JP2001267054A - Induction heating cooker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent two fans of the two cooling units used for cooling a board consituting two inverter circuits driving two induction heating coils from generating a resonance and a howling noise giving rise to a louder noise, and to prevent after-cooling hot air from hitting a user of the cooker or raising temperature of the inside of the cabinet which is a natural result of the necessity of exhausting air toward front or into the inside of a cabinet since each fan needs an air intake port is necessary, and further, to avoid a cost hike. SOLUTION: The induction heating cooker has a structure of a multistage stack of boards for cooling, with a plurality of induction heating coils 3, a plurality of boards 8 which drive the coils 3, a fan 10 cooling the base, and a motor 12 driving the fan 10. Cooling air can be sent by one fan to the plurality of the boards arrayed in parallel, so all the boards are hit by cooling air, and can be cooled effectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an induction heating cooker having a plurality of induction heating coils and a plurality of inverters for driving them.

[0002]

2. Description of the Related Art In recent years, with the airtightness of houses, induction heating cookers have begun to spread as heating cookers used in kitchens, as fire-free, safe and clean heat sources free of combustion gas. . The conventional configuration of these induction heating cookers is as follows.

FIG. 7 shows a schematic configuration of the whole conventional induction heating cooker. This induction heating cooker is configured to be used by being incorporated in a cabinet 1 of a system kitchen. The top plate 2 is placed on the upper surface of the outer case 7, and two induction heating coils 3-a and b and one heater 4 are installed under the top plate. Further, two induction heating coils 3 are provided inside the outer case 7.
-Substrates 8-a and b constituting two inverter circuits for driving a and b are provided. The substrate 8-a is placed on the roaster 5 and the substrate 8-b is placed flat on the operation unit 6, and the outside air sucked from the air inlet 13 provided at the rear of the top plate 2 is supplied to the substrate 8 respectively. -A cooling configuration in which air is blown toward a and b and exhausted from the front to the outside of the body.

Usually, two sets of cooling devices are required for the boards 8-a and 8-b forming two inverter circuits from the viewpoint of the size, arrangement, cooling performance, and the like of the boards. The cooling device includes a fan 10, a motor 12 for driving the fan, and a cooling duct (not shown) for guiding cooling air to heat-generating components forming an inverter circuit. The cooling air from the fan 10 forces the inverter circuit. It is designed to cool down.

[0005] In addition, the roaster 5, an operating unit 6 for operating the heating units (the induction heating coils 3-a and b, the heater 4, and the roaster 5), and a display unit (not shown) for indicating the heating state of each heating unit Is installed.

[0006]

However, there is a substrate constituting two inverter circuits for driving two induction heating coils, and two sets of cooling devices for cooling the circuit are required. The configuration was not excellent in cooling efficiency with respect to the calorific value. In such a configuration, there is a problem that resonance occurs due to the two fans, a beat sound is generated, noise is increased, and a sense of hearing is poor. In addition, since a large air inlet area is required for each fan, it is not possible to secure an equivalent exhaust area behind the top plate on the top surface. Therefore, the exhaust air must be forward or inside the cabinet. As a result, the hot air after cooling hits the cooker user or raises the temperature inside the cabinet. Further, since there are two sets of cooling devices, the cost increases.

[0007] On the other hand, in addition to the substrate, those requiring cooling include an induction heating coil and an outer case around the roaster. As a means for cooling these, a cooling unit may be provided exclusively, but it is considered difficult due to cost and space restrictions.

[0008]

According to the present invention, there is provided a drive circuit board provided with a plurality of induction heating coils and a plurality of inverter circuits for driving the coils.
A fan for cooling these inverter circuits and a motor for driving the fans are provided, the boards are stacked and mounted in multiple stages, and an inverter circuit portion is provided near the fans.

In the configuration described above, since a single fan can send cooling air to a plurality of substrates in parallel, a cool air hits any of the substrates, and cooling can be performed efficiently. Thereafter, the air used for cooling the substrate is sent around the induction heating coil and the roaster to be cooled.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a first embodiment of the present invention; FIG. 2 is a schematic diagram of a first embodiment of the present invention; A motor is provided, the boards are stacked and mounted in multiple stages, and an inverter circuit section is provided near a fan, and cooling is performed by sending air in parallel to heating elements on a plurality of boards. Therefore, the cool air can hit the elements on any of the substrates, and the elements can be efficiently cooled. Therefore,
Only one fan, fan case, and motor are required, and the two fans have the effect that resonance occurs, no humming noise is generated, and noise can be reduced. In addition, costs can be reduced.

According to a second aspect of the present invention, there are provided a plurality of induction heating coils, a board constituting a plurality of inverter circuits for driving the coils, a fan for cooling the inverter circuits, and a motor for driving the fans. The above-mentioned boards are stacked and attached in multiple stages, and the induction heating coils placed on the stacked drive circuit boards are energized from the uppermost drive circuit board.
Since the distance to -a is short, the connection to the induction heating coil can be made with a short conducting wire, and the large current portion where noise is easily applied becomes short, so that it has an effect of being less susceptible to noise.

