JP2000332474A - Cooling structure for electrical components - Google Patents

Abstract

(57) [Problem] To provide a cooling structure of an electric component which can be made compact by providing a heat sink and a cooling fan in a rice cooker main body and can improve cooling efficiency. . SOLUTION: A heat sink 33 is provided with a boss portion 33q for attaching a fan, and the heat sink 33 is provided with a cooling fan 3q.
Connect 4 directly. Also, each fin 33 of the heat sink 33
f · 33g end face and fan case 34 of cooling fan 34
A predetermined gap 33s is provided between the end face c and the end face c. Thereby, the space between the heat sink 33 and the cooling fan 34 can be formed as small as possible, so that the overall size can be reduced, and the ventilation between the fins can be further improved. Smooths and improves cooling efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling structure for electric components in a cooking device such as a rice cooker.

[0002]

2. Description of the Related Art For example, a rice cooker is provided with an inner pan detachable from a rice cooker main body and a heating means for heating the inner pan. An example of the configuration of such a rice cooker will be described with reference to FIG. In the figure, reference numeral 51 denotes a rice cooker main body. The rice cooker main body 51 is formed by providing an outer case 52 and an inner case 53 forming an outer wall surface.
The inner pot 54 is accommodated therein. Electromagnetic induction coils 55 are disposed as heating means at the lower side of the inner case 54 and the outer peripheral side of the bottom part, and at a substantially intermediate height in the vertical direction. An eddy current is generated in the inner pot 54 with the energization of these coils 55.
The inner pot 54 generates heat, so that heating during rice cooking and heat retention after rice cooking are performed.

[0003] By the way, the induction heating method (IH
In the rice cooker of the formula), an electric component such as a power transistor having a large current capacity is used to control the energization of the electromagnetic induction coils 55. Such an electric component also generates a large amount of heat. Therefore, a heat sink 56 is provided to prevent overheating, and the electric component having a large amount of heat is attached to the heat sink, and its lead terminals are connected to the circuit board 57. Is adopted. In the figure, reference numeral 58 denotes a cooling fan fixed along the bottom wall of the outer case 52. Air is sent from the cooling fan 58 to the heat sink 56 to be cooled.

[0004]

However, in the conventional rice cooker described above, the cooling fan 58 is provided separately from the heat sink 56 attached to the circuit board 57.
In this case, the overall structural restrictions and assembly restrictions due to, for example, the position of the circuit board 57 and the shape of the outer case 52 are likely to occur. As a result, the relative positional relationship between the heat sink 56 and the cooling fan 58 cannot be adequately adjusted. As a result, for example, the space between the heat sink 56 and the cooling fan 58 is increased, and the overall size is reduced. Is not enough,
In addition, there is a problem in that the heat sink 56 is displaced from the air blow path from the cooling fan 58 so that sufficient cooling efficiency cannot be obtained.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and has as its object to reduce the size of a heating cooker such as a rice cooker as a whole.
An object of the present invention is to provide a cooling structure for an electric component that can improve cooling efficiency.

[0006]

SUMMARY OF THE INVENTION Therefore, a cooling structure for an electric component according to a first aspect of the present invention comprises a circuit board on which an electric component is mounted and a plurality of fins in a main body of a cooking device having a heating means. A heat sink arranged in parallel and a cooling fan for cooling the heat sink are provided, a specific electric component is attached to a component mounting portion of the heat sink, and a lead terminal of the specific electric component is fixed to the circuit board. A cooling case for a cooling fan attached to the heat sink, and a predetermined gap is provided between a tip end surface of each fin extending toward the blowing direction of the cooling fan and the fan case. Thus, the air gap is formed as a ventilation passage from the cooling fan.

As described above, the configuration in which the cooling fan is directly attached to the heat sink makes it easy to optimize the relative positional relationship between the cooling fan and the heat sink. As a result, the space between the two can be formed as small as possible, so that the overall size can be reduced and the cooling efficiency can be improved.

Particularly, in the above, a predetermined gap is provided between the tip surface of each fin and the fan case,
The cooling efficiency is further improved. In other words, the wind from the cooling fan has a large directivity in the area immediately after the cooling fan such that it goes obliquely outward from the axis in accordance with the torsion angle of the rotor blades. In the case of the shape extending to the fins, the wind will obliquely hit these fins. As a result, a so-called wind noise is generated, and the wind flowing between the fins is disturbed, so that a smooth air blowing state along the surface of each fin cannot be obtained, and the cooling efficiency is reduced. Therefore, by providing a predetermined gap between each fin and the fan case as described above, the above-described directionality at the time of reaching the tip end surface of each fin is relaxed, and thus, a more smooth airflow is provided between the fins. Cooling efficiency is improved as a state occurs.

According to a second aspect of the invention, there is provided a cooling structure for an electric component, wherein a fan motor directly connected to a shaft of a rotating blade of a cooling fan is located between the rotating blade and the heat sink. Features.

According to this configuration, for example, in the case of a cooling fan of a type in which the end face of the fan motor is substantially flush with the end face of the fan case, the gap between the rotor and the end face of each fin is reduced. It will spread further by the size of the fan motor in the axial direction. Therefore, the directionality when the wind from the cooling fan reaches the tip end surfaces of the respective fins is further reduced, so that the cooling efficiency is further improved.

