JP2011096424A - Induction cooking device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a noise filter unit that facilitates assembling, capable of cooling components so as to lower the temperature rise thereof to an allowable component temperature value or less, and improving noise shielding performance from magnetic noise generated from leakage magnetic flux from heating coils and a switching power supply. <P>SOLUTION: The noise filter unit 12 is vertically disposed in a body 1, is held with the side face of a noise filter substrate 9 facing the front side of the body 1, and is covered with a metal shield plate 11 in which slit holes 14 are provided. The rear face of the noise filter unit 12 and the rear face of the body 1 are designed so as to face each other with a prescribed space kept between them, and an exhaust path of cooling wind from a cooling fan 13 provided in front of the body to the noise filter 12 can be thereby secured. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an induction heating cooker.

  FIG. 6 shows a circuit diagram of a conventional induction heating cooker described in Patent Document 1. In FIG. Conventionally, an induction heating cooker supplies a constant DC voltage to an inverter circuit 7 that generates a high-frequency current in the heating coil 4 with the commercial power source 5 from the power cord 6 as an input, and a control circuit 8 that receives the commercial power source 5 as an input. The switching power supply 28 is included in the same casing, and in such a configuration, switching noise generated by the switching power supply 28 interferes with the inverter circuit 7 and the heating coil 4, and a cooking pan or the like is used when the induction heating cooker is used. An unpleasant roaring sound is generated from the load to the user. Therefore, as shown in FIG. 6, the heating coil 4 of this induction heating cooker, the rectifier circuit 23, the inverter circuit 7 connected to the rectifier circuit 23 and generating a high-frequency current in the heater coil 4, and the heating by the heating coil 4 A main unit 24 having a control circuit 8 for controlling the power supply, a switching power supply 28 for supplying a constant DC voltage to the control circuit 8, a first noise filter 12a connected between the commercial power supply 5 and the rectifier circuit 23, A noise filter unit 12 having a second noise filter 12b connected between the power supply 5 and the switching power supply 9 is provided, and a main unit unit housing 25 constituting the main unit 24 is formed of a conductive magnetic material. The configuration is such that noise interference with the noise filter unit 12 is prevented.

  FIG. 7 shows a conventional induction heating cooker described in Patent Documents 2 and 3. In recent years, an induction cooking device having a cooling means for cooling internal components in front of the main body has become common. Compared to the configuration in which an opening is provided behind the top of the cooker and one is an intake port and the other is an exhaust port, the conventional configuration has oil smoke, steam, and cooked food together with air that is heated when the cooked product is heated. It is difficult to inhale boiled juice etc. from the intake port, so there is little possibility of impairing the durability of internal parts, and cooling efficiency is improved because air with a relatively low temperature close to the outside temperature taken in by the cooling fan can be guided It is known to be expensive (Patent Document 2 and Patent Document 3).

JP 2007-311244 A JP 2009-59564 A JP 2009-52864 A

  However, in recent years, in this type of induction heating cooker, a large current flows through the noise filter disposed in the power supply unit, and the temperature rise of the component due to the electric resistance in the noise filter increases, and depending on the component, cooling is required. For this reason, there has been a problem of component cooling of a noise filter configured separately from the main body. In particular, a noise filter is often mounted behind the power cord, and noise generated by the control unit, induction heating coil, etc. overlaps the current path leading to the power cord and exits from the power cord. In order to prevent this, the noise filter substrate is covered with a metallic shield plate, and cooling is difficult in a configuration in which a cooling means is provided in front.

The present invention solves the above-mentioned conventional problems, and a noise filter is arranged in a restricted main body so that it can be easily assembled, and cooling is performed so that the temperature rise of the noise filter component is less than the component temperature allowable value. It is an object of the present invention to provide an induction heating cooker that can improve noise shielding performance from magnetic flux leaked from a heating coil to a noise filter and electromagnetic noise emitted from a switching power supply.

  In order to solve the above-described conventional problems, an induction heating cooker according to the present invention includes a main body, a top plate on which a cooked utensil arranged on the top surface of the main body, and the top plate on the main body. A metal frame that supports the top plate for installation, an induction heating coil provided below the top plate, a commercial power source, a power cord, and the commercial power source from the power cord as inputs. A control unit having an inverter circuit for generating a high-frequency current in a coil; and the power cord connected between the power cord and the control unit and superimposed on a current path generated in the control unit and connected to the power cord A noise filter substrate that suppresses noise coming out of the main body from the resin, a resin-made noise filter substrate holding part for holding the noise filter substrate, and the noise filter substrate Provided on the top surface for exhausting the cooling air, a metal shield plate for shielding noise from the induction heating coil and the like, a cooling fan that blows air from the front to the rear An exhaust port, wherein the noise filter substrate, the noise filter substrate holding portion, and the shield plate are configured as a noise filter unit, and the rear surface of the noise filter unit is designed and opposed to the rear surface of the main body at a predetermined interval. It is said.

