as described above, the leakage magnetic flux can be reduced, and the input power can be reduced. Therefore, since the cross-sectional area of the magnetic core 300 can be reduced,
It is possible to cope with a smaller small-diameter hole portion 810 and to improve the efficiency.

When the magnetic core 300 is a closed circuit as described above, it is necessary to divide the magnetic core 300 into a substantially U-shape in order to insert the core 300 into the small-diameter hole 810.

The heating coil 100 may be as shown in FIG. This heating coil 100 is shown in FIG.
Is different from the first loop part in the directions of the first loop part 111C and the second loop part 111D. That is, FIG.
In the heating coil 100 shown in FIG.
Are formed inward, and the second loop portion 111D is formed outward.

When the two loop portions 111C and 111D are configured as described above, the magnetic core 200 must be inserted into the small-diameter hole portion 810 via the lower second loop portion 111D. Therefore, the magnetic core 200 may be inserted into and removed from the small-diameter hole 810 by an air cylinder or the like (not shown). The magnetic core 200 in this case is
A portion corresponding to the stopper portion 220 is unnecessary, and only a portion corresponding to the insertion portion 210 need be provided.

Of course, even in the case of the heating coil 100 shown in FIG.
00 may be inserted into and removed from the small-diameter hole 810. Also in this case, the stopper 220 may not be provided, and the high-frequency heating can be automated.

[0045]

The heating device for a small-diameter hole portion according to the present invention is a heating device for a small-diameter hole portion for heating the inner peripheral surface of the small-diameter hole portion formed in a work. A heating coil having a pair of loop portions facing the portion, and a magnetic core inserted into the small-diameter hole portion through the loop portion, wherein the loop portion is configured so that current flows in the same direction. I have. Therefore, since the inner peripheral surface of the small-diameter hole is heated by the magnetic field lines passing through the magnetic core, it is not necessary to use a heating coil that bends a thin pipe as in the related art. For this reason, it became possible to heat the inner peripheral surface of the small-diameter hole having a smaller diameter. For example, in a conventional heating coil, φ1
Although the limit is 5 mm, the inner peripheral surface of the small-diameter hole having a diameter of about 6 mm can be heated by the small-diameter hole heating device according to the present invention.

Further, since the magnetic core faces the entire inner peripheral surface of the small-diameter hole, it is possible to heat the workpiece uniformly without rotating the workpiece.

Further, in the magnetic core, the insertion portion facing the inner peripheral surface of the small-diameter hole portion and the stopper portion having a diameter larger than the loop portion are integrally formed. Since the magnetic core is hooked, the magnetic core can be easily inserted into the small-diameter hole.

Further, when the magnetic core is a closed circuit, the inner peripheral surface of the small-diameter hole can be more efficiently heated.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of a heating device for a small diameter hole according to an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view showing a relationship among a small-diameter hole, a heating coil, and a magnetic core.

FIG. 3 is a schematic sectional view illustrating the principle of the heating device for the small-diameter hole.

FIG. 4 is a schematic sectional view of a heating device for a small-diameter hole showing another embodiment.

FIG. 5 is a schematic perspective view of a heating device for a small-diameter hole showing another embodiment.

FIG. 6 is a schematic cross-sectional view showing a conventional heating coil for heating the inner peripheral surface of a small-diameter hole.

FIG. 7 is a schematic perspective view showing a conventional heating coil for heating an opening of a small diameter hole.

[Explanation of symbols]

 Reference Signs List 100 heating coil 111A first loop portion 111B second loop portion 200 magnetic core 800 work 810 small-diameter hole portion 811 inner peripheral surface

Claims (3)

(57) [Claims] 1. A heating device for a small-diameter hole portion for heating an inner peripheral surface of a small-diameter hole portion opened in a work, comprising: a heating coil having a pair of loop portions facing openings on both front and back surfaces of the small-diameter hole portion; A magnetic core inserted into the small-diameter hole portion through the loop portion, wherein a current flows in the same direction in the loop portion. 2. The magnetic core according to claim 1, wherein an insertion portion facing the inner peripheral surface of the small-diameter hole portion and a stopper portion having a diameter larger than the loop portion are integrally formed. A heating device for a small-diameter hole as described in the above. 3. The heating device for a small-diameter hole according to claim 1, wherein the magnetic core has a closed circuit.