On the other hand, in the case of a cooling fan in which the fan motor projects from the end face of the fan case, the projecting portion of the fan motor is located in a predetermined gap region between each fin and the cooling fan. Therefore, it is not necessary to separately provide an installation space dedicated to the protruding portion, so that the overall size can be reduced.

According to a third aspect of the present invention, there is provided a cooling structure for an electric component according to the first or second aspect, wherein an end fin is formed at a side end of the heat sink in contact with a fan case of the cooling fan. It is characterized in that the end fin is used as a guide wall of the air passage.

[0013] According to this configuration, the wind sent from the cooling fan while spreading is blocked by the end fins toward the outside, and the amount of the wind toward the heat sink is increased by that amount. Efficiency is improved.

According to a fourth aspect of the present invention, there is provided a cooling structure for an electric component according to the first, second or third aspect, wherein a notch is formed in the circuit board, and the notch intersects the notch so as to be substantially orthogonal to the circuit board. It is characterized in that it is fitted in a state of being fitted.

According to this structure, the length of each fin in the direction intersecting with the circuit board can be formed to be long so as to straddle both sides of the circuit board. The area can be larger, which improves the cooling efficiency. In addition, the size of the protrusion of the heat sink per side from the circuit board can be reduced as much as possible, so that the overall shape can be made more compact.

According to a fifth aspect of the present invention, there is provided a cooling structure for an electric component according to any one of the first to fourth aspects, wherein a blower passage through which a wind from a cooling fan passes is formed in the heat sink, and the blower is provided in the circuit board. An electric component having a large calorific value other than the specific electric component is disposed at a position on a ventilation path passing through the passage opening.

In this configuration, the wind from the cooling fan reaches the circuit board through the air passage of the heat sink, and cools the electrical components on the circuit board that generate a large amount of heat. Therefore, for example, even when a circuit is configured by providing an electrical component that is difficult to attach closely to a heat sink, such as a choke coil or a capacitor, even if the circuit is configured, by arranging this at the above-described position on the circuit board,
It is possible to prevent overheating by directly cooling with the air from the cooling fan. Thereby, circuit reliability is improved.

According to a sixth aspect of the present invention, there is provided a cooling structure for an electric component, wherein the ventilation passage is provided in a central region of the heat sink corresponding to a position on the axis of the cooling fan. .

According to this configuration, since the wind at the center having a higher wind speed hits the electric components on the circuit board from the cooling fan, the components are sufficiently cooled and the reliability is further improved. I do.

According to a seventh aspect of the present invention, there is provided the electrical component cooling structure according to the fifth or sixth aspect, wherein the heat sink is provided with horizontal fins oriented so as to guide the wind from the cooling fan to the side, and the circuit board is provided with a horizontal fin. Is characterized in that the electric component is arranged at a position where the wind flowing out of the heat sink is applied along the horizontal fins.

According to this structure, the electric components on the circuit board are further cooled by the air from the cooling fan by the cooling air flowing along the horizontal fins, so that the cooling efficiency is improved and the electric components are overheated. And the reliability is improved.

According to an eighth aspect of the present invention, in the electric component cooling structure according to any one of the first to seventh aspects, the heating cooker includes an inner case accommodating an inner pot and an outer case forming an outer body. A rice cooker in which a main body is formed, wherein the circuit board is disposed in a space formed between an inner case and an outer case, and a heat sink and a cooling fan are formed between a bottom side of the inner case and the outer case. It is characterized by being arranged in a space where

According to this configuration, as described above, the height dimension of the rice cooker main body can be made as small as possible by directly connecting the cooling fan to the heat sink.
By arranging the heat sink in the space around the curved portion on the bottom side of the inner case, the area of each fin can be increased without increasing the shape of the outer case. As a result, the overall size can be reduced, and the rice cooker can be provided with improved cooling efficiency and thus improved reliability.

A ninth aspect of the present invention is the electric component cooling structure according to the eighth aspect, wherein the shape of the heat sink on the inner case side is formed in a curved shape along the shape of the inner case. I have.

According to this configuration, since each fin of the heat sink is formed so as to be as close as possible to the outer periphery of the inner case so that each area is as large as possible, the cooling efficiency and reliability are further improved. Can be.

[0026]

Next, specific embodiments of the present invention will be described in detail with reference to the drawings. First, an induction heating type (IH type) rice cooker will be described as an example of a heating cooker, and the overall configuration thereof will be described with reference to FIG.

This rice cooker includes a rice cooker main body 1, a lid 2 attached to an upper portion of the rice cooker main body 1, and a rice cooker main body 1.
And an inner pot 3 which is removably mounted in a downwardly recessed space formed substantially at the center of the inner pot. The rice cooker main body 1 includes a bottomed cylindrical outer case 4 forming an exterior body,
An inner case 5 surrounding the recessed space;
Shoulder members 6 provided to connect the upper ends of the
, And a device disposition space 7 is formed between them.

A center sensor unit 8 is arranged in the equipment installation space 7 on the bottom side on the center line of the inner case 5. The unit 8 is provided with a temperature sensor 9 made of a thermistor or the like in a sensor mounting portion that penetrates through the inner case 5 and protrudes upward. The mounting portion of the temperature sensor 9 is configured to be able to move up and down, and is urged by a spring so as to be located at its upper limit position. When the inner pan 3 is mounted, the inner pan 3 is slightly pressed down by the bottom wall, and the temperature of the inner pan 3 is reduced in a state where the temperature sensor 9 is almost in close contact with the bottom wall of the inner pan 3. Is to be detected.

