JPH1055924A - Output transformer for high frequency heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the size and wt. of an output transformer by winding prim. conductors round protrusions of a core disposed in a U-shaped recess of a sec. conductor so as to increase the winding number ratio of the prim. coil to the core 3. SOLUTION: The output transformer comprises a plate-like sec. coil 2, core 3, prim. coil 4 and heating coil. The core 3 is disposed in a U-shaped recess of the sec. coil 2. The prim. coil 4 is wound round protrusions 3a, 3b of the core 3, extending from the upper and lower faces 2a, 2b of the sec. coil 2. This allows the number of windings of the prim. coil to be increased in approximately parallel to the sec. coil 2 and hence the winding number ratio of the prim. coil 4 to the core 3 to increase. Thus it is possible to reduce the sizes of the core 3 and prim. coil 4 and hence the size and wt. of the transformer itself.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an output transformer suitable for use in a high-frequency heating device such as a high-frequency induction heating device or an induction hardening device.

[0002]

2. Description of the Related Art Conventionally, as an output transformer used in a high-frequency heating device, for example, one disclosed in Japanese Patent Application Laid-Open No. 6-151212 is known. This output transformer includes a core portion formed by combining a plurality of E-type ferrite cores, a coil portion disposed so as to wind the core portion a plurality of times by bending a copper pipe, and The coil includes a first conductive member connected to a start end and a rear end of the coil portion, respectively, and a pair of second conductive members connected between the first conductive members of the coil portion.

[0003]

However, in this output transformer, since the coil is wound around the middle leg of the E-shaped core, when the number of turns of the coil is large, a large E-shape is required. It is necessary to use a mold core, and it is difficult to reduce the size of the output transformer itself. For example, there is a problem that the output transformer cannot be easily moved and its use range is limited. In addition, since it is necessary to use a relatively expensive E-type core as the core, there is a problem that the output transformer itself tends to be expensive.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and the output transformer can be reduced in size and weight, can be easily moved, can be used in a wider range, and can be constructed at a low cost. It is an object of the present invention to provide an output transformer of a high-frequency heating device.

[0005]

In order to achieve the above object, an output transformer of a high-frequency heating apparatus according to the first aspect of the present invention comprises a plate-shaped secondary conductor having a substantially U-shaped concave portion, and a secondary conductor having a substantially U-shaped concave portion. A core disposed in the U-shaped concave portion, and a primary conductor wound around a protruding portion projecting from the upper and lower surfaces of the secondary conductor of the core,
A heating coil connected to the opening-side end of the U-shaped concave portion of the secondary conductor.

According to the output transformer of the high-frequency heating device, a predetermined current supplied from the primary conductor is induced as a large current in the plate-shaped secondary conductor, and the large current is supplied to the heating coil. The work placed near the heating coil is induction heated. Since the primary conductor is wound around the protruding portion of the core disposed in the U-shaped concave portion of the secondary conductor, for example, the number of turns can be increased with respect to the size of the core, so that the output The size of the vessel itself can be reduced. The core may be an inexpensive core having a square cross section penetrating vertically through the U-shaped concave portion of the secondary conductor, and the output transformer itself can be configured at low cost.

The output transformer according to a second aspect of the present invention is characterized in that a cooling water flow path is formed inside the secondary conductor. The cooling water is circulated and supplied inside the copper pipe. According to these output transformers, the cooling water can suppress the heat generation of the secondary conductor and the primary conductor through which a large current flows, thereby preventing the output characteristics from deteriorating due to the heat generation.

Further, according to the output transformer of the fourth aspect, the primary conductor is wound so that the outer surface thereof is substantially circular, and the primary conductor, the secondary conductor, and the core are accommodated in a cylindrical case. It is characterized by being. According to this output transformer,
The outer shape is substantially circular, so that further miniaturization and weight reduction can be achieved, and, for example, portability can be further facilitated.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings. 1 to 4 show an embodiment of an output transformer of a high-frequency heating device according to the present invention, FIG. 1 is a cross-sectional view thereof, FIG. 2 is a cross-sectional view taken along line AA of FIG. 1, and FIG. FIG. 4 is a sectional view taken along line BB of FIG. 1, and FIG. 4 is a sectional view taken along line CC of FIG. 1.

