JP2864879B2 - High frequency heating equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-frequency heating device,
In particular, the present invention relates to a configuration for cooling a fuse holder of a current fuse for overcurrent protection.

[0002]

2. Description of the Related Art As shown in FIG. 7, a conventional high-frequency heating apparatus comprises a main body case 1, a heating chamber 2 for accommodating an object to be cooked, and a heating chamber 2.
A high-frequency generator for generating a high-frequency wave to the heating chamber 2, and a motor 5 with a propeller fan for cooling electric components such as a magnetron 3 and a high-voltage transformer 4 constituting the high-frequency generator.
And a control unit 6 for controlling the operation of the high-frequency heating device. In addition, a current fuse 7 that cuts off the current when an overcurrent occurs is attached to the bottom 8 of the main body case 1 via a fuse holder 9.

As shown in FIG. 8, a high-frequency generator forms a half-wave voltage rectifier circuit by a high-voltage capacitor 10 and a high-voltage diode 11, and is connected to a secondary winding 12 of a high-voltage transformer 4. Are configured by connecting magnetrons 3 in parallel. In addition, a time switch 14 as a time limiter for setting the cooking time of the object to be cooked in series with the primary winding 13 of the high-voltage transformer 4, a door switch 15 linked to the door, and a short circuit due to an abnormal failure of the electric component. Alternatively, the current fuse 7 for interrupting the current and protecting the high-frequency heating device at the time of an overcurrent such as a ground fault due to an abnormal failure of the electric wire connecting the electric components is provided with the primary winding 13 of the high voltage transformer 4
Are connected in series to supply a commercial power supply 16.

On the other hand, the high frequency generator generates noise from the high voltage circuit of the high voltage transformer 4, the high voltage capacitor 10, the high voltage diode 11 and the magnetron 3 when generating high frequency, and transmits the noise to the power plug through the internal wiring. As a result, noise is transmitted to the other electrical equipment connected to the same outlet via the power plug, and when the other electrical equipment has a microcomputer, malfunction occurs due to noise of the high-frequency heating device and the power supply is reset. In recent years, social problems have been developed, such as causing an unsafe operation such as turning off the power supply or, in the worst case, turning off the power due to a runaway of a microcomputer program.
Therefore, when the high-frequency heating device generates a high frequency, a high-voltage transformer 4, a high-voltage capacitor 10, a high-voltage circuit of the high-voltage diode 11, and a power supply noise filter circuit for reducing noise generated from the magnetron 3 have become necessary.

[0005] Noise generated by the high-frequency heating device includes a normal mode that propagates between lines and a common mode that propagates between both lines and ground. FIG. 9 shows an example of a power supply noise filter circuit for reducing them. A common mode choke coil 17 for reducing low frequency common noise is a line-to-line capacitor 18 for reducing low frequency normal mode noise, and a line and earth for reducing high frequency common and normal mode noise. It is composed of three kinds of electric components of the condenser 19.

FIG. 10 shows a configuration circuit of a high-frequency heating device to which a power supply noise filter circuit is connected. Originally, the power supply noise filter circuit was a small electric component common mode choke coil 17, line capacitor 18, line
Since it is composed of the condenser 19 between the grounds, a printed circuit board is used to fix and electrically connect them.

[0007]

However, since the conventional fuse holder 9 is composed of a clip portion for holding and electrically connecting the current fuse 7 and a synthetic resin mounting portion, the Joule heat generated by the current fuse 7 is converted to copper. Although it is transmitted to the clip portion of the alloy, there is a problem that the heat-radiating effect of heat is small because the portion to be attached to the bottom portion 8 of the main body case 1 is made of a synthetic resin, and heat can be radiated only from the clip portion, so that the temperature rise value becomes high.