On the side of the center sensor unit 8,
A first electromagnetic induction coil 11A wound in a donut shape so as to surround the sensor unit 8 and having a planar shape as a whole is disposed close to the bottom wall of the inner case 5 from below. The outer peripheral side of the bottom portion of the inner case 5 is formed in a curved shape, and a second electromagnetic induction coil 11B wound substantially in a truncated cone shape is provided along the curved portion. Hereinafter, the first and second electromagnetic induction coils 11A and 11B will be collectively referred to as a work coil 11. An electric heater 12 of a resistance heating type is further wound around the upper outer periphery of the inner case 5 for keeping the temperature.

The lid 2 is rotatably attached to the upper end of the shoulder member 6 by a hinge mechanism 13 at the rear end side (right end side in the figure). On the front end side, a lock mechanism 14 for locking the lid 2 to the rice cooker main body 1 at a closed position (position shown) covering the upper surface opening of the inner case 5 is provided.
Is provided. A radiator plate 15 is attached to the lower surface of the lid 2. The heat radiating plate 15 is configured to be heated by a shoulder heater 16 disposed on the inner peripheral side of the upper end of the shoulder member 6.
In addition to preventing dew condensation, the inside of the inner pot 3 can be effectively kept warm from above. A steam port cap 17 is attached to the center of the heat radiating plate 15, and a pressure regulating valve unit 18 is further provided above the steam port cap 17.

On the other hand, the front side (the left side in the figure) of the outer case 4 is formed so as to protrude forward, and an operation display section is provided on the upper side of this portion along the inclined surface. In the area, in addition to the liquid crystal display section 19, a microcomputer and an operation circuit board 21 provided with various switches and display lamps necessary for cooking rice (not shown) are arranged. The microcomputer controls the work coil 11, the electric heater 12, and the shoulder heater 1.
6 is controlled in accordance with the setting on the operation circuit board 21.

FIG. 3 shows a configuration example of a power supply circuit for the work coil 11. This circuit is provided with a rectifying diode bridge 23 for converting a commercial AC power supply 22 to DC, and a choke coil 24 for absorbing a surge current or the like. IG, a type of transistor
A BT (Insulated Gate Bipolar Mode Transistor) 26 is connected. A series circuit of the work coil 11 and the filter capacitor 27 is connected in parallel with the resonance capacitor 25, and a flywheel diode 28 is connected to the IGBT 26 in parallel. With such a circuit configuration, the IGBT 26 is ON / OFF controlled by the control circuit 29 composed of the microcomputer, and the energization to the work coil 11 is controlled. The power supply circuit includes a fan motor 3 of a cooling fan 34 described later.
A fan control circuit 30 for controlling the driving of the fan 4b based on the temperature detected by the temperature sensor 9 and the like is further connected.

As shown in FIG. 2, the electric components constituting the power supply circuit are connected to the operation circuit board 21 as described above.
Is mounted on a circuit board (hereinafter, referred to as a power supply circuit board) 31 which is disposed vertically (right side in the figure) between the inner case 5 and the rear side. This power supply circuit board 31
The substrate cover 32 is fixed to the substrate cover 32 which covers it from behind, and the upper end side of the substrate cover 32 is fixed to the inner case 5. A heat sink 33 and a cooling fan 34 for cooling the heat sink 33 are further provided below the power supply circuit board 31. Although not shown, a grid-shaped suction grille for sucking air into the main body 1 in accordance with the operation of the cooling fan 34 is provided in a region below the cooling fan 34 on the bottom wall of the outer case 4. Have been.

The aforementioned diode bridge 23 and IGB
T26 generates a large amount of heat. Therefore, these electrical components (specific electrical components) 23 and 26 are mounted on a heat sink 33 and their lead terminals are soldered to a power supply circuit board 31. Hereinafter, this power supply circuit board 31
Heat sink 33 and cooling fan 34,
And their connection structures will be described in detail.

FIG. 4 shows the heat sink 33 made of an aluminum alloy and the cooling fan 34 made of a flat DC fan. First, the heat sink 33
Is provided with a horizontal beam portion 33a having a substantially rectangular cross section extending in the left-right direction (LR direction in the figure) at the upper end side substantially at the center in the front-rear direction (FB direction in the figure). A pair of left and right component mounting portions 33b and 33c are formed on the front end surface (F side) of the cross beam portion 33a so as to project forward.

The component mounting portions 33b and 33c are each formed in a substantially rectangular shape in plan view. The diode bridge 23 is provided on the left component mounting portion 33b, and the IGBT 26 is provided on the right component mounting portion 33c. It is fixed by component mounting screws 35. In addition, since each component attachment part 33b / 33c is formed separately on the left and right as described above, the space between these parts is
The air from the cooling fan 34 is formed as a ventilation passage 33d through which the air passes from below to above in the drawing.

On the lower surface of the left component mounting portion 33c, a plurality of portions are provided at predetermined intervals in the R direction from the left end position.
A plurality of thin plate-shaped fins (hereinafter, the leftmost fin is referred to as a leftmost fin 33e, and the four rightmost fins are referred to as a leftmost fin 33f) are juxtaposed in a downwardly downward shape. In the area of the ventilation passage 33d, the cross beam portion 3 is provided.
In the case shown in the figure, two intermediate fins 33g extending forward from the lower end side of 3a are formed. These intermediate fins 33
g is formed by shortening its vertical dimension.
Thereby, the region of the ventilation passage opening 33d can also face the cross beam portion 33a from the front, and a heat sink mounting hole 33h penetrating in the front-rear direction is formed in the cross beam portion 33a in this region. .

