JP2001068360A - Output transformer of high frequency heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To downsize and lighten an output transformer by a method wherein a primary conductor is housed by winding and disposed in a substantially annular groove of a pair of barrel-like cores having a bottom, and a secondary conductor is housed and disposed inside or outside this primary conductor. SOLUTION: In an output transformer 1 of a high frequency heater, an overall shape of a pair of cylindrical cores 2, 4 having a bottom is formed to be substantially circular, and rod parts 2b, 3b are erected at central positions of bottom parts 2a, 3a, and also substantially annular grooves 7, 8 are formed between the rods 2b, 3b and outer peripheral walls 2c, 3c. Also, at diametrical positions of the outer peripheral walls 2c, 3c of the cores 2, 3, cutouts 9, 10 having predetermined angles are formed along the axial direction, and also at central positions of the rods 2b, 3b, axial holes 11 penetrating axially are formed, respectively. The pair of cores 2, 3 are disposed in a state such that opening ends 7a, 8b of both the grooves 7, 8 are counter to each other, and a primary coil 4 and a secondary coil 5 are housed and disposed in both the grooves 7, 8.

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 has 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 the start end and a terminal end of the coil, and a pair of second conductive members connected between the first conductive members of the coil.

[0003]

However, in this output transformer, since a coil portion is wound around the middle leg of the E-shaped core, a large output is required for the output transformer. A large E-shaped core must be used,
Further, since the outer shape of the output transformer itself is square and the core is E-shaped, it is difficult to reduce the size thereof. As a result, in the case of a portable output transformer in which a heating coil is directly connected to the coil portion of the output transformer, the output transformer itself cannot be easily moved, and its use range is limited. There is a problem that the usability (general versatility) of the output transformer is inferior.

The present invention has been made in view of such circumstances, and an object of the first aspect of the present invention is to reduce the size and weight of an output transformer by forming the outer shape to be substantially circular. An object of the present invention is to provide an output transformer of a high-frequency heating device.
In addition, the object of the invention described in claim 2 can be achieved in addition to the object of the invention described in claim 1 in that the size of the output transformer can be reduced, and the movement of the portable output transformer can be easily performed. Provided is an output transformer of a high-frequency heating device that can be performed. The object of the invention described in claim 3 is to reduce the weight of the core itself and reduce the weight of the output transformer in addition to the object of the invention described in claim 1 or 2. An object of the present invention is to provide an output transformer of a high-frequency heating device which can be easily formed and can easily arrange a primary conductor and a secondary conductor.

[0005]

In order to achieve the above object, according to the first aspect of the present invention, a substantially annular groove portion is provided between a cylindrical portion and an outer peripheral wall portion, and an opening end of the groove portion is provided. A pair of bottomed cylindrical cores arranged in a state of facing each other,
A primary conductor housed and arranged in the groove of the core, and a secondary conductor housed and arranged inside or outside the primary conductor in the groove of the core are provided.

With this configuration, when a predetermined high-frequency current is supplied to the primary conductor, a large current is induced in, for example, a plate-shaped secondary conductor, and the large current is heated by the heating device connected to the secondary conductor. The workpiece supplied to the coil and arranged near the heating coil is subjected to, for example, induction heating. The primary conductor is
A pair of bottomed cylindrical (cup-shaped) cores are wound and housed in a substantially annular groove, and a secondary conductor is housed and arranged inside or outside of the primary conductor. Each conductor can be stored and arranged inside the core,
The output transformer itself can be reduced in size and weight.

According to a second aspect of the present invention, a cable connecting portion is provided on the bottom outer surface of one of the pair of cores, and a heating coil connecting portion is provided on the bottom outer surface of the other core. It is characterized by having been done. With this configuration, it is possible to connect the heating coil to the connection portion at one end in the axial direction of the output transformer having a circular outer shape, and to connect a flexible cable to the connection portion at the other end. Since the output transformer can be made smaller, the output transformer can be easily moved when the output transformer is used as a portable type.

The invention according to claim 3 is characterized in that the core has a notch formed in a part of the outer peripheral wall along the axial direction. With this configuration,
Notches provided in the axial direction of the core lighten the weight of each core itself, making it possible to further reduce the weight of the output transformer, and use the notches as a wiring location for primary and secondary conductors, The degree of freedom in designing the output transformer is increased, for example, the output transformer can be easily obtained.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings. 1 to 6 show an embodiment of an output transformer according to the present invention. In the figure,
The output transformer 1 includes a pair of cores 2 and 3 having a bottomed cylindrical shape (pot type), a primary coil 4 and a secondary coil 5 housed and arranged in the cores 2 and 3, and a bottom outer side of the core 3. It has a heating coil 6 and the like arranged.