On the other hand, the temperature limit of such a clip type fuse holder in a normal temperature rise test is determined by the technical standards of the Electrical Appliance and Material Control Law, and the temperature limit of the clip portion is 90 ° C. at a standard ambient temperature of 30 ° C. It has become.
Therefore, for example, the high frequency output of the high frequency heating device is set to 500 W
In this case, about 10 A will flow through the current fuse 7, and the temperature in the normal temperature rise test of the clip part at that time will be close to 90 ° C at the reference ambient temperature of 30 ° C, so allow a margin for the technical standards. Was difficult. Also, increasing the high-frequency output increases the current, and further increases the temperature of the clip portion, so that it has been difficult to increase the high-frequency output.

Therefore, the torque of the electric motor 5 with a propeller fan for cooling the electric parts is increased to increase the air flow to improve the cooling of the current fuse 7, or the current fuse having a large diameter and a large fuse having less self-heating of the current fuse. Had to use a holder.

However, in a high-frequency heating device with an electric heating device, the motor 5 with a propeller fan is often not rotated in order to increase the temperature efficiency of the heating chamber of the electric heating device.
At that time, electric motor 5 with propeller fan of current fuse 7
, And only natural heat radiation of the clip portion of the current fuse 7 and the fuse holder 9 can be expected, so that the temperature rise value of the clip portion in the normal temperature rise test is further disadvantageous. As a result, the current that can be passed through the current fuse 7 can be limited, and the electric power of the heater of the electric heating device cannot be increased.

When the power supply noise filter circuit is provided in the high-frequency heating device, the power supply noise filter circuit and the current fuse 7 are connected in series as can be seen from the circuit diagram of FIG. Therefore, as shown in FIG. 11, if a printed circuit board mounting clip type fuse holder 22 that can be mounted on a printed circuit board 21 and a suitable current fuse 20 are used, the power supply noise filter circuit can be integrally mounted.

However, even with such a clip-type fuse holder 22 mounted on a printed circuit board, the temperature limit in the normal temperature rise test according to the technical standards of the Electrical Appliance and Material Control Law is the same, and the temperature limit of the clip portion is around the reference ambient. Temperature 3
90 ° C at 0 ° C. Therefore, it is difficult to make room for the technical standards as in the case of the conventional fuse holder 9.

Therefore, the electric motor 5 with a propeller fan for cooling the electric parts is increased in torque and air flow to increase the cooling of the current fuse 20, or the current fuse having a large diameter and a large printed circuit board which causes less self-heating of the current fuse. It is necessary to use a mounting clip type fuse holder, or to increase the area of a printed and wired copper foil for soldering the printed board mounting clip type fuse holder 22 to improve heat radiation.

However, in the high-frequency heating device with the electric heating device, the electric motor 5 with the propeller fan is often not rotated as described above, so there is no cooling at this time, and the current fuse 20 and the clip type fuse holder 22 are mounted on the printed circuit board. Since only natural heat radiation of the clip portion and the printed and wired copper foil to which the printed circuit board mounted clip type fuse holder 22 is soldered can be expected, the temperature of the clip portion in the normal temperature rise test is further disadvantageous. To improve this, use a large diameter current fuse with a small self-heating of the current fuse and a large printed circuit board mounted clip type fuse holder, or a printed wiring copper soldered printed circuit board mounted clip type fuse holder 22. There was no other way but to increase the area of the foil. However, there is a limit to the size of the printed circuit board 21 in increasing the area of the copper foil, and the current flowing through the current fuse 20 can naturally be limited, and the electric power of the heater of the electric heating device cannot be increased. There is a problem that the rise of the temperature cannot be improved.

The present invention solves the above-mentioned problems, and mounts a clip-type fuse holder on a same printed circuit board with a power supply noise filter for reducing noise generated by a high frequency generator and a current fuse for overcurrent protection. It is another object of the present invention to reduce the temperature rise of the clip portion of the clip-type fuse holder mounted on a printed circuit board with a printed circuit board having a small area.