The output transformer 1 has a flat secondary coil 2.
, A core 3, a primary coil 4 and a heating coil 5. The secondary coil 2 is formed in a flat plate shape by brazing a pair of L-shaped copper square pipes 7 on the outside of a U-shaped copper plate 6, and has a U-shaped concave portion 8 at the center thereof. Are formed.

The square pipe 7 of the secondary coil 2 has a hole 7a therein, and has one end 7b (the opening end 8a of the U-shaped recess 8).
Side) are open, and hose connectors 9 are fixed to the other end side 7c, respectively. A disc-shaped copper plate 10 is brazed to the opening end side 8a of the U-shaped concave portion 8 of the secondary coil 2, and holes 10a communicating with the holes 7a of the square pipe 7 are formed in the copper plate 10. In addition, four screw holes 10b (see FIG. 4) are formed.

The heating coil 5 has a fixed portion 11 made of a copper plate.
And a straight portion 12 formed of a copper square pipe, and a substantially ring-shaped coil portion 13 formed at the tip of the straight portion 12. In the fixing portion 11, a hole 11a communicating with the hole 10a of the copper plate 10 is formed, and four mounting holes 11b (see FIG. 4) are formed.
The fixing portion 11 is fastened and fixed to the copper plate 10 by screwing the bolt 14 from 1b into the screw hole 10b of the copper plate 10.

Thus, the heating coil 5 and the copper plate 10, ie, the secondary coil 2, are electrically connected, and the hole 7a of the square pipe 7, the hole 12a of the straight portion 12 of the heating coil 5, and the hole of the coil portion 13 are formed. 13a is communicated through the hole 10a of the copper plate 10 and the hole 11a of the fixing portion 11.
An O-ring 15 for preventing leakage of cooling water is provided on a surface of the fixing portion 11 facing the copper plate 10 in the hole 11a, and an insulating plate 2 is provided between the pair of straight portions 12.
1 is interposed.

The core 3 is formed of a rectangular parallelepiped ferrite core, and is disposed in the U-shaped concave portion 8 of the secondary coil 2 so as to protrude from the upper surface 2a and the lower surface 2b of the secondary coil 2 by a predetermined length. Has been established. The protruding portions 3a, 3b projecting from the upper and lower surfaces 2a, 2b of the secondary coil of the core 3
The primary coil 4 is wound a predetermined number of times via a thin insulating plate 16.

The primary coil 4 is formed of a copper round pipe, and in a state where an insulating tube (not shown) is fitted on the outer peripheral surface thereof, the primary coil 4 is serially connected to the outer periphery of the protruding portions 3a, 3b of the core 3. Are wound a predetermined number of times substantially in parallel with the secondary coil 2. A hose connector 17 and a terminal plate 18 are fixed to both ends of the primary coil 4, respectively, and an output terminal of, for example, a high-frequency heating device (inverter) (not shown) is electrically connected to the terminal plate 18.

The primary coil 4 is wound around the upper and lower portions of the secondary coil 2 so that the outer surface thereof is substantially circular. The primary coil 4, the secondary coil 2 and the core 3 are made of an insulating material. It is housed in a cylindrical case 19. At this time, one opening 19a of the case 19 is closed by the copper plate 10,
The other opening 19 b of the case 19 is closed by a circular insulating plate 20.

Accordingly, the output transformer 1 is connected to the case 19
The hose connector 9 is attached to one end surface (the insulating plate 20 side) of
The heating coil 5 protrudes from the other end surface (the copper plate 10 side) of the case 19, and the entire outer shape is formed in a substantially cylindrical shape. In addition, the turns ratio of the primary coil 4 and the secondary coil 2 is n:
1 is set in advance.

When a predetermined high-frequency current is supplied to the primary coil 4 via a terminal plate 18 from a high-frequency heating device (not shown), the output transformer 1 has an inductive coupling to the secondary coil 2 according to the turns ratio. Large current flows. This large current is supplied to the heating coil 5 to inductively heat a work (not shown) arranged close to the heating coil 5. Simultaneously with the supply of the high-frequency current, a cooling water supply device (not shown) is operated to circulate and supply the cooling water into the square pipe 7 of the secondary coil 2, the heating coil 5 and the primary coil 4. Heat generation of the coil 4, the secondary coil 2, the heating coil 5, and the like is suppressed.