The cores 2 and 3 are formed to have a substantially circular outer shape, and have cylindrical portions 2b and 3b at the center positions of the bottoms 2a and 3a.
Are formed upright, and substantially annular grooves 7, 8 are formed between the cylindrical portions 2b, 3b and the outer peripheral wall portions 2c, 3c. Notches 9, 10 of a predetermined angle along the axial direction are provided at diametrical positions of the outer peripheral wall portions 2 c, 3 c of the cores 2, 3.
Are formed, and axial holes 11 penetrating in the axial direction are respectively formed at the center positions of the cylindrical portions 2b and 3b. In the present invention, the shaft hole 11 is not always necessary and can be omitted.

Then, the pair of cores 2 and 3 are
8 open ends 7a, 8b are opposed to each other (the cylindrical portions 2b, 3b
Are arranged in a state where they face each other with a predetermined gap, and the outer peripheral wall portions 2c and 3c are in contact with each other). The primary coil 4 and the secondary coil 5 are housed and arranged in the grooves 7 and 8. The primary coil 4 is formed by winding a circular copper pipe having an outer peripheral surface insulated with an insulating paint or an insulating tube or the like a predetermined number of times around the cylindrical portions 2b and 3b of the cores 2 and 3, Both ends are pulled out of the cutout 9 of the core 2 to the outside of the bottom 2 a, and are connected to hose connectors 13 each having a terminal plate 14 fixed to the insulating plate 12.

A flexible cable 15 (see FIG. 1) is connected to the hose connector 13 and the terminal plate 14, and the cable 15 has a hose (not shown) through which cooling water is circulated and supplied. And an electric wire (not shown) composed of a mesh wire and the like. The hose is connected to the hose connector 13, and the other end of the electric wire whose one end is connected to the output terminal of a transistor inverter (not shown) as a high-frequency heating device is electrically connected to the terminal plate 14. .

The secondary coil 2 is formed of a substantially cylindrical copper plate having a predetermined thickness and having, for example, a slit 16 (see FIG. 3) in the axial direction, and cooling water is circulated and supplied to an appropriate position on the outer peripheral surface thereof. A rectangular or circular copper pipe 17 is brazed and fixed. One end of the copper pipe 17 is connected to a hose connector 18 fixed to the insulating plate 12, and the other end of the copper pipe 17 is
The heating coil 6 is connected to a pair of copper plates 19 disposed on the outside of the bottom 3a.

The heating coil 6 includes a pair of copper plates 20 insulated from each other and a pair of fixing portions 21 made of a copper square pipe.
And a pair of straight portions 22 formed of a copper square pipe, and a coil portion 23 having, for example, a substantially ring shape formed at the tip of the straight portion 22. The fixing portions 21 are respectively brazed and fixed to a flat copper plate 20. The copper plate 20 has holes 20 a communicating with the holes 19 a of the copper plate 19.
1 (see FIG. 1), and two mounting holes (not shown) are formed. The bolts 24 (see FIG. 5) are screwed into the screw holes of the copper plate 19 from the mounting holes, whereby the pair of copper plates 20, that is, the heating coils 6 are fixed to the copper plate 19, respectively.

Thus, the heating coil 6 and the pair of copper plates 1
9, that is, both ends of the secondary coil 5 are electrically connected, and the hole 17a of the copper pipe 17 and each hole of the heating coil 6 are communicated through the holes 19a, 20a of the copper plates 19, 20. The hole 20a of the copper plate 20 corresponds to the hole 19a of the copper plate 19.
O-ring 25 for preventing leakage of cooling water
(Refer to FIG. 1).
Between the copper plates 20 and between the straight portions 22 of the heating coil 6 are insulated by an insulating plate 26.

Further, the outer peripheral surfaces of the cores 2 and 3 and the insulating plate 1
A resin-made cylindrical case 27 is provided on the outer peripheral surface of the metal plate 2 and the copper plate 19 for the purpose of protecting the cores 2 and 3 and the like, and the overall shape of the output transformer 1 is circular. A handle (not shown) is attached to the case 27 as needed, and is used when the output transformer 1 is moved. Also,
The turn ratio between the primary coil 4 and the secondary coil 5 of the output transformer 1 is preset to n: 1 in accordance with the required output characteristics and the like. , 8 are also set in advance in accordance with the output characteristics.