According to a third aspect of the present invention, an inverter circuit for driving a plurality of induction heating coils is formed on separate substrates.
The substrates have substantially the same shape and are arranged so as to be shifted from each other when viewed from above. Since the upper substrate is shifted, the hot air after cooling is improved and the cooling efficiency is increased. Also, in the case of wiring between boards, wiring after the board is installed, etc., work efficiency at the time of assembly and service is increased by providing a terminal at a place where there is no board on the board and connecting it there. It has such an effect.

According to a fourth aspect of the present invention, the substrate having the largest outer shape is placed below, and the substrate becomes smaller as it goes upward. The escape of hot air after cooling is improved, and the cooling efficiency is increased. Also, in the case of wiring between boards, wiring after the board is installed, etc., work efficiency at the time of assembly and service is increased by providing a terminal at a place where there is no board on the board and connecting it there. It has such an effect.

According to a fifth aspect of the present invention, a power supply wire is connected to the lowermost substrate. Since a large current portion where noise tends to be generated is shortened, the distance from the induction heating coil is increased. Has the effect of being less affected by noise and stabilizing the quality.

According to a sixth aspect of the present invention, a plurality of induction heating coils are connected to a substrate placed at the top. When a plurality of substrates are unitized, the connection is made after the substrates are assembled. Thus, the induction heating coil can be easily attached, and the working efficiency at the time of assembling and service is improved.

According to a seventh aspect of the present invention, when it is necessary to reduce the output of any one of the heaters and control the total to be 4.8 kW, the induction heating coil driven by the lower substrate is required. The output is suppressed, and even when the heating value inside the heating cooker is maximized when all heaters are used, the cooling performance of the upper and lower substrates can be balanced and stable cooling performance can be obtained. Has the effect of being able to.

According to the eighth aspect of the present invention, when the output of one of the induction heating coils is increased to 2.4 kW or 3 kW, the induction heating coil on the high output side where the heat generation amount of the substrate is large is controlled. The board with the inverter circuit to be placed is placed on the upper side, and the board board with the inverter circuit for controlling the low-output induction heating coil with the least heat generation of the board is placed at the bottom. By preferentially suppressing the output of boards with poor cooling performance, the cooling performance of the heating elements on each stacked board can be balanced, and even in the worst-case usage conditions, stable cooling performance can be achieved. Can be obtained.

According to a ninth aspect of the present invention, a substrate base for holding a substrate is provided on each substrate, and the upper substrate base constitutes a cooling duct for the lower substrate. By having one component, there is an effect that the material cost can be reduced and the work process can be shortened.

According to a tenth aspect of the present invention, the component supporting the induction heating coil constitutes a cooling duct of the uppermost substrate, and the two components, the support component of the induction heating coil and the duct, constitute one component. This has the effect of reducing material costs and shortening the work process.

According to the eleventh aspect of the present invention, a centrifugal fan (sirocco fan) is used and its rotation axis is set in the vertical direction. Even when there is an obstacle (cooled object) in the vicinity of the fan. , While maintaining the cooling performance,
After guiding from the intake port provided at the rear of the top of the heating cooker to the vicinity of the bottom of the outer case, it is possible to take measures against flooding by sucking it with a fan, and compared to using an axial fan. Therefore, it has the effect of reducing noise and making it easier to hear as sound quality.

[0021]

(Embodiment 1) Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a schematic configuration of the whole induction heating cooker of the present invention. This induction heating cooker is a system kitchen cabinet 1
It is of a configuration that is used by incorporating it into a. A glass top plate 2 is provided at the top of the cabinet 1. Under the top plate 2, two induction heating coils 3-a and b are provided on the left and right sides, and a one-port radiant heater 4 is provided on the center back.
Is placed. On the front, on the left, roaster 5
The operation unit 6 is placed on the right side, and these are housed in the outer case 7.

FIG. 2 is a sectional view of the right side of the induction heating cooker. Inside the outer case 7, a plurality of drive circuit boards 8-a and b (hereinafter, referred to as boards) constituting an inverter circuit for driving and controlling the induction heating coils 3-a and b are respectively formed of a resin-made board base 9-. a, b, the lower substrate base 9-b is configured to support the upper substrate base 9-a, and a plurality of substrates are stacked and placed (see FIG. 5). The lower substrate base 9-b is fixed to the outer case 7. A fan 10 (centrifugal fan in the drawing) is attached to the back of the substrates 8-a and 8-b,
5 is provided so as to straddle the upper and lower substrates 8-a and 8-b. A fan case 11 (constituting a casing) is provided around the fan 10, and a motor 12 for driving the fan 10 is mounted on the upper part of the fan case 11.

A top plate 2 is provided on the top surface,
An induction heating coil 3 is placed under the coil, and is supported by a spring 18 from below to be pressed against the top plate 2 so that the distance between the top plate and the induction heating coil can be kept constant. The spring 18 is supported and positioned by a coil support plate 20, and the coil support plate 20 is placed on the upper substrate base 9-a.