The left end fins 33e and the left fins 33f are formed to extend to the rear beyond the cross beams 33a. In the region behind the cross beam portion 33a, the vertical dimension is changed so as to be flush with the upper surface of the cross beam portion 33a. The intermediate fins 33g are also formed so as to extend from the cross beam portion 33a to the rear side. However, the intermediate fins 33a are formed to have the same vertical dimension as the front side even in the rear area.

Further, as shown in FIG.
In a region further rearward (upward in the drawing) and in a region corresponding to the right component mounting portion 33c, a plurality of fins extending rearward from the rear end face of the cross beam portion 33a, in the case of the drawing, three fins (hereinafter, referred to as three fins)
Of these fins, the left two fins are formed as right fins 33i and the right end fin is formed as right end fin 33j.

On the other hand, as shown in FIG.
A front wall 33k is formed on the front end face of 3c so as to hang downward. The center fin 33i of the right fins 33i is formed in such a shape that its rear end continues beyond the cross beam portion 33a and continues to the left end of the front wall 33k. In the space surrounded by the fins 33i and the front wall 33k in an L-shape, as shown in FIG. 7, two horizontal fins 33m extending in the left-right direction extend from the lower surface of the right component mounting portion 33c. It is formed in a hanging shape.

As shown in FIG. 6, the left end fin 33e, the front wall 33k, and the right end fin 33
Each end fin with j is formed so as to serve as a guide wall of an air passage from the cooling fan 34 which will be described later.
Each lower end is formed to have a length in the vertical direction such that the lower end protrudes downward by a predetermined size from the other fins 33f, 33g, 33i, and 33m.

The rear end side (lower right side in the figure) of each fin except the horizontal fins 33m is formed in an arc shape in the vertical direction along the shape of the inner case 5, respectively.
In the left-right direction, the whole is formed in an arc shape along the inner case 5. Further, in the lateral beam portion 33a, a heat sink mounting screw hole 33n penetrating in the front-rear direction is formed in an end region protruding left and right from the left end fin 33e and the right end fin 33j, respectively. Furthermore, the left end fin 33
e, a boss 33q in which female threads 33p are formed in the vertical direction at the rear end and on the right end of the front wall 33k, respectively.
Are formed as fan mounting portions.

As shown in FIG. 4, the cooling fan 34 is constructed by directly connecting a thin fan motor 34b to the shaft of a plurality of radially arranged rotating blades 34a. A mounting hole 34d is formed at a corner portion of the outer peripheral rectangular fan case 34c surrounding the mounting holes 34c.
Through the fan mounting screws (not shown)
The cooling fan 34 is fixed along the lower end of the heat sink 33 by fastening to the female screw 33p of the boss 33q. The cooling fan 34 is fixed to the heat sink 33 in a direction in which the fan motor 34b is located on the heat sink 33 side.

FIG. 8 shows the power supply circuit board 31. FIG. 3 shows only the choke coil 24, the resonance capacitor 25, and the filter capacitor 27, which generate the largest amount of heat, next to the diode bridge 23 and the IGBT 26 on the power supply circuit board 31 to constitute the fan control circuit 30. Electrical components that generate relatively little heat, such as resistors and capacitors / transistors, are omitted.

In the power supply circuit board 31, a substantially rectangular notch 31a is formed at the lower center side in a concave shape upward from the lower edge. Heatsink mounting holes 31b are formed on both upper sides of the cutout 31a. On the other hand, board mounting holes 31c are formed at the upper left end and at the intermediate height position at the right end.

The choke coil 24 is mounted at an upper position substantially at the center of the notch 31a. Also,
The filter capacitor 2 is located on the right side of the choke coil 24.
7 is attached obliquely. The resonance capacitor 25 is mounted on the right side of the upper right corner of the notch 31a, also at an angle.

The heat sink 33 to which the cooling fan 34 is attached as described above is fixed to the power supply circuit board 31. That is, through the heat sink mounting hole 31 b of the power supply circuit board 31, a mounting screw (not shown) is inserted from the rear side into the heat sink mounting screw hole 33 of the heat sink 33.
n, the heat sink 33 is fixed to the power supply circuit board 31. At this time, each lead terminal of the diode bridge 23 and the IGBT 26 is inserted into a corresponding pin hole of the power supply circuit board 31 and soldered.

On the other hand, as shown in FIG.
Is formed by providing a short rising edge 32b facing forward on the periphery of the substantially vertical face plate portion 32a. Face plate 3
2a is formed in a shape substantially similar to the power supply circuit board 31. Therefore, a substantially rectangular notch 3
2c is formed as described above. Mounting portions 32d extending rearward are formed on the left and right sides of the upper end of the rear surface of the substrate cover 32, respectively, and are fixed to the inner case 5 by these mounting portions 32d. Also, the face plate portion 32a
Each board mounting hole 31 in the power supply circuit board 31
At a position corresponding to c, a board mounting boss portion 32f provided with a female screw 32e is provided. Further, a substantially central portion of the upper edge of the heat sink insertion opening 32c is formed so as to hang slightly downward.
A heat sink mounting boss portion 32h on which 2g is formed is formed.