  With this configuration, the noise filter unit can be mounted with high density in the space inside the main body, and assembling becomes easy by unitizing. In addition, since the rear surface of the noise filter unit is opposed to the rear surface of the main body by a predetermined distance, a cooling air exhaust path to the noise filter unit can be secured, so that a configuration with high cooling efficiency can be achieved. Furthermore, since it is covered with a metal plate, it is possible to provide an induction heating cooker that further reduces noise superposition.

  The induction heating cooker of the present invention unitizes the noise filter so that the noise filter can be easily assembled within the constraints of the main body, cools the noise filter components, and leaks magnetic flux from the heating coil to the noise filter. Noise shielding performance from electromagnetic noise emitted from the switching power supply can be improved.

The whole block diagram of the induction heating cooking appliance in Embodiment 1 of this invention The figure of the cooling air path of the induction heating cooking appliance in Embodiment 1 of this invention Noise filter unit diagram of induction heating cooker in Embodiment 2 of the present invention Noise filter unit diagram of induction heating cooker in Embodiment 3 of the present invention The figure of the shield board and metal plate in Embodiment 3 of this invention Circuit diagram of conventional induction heating cooker Figure of conventional induction heating cooker

1st invention is a metal frame which supports the said top plate in order to install a main body, the to-be-heated cooking appliance distribute | arranged to the top | upper surface of the said main body, and the said top plate in the said main body And a control unit having an induction heating coil provided below the top plate, a commercial power source, a power cord, and an inverter circuit for generating a high-frequency current in the heating coil with the commercial power source from the power cord as an input And a noise filter substrate that is connected between the power cord and the control unit, and suppresses noise that is generated in the control unit or the like and is superimposed on a current path that leads to the power cord and exits from the power cord to the outside of the main body. A resin-made noise filter substrate holding portion for holding the noise filter substrate, noise from the noise filter substrate, the induction heating coil, and the like A metal shield plate for shielding noise, a cooling fan for blowing air from the front to the rear, and an exhaust port provided on the top surface for exhausting the cooling air, the noise filter substrate, The noise filter substrate holding part and the shield plate are configured as a noise filter unit, and the rear surface of the noise filter unit is opposed to the rear surface of the main body with a predetermined interval, thereby preventing leakage magnetic flux from the heating coil and switching power supply. Since the cooling air exhaust path to the noise filter unit can be secured while maintaining the noise shielding performance from the generated electromagnetic noise, a configuration with high cooling efficiency can be achieved.

  In the second invention, in particular, the shield plate of the first invention is provided with a slit hole at a position facing the cooling fan, so that the cooling plate introduced into the noise filter unit from the slit hole and passed through the switch power supply board. A cooling air path can be secured so that the wind is guided to a predetermined distance provided on the rear surface of the noise filter unit and the rear surface of the main body, and temperature rises of components of the switch power supply board and solder connection portions can be reduced.

  In particular, the third invention can be configured compactly in the product by arranging the noise filter unit of the second invention vertically in the main body and the side face of the noise filter substrate facing the front side of the main body. In addition, the range in which the noise filter unit covers the cooling air exhaust path of the control unit having the inverter circuit can be reduced, and the cooling efficiency can be improved.

  In the fourth aspect of the invention, in particular, when the noise filter unit is arranged on the main body by providing the wiring fixing portion for fixing the wiring that is output from the noise filter substrate in the noise filter substrate holding portion of the first invention, Wiring does not easily interfere with other parts, and can be easily assembled.

  In the fifth invention, in particular, the shield plate of the first invention covers the three side surfaces of the noise filter substrate holding part, opens the upper part of the noise filter unit as a wiring outlet, and the metal frame at the time of assembly has the noise The configuration covering the upper part of the filter unit makes it easy to connect the power cord and the like from the upper opening of the noise filter unit, and the metal part is electrically connected to the ground by screwing or the like, resulting in a potential difference of 0. Since the metallic frame further covers the noise filter unit, the noise leakage reduction effect can be enhanced.

  In the sixth invention, in particular, the shield plate of the first invention is provided with a screw hole for fixing and connecting to the main body of the metal shell with a screw and grounding, so that the leakage magnetic flux generated in the heating coil is provided in the main body. Since the shield is shielded by the outer shell and the shield plate, the shield plate is connected to the ground by screwing, and the shield plate is at the same potential as the ground, which is the ground potential, so that noise is absorbed, so that the noise shielding performance can be improved. Furthermore, it can also play a role of fixing the noise filter unit itself inside the main body.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 shows the overall configuration of an induction heating cooker according to the first embodiment of the present invention.