[0016]

A heating chamber for accommodating an object to be cooked, a high frequency generator for generating a high frequency to the heating chamber, a power noise filter circuit for reducing a power noise generated by the high frequency generator, A current fuse for interrupting the current when an abnormality occurs, a clip-type fuse holder for holding and electrically connecting the current fuse, and a printed circuit board for holding and electrically connecting the electric components. Attach the filter circuit parts, the clip-type fuse holder mounted on the printed circuit board, and the current fuse, and install a heat sink near the clip-type fuse holder mounted on the printed circuit board. It is configured to be electrically connected.

[0017]

According to the present invention, a power supply noise filter circuit component, a clip-type fuse holder mounted on a printed circuit board, and a current fuse are mounted on the same printed circuit board, and a radiator is provided near at least one clip-mounted fuse holder mounted on the printed circuit board. With this arrangement, Joule heat generated by the current flowing through the current fuse is transmitted to the clip portion of the clip-type fuse holder mounted on the printed circuit board. The heat is dissipated in the clip portion and is also transmitted to the copper foil of the printed wiring board to which the printed circuit board-mounted clip-type fuse holder is soldered, thereby dissipating the heat. In addition, since a radiator electrically connected to the clip-type fuse holder mounted on the printed circuit board is provided, heat is further transmitted to the radiator to radiate heat.

As a result, even when used as a high-frequency heating device, the temperature rise value of the clip portion is reduced, and the reference ambient temperature of 30 ° C., which is the temperature limit of the clip portion in the normal temperature rise test in the technical standards of the Electrical Appliance and Material Control Law. At 90 ° C,
I can have enough room. In addition, with the high-frequency heating device with the electric heating device, even when the electric motor with the propeller fan does not rotate, the technical standard can be satisfied by the temperature of the clip portion in the normal temperature rise test due to the heat radiation effect.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A high-frequency heating apparatus according to one embodiment of the present invention will be described below with reference to the drawings.

A feature of the present invention is that a heat radiator is mounted near the current fuse in order to improve the heat radiation of the current fuse.

As shown in FIG. 2, a cooling propeller fan 24 and an electric motor 25 attached to the back surface 23a of the main body case 23 have an air inlet 2 provided on the back surface 23a of the main body case 23.
6, a magnetron 28 for generating high frequency to supply air to the heating chamber 27, and a high-voltage transformer 2
After cooling the electric components such as 9 and cooling the magnetron 28, the warmed air is guided by the air guide 30 and sent into the heating chamber 27 through the suction hole 31 provided in the side surface 27 a of the heating chamber. Further, a printed circuit board 32 is attached to a bottom surface 23 b of the main body case 23 by a holder 33.

As shown in FIG. 1, the printed circuit board 32 has a common mode choke coil 34 for reducing low-frequency common noise constituting a power supply noise filter circuit.
Equipped with three types of electrical components, a line-to-line capacitor 35 for reducing low-frequency normal mode noise, a line-to-ground capacitor 36 for reducing both high-frequency common and normal mode noise, and a current fuse 37. Printed circuit board mounting clip type fuse holder 38
And a tab terminal A39 for connecting a power supply line for supplying power from a commercial power supply to an input side of the printed wiring of the printed circuit board 32.
A tab terminal B40 for connecting the output side of the printed circuit of the printed circuit board 32 to the control of the high-frequency heating device and the high-frequency generation device; and a radiator plate 41 as a radiator near the printed circuit board mounting clip-type fuse holder 38. The printed circuit board 32 has a configuration in which it is soldered to the printed wiring on the back surface and electrically connected.

The circuit of the printed circuit board 32 is as shown in FIG. 3, and the back surface of the printed circuit board 32 is made of copper foil 42 of the printed circuit board 32 by printing as shown in FIG. It is configured to be electrically connected to electric parts and the like.

As shown in FIG. 5, the heat radiating plate 41 is made of a copper alloy and has a U-shape, and the claw portions 43 are formed so that both ends can be inserted into square holes formed in the printed circuit board 32.
have.