The power supply circuit board 31, in which the heat sink 33 and the cooling fan 45 are connected to the board cover 32, attaches mounting screws (not shown) through the board mounting holes 31c to female threads of each board mounting boss 32f of the board cover 32. 3
Fastened to 2g and fixed. At the same time, the heat sink attachment hole 33h of the heat sink 33 is inserted from the front through the above-mentioned air passage passage 33d in the heat sink 33.
10 is fastened to the female screw 32g of the heat sink mounting boss portion 32h of the board cover 32, and the heat sink 33 is also fixed to the board cover 32, thereby forming an assembly as shown in FIG. You.

As shown in the drawing, in this assembled state, each boss 33q of the heat sink 33, the left end fin 33e, the front wall 33k, and the right end fin 33j are provided on the outer peripheral side of the upper surface of the fan case 34c of the cooling fan 34. Of the other fins, such as the left fin 33f and the intermediate fin 33g, and a gap of a predetermined size is formed between the upper end surface of the fan case 34c.

Further, the cross beam portion 33a is fixed along the front surface of the power supply circuit board 31, and the portion of each fin extending rearward from the cross beam portion 33a is a cooling fan 34.
At the same time, the power supply circuit board 31 and the board cover 32 are configured to penetrate the notches 31a and 32c and project rearward.

In this manner, the heat sink 33 and the cooling fan 34 are orthogonally intersected with the power supply circuit board 31 and the board cover 32, and these are fitted into the respective notches 31a and 32c to constitute the above assembly. And
This assembly is assembled in the rice cooker main body 1 as shown in FIG. In this assembled state, the power supply circuit board 31 is positioned substantially perpendicular to the space 7a between the outer case 4 and the inner case 5 as described above,
Is located in a space 7b formed outside the bottom curved portion 5a of the inner case 5, and the rear end 33r of the curved shape of each of the fins follows the bottom curved portion 5a of the inner case 5. It is assembled as.

In the rice cooker having the above configuration, for example, by setting a desired cooking time on the operation display section and pressing a rice cooker switch, the power to the work coil 11 is automatically turned on at a time corresponding to the set time. Started. When the work coil 11 is energized, an eddy current is generated in the inner pot 3 to generate heat, thereby increasing the temperature of the inner pot 3 and starting heating the inside.

When it is detected that the energizing state of each work coil 11 has reached the boiling temperature, the amount of energization is controlled so as to maintain the temperature at this temperature. Further, in this state, when the water is gradually absorbed by the rice and the water is lost and the rice is cooked, the temperature of the inner pot 3 rapidly changes from the boiling temperature. When such a temperature change is detected, energization control of the work coil 11 is performed so as to lower the temperature of the inner pan 3 to the boiling temperature, and by maintaining this state for a predetermined time, the cooked rice is controlled. Steaming is further performed. Thereafter, the amount of electricity to the work coil 11 is further reduced, and the electric heater 12 and the shoulder heater 1
While controlling the amount of power to 6, the state is switched to the heat retention control state after cooking rice.

During such a rice cooking operation, each electric component mounted on the power supply circuit board 31 generates heat, and the cooling fan 34 is driven so as not to overheat. The wind from the cooling fan 34 hits the heat sink 33 to cool the heat sink 33, thereby preventing the diode bridge 23 and the IGBT 26 attached to the heat sink 33 from overheating.

At this time, as shown in FIG. 1, on the air blowing passage extending upward from the cooling fan 34, there is a space between the end surfaces of the left and right fins 33 f and 33 g and the end surface of the cooling fan 34. Since the predetermined gap 33s is provided as described above, an operation with further improved cooling efficiency is performed. In other words, the wind from the cooling fan 34, in the area immediately after the cooling fan 34,
The directionality is large such that the fins extend obliquely outward from the axis according to the twist angle of the fins. Therefore, in the case where each fin has a shape extending to this region, the wind is obliquely applied to these fins. Will be. As a result, a so-called wind noise is generated, and the wind flowing between the fins is disturbed, so that a smooth air blowing state along the surface of each fin cannot be obtained, and the cooling efficiency is reduced. Therefore, as described above, each fin 33f
Since the predetermined gap 33s is provided between the cooling fan 34g and the cooling fan 34, the above-described directionality when reaching the tip end surface of each fin is relaxed, so that a smoother air blowing state between the fins is achieved. As it occurs, the cooling efficiency is improved.

In the above description, the cooling fan 34 is connected to the fan motor 34b directly connected to the rotor 34a as described above.
Is attached to the heat sink 33 side, so that the gap between the end faces of the fins 33f and 33g further increases by the axial dimension of the fan motor 34b. Therefore, the above-described directionality when the wind from the cooling fan 34 reaches the tip surfaces of the fins 33f and 33g is further relaxed, thereby also improving the cooling efficiency.

Further, on the outer peripheral side of the cooling fan 34, the left end fin 33 e and the front wall 33 k connected to the boss 33 q of the heat sink 33 and the right end fin 3
3j is in contact, so that the cooling fan 34 can be stably mounted. In addition, these fins 33e and 33
j and the front wall 33k function as a guide wall for guiding the wind from the cooling fan 34 upward, whereby the cooling fan 3
The air that is sent while spreading from 4 is blocked from flowing outward, and the amount of air flowing toward the heat sink 33 increases accordingly, thereby improving the cooling efficiency.