As described above, according to the above embodiment, the core 3 is disposed in the U-shaped concave portion 8 of the plate-shaped secondary coil 2, and the upper and lower surfaces 2 a and 2 b of the secondary coil 2 of the core 3 Since the primary coil 4 is wound around the outer circumferences of the projections 3a and 3b, the primary coil 4 can be wound many times in a state substantially parallel to the secondary coil 2, and the winding ratio of the primary coil 4 to the core 3 Can be increased.

As a result, the shapes of the core 3 and the primary coil 4 and the like can be reduced in size, that is, the output transformer 1 itself can be reduced in size and weight, and can be easily carried. It can be easily used for soldering work, brazing and soldering work of a large work that is difficult to move, and the use range of the heating coil 5 can be greatly expanded.

The outer shape of the output transformer 1 is the case 1
9, the outer shape can be further reduced in size and the usability can be improved. Furthermore, since a rectangular parallelepiped ferrite core is used as the core 3, the cost of the core 3 can be reduced, and the output transformer 1 itself can be configured at low cost. Furthermore, the primary coil 4
Can be densely wound around the outer periphery of the core 3, and an output transformer 1 having a good coupling coefficient substantially equal to the conventional one can be obtained.

In the above-described embodiment, the secondary coil 2 is formed of one (one turn) conductor. However, the present invention is not limited to this. The primary coil 4 may be wound in series between the conductors and the upper and lower surfaces thereof.

In the above embodiment, the case 19
Is formed in a cylindrical shape, but may be formed in, for example, a rectangular tube shape or a polygonal tube shape. Further, the shapes of the secondary coil 2 and the heating coil 5 in the above embodiment,
The position where the terminal plate 18 is fixed to the primary coil 4, the shape of the terminal plate 18 and the like are also examples, and it goes without saying that various changes can be made without departing from the spirit of the present invention.

[0024]

As described above in detail, according to the output transformer of the high-frequency heating device according to the first aspect, the core is disposed in the U-shaped concave portion of the secondary conductor, and the upper and lower projecting portions of the core are provided. For example, the number of turns of the primary conductor can be increased with respect to the size of the core, so that the size and weight of the output transformer itself can be reduced, so that the output transformer can be easily moved. Since the range of use is greatly expanded and the shape of the core may be a square cross section, the output transformer itself can be constructed at low cost.

Further, in the output transformer according to the second aspect, since the flow path is formed inside the secondary conductor, heat generated in the secondary conductor can be suppressed by the cooling water flowing through the flow path. Deterioration of the output characteristics of the output transformer is prevented.

Further, in the output transformer according to the third aspect, since the primary conductor is formed by a pipe, cooling water can be circulated and supplied into the conductor, and heat generation of the primary conductor is suppressed.

In the output transformer according to the fourth aspect, since the primary conductor, the secondary conductor, and the core are accommodated in a cylindrical case, the outer shape can be made substantially cylindrical, and the output transformer can be formed. The container itself can be further reduced in size and weight, and for example, can be more easily carried.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an output transformer of a high-frequency heating device according to the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG. 1;

FIG. 3 is a sectional view taken along line BB of FIG. 1;

FIG. 4 is a sectional view taken along line CC of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Output transformer 2 Secondary coil 2a Upper surface 2b Lower surface 3 Core 3a, 3b Projection 4 Primary coil 5 Heating coil 7 Square pipe 8 U-shaped concave part 10 Copper plate 13 Coil part 19 Case

Claims (4)

[Claims] 1. A secondary conductor having a plate-shaped and substantially U-shaped concave portion,
A core disposed in a U-shaped concave portion of the secondary conductor, a primary conductor wound around a protruding portion of the core projecting from upper and lower surfaces of the secondary conductor, and a U-shape of the secondary conductor And a heating coil connected to the opening-side end of the concave portion. 2. The output transformer according to claim 1, wherein a cooling water flow path is formed inside the secondary conductor. 3. The method according to claim 1, wherein the primary conductor is formed of a copper pipe, and cooling water is circulated and supplied into the copper pipe.
An output transformer for the high-frequency heating device according to claim 1. 4. The primary conductor is wound so that an outer surface thereof is substantially circular, and the primary conductor, the secondary conductor, and the core are housed in a cylindrical case. An output transformer for a high-frequency heating device according to claim 1 or claim 3.