Therefore, according to the configuration of this embodiment, when the high-frequency heating device operates and a current flows through the current fuse 37, the Joule heat generated by the current fuse 37 is transferred to the clip-type fuse holder 3 mounted on a copper alloy printed circuit board.
8 to the clip section. The common mode choke coil 34 is formed by winding an electric wire,
Since the same current as the current flowing in the common mode choke coil 34 flows, Joule heat is also generated in the electric wire constituting the common mode choke coil 34. Although part of the heat is naturally radiated from the surface of the common mode choke coil 34, part of the heat is also transmitted to the printed copper foil 42 of the printed circuit board 32 through the terminals of the common mode choke coil 34. In addition, the copper foil 42 is mounted on the printed circuit board clip type fuse holder 38 on the circuit.
, The temperature of the printed circuit board mounted clip-type fuse holder 38 is further increased.

The heat is dissipated in the clip portion and the copper foil 42 of the printed wiring board 32 on which the printed circuit board mounting clip type fuse holder 38 is soldered.
But it dissipates heat. Further, a heat sink 41 electrically connected to the vicinity of the clip type fuse holder 38 mounted on the printed circuit board.
Is provided, heat is further transmitted to the heat radiating plate 41 to radiate heat.

As a result, even when used as a high-frequency heating device, the temperature rise value of the clip portion is reduced, and the reference ambient temperature of 30 ° C., which is the temperature limit of the clip portion in the normal temperature rise test in the technical standards of the Electrical Appliance and Material Control Law. At 90 ° C. Moreover, even in the case of a high-frequency heating device with an electric heating device, even when the electric motor 25 with a propeller fan is not rotated, the above-mentioned heat dissipation effect allows the temperature of the clip portion in the normal temperature rise test to sufficiently satisfy the technical standards. The electric power of the heater of the electric heating device can be increased, and the rise of the temperature of the heating chamber can be improved.

In the above-described embodiment, a heat sink having a U-shape is used to radiate heat from the clip-type fuse holder mounted on the printed circuit board. It goes without saying that the same effect can be obtained even when used.

Next, with reference to FIG. 6, an embodiment using a radiator as a radiator will be described. As shown in FIG. 6, a jacket 4 made of an insulator such as a synthetic resin having electric insulation performance is provided outside a wire 44 having a circular cross section made of a copper alloy.
Cover with 5. Moreover, both ends have bare portions 46 so that they can be inserted into round holes provided in the printed circuit board 32. This heat radiation line is attached to the printed circuit board 32 near the printed circuit board mounting clip type fuse holder 38, and the printed circuit board 32 is mounted.
Is soldered to the printed wiring on the back surface of the device and electrically connected.

With such a heat radiating line, the temperature rise value of the clip portion of the clip-type fuse holder 38 mounted on the printed circuit board is reduced even when used as a high-frequency heating device or as a high-frequency heating device with an electric heating device. Although the effect is the same as that of the embodiment using the heat sink,
Since the heat radiating wire is configured to be covered with the jacket 45 having an electric insulating property, even if the heat radiating wire is electrically connected to the clip-type fuse holder 38 mounted on the printed circuit board and becomes a charged portion of 100V in potential, the surrounding heat radiating wire can be used. It is composed of metal and has a potential of 0 V
The printed circuit board 3 on which the power supply noise filter circuit component and the printed circuit board mounting clip-type fuse holder 38 are attached, which can be electrically insulated from other components.
When mounting 2 on the main body case, it is insulated from other parts, and there is no restriction on the clearance distance and creepage distance, which is advantageous in terms of mounting space. In a configuration in which there is no possibility of electrical contact with other components, the outer cover 45 is unnecessary, and in this case, heat radiation is further improved.

In the above-described embodiment, a wire having a circular cross section is provided with a synthetic resin jacket having an electric insulating property for heat radiation and insulation of the clip type fuse holder mounted on the printed circuit board. It goes without saying that the same effect can be obtained by using a heat sink provided with a synthetic resin jacket having electrical insulation performance using a rectangular plate.

In the above description, the case where a heat radiating plate or a heat radiating line is used as the heat radiating body is described. However, since the purpose is to improve heat radiation, the present invention is not limited to this configuration. Other shapes may be used. Although the case where a copper alloy is used as the constituent material has been described, it goes without saying that a metal material having good heat conductivity, an alloy thereof, or ceramics may be used.