On the other hand, on the heat sink 33, a left component mounting portion 33b and a right component mounting portion 33c are formed separately on the left and right sides, and the above-described ventilation passage 33d is formed therebetween. Therefore, in the region of the ventilation passage 33d, the wind from the cooling fan 34 passes through the space between the intermediate fins 33g and then directly reaches above the heat sink 33 as indicated by the solid arrow in the drawing. A choke coil 24 having a large calorific value is arranged on the air flow path. Therefore, even if the choke coil 24, which is difficult to form in close contact with the heat sink, is mounted on the power supply circuit board 31, it is cooled by the direct wind from the cooling fan 34, Overheating is prevented and circuit reliability is improved.

In particular, in the above description, the ventilation passage opening 33d is placed substantially in the center area of the heat sink 33, that is, the cooling fan 34.
Is provided in the region near the axis of the cooling air blower 33d, so that the wind on the central side where the wind speed is higher hits the choke coil 24 from the cooling fan 34 through the blowing passage opening 33d. Cooled. Further, in the above description, the cooling air that hits the choke coil 24 and changes the flow direction according to the outer peripheral shape thereof is applied to the filter capacitor 27 attached to the side of the choke coil 24.
In this case, as a result, the cooling of the condenser 27 is performed appropriately, and the reliability is also improved.

The horizontal fins 33m are provided below the right component mounting portion 33c as described above. Therefore, the wind from the cooling fan 34 that has flowed into this region hits the lower surface of the right component mounting portion 33c and is guided by the lateral fins 33m to the right side of the heat sink 33, as shown by the dashed arrow in the drawing. Will be leaked. A resonance capacitor 25 that generates a large amount of heat is arranged on the air passage, and the capacitor 25 is cooled. Therefore, this also improves the reliability of the circuit.

As described above, in the present embodiment, the heat sink 33 attached to the power supply circuit board 31
Further, a cooling fan 34 is directly attached. Thereby, in addition to the above-described improvement of the cooling efficiency, the overall height of the heat sink 33 and the cooling fan 34 is further reduced, and the height of the power supply circuit board 31 is reduced.
, The overall height including the power supply circuit board 31 is also reduced. As a result,
It is possible to form the whole rice cooker more compact.

Further, as described above, the heat sink 33 and the cooling fan 34 intersect with the power supply circuit board 31,
That is, the length of each fin of the heat sink 33 is long so as to straddle both sides of the power supply circuit board 31, and the contact area of each fin with the cooling air is made larger. This also improves the cooling efficiency.

Moreover, the fins projecting rearward from the power supply circuit board 31 are arranged so as to be located in the space 7b formed outside the bottom curved portion 5a in the inner case 5,
Furthermore, by forming the rear end 33r of each fin in an arc shape so as to be close to the inner case 5, the area of each fin can be further increased without separately providing a space for disposing such fins. Is possible. Therefore, it is possible to improve the cooling efficiency due to the fin area without impairing the overall size of the rice cooker.

FIG. 11 is a partially enlarged view of the rice cooker shown in FIG. 2 above the rear part. A shoulder ring formed so that the inner surface is flush with the inner case 5 is provided on the inner peripheral upper end side of the shoulder member 6 provided so as to straddle each upper end of the outer case 4 and the inner case 5. 6a is further mounted. The shoulder heater 16 is mounted on the upper surface of the shoulder ring 6a.

The shoulder heater 16 includes a resistance heating type heating element (heater) 16a, a heater cover 16b having an arc-shaped cross section that covers the heating element 16a from below, and a heat conductive plate having a rectangular cross section surrounding the whole. The heat conduction plate 16c is attached to the shoulder ring 6a with the upper surface and the inner surface thereof being exposed.

When the lid 2 is closed, the peripheral edge of the heat radiating plate 15 contacts the upper surface of the heat conducting plate 16c from above, and heat is transmitted from the shoulder heater 16 to the heat radiating plate 15 to be heated. As a result, as described above, dew condensation on the heat radiating plate 15 is prevented, and the heating and keeping of the temperature in the inner pan 3 can be suitably performed from above.

Further, the heat conduction plate 16c is configured such that the inner surface side is also exposed together with the upper surface thereof, and the outer peripheral edge of the upper end of the inner pot 3 is located close to this surface. This inner pot 3
A packing 15a fitted to the outer edge of the heat radiating plate 15 is in contact with the inside from the upper end of the heat sink 15, so that heat can easily escape from the upper end of the inner pot 3 through the packing 15a. Therefore, as described above, the inner surface side of the heat conducting plate 15c is also exposed, and the region of the packing 15a in contact with the upper end side of the inner pot 3 is heated by radiant heat from this surface.

In a conventional rice cooker provided with the above-described shoulder heater, only the upper surface of the heat conductive plate is exposed as a contact heating portion, and the upper end of the inner pot is separated from the shoulder heater. It is configured to be located, or to have a rising portion provided between the shoulder heater and the inner pot on the inner peripheral side of the shoulder ring. Therefore, in these conventional rice cookers, no consideration is given to heating the upper end side of the inner pot, which is liable to decrease in temperature, by the shoulder heater.

On the other hand, in the rice cooker according to the present embodiment, since the upper end side of the inner pot 3 is heated by the shoulder heater 16 as described above, the entire inner pot 3 is cooked or kept warm. Temperature distribution can be made more uniform.