The main body 1 bends metal into a box shape, has an opening on the upper side, and installs the top plate 2 on which the cooked utensils arranged so as to cover the upper opening of the main body 1 and the top plate 2 are installed on the main body 1. For this purpose, it is composed of a metal frame 3 having screw holes for supporting and connecting the top plate 2. In addition, the induction heating cooker of the present invention includes an induction heating coil 4 for heating a cooked utensil provided below the top plate 2, and introduces a commercial power source 5 and the commercial power source 5 into the main body 1. A control unit 8 having an inverter circuit 7 for generating a high-frequency current in the heating coil 4 with the commercial power supply 5 as an input, and a noise filter for supplying a DC constant voltage to the control circuit or the like with the commercial power supply 5 as an input. The main body 1 is controlled and driven by the control circuit via the substrate 9. The noise filter substrate 9 suppresses noise that is generated in the control unit 8 or the like and is superimposed on a current path that is connected to the power cord, and exits from the power cord.

  Further, a noise filter substrate 9, a resin noise filter substrate holding part 10 for holding the noise filter substrate 9, and a metal shield plate 11 for shielding noise from the noise filter substrate 9, 1 The noise filter unit 12 is configured such that the rear surface of the noise filter unit 12 is opposed to the rear surface of the main body 1 with a predetermined interval.

  Here, the noise filter unit 12 is arranged vertically in the main body 1, the side surface of the noise filter substrate 9 faces the front surface side of the main body 1, and the shield plate 11 includes three side surfaces of the noise filter substrate holding unit 10. And the uncovered side is arranged so as to face the main body 1 of the metal shell, the upper part of the noise filter unit 12 is opened as a wiring outlet, and the metal frame 3 is the noise filter unit during assembly. 12 It is set as the structure which covers upper direction. In addition, a cooling fan 13 installed in the main body 1 for blowing air from the front to the rear, and a slit hole 14 is provided in the shield plate 11 at an opposing position.

  The noise filter unit 12 is provided below the exhaust port 15 provided on the top surface 2, and the heat generating component 16 mounted on the noise filter substrate 9, for example, a coil, is a slit provided on the shield plate 11. It is cooled by the cooling air introduced from the hole 14. Furthermore, since the predetermined distance (for example, 5 mm) between the side not covered with the shield plate 11 of the noise filter substrate holding unit 10 and the outline of the main body 1 is opposed, the cooling air passes through the gap, A cross-sectional area of the cooling air passage exhausted from the exhaust port 15 is secured.

  With the above configuration, as shown in FIG. 2, the cooling air from the cooling fan 13 enters from the slit hole 14 provided in the shield plate 11, is guided to the side surface of the noise filter substrate 9, and is exhausted from the exhaust port 15. Since the cooling air path can be secured, the noise filter unit 12 having the heat generating component 16 and the like mounted on the noise filter substrate 9 can be efficiently cooled.

  Further, the slit hole 14 is arranged on the air path from the cooling fan 13 to the slit hole 14 in a portion where the heat sink for cooling the switching element of the inverter circuit 7 included in the control unit 8 is not present, for example, on the upper rear side passing above the heat sink. Thus, the cooling air having a low temperature rise is guided into the noise filter unit 12, and the cooling efficiency can be further improved.

  In addition, by arranging the noise filter unit 12 vertically in the main body 1, the noise filter unit 12 is mounted with high density in the space within the restricted main body 1 in many cases where there is almost no space for mounting the unit in the horizontal direction. can do. Furthermore, since it can be configured with high density as described above, the range in which the noise filter unit 12 covers the cooling air exhaust path of the control unit 8 on which the inverter circuit 7 on the cooling fan 13 side is mounted in front of the noise filter unit 12. The cooling efficiency can be improved. When the power cord 6 is connected from above the main body 1, the length of the cord 17 for connecting the power cord 6 and the noise filter substrate 9 from the upper opening of the filter unit 12 can be minimized, and noise superimposition can be performed. Can be reduced.

  Furthermore, although the upper part of the noise filter unit 12 is opened for connection, noise leakage to the noise filter unit 12 can be reduced by covering the upper part with the frame 3 made of a metal member. In addition, the frame 3 is connected to the metal shell by screwing or the like and is electrically connected to the ground. The frame 3 covers the upper opening of the noise filter unit 12 at the same potential as the ground, so that the noise reduction effect can be further enhanced. it can.

(Embodiment 2)
FIG. 3 shows a noise filter unit of the induction heating cooker in Embodiment 2 of the present invention.