Next, a method of cooling the inverter circuits on the substrates 8-a and 8-b will be described. First, top plate 2
Outside air enters through an intake port 13 provided at the rear, passes through an intake duct section 14 of the fan case 11, and is sucked from below the fan 10. The air sucked into the fan 12
The heat is discharged from the discharge port 15 toward the heat sink 16 placed on the substrates 8-a and 8-b, so that the heating element (not shown) constituting the inverter circuit attached to the heat sink 16 is cooled. ing. In FIG.
The fan 10 is a double suction type, and the motor 12
The structure is such that the air and the bearings of the motor 12 are cooled by passing air from the side where the motor is installed.

Although there is a possibility that water enters from the intake port 13 due to the structure, it is necessary to prevent water from being applied to the fan 10, the motor 12, and the substrate 8. Therefore, by adopting a configuration in which the air is once guided downward by the intake duct portion 14 and then sucked up by the fan 10, water and the like accumulate in the lower portion of the fan case 11 and only air is
-Sent to a, b. The accumulated water spontaneously evaporates if the amount is small, and if the amount is large, the drainage port (not shown) provided at the bottom of the fan case 11 connects the outer case 7 and the bottom substrate base 9-b. The space is drained from below the operation section 6 to the outside of the vessel through the space. Further, as one of the countermeasures against such overflow, the motor 12 is configured to be mounted on the upper part of the fan case 11. Louvres and filters can be installed to increase the effectiveness of flood control.

According to the above embodiment, the following effects can be obtained. By stacking the boards 8-a and b constituting the plurality of inverter circuits in multiple stages, the switching elements fixed to the heat sink 16 on the plurality of boards 8 and other heating elements can be cooled in parallel. Cold air hits the elements on any of the substrates 8 and can be efficiently cooled. Therefore,
There are two substrates 8-a and b corresponding to the two induction heating coils 3-a and b, which are the conventional configuration.
Unlike the configuration in which two cooling devices are required for -a and b, the problem of resonance occurring due to the presence of two fans and generating a beat noise is eliminated. At the same time, only one fan 10, fan case 11, and motor 12 are required, so that material costs can be reduced and work steps can be shortened.

Further, in the conventional configuration, the substrate 8-b is installed on the roaster 5. However, since the substrate 8-b can be installed apart from the roaster 5, the heat from the roaster 5 can be reduced. Transmission can be reduced, and the cooling efficiency increases. In addition, since the substrate 8-b is not provided on the roaster 5, the height of the roaster 5 can be increased. , The roaster 5 can also be made into a double-sided baking configuration.

Furthermore, since the intake port 13 and the exhaust port can both be provided at the rear of the top plate 2, there is a problem that the cooled hot air hits the cooker user and raises the temperature inside the cabinet 1. Can be solved.

Further, since a plurality of substrates 8 can be unitized and assembled, a plurality of substrates 8-a and b can be handled at a time, and work efficiency during assembly and service is increased. Further, the wiring between the stacked substrates 8-a and b and the wiring to the operation unit 6 can be shortened, which leads to a reduction in material costs.

(Embodiment 2) Hereinafter, a second embodiment of the present invention will be described with reference to the drawings. FIG. 3 is a sectional view of the right side surface of the induction heating cooker. Outer case 7
, A plurality of substrates 8-a and 8-b constituting an inverter circuit for driving and controlling the induction heating coil 3 are stacked. The respective substrates 8-a, b are fixed to resin substrate bases 9-a, b. Substrate base 9
Are formed in a wall shape, and the lower substrate base 9 supports and fixes the upper substrate base 9. The lower substrate base 9-b is fixed to the outer case 7. Also,
A top plate 2 is provided on the top surface, and an induction heating coil 3 is placed underneath. It is configured to keep it constant. Further, the spring 18 is supported and positioned by the coil support plate 20, and the coil support plate 2
0 is located on the upper substrate base 9-a.

With respect to the induction heating coil 3-a placed on the side on which such a substrate is installed, the power supply to the induction heating coil from the drive circuit is applied to the top of the stacked substrates. It was configured to be performed from the substrate 8-a.

Although the coil support plate 20 is located below the induction heating coil 3-a, the heat sink 16 on the upper substrate 8-a, cooling of the element, and cooling of the induction heating coil 3-a are required. However, the heat sink 16 and the induction heating coil 3
In consideration of the insulation between the substrate 8-a and the induction heating coil 3,
It is preferable that the coil support plates located between them are partitioned by resin to form cooling passages respectively.

According to the above-described embodiment, the following effects can be obtained. Since the distance between the substrate and the induction heating coil 3-a is short, connection can be made with a short conducting wire, and the large current portion where noise is easily applied becomes short, so that it is less affected by noise and the quality is stabilized. Further, since the resistance of the electric wire itself is reduced, heat generation can be suppressed. In addition, material costs can be reduced because only short wires are required.

Embodiment 3 Hereinafter, a third embodiment of the present invention will be described with reference to the drawings. FIG. 3 is a sectional view of the right side surface of the induction heating cooker. Outer case 7
Inside, a plurality of drive circuit boards 8-a, which constitute an inverter circuit for driving and controlling the induction heating coils 3-a, b,
b (hereinafter referred to as a substrate) is a substrate base 9 made of resin, respectively.
-A, b, the lower substrate base 9-b supports the upper substrate base 9-a, and a plurality of substrates are stacked and placed (see FIG. 5). The lower substrate base 9-b is fixed to the outer case 7. A fan 10 (a centrifugal fan in the drawing) is provided behind the boards 8-a and 8-b.
Is attached, and the discharge port 15 is provided so as to straddle the upper and lower substrates 8-a and 8-b. A fan case 11 (constituting a casing) is provided around the fan 10, and a motor 12 for driving the fan 10 is connected to the fan case 1.
1 attached to the top.