Further, in the rice cooker according to the present embodiment, as shown in FIG. 2, the rear end side of the bottom wall of the outer case 4 is formed so as to be recessed upward in a substantially rectangular shape, and the plug storage portion 4a is formed. A plug 41 is formed in the plug storage portion 4a.
Is configured to be stored. The power cord connected to the plug 41 is wound upright on a cord reel 42 installed in the main body 1 as shown by a broken line in the figure.

Conventionally, the above-mentioned cord reel is configured horizontally, and in this case, a space corresponding to the thickness of the cord reel is required between the inner case and the outer case. The height of the entire vessel was large.

On the other hand, as described above, the code reel 4
By placing 2 vertically, it is possible to minimize the height of the rice cooker. When the power cord is wound on the cord reel 42, the plug 4 is inserted into the plug housing 4a provided on the bottom wall of the outer case 4 as described above.
1 is stored and the plug 41 does not protrude from the outer surface of the outer case 4, so that the appearance is also improved.

Further, an exhaust hole 4b communicating between the inside and the outside of the main body 1 is formed on a wall surface surrounding the plug housing portion 4a, and hot air generated inside during rice cooking or the like is indicated by a dashed arrow in FIG. The air is exhausted outside the machine through the exhaust hole 4b. Conventionally, such an exhaust hole is provided on the rear surface 4c of the outer case 4. It should be noted that the rear surface 4c is also a region where a rating seal describing the specifications of the rice cooker and the like is affixed, and an exhaust hole is formed below the rating seal.

However, if an attempt is made to reduce the height of the rice cooker to make it compact, it is not possible to secure a region for forming an exhaust hole below the rating seal. Therefore, for example, it is conceivable to form an exhaust hole in a region extending from the rear surface 4c to the side surface. However, in this case, a problem occurs in that hot air is discharged from the inside of the device to the side.

Therefore, in the present embodiment, the plug 41 is drawn out from the plug housing 4a at the time of energization or heat retention by using the plug housing 4a formed as described above. An exhaust hole 4b is formed in a wall surrounding the portion 4a. Thereby, the exhaust from the inside of the machine is effectively performed as a compact rice cooker structure.

Although the specific embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various changes can be made within the scope of the present invention. For example, in the above-described embodiment, as the cooling fan 34, an example in which a flat DC fan in which the rotating blades 34a and the fan motor 34b are accommodated in the thickness direction of the fan case 34c is used. It is also possible to use the fan of the above. In this case, even if the fan motor directly connected to the axis of the rotor blades protrudes from the fan case, in a configuration in which a predetermined gap is provided between the tip of each fin of the heat sink 33 and the fan case,
The protruding portion of the fan motor is located in this gap region, and there is no need to separately provide a dedicated space for the protruding portion, so that the overall size can be reduced.

In the above description, when the power supply circuit board 31 and the heat sink 33 and the cooling fan 34 are configured to cross each other, an example of the configuration in which these are orthogonal to each other has been described. However, the crossing angle is limited to 90 degrees. In addition, it is also possible to configure so as to intersect at an arbitrary angle. Further, in the above description, the component mounting portions 33b
Although the example in which the air passage opening 33d is formed in the center by dividing c into right and left has been described, in the range of claim 5, the air passage passage 33d is formed.
May be provided on the end side or the like.

In the above embodiment, a rice cooker has been described as an example. However, in the scope of claims 1 to 7, other cookers having a circuit board, a heat sink, and a cooling fan built in a main body are described. The present invention can be applied.

[0080]

As described above, in the electric component cooling structure according to the first aspect of the present invention, the cooling fan is attached to the heat sink, and the tip surfaces of the fins of the heat sink and the end surface of the fan case of the cooling fan are connected to each other. Since a predetermined gap is provided between the heat sink and the cooling fan, the space between the heat sink and the cooling fan can be formed as small as possible, and the overall size can be reduced. The state of ventilation between them becomes smoother and the cooling efficiency is improved.

In the cooling structure for electric parts of the present invention, the cooling fan is attached to the heat sink so that the fan motor of the cooling fan is located between the rotor and the heat sink. The gap between the end face is further widened, so that a smoother ventilation state is obtained between the fins, and the cooling efficiency is improved. Also,
In the case of a cooling fan of the type in which the fan motor projects from the end face of the fan case, the projecting portion of the fan motor is located in a predetermined gap region between each fin and the cooling fan. Since it is not necessary to separately provide an installation space dedicated to the protruding portion, the overall size can be reduced.

In the cooling structure for an electric component according to the third aspect, since the end fins serving as the guide walls of the blower passage of the cooling fan are provided on the side ends of the heat sink, the flow from the cooling fan to the outside can be prevented by the heat sink. Since it is guided to the side, this also improves the cooling efficiency.

In the cooling structure for electric parts of the present invention, since the heat sink is fitted into the notch formed in the circuit board, and the heat sink and the circuit board are mounted in an intersecting state, each fin crosses the circuit board. In this case, the length of the fin can be made longer, so that it is possible to form a fin having a larger area, thereby improving the cooling efficiency. In addition, the size of the protrusion of the heat sink from one side of the circuit board can be reduced as much as possible, so that the overall shape can be made more compact.