According to the output transformer 1, the cable 15 and the terminal plate 1
When a predetermined high-frequency current is supplied to the primary coil 4 via the coil 4, a large current corresponding to the turns ratio flows through the secondary coil 5 by inductive coupling. This large current is supplied to the heating coil 6 via the copper plates 19, 20 and the like, so that a work (not shown) disposed close to the heating coil 6 is induction-heated.

Simultaneously with the supply of the high-frequency current, the cooling water supply device provided in the transistor inverter is operated, and the hose in the cable 15 is connected to the hose connector 18, the copper pipe 17 of the secondary coil 5, the heating coil 6. The cooling water is circulated and supplied through the hose in the hose connector 18 and the cable 15, and the cooling water is also circulated and supplied into the primary coil 4 through the hose connector 13. Next coil 5 and heating coil 6
Heat generation is suppressed.

Here, an example of a method of assembling the output transformer 1 will be described with reference to FIG. First, a pair of cores 2 and 3 formed in a predetermined shape are prepared, and a primary coil 4 having an inner diameter corresponding to the size of the grooves 7 and 8 of the cores 2 and 3 is prepared.
Is wound using, for example, an appropriate jig (not shown) corresponding to the shape of the cylindrical portions 2b and 3b of the cores 2 and 3.
Then, in the shaft hole 4a of the wound primary coil 4,
The cylindrical portion 3b of the core 3 is inserted into one end of the core 3 via an appropriate insulating material or the like (not shown), and the right half of the primary coil 4 is positioned in the groove 8 of the core 3.

Next, a secondary coil 5 to which a copper pipe 17 is previously brazed and fixed is inserted into the outside of the primary coil 4 via an insulating material (not shown). At this time, the primary coil 4
And the length of the secondary coil 5 is set to be substantially the same as the depth of the grooves 7, 8 when the pair of cores 2, 3 are opposed to each other, so that the left halves of both coils 4, 5 are exposed to the outside. It is in a state where it has been done.

Then, the core 2 is put on the exposed portion,
By locating the left halves of the coils 4 and 5 in the groove 7, the primary coil 4 and the secondary coil 5 are completely housed and arranged in the grooves 7 and 8 of the cores 2 and 3. In this state, both ends of the primary coil 4 and both ends of the copper pipe 17 of the secondary coil 5 are pulled out using the cutouts 9 and 10 of the cores 2 and 3 and fixed to the insulating plate 12 and the copper plate 19.

After that, the insulating plate 12 and the copper plate 19 are
3, placed on the outside of the bottoms 2a, 3a and covered with the case 27,
Further, the power transformer 1 is manufactured by fixing the heating coil 6 to the copper plate 19. In addition, the primary coil 4 and the secondary coil 5 housed and arranged in the grooves 7 and 8 of the cores 2 and 3 can be made of resin for stabilization, and the two cores 2 and 3 can be connected and fixed. To ensure strength,
Insulating plate 12 and copper plate 19 by fixing both ends of copper pipe 17
In addition to the pinching force described above, a connection structure using screws or the like utilizing the shaft holes 11 of the cores 2 and 3 may be adopted.

As described above, according to the output transformer 1 of the above embodiment, the primary coil 4 and the secondary coil 5 are provided in the substantially annular grooves 7 and 8 of the pair of cores 2 and 3 having a bottom. , The outer shape of the output transformer 1 can be formed in a circular shape, and its size and weight can be reduced as compared with a conventional rectangular shape. Further, since the outer peripheral wall portions 2c and 3c of the cores 2 and 3 are located outside the secondary coil 5, leakage of magnetic flux to the outside can be suppressed, and the coupling coefficient between the primary coil 4 and the secondary coil 5 can be reduced. The size of the output transformer 1 can be further reduced (with respect to output characteristics).

Further, since the heating coil 6 is directly connected to the secondary coil 5 of the output transformer 1 and is connected to a high-frequency heating device such as a transistor inverter by a flexible connection cable 15, the output transformer is The diameter of the output transformer 1 can be reduced as much as possible, the size and weight of the power transformer 1 can be further reduced, and the output transformer 1 can be easily moved. It can be easily applied to brazing and soldering work of a large work. As a result, the usability of the output transformer 1 can be greatly improved, for example, it can be used as the portable output transformer 1 and its use range can be expanded.