FIG. 4 is a plan view of a board constituting an inverter circuit for driving the induction heating coil of the induction heating cooker. The respective substrates 8-a and b have substantially the same shape, and the arrangement of heat-generating components such as heat sinks and capacitors placed on the substrates 8-a and b is substantially the same. Is concentrated on However, the upper substrate 8-a is shifted to the left rear with respect to the lower substrate 8-b (the left is the front in FIG. 4).
The terminal 21 is arranged in such a portion that does not overlap with the substrate 8-a, and a lead wire (not shown) is connected to the terminal 21.

According to the above-described embodiment, the following effects can be obtained. By arranging the heat sinks 16 and the heat generating elements on the plurality of substrates 8-a and b near the discharge port 15 of the fan 10, any of the heat generating elements can be efficiently cooled by the wind. Therefore, since cooling can be performed even with a small amount of air, noise countermeasures such as lowering the rotation speed of the fan 10 and changing the shape of the blades can be taken, and noise can be reduced.

Further, the upper substrate 8-a is replaced with the lower substrate 8-b
, The hot air after cooling easily rises, and the cooling efficiency increases. Also, the upper substrate 8-
Since a is small, the outlet area of the wind passing through the lower substrate 8-b is increased, so that the ventilation resistance is also reduced. In addition, by aligning the front end surfaces of the upper and lower substrates 8-a, b, the distance between the upper substrate 8-a and the operation unit 6 is reduced due to the configuration of the operation unit 6. , And the outlet area of the wind passing through the lower substrate 8-b is increased, and the same effect can be obtained.

Further, when wiring is performed between the boards 8-a and 8-b and wiring after the board is installed, even when a lead wire is connected to the lower board 8-b, the upper board 8-a does not overlap. However, by providing the terminal 21 and connecting it to the terminal 21, work efficiency at the time of assembly and service is increased. Further, the wiring between the stacked substrates 8-a and b and the wiring to the operation unit 6 can be shortened, which leads to a reduction in material costs.

(Embodiment 4) Hereinafter, a fourth embodiment of the present invention will be described with reference to the drawings. FIG. 4 is a plan view of a board constituting an inverter circuit for driving an induction heating coil of the induction heating cooker. The outer shape of the upper substrate 8-a is smaller than that of the lower substrate 8-b. As a result, there are non-overlapping portions of the substrate. The terminal 21 is arranged in such a portion that does not overlap the substrate, and a lead wire is connected to the terminal 21.

As shown in FIG. 5, the shape of the lower substrate is substantially the same as that of the upper substrate, and a certain part is added (FIG. 5).
2) Terminal 2
It is also conceivable to arrange them in a concentrated manner and connect the lead wires.

According to the above-described embodiment, the following effects can be obtained. By arranging the heat sinks 16 and the heat generating elements on the plurality of substrates 8-a and b near the discharge port 15 of the fan 10, any of the heat generating elements can be efficiently cooled by the wind. Therefore, since cooling can be performed even with a small amount of air, noise countermeasures such as lowering the rotation speed of the fan 10 and changing the shape of the blades can be taken, and noise can be reduced.

Further, the upper substrate 8-a is replaced with the lower substrate 8-b.
, The hot air after cooling easily rises, and the cooling efficiency increases. Further, the lower substrate 8-
Since the outlet area of the wind passing through b becomes large, the ventilation resistance is also reduced.

Further, when wiring is performed between the substrates 8-a and 8-b and wiring after the substrates are installed, even when a lead wire is connected to the lower substrate 8-b, the upper substrate 8-a does not overlap. However, by providing the terminal 21 and connecting it to the terminal 21, work efficiency at the time of assembly and service is increased. Further, the wiring between the stacked substrates 8-a and b and the wiring to the operation unit 6 can be shortened, which leads to a reduction in material costs.

(Embodiment 5) Hereinafter, a fifth embodiment of the present invention will be described with reference to the drawings. FIG. 3 is a cross-sectional view of the right side of the induction heating cooker, and FIG. 4 is a plan view of a substrate constituting an inverter circuit for driving the induction heating coil of the induction heating cooker. In order to supply power from an external power source, the induction heating cooker has a power cord for connecting an outlet in a cabinet and a board. In general, the power cord 17 protrudes outside the outer case (inside the cabinet) from a hole in the inner surface of the outer case 7. In this configuration, the power cord 17 is connected to the board 8 placed at the bottom. In this case, the connection between the terminal on the board and the power cord is done by setting the board in the outer case and then fixing it to the power cord and the terminal with screws. It is preferable to arrange the power supply terminal 21 in a place where the substrates do not overlap and connect the power supply cord 17 to the terminal 21 because the work during assembly and service is facilitated.