  In the present embodiment, a wiring fixing unit 19 is further provided on the bottom surface of the noise filter substrate holding unit 10 of the first embodiment for fixing the wiring 18 that comes out of the noise filter substrate 9 and is connected to the control unit 8. Yes. The wiring fixing portion 19 is not limited to be provided only on the bottom surface of the noise filter substrate holding portion 10. Others are the same as those in the first embodiment, and thus the description thereof is omitted.

  With the above configuration, when the noise filter unit 12 is installed in the main body 1, the wiring 18 can be incorporated while being fixed to the wiring fixing portion 19, so that the wiring 18 interferes with other parts and is difficult to incorporate. Can be easily prevented.

  Further, since the position of the wiring 18 is fixed, it is not unspecified that the wirings 18 are separated or close to each other. Therefore, the variation in the loop area where the wires are separated from each other is reduced, and the noise superimposed on the loop area can be reduced and the variation can be suppressed when the wires 18 are close to each other.

(Embodiment 3)
FIG. 4 shows a noise filter unit of the induction heating cooker in Embodiment 3 of the present invention.

  In the present embodiment, the shield plate 11 according to the first embodiment is cut and raised to constitute the screw 20, and the screw hole 21 is provided in the cut and raised 20. The screw hole 21 may not be provided in the cut and raised part 20 of the shield plate 11, and a metal plate 22 provided with the screw hole 21 may be welded to the shield plate 11 as shown in FIG. 5. However, in this case, the metal plate 22 and the shield plate 11 are electrically connected. Others are the same as those in the first embodiment, and thus the description thereof is omitted.

  By adopting the above configuration, the casing constituting the outline of the main body 1 is connected to the ground via the power cord, so that the leakage magnetic flux generated in the heating coil 4 is shielded by the main body 1 outline and the shield plate 11, Since the shield plate 11 is cut and raised 20 and through the screw hole 21 of the metal plate 22, it is connected to the housing via screws by screw tightening and connected to the ground via the power cord, and is absorbed by the ground as a ground potential portion. The noise shielding performance can be improved.

  Furthermore, the role of fixing the noise filter unit 12 itself inside the main body 1 can be fulfilled at the same time.

  As described above, since the induction heating cooker according to the present invention increases the cooling efficiency of the noise filter unit and reduces noise superposition, it can also be applied to uses such as a heating cooker having a noise filter unit.

DESCRIPTION OF SYMBOLS 1 Main body 2 Top plate 3 Frame 4 Induction heating coil 5 Commercial power supply 6 Power cord 7 Inverter circuit 8 Control unit 9 Noise filter board 10 Noise filter board holding part 11 Shield board 12 Noise filter unit 13 Cooling fan 14 Slit hole 15 Exhaust port 16 Heat-generating component 17 Code 18 Wiring 19 Wiring fixing part 20 Cutting and raising 21 Screw hole 22 Metal plate 23 Rectifier circuit 24 Main unit 25 Main unit housing 26 Roaster 27 Inlet 28 Switching power supply

Claims (6)

A main body, a top plate for placing a cooking utensil disposed on the top surface of the main body, a metal frame that supports the top plate for installing the top plate on the main body, and An induction heating coil provided below, a commercial power source, a power cord, a control unit having an inverter circuit for generating a high-frequency current in the induction heating coil with the commercial power source from the power cord as an input, and the power cord A noise filter substrate that is connected between the control unit and the control unit and suppresses noise that is generated in the control unit or the like and is superimposed on a current path that is connected to the power cord and exits from the power cord, and the noise filter substrate. Resin-made noise filter substrate holding part to hold the noise, noise from the noise filter substrate and noise from the induction heating coil, etc. A shield plate made of metal for cooling, a cooling fan for blowing air from the front to the back, and an exhaust port provided on the top surface for exhausting the cooling air, and the noise filter substrate and the noise An induction heating cooker configured such that the filter substrate holding part and the shield plate are configured as a noise filter unit, and the rear surface of the noise filter unit is opposed to the rear surface of the main body with a predetermined interval. The induction heating cooker according to claim 1, wherein a slit hole is provided in the shield plate at a position facing the cooling fan. The induction heating cooker according to claim 2, wherein the noise filter unit is arranged vertically in the main body, and the side surface of the noise filter substrate faces the front side of the main body. 2. The induction heating cooker according to claim 1, wherein a wiring fixing part for fixing a wiring coming out of the noise filter substrate is provided on the noise filter substrate holding part. The shield plate covers three side surfaces of the noise filter substrate holding portion, opens the upper portion of the noise filter unit to be a wiring outlet, and has a structure in which a metal frame covers the upper portion of the noise filter unit at the time of assembly. Induction heating cooker. The induction heating cooker according to claim 1, wherein the shield plate is provided with a screw hole for a fixed connection with the main body and a ground connection with screws.