[0033]

As described above, the high-frequency heating apparatus according to the first aspect has the following advantages.

(1) A power supply noise filter circuit component and a clip-type fuse holder are mounted on the same printed circuit board, and a radiator is provided near the clip-type fuse holder. The temperature rise in the normal temperature rise test of the clip portion of the clip type fuse holder mounted on a printed circuit board due to heat and Joule heat generated in the electric wire constituting the common mode choke coil can be reduced by the heat dissipation effect of the heat radiator. .

(2) Therefore, even when the electric heating device is attached, the electric power of the heater of the electric heating device can be increased, so that the rise of the temperature of the heating chamber can be improved.

(3) In addition, since the heat radiation from the clip portion of the clip-type fuse holder mounted on the printed circuit board is improved, a power supply noise filter circuit component and a clip-type fuse holder can be mounted on a small printed circuit board. It has become possible to reduce the size.

Further, in the heat radiator of the second aspect,
(1) Since the heat radiator is covered with a jacket having an electric insulating property, even when used as a high-frequency heating device or a high-frequency heating device with an electric heating device, the temperature rise of the clip portion of the printed circuit board mounted clip type fuse holder. Although the effect of reducing the value is almost the same as the effect of the one embodiment,
Since the radiator is covered with a jacket having electrical insulation performance, even if the radiator is electrically connected to the clip-type fuse holder mounted on the printed circuit board and has a charged portion of 100V in potential, the surrounding metal It can be electrically insulated from other components which are configured and have a potential of 0 V, and are insulated from other components, so that there is no restriction on the space distance and creepage distance, which is advantageous in terms of mounting space.

[Brief description of the drawings]

FIG. 1 is a perspective view of a printed circuit board of a high-frequency heating device according to an embodiment of the present invention.

FIG. 2 is a perspective view of a main part of the high-frequency heating device.

FIG. 3 is a circuit diagram of the printed circuit board.

FIG. 4 is a configuration diagram of the back surface of the printed circuit board.

FIG. 5 is a perspective view of the heat sink.

FIG. 6 is a perspective view of a heat radiation wire according to another embodiment of the present invention.

FIG. 7 is a perspective view of a main part of a conventional high-frequency heating device.

FIG. 8 is a circuit diagram of a conventional high-frequency heating device.

FIG. 9 is a circuit diagram of a power supply noise filter of a conventional high-frequency heating device.

FIG. 10 is a circuit diagram incorporating a power supply noise filter of a conventional high-frequency heating device.

FIG. 11 is a perspective view of a printed circuit board of a conventional high-frequency heating device.

[Explanation of symbols]

 28 High frequency generator 32 Printed circuit board 37 Current fuse 38 Clip type fuse holder mounted on printed circuit board 41 Heat radiator (radiator)

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-1480 (JP, A) Japanese Utility Model Showa 58-64096 (JP, U) Japanese Utility Model Showa 60-2289 (JP, U) (58) Investigation Field (Int.Cl. ⁶ , DB name) H05B 6/64 H01H 85/22 H05B 6/66

Claims (2)

(57) [Claims] 1. A heating chamber for accommodating an object to be cooked, a high-frequency generator for generating a high frequency to the heating chamber, a power noise filter circuit for reducing a power noise generated by the high-frequency generator, A power supply noise filter including a current fuse to be cut off, a printed circuit board mounted clip-type fuse holder for holding and electrically connecting the current fuse, and a printed circuit board for holding and electrically connecting the electric component; Attach circuit components, PCB mounted clip-type fuse holders and current fuses, provide a radiator near the PCB mounted clip-type fuse holders, and electrically connect the PCB mounted clip-type fuse holders to the radiator. Become a high-frequency heating device. 2. The high-frequency heating apparatus according to claim 1, wherein the heat radiator other than the terminals to be electrically connected is covered with a sheath having an electric insulating property.