According to the above-described embodiment, the following effects can be obtained. Power supply terminal 2 at the back of the lower substrate
1 and connecting to it, the power supply wire can be shortened, and the material cost can be reduced. In addition, since the large current portion where noise is likely to flow is shortened, the distance is increased from the induction heating coils 3-a and 3-b, the influence of the noise is reduced, and the quality is stabilized. Further, since the resistance of the electric wire itself is reduced, heat generation can be suppressed.

(Embodiment 6) Hereinafter, a sixth embodiment of the present invention will be described with reference to the drawings. FIG. 6 is a plan view of a substrate constituting an inverter circuit for driving an induction heating coil of the induction heating cooker. A typical induction heating cooker has two induction heating coils on the left and right. In order to drive two induction heating coils, there was a substrate constituting two inverter circuits, and each substrate was connected to the induction heating coil. In contrast to such a configuration, as shown in FIG. 6, a connection terminal 21 is provided on the uppermost substrate 8-a, and an induction heating coil 3-a is connected to the terminal 21.

According to the above-described embodiment, the following effects can be obtained. Generally, the induction heating coil is directly below the top plate, so that the board is assembled and then connected to the board. Also, since a large current flows through the induction heating coil, the wire diameter is large and hard, so that it is difficult to connect to a narrow place. From such a point, by providing the connection terminal 21 on the substrate 8-a placed on the top and connecting the terminal 21 to the induction heating coils 3-a and b,
The induction heating coils 3-a, b connected after incorporating the substrates 8-a, b can be easily attached.
This has the effect of increasing work efficiency during service. Also, regarding the power cord 17, the boards 8-a, b
Is generally connected to the substrates 8-a and b after being assembled, and is the same in that the wire diameter is large and hard.
Like the induction heating coils 3-a and b, the uppermost substrate 8-a
By adopting a configuration to connect to the system, the work efficiency at the time of assembly and service is further improved.

Embodiment 7 Hereinafter, a seventh embodiment of the present invention will be described with reference to the drawings. FIG. 2 is a sectional view of the right side surface of the induction heating cooker. Generally, the maximum value of the total power consumption of a 200 V cooking heater is 4.8 kW (extension rule). When two IH heaters and a roaster are used at the same time, for example, when two 2 kW IH heaters and a 1.2 kW roaster are used at the same time, the total power exceeds 4.8 kW. It is necessary to control the total to be 4.8 kW. In this case, if the output of the roaster is suppressed, the cooking performance is reduced. Therefore, the output of the IH heater is generally reduced. When suppressing the output of any one of the induction heating coils, the induction heating coil 3-b is driven by the lower substrate 8-b. As is clear from FIG. 2, since the lower substrate 8-b has a configuration in which the cooling air does not easily pass through on the pattern side (back side), the heat generation amounts of the upper and lower substrates 8-a and 8-b are the same. If there is, the lower substrate 8
-B has a configuration that is less likely to be cooled. When all heaters are used, the substrates 8-a, b, the induction heating coil 3-a,
b. The heat generated by the roaster 5 maximizes the amount of heat generated in the heating cooker, resulting in reduced cooling performance. Therefore, under such use conditions, the output of the IH heater driven by the inverter circuit of the lower substrate 8-b is reduced to balance the cooling performance of the upper and lower substrates 8-a and 8-b. In addition, the cooling performance can be made constant by adjusting the number of revolutions of the cooling fan 10 according to the amount of heat generated by the inverter circuit and the temperature inside the case.

According to the above-described embodiment, the following effects can be obtained. In the usage condition where the heat generation inside the housing is maximized, by preferentially suppressing the output of the boards with poor cooling performance, the cooling performance of the heating elements on each stacked board can be balanced, and the worst Even in a conceivable use state, stable cooling performance can be obtained. As a result, the trouble of the heat-generating parts is reduced, and the quality is stabilized.

Embodiment 8 Hereinafter, an eighth embodiment of the present invention will be described with reference to the drawings. FIG. 2 is a sectional view of the right side surface of the induction heating cooker. In recent years, high heating power has also been desired for induction heating cookers. Therefore, the output of the two induction heating coils up to now is 2 kW
Unlike the one that has become, set a high thermal power heater,
Output power of either induction heating coil is 2.4kW or 3kW
And that is getting more and more. Increasing the output of the induction heating coil means that the amount of heat generated by the inverter circuit and the amount of heat generated by the induction heating coil are also increased. Therefore, the substrate on the high output side needs to be further cooled.

As described in the seventh embodiment, the cooling performance of the substrate is such that the lower substrate 8-b is deteriorated. Place the board with the inverter circuit that controls the coil on the upper side, and put the board with the inverter circuit that controls the low-output side induction heating coil that generates the least amount of heat on the board at the bottom. To be configured.

According to the above embodiment, the following effects can be obtained. By preferentially suppressing the output of boards with poor cooling performance, it is possible to balance the cooling performance of the heating elements on each stacked board, and to achieve stable cooling performance even in the worst-case usage conditions. Obtainable. As a result, the trouble of the heat-generating parts is reduced, and the quality is stabilized.