In the cooling structure for electric parts of the present invention, the heat sink is provided with a ventilation passage, and the air passing through the ventilation passage and reaching the circuit board cools the electric parts on the circuit board. Since, for example, even electrical components that are difficult to form in close contact with the heat sink, such as choke coils and capacitors, by arranging them at the above-described positions on the circuit board,
It is cooled by the wind from the cooling fan to prevent overheating. Thereby, circuit reliability is improved.

In the cooling structure for an electric component according to the present invention, the air passage is provided in the central region of the heat sink corresponding to the position on the axis of the cooling fan. The side wind will hit the electrical components on the circuit board, which will allow the components to cool sufficiently and further improve reliability.

In the cooling structure for electric parts of the present invention, the heat sink is provided with lateral fins for guiding the wind from the cooling fan to the side, and the electric parts on the circuit board are guided by the wind guided by the fins to the side. Since cooling is performed, overall cooling efficiency is improved, and overheating of the electric component is suppressed, so that reliability is improved.

In the electric component cooling structure of the present invention, a circuit board is disposed between an inner case and an outer case in a rice cooker, and a heat sink is provided in a space beside the curved portion on the bottom side of the inner case. Since they are located, the overall shape can be made more compact, and the area of each fin can be made larger to improve the cooling efficiency and thus improve the reliability.

In the electric component cooling structure of the ninth aspect, the shape of the heat sink on the inner case side is formed in a curved shape along the shape of the inner case, so that each fin is brought closer to the outer periphery of the inner case. Each area can be made as large as possible, which can further improve the cooling efficiency and reliability.

[Brief description of the drawings]

FIG. 1 is a front view of an assembly of a power supply circuit board, a heat sink, and a cooling fan installed in a rice cooker according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view showing the overall configuration of the rice cooker.

FIG. 3 is a circuit diagram of a circuit for supplying power to a work coil in the rice cooker.

FIG. 4 is a perspective view of the heat sink and the cooling fan.

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

FIG. 6 is a perspective view of the heat sink as viewed from below.

FIG. 7 is a bottom view of the heat sink.

FIG. 8 is a perspective view of the power supply circuit board.

FIG. 9 is a perspective view of a board cover to which the power supply circuit board is fixed.

FIG. 10 is a perspective view of the assembly.

FIG. 11 is an enlarged sectional view of a main part of the rice cooker.

FIG. 12 is a longitudinal sectional view showing a conventional rice cooker.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rice cooker main body 3 Inner pan 4 Outer case 5 Inner case 11 Work coil 23 Diode bridge (specific electrical component) 24 Choke coil (electric component) 25 Resonant capacitor (electric component) 26 IGBT (specific electrical component) 31 Power supply circuit board 31a Notch 32 Board cover 33 Heat sink 33d Ventilation passage 33e Left fin (end fin) 33f Left fin 33g Intermediate fin 33i Right fin 33j Right end fin (end fin) 33m Lateral fin 34 Cooling fan 34a Rotor blade 34b Fan motor 34c Fan case

Claims (9)

[Claims] 1. A heating cooker provided with a heating means, a circuit board on which electric components are mounted, a heat sink having a plurality of fins arranged in parallel, and a cooling fan for cooling the heat sink are provided in a main body of the cooking device. A cooling structure for an electrical component in which a specific electrical component is mounted on a component mounting portion of the heat sink and a lead terminal of the specific electrical component is fixed to the circuit board, and a fan case of a cooling fan is mounted on the heat sink. An electric component, wherein a predetermined gap is provided between the tip surface of each fin extending toward the air blowing direction of the cooling fan and the fan case, and the air gap is used as a ventilation passage from the cooling fan. Cooling structure. 2. The cooling structure for an electric component according to claim 1, wherein a fan motor directly connected to the axis of the rotor of the cooling fan is located between the rotor and the heat sink. 3. An end fin which is located in contact with a fan case of a cooling fan on a side end side of a heat sink, and the end fin is used as a guide wall of an air passage. Item 5. A cooling structure for an electric component according to item 1 or 2. 4. A notch is formed in a circuit board, and the notch is
2. The heat sink is fitted in a state where the heat sink crosses the circuit board so as to be substantially orthogonal.
Cooling structure for 2 or 3 electric parts. 5. A heat sink is provided with an air passage through which air from a cooling fan passes, and a circuit board is provided with a heat generation amount other than the specific electric component at a position on an air passage passing through the air passage. 5. The cooling structure for an electric component according to claim 1, wherein a large electric component is arranged. 6. The cooling structure for an electric component according to claim 5, wherein the ventilation passage is provided in a central region of the heat sink corresponding to a position on the axis of the cooling fan. 7. A heat sink is provided with horizontal fins oriented so as to guide wind from a cooling fan to the side,
7. The cooling structure for an electric component according to claim 5, wherein an electric component is disposed on the circuit board at a position where wind flowing out of the heat sink is applied along the horizontal fins. 8. The rice cooker, wherein the heating cooker is a rice cooker in which a main body is formed by an inner case accommodating an inner pot and an outer case forming an outer body, and the circuit board is formed by an inner case and an outer case. 8. The method according to claim 1, wherein the heat sink and the cooling fan are arranged in a space formed between the bottom side of the inner case and the outer case. Cooling structure of electric parts. 9. The cooling structure for an electric component according to claim 8, wherein the shape of the heat sink on the inner case side is curved along the shape of the inner case.