Further, since axial cutouts 9 and 10 are formed in the outer peripheral wall portions 2c and 3c of the cores 2 and 3, the cutouts 9 and 10 are used to form the copper of the primary coil 4 and the secondary coil 5. For example, the pipe 17 can be pulled out, so that the work of arranging the primary coil 4 and the secondary coil 5 can be easily performed, and the manufacturing cost can be reduced. The degree of freedom in designing the layout of the secondary coil 5 can be increased.

Furthermore, since the outer peripheral walls 2c, 3c and the bottoms 2a, 3a of the cores 2, 3 are located on the outer peripheral portion of the output transformer 1, substantially the entire outer periphery of the primary coil 4 and the secondary coil 5 is , 3 so that the occurrence of external noise from the output transformer 1 due to the leakage of magnetic flux to the outside can be suppressed, and other devices due to external noise at the place where the output transformer 1 is used. And the like (electromagnetic interference) can be prevented.

In the above embodiment, the secondary coil 5 is formed of a single (1 turn) copper plate and is disposed outside the primary coil 4. However, the present invention is not limited to this. Instead, for example, a plurality of copper plates may be laminated at intervals, and the primary coil 4 may be wound in series between the copper plates and on the upper and lower surfaces thereof, or the secondary coil 5 may be connected to the primary coil 4.
It can be arranged inside instead of outside.

In the above embodiment, the primary coil 4 and the secondary coil 5 are formed as one member, respectively, and are set so as to correspond to the depths of the grooves 7, 8 of the cores 2, 3. By setting the coils 4 and 5 to shapes corresponding to the cores 2 and 3, respectively, and connecting the coils 4 and 54 in series or in parallel by appropriate means, the primary coil 4 and the secondary coil 5 are electrically connected. May be formed. With this configuration, the characteristics of the output transformer 1 can be more easily adapted to various required characteristics.

Further, in the above embodiment, the case where the heating coil 6 is directly connected to the output side of the secondary coil 5 has been described. However, the present invention also relates to an output transformer in which the heating coil 6 is not connected. Needless to say, the grooves 7 and 8 of the cores 2 and 3 in the above embodiment can be included.
The shapes of the notches 9, 10 and the like, the shapes of other members, the number of turns of the primary coil 4, and the like are also examples, and can be variously changed.

[0030]

As described above in detail, according to the first aspect of the present invention, since the primary conductor and the secondary conductor are housed and arranged in the groove of the bottomed cylindrical core, the output transformer has The outer shape can be formed in a circular shape, and the size, weight, and cost of the output transformer itself can be reduced.

According to the second aspect of the present invention, in addition to the effects of the first aspect, a heating coil is connected to a connection portion at one axial end of the output transformer having a circular outer shape.
For example, a flexible cable can be connected to the connection portion on the other end side, so that the output transformer can be made more compact and the output transformer can be easily moved even when it is used as a portable type. Can be done.

According to the third aspect of the present invention, in addition to the effect of the first or second aspect, the notch is provided in the axial direction of the core, so that the weight of each core itself is reduced by the notch. It becomes lighter, the output transformer can be made lighter, and the notch can be used as a wiring location for primary and secondary conductors, so that output transformers with various characteristics can be easily obtained.
The degree of freedom in designing the output transformer can be increased.

[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 an arrow view along the line AA in FIG. 1;

FIG. 3 is an arrow view along the line BB in FIG. 2;

FIG. 4 is a view taken along the line CC in FIG. 1;

FIG. 5 is an arrow view along the line DD in FIG. 1;

FIG. 6 is a schematic exploded view showing an example of the assembling method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Output transformer 2, 3 Core 2a, 3a Bottom part 2b, 3b Column part 2c, 3c Outer peripheral wall part 4 Primary coil 5 Secondary coil 6 Heating coil 7, 8 Groove part 7a, 8a Open end 9, 10 Notch 12 Insulating plate 15 Cable 17 Copper pipe 19, 20 Copper plate 21 Fixed part 22 Straight part 23 Coil part 27 Case

Claims (3)

[Claims] 1. A pair of cores having a bottomed cylindrical shape having a substantially annular groove portion between a columnar portion and an outer peripheral wall portion and arranged so that open ends of the groove portions face each other, and inside the groove portion of the core. And a secondary conductor housed inside or outside the primary conductor in the groove of the core. 2. A connection portion for a cable is provided on a bottom outer surface side of one of the pair of cores, and a connection portion for a heating coil is provided on a bottom outer surface side of the other core. The output transformer of the high-frequency heating device according to claim 1 or 2, wherein: 3. The output transformer according to claim 1, wherein the core has a cutout formed in a part of an outer peripheral wall thereof along an axial direction.