Embodiment 9 Hereinafter, a ninth embodiment of the present invention will be described with reference to the drawings. FIG. 2 is a sectional view of the right side surface of the induction heating cooker. Outer case 7
, A plurality of substrates 8-a, b constituting an inverter circuit for controlling the induction heating coils 3-a, b are stacked and placed. Each of the substrates 8-a, b is fixed to a resin-made substrate base 9-a, b, and the lower substrate base 9-b supports the upper substrate base 9-a (FIG. 5).
reference). The lowermost substrate base 9-b is fixed to the outer case 7.

FIG. 5 is a perspective view from the right front of the periphery of the substrate inside the induction heating cooker. The portion for supporting the substrate base (the left and right walls of the substrate base in FIG. 5) has a wall shape, and the wall and the upper substrate base 9-a form the substrate 8-b.
The cooling duct of the upper heat sink 16 is constituted. Further, the rib 19 is provided on the upper substrate base 9-a.
Is provided, and the cooling air is concentrated around the heat sink 16,
The cooling efficiency can be increased. In terms of cooling efficiency, it is better to make the distance between the upper end of the heat sink 16 and the upper substrate base 9 shorter in order to increase the wind speed around the heat sink 16. It causes loss. It is desirable to narrow the passage so as not to increase the pressure loss as much as possible. In addition, if a similar configuration is adopted for a heating element such as a capacitor in addition to the heat sink 16, cooling performance is improved.

According to the above-described embodiment, the following effects can be obtained. By providing a cooling duct,
Since the wind can be concentrated around the heat sink 16 and other heat generating elements on the boards 8-a and 8-b to increase the wind speed, the cooling performance of the inverter circuit is improved. for that reason,
Cooling can be performed with a small amount of air, and noise countermeasures such as lowering the rotation speed of the fan 10 and changing the shape of the blades can be taken, so that noise can be reduced. In addition, by configuring the two components, the substrate base and the cooling duct, into one, it is possible to reduce the material cost and to shorten the work steps at the time of assembly and service.

(Embodiment 10) Hereinafter, a tenth embodiment of the present invention will be described with reference to the drawings. FIG. 2 is a sectional view of the right side surface of the induction heating cooker. An induction heating coil 3 is placed under the top plate 2. The induction heating coil 3 is supported by a spring 18 and pressed against the top plate 2 so that the distance between the induction heating coil 3 and the top plate 2 becomes constant. A component for supporting and positioning the spring 18 is required, but a substrate on which the component (lid 19) is stacked constitutes a top cooling duct (see FIG. 5). Further, the coil support plate 20 also serves to insulate the induction heating coil 3 from the heat sink 16 on the substrate 8 and elements (not shown). Since the distance from the induction heating coil 3 is short, if the coil supporting plate 20 is formed of a sheet metal, there is a possibility of self-heating. Therefore, it is better to form this part with a resin.

Since the induction heating coil 3 itself generates heat, it needs to be cooled. As one of the cooling methods, it is conceivable to use air that has cooled the uppermost substrate 8. For this reason, a hole is provided in the coil support plate 20, and air is blown from the hole toward the induction heating coil 3. It is also conceivable to increase the seam between the substrate base 9 and the coil support plate 20 so that the wind is blown out therefrom.

According to the above-described embodiment, the following effects can be obtained. Two parts, the support part of the induction heating coil and the duct, can be constituted by one part, so that the material cost can be reduced and the work process can be shortened. In addition, by drilling holes in the support components, the air used for cooling the heat-generating components such as the heat sink 16 can be used for cooling the induction heating coil, thereby increasing the cooling efficiency.

Embodiment 11 Hereinafter, an eleventh embodiment of the present invention will be described with reference to the drawings. FIG. 2 is a sectional view of the right side surface of the induction heating cooker. A plurality of drive circuit boards 8-forming an inverter circuit for driving and controlling the induction heating coils 3-a and b are provided inside the outer case 7.
a and b (hereinafter, referred to as substrates) are stacked and placed. The respective substrates 8-a, 8-b are fixed to resin-made substrate bases 9-a, 9-b, and the lower substrate base 9-b supports the upper substrate base 9-a (FIG. 5). reference). The lower substrate base 9-b is fixed to the outer case 7. A fan 10 (centrifugal fan in the drawing) is attached to the back of the substrates 8-a, b, and the discharge port 15 is provided so as to straddle the upper and lower substrates 8-a, b. A fan case 11 (constituting a casing) is provided around the fan 10, and a motor 12 for driving the fan 10 is mounted on the upper part of the fan case 11. In such a configuration, the fan 12 is a centrifugal fan (a sirocco fan in the figure) and is installed so that the rotation axis is in the vertical direction. At this time, the position of the motor is set on the fan so that the charged portion of the motor is not splashed with water by the ingress of water from the intake port (measures against overflow). Further, the fan 10 is of a double suction type, so that air flows from the side where the motor 12 is installed, so that the windings and bearings of the motor 12 are cooled.

According to the above embodiment, the following effects can be obtained. By using a centrifugal fan (sirocco fan) with a strong blowing pressure, even if there is an obstacle (cooled object) near the fan in the arrangement of the board and cooling device in a limited space inside the outer case The cooling performance can be maintained without reducing the air volume unlike the axial fan.

When a sirocco fan is used, the suction port of the fan can be either up or down or both up and down by turning the rotating shaft up and down. It is possible to adopt a configuration in which the fan is sucked after guiding it from the intake port provided at the rear of the top of the body to the vicinity of the bottom of the outer case, and it is possible to make it difficult for the substrate (charging part) to be watered. .

Similarly, by installing the motor on the fan, it is possible to take measures against overflow of the motor charging section. As a result, even when cooked food (juice) overflows into the intake port, safety can be ensured without product breakdown. The centrifugal fan tends to have less noise and to be more audible than an axial fan.

[0063]

According to the first aspect of the present invention, a plurality of substrates constituting an inverter circuit are stacked in multiple stages and cooled, whereby a switching element fixed to a heat sink on the plurality of substrates, and other heating elements. Can be cooled in parallel, so that the cold air hits the elements on any of the substrates, and cooling can be performed efficiently.
Therefore, unlike the conventional configuration in which there are two substrates corresponding to the two induction heating coils and two cooling units are required for each of these substrates, resonance occurs due to the two fans and a beat sound is generated. And noise can be reduced. Further, only one fan, one fan case, and one motor are required, and the cost can be reduced.

Further, since the substrate can be set apart from the roaster, the transfer of heat from the roaster can be reduced, and the cooling efficiency can be improved. In addition, since there is no substrate on the roaster, the height of the roaster can be increased, and the size of the inside of the roaster is widened, thus improving usability. Also, the roaster can be a double-sided baking type.
Further, since a plurality of substrates can be assembled as a unit, a plurality of substrates can be handled at a time, so that the work efficiency at the time of assembly and service is improved. In addition, the wiring between the stacked substrates and the wiring to the operation unit can be shortened, which leads to a reduction in material costs.

According to the second aspect of the present invention, the configuration is such that the induction heating coils placed on the stacked substrates are energized from the substrate placed on the top, so that the substrate and the induction heating coils can be electrically connected to each other. Because the distance is short, the large current section where noise is likely to flow becomes shorter, making it less susceptible to noise.
Quality is stable.

According to the third aspect of the present invention, the drive circuit boards have substantially the same shape and are arranged so as to be shifted from each other when viewed from above.
By arranging the heating elements in the vicinity of the outlet of the fan, the air hits any of the heating elements and can be cooled efficiently, and can be cooled with a small amount of air. It is possible to take noise countermeasures such as changing the shape of the device, thereby reducing noise.
In addition, since the upper substrate is shifted with respect to the lower substrate, the heated air after cooling tends to rise, and the outlet area of the wind passing through the lower substrate is increased, so that the ventilation resistance is also reduced. The cooling efficiency is reduced.

According to the fourth aspect of the present invention, the drive circuit board having the largest outer shape is placed on the lower side, and the drive circuit board having the smaller outer shape is attached to the upper side. By arranging the heating elements in the vicinity of the outlet of the fan, any of the heating elements is hit by the wind and can be efficiently cooled.
Since cooling can be performed with a small air volume, noise countermeasures such as lowering the rotation speed of the fan 10 and changing the shape of the blades can be taken, and noise can be reduced. In addition, since the upper substrate is shifted with respect to the lower substrate, the heated air after cooling tends to rise, and the outlet area of the wind passing through the lower substrate is increased, so that the ventilation resistance is also reduced. The cooling efficiency is reduced.

According to the fifth aspect of the present invention, a power supply wire is connected to the lowermost drive circuit board, so that a power supply terminal is provided on the back side of the lower board and connected there. By doing so, the power supply wire can be shortened,
Material costs can be reduced. In addition, since the large current portion where noise is easily applied becomes short, the distance is increased from the induction heating coil, the influence of the noise is reduced, and the quality is stabilized. Further, since the resistance of the electric wire itself is reduced, heat generation can be suppressed.

According to the sixth aspect of the invention, by connecting a plurality of induction heating coils to the substrate placed on the uppermost portion, the induction heating coil to be connected after the substrate is assembled can be easily attached. This has the effect of increasing work efficiency during assembly and service.

According to the seventh aspect of the present invention, when the power consumption exceeds a preset power consumption, the output is reduced by the lowermost drive circuit board, so that the board with poor cooling performance is preferentially output. In this way, it is possible to balance the cooling performance of the heat-generating elements on each stacked substrate, even in the worst-case usage conditions.
Stable cooling performance can be obtained, troubles of heat-generating parts are reduced, and quality is stabilized.

According to the eighth aspect of the present invention, the maximum output is set in advance for a plurality of drive circuit boards, and the plurality of drive circuit boards are arranged from the top in descending order of the maximum output. By suppressing the output preferentially, it is possible to balance the cooling performance of the heating elements on each stacked substrate, and to obtain a stable cooling performance even in the worst use condition,
The trouble of heat-generating parts is reduced, and the quality is stabilized.

According to the ninth aspect of the present invention, a board base for supporting the drive circuit boards is provided on each of the drive circuit boards, and the periphery of the lower drive circuit board is covered with the upper board base, and the fan blower is used. By forming a passage, a cooling duct can be provided, and the wind can be concentrated around the heat sink and other heating elements on the board to increase the wind speed, thereby improving the cooling performance of the inverter circuit. I do. Therefore, cooling can be performed with a small amount of air flow, noise countermeasures such as lowering the number of rotations of the fan and changing the shape of the blades can be taken, and noise can be reduced.

According to the tenth aspect of the present invention, a coil support plate for supporting the induction heating coil is provided, the uppermost drive circuit board is covered with the coil support plate, and a fan air passage is formed. Thus, a cooling duct can be provided, and the wind can be concentrated around the heat sink and other heat generating elements on the substrate, thereby increasing the wind speed, thereby improving the cooling performance of the inverter circuit. Further, two parts, the supporting part of the induction heating coil and the duct, can be constituted by one part, so that the material cost can be reduced and the work process can be shortened.

According to the eleventh aspect of the present invention, by using a centrifugal fan and setting the rotation axis of the centrifugal fan in the vertical direction, the influence of pressure loss can be reduced even when there is an object to be cooled near the fan. Take measures to prevent flooding by keeping the cooling performance to a minimum and guiding the fan from the intake port provided behind the top of the cooking device to the bottom of the outer case, and then letting the fan suck it. Can be.
Further, compared with the case where an axial fan is used, the noise is reduced and the audibility is improved.

[Brief description of the drawings]

FIG. 1 is an external perspective view of a built-in induction heating cooker according to the present invention.

FIG. 2 is a cross-sectional view of a right side surface of the induction heating cooker according to the first embodiment of the present invention.

FIG. 3 is a sectional view of a right side surface of the induction heating cooker according to the second embodiment of the present invention.

FIG. 4 is a plan view of a substrate of an induction heating cooker according to a third embodiment of the present invention.

FIG. 5 is a plan view of a substrate of an induction heating cooker according to a fourth embodiment of the present invention.

FIG. 6 is a plan view of a substrate of an induction heating cooker according to a sixth embodiment of the present invention.

FIG. 7 is a schematic exploded perspective view of a conventional built-in induction heating cooker.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cabinet 2 Top plate 3-a, b Induction heating coil 4 Radiant heater 5 Roaster 6 Operating part 7 Outer case 8-a, b Drive circuit board 9-a, b Board base 10 Fan 11 Fan case 12 Motor 13 Inlet 14 Rib 15 Discharge port 16 Heat sink 17 Power cord 18 Spring 19 Rib 20 Coil support plate 21 Terminal 22 Coil cooling hole 23 Roaster cooling hole

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Akira Kataoka 1006 Kazuma Kadoma, Osaka Pref.Matsushita Electric Industrial Co., Ltd. F term (reference) 3K051 AA01 AB09 AC37 AD07 AD35 CD42 CD43

Claims (11)

[Claims] 1. A drive circuit board comprising: a top plate; a plurality of induction heating coils provided below the top plate; and a plurality of drive circuit boards each provided with an inverter circuit unit for driving the induction heating coil. A fan that blows the substrate, a motor that drives the fan, a roaster, an operation unit that operates the induction heating coil and the roaster, the induction heating coil, the drive circuit board, the fan, the motor, the roaster, An induction heating cooker having an outer case for accommodating the operation unit therein, wherein the drive circuit boards are stacked and mounted in multiple stages, and an inverter circuit unit of each drive circuit board is provided near a fan. 2. A drive circuit board comprising: a top plate; a plurality of induction heating coils provided below the top plate; and a plurality of drive circuit boards each provided with an inverter circuit unit for driving the induction heating coil. A fan that blows the substrate, a motor that drives the fan, a roaster, an operation unit that operates the induction heating coil and the roaster, the induction heating coil, the drive circuit board, the fan, the motor, the roaster, An outer casing for accommodating the operation unit therein, the drive circuit boards are stacked and mounted in multiple stages, and power is supplied to the induction heating coil placed on the stacked drive circuit boards from the uppermost drive circuit board Induction heating cooker configured. 3. The induction heating cooker according to claim 1, wherein the drive circuit boards have substantially the same shape and are arranged so as to be shifted from each other when viewed from above. 4. The induction heating cooker according to claim 1, wherein the drive circuit board having the largest outer shape is placed below, and is attached to the drive circuit board having the smaller outer shape as it goes upward. 5. The power supply line is connected to the lowermost drive circuit board.
An induction heating cooker as described. 6. The induction heating cooker according to claim 1, wherein a plurality of induction heating coils are connected to a substrate placed at an uppermost position. 7. The induction heating cooker according to claim 1, wherein when the power consumption exceeds a preset power consumption, the output is reduced by the lowermost drive circuit board. 8. The induction heating cooker according to claim 1, wherein a maximum output is previously set for a plurality of drive circuit boards, and the plurality of drive circuit boards are arranged from the top in descending order of the maximum output. 9. A structure in which a board base supporting the drive circuit board is provided on each drive circuit board, and a periphery of the lower drive circuit board is covered with an upper board base to form a fan air passage. The induction heating cooker according to claim 1 or 2. 10. A structure in which a coil support plate for supporting an induction heating coil is provided, the uppermost drive circuit board is covered with the coil support plate, and a fan air passage is formed.
Or the induction heating cooker according to claim 2. 11. A centrifugal fan, wherein the fan is installed so that the rotation axis of the fan is in the vertical direction, and the fan is blown to each drive circuit board.
The induction heating cooker according to claim 1 or 2.