JP2008284010A - Electric rice cooker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve cooling efficiency by securing a cooling space for cooling a control board with the use of an insulation cover disposed on the inside of a copper case. <P>SOLUTION: An electric rice cooker includes a rice cooker body 1 for removably storing an inner pot 3, a lid body 2 for the rice cooker body 1, the cylindrical copper case 5 constituting the outer periphery of the rice cooker body 1, and a cooling fan 39 for cooling electronic components attached to the control board 36. The inside of the copper case 5 is disposed with the insulation cover 38 made of an electrically insulating material, and is formed with the cooling space S of the insulation cover 38 and a control board cover 37 for attaching the control board 36 thereon, as a passage for cooling air from the cooling fan 39, the shape of the rice cooker body is maintained compact, and the control board 36 is efficiently cooled. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electric rice cooker, and more particularly to a substrate cooling structure in an electric rice cooker.

  Well-known electric rice cookers, especially in the case of electromagnetic induction-type electric rice cookers using small-capacity earthenware pots, the temperature of the heating element of the earthenware pot during heating is 100 ° C than the surface temperature of a metal pan with a multilayer structure May be higher. The body is also designed to be very compact.

  Therefore, the initial cooling efficiency is very poor, and the temperature of semiconductors (ie, electronic components) such as IGBTs and diode bridges becomes too high, resulting in thermal destruction during operation, and electromagnetic induction coils (hereinafter referred to as work coils). There was a problem that the high temperature was close to 200 ° C., and the fusion layer melted and deformed greatly by its own magnetic force.

  Moreover, in the case of the electric rice cooker of the said structure, the outer peripheral surface of a main body is often comprised with a cylindrical steel plate case. However, as described above, as a result of the compact design of the main body, depending on the position of the control board provided with the electronic components, the control board and the steel plate case are close to each other, and leakage to the steel plate case is a problem. There is a risk. Therefore, an insulating cover made of an electrically insulating material is disposed on the inner surface side of the steel plate case.

  By the way, in the electric rice cooker, the control board is attached to the board holder, and the board holder is provided with an upper surface cover part covering the upper part of the control board and a front cover part covering the front surface of the control board. (See Patent Document 1).

Japanese Patent No. 3880773.

  By the way, in the case of the electric rice cooker of the structure which has arrange | positioned the insulating cover in the inner surface side of the steel plate case similarly to the case of the electric rice cooker currently disclosed by patent document 1, a control board is comprised with a control board cover and an insulating cover. It is conceivable to form a cover unit that covers and encloses, but in the case of such a cover unit, there is a possibility that a problem that it is difficult to obtain a good flow of cooling air may occur depending on the position of the cover unit.

  The present invention has been made in view of the above points, and by utilizing an insulating cover disposed on the inner surface side of the steel plate case, by securing a cooling space for cooling the control board, the cooling efficiency can be improved. The purpose is to improve.

  In this invention, as a 1st means for solving the said subject, the rice cooker main body which accommodates an inner pot detachably, the cover body of this rice cooker main body, and the cylinder which comprises the outer peripheral surface of the said rice cooker main body In an electric rice cooker provided with a shaped steel plate case and a cooling fan for cooling electronic components attached to the control board, an insulating cover made of an electrically insulating material is disposed on the inner surface side of the steel plate case. The insulating cover and the control board cover to which the control board is attached form a cooling space that serves as a path for cooling air from the cooling fan.

  By comprising as mentioned above, it becomes possible to form a cooling space that becomes a passage of cooling air for cooling the control board using an insulating cover disposed on the inner surface side of the steel plate case, The control board can be efficiently cooled while keeping the shape compact.

  In the present invention, as a second means for solving the above-mentioned problems, in the electric rice cooker provided with the first means, the cooling fan can be attached to the control board, and so configured. In this case, the cooling fan mounting structure can be simplified.

  In the present invention, as a third means for solving the above-described problem, in the electric rice cooker provided with the second means, the cooling fan and the control board are connected to the lid body pivot in the rice cooker body. It can also be installed on the side where the supporting hinge unit is attached, and in such a case, a space for installing the power supply board and operation board is secured on the anti-hinge unit side of the rice cooker body. can do.

  In the present invention, as a fourth means for solving the above problems, in the electric rice cooker provided with the first, second or third means, in the bottom member constituting the bottom of the rice cooker body The cooling air intake port may be formed on the hinge unit side while the cooling air exhaust port may be formed on the anti-hinge unit side of the bottom member. Can be made to flow from the hinge unit side to the anti-hinge unit side in the rice cooker body, and the cooling efficiency in the rice cooker body can be improved.

  In the present invention, as a fifth means for solving the above-mentioned problems, in the electric rice cooker provided with the first, second, third or fourth means, the insulating cover and the control board cover are provided. In addition, it is possible to form an outlet hole serving as an outlet for cooling air from the cooling space, and in such a case, a sufficient amount of cooling air flowing in the cooling space can be secured, and the control board The cooling efficiency can be improved.

  According to the first means of the present invention, the rice cooker body that detachably houses the inner pot, the lid of the rice cooker body, and the cylindrical steel plate case that constitutes the outer peripheral surface of the rice cooker body, In an electric rice cooker provided with a cooling fan for cooling an electronic component attached to the control board, an insulating cover made of an electrically insulating material is disposed on the inner surface side of the steel plate case, and the insulating cover and the Cooling air that cools the control board using an insulating cover disposed on the inner surface side of the steel plate case, forming a cooling space as a path for cooling air from the cooling fan by the control board cover to which the control board is attached Since the cooling space which becomes a passage way can be formed, there is an effect that the control board can be efficiently cooled while the shape of the rice cooker body is kept compact.

  As in the second means of the present invention, in the electric rice cooker provided with the first means, the cooling fan can be attached to the control board. Can be simplified.

  As in the third means of the present invention, in the electric rice cooker provided with the second means, the cooling fan and the control board are attached with a hinge unit for pivotal support in the rice cooker body. It can also arrange | position to the side which is provided, and when comprised in that way, the space for arrange | positioning a power supply board | substrate and an operation board | substrate can be ensured in the anti-hinge unit side of the rice cooker body.

  As in the fourth means of the present invention, in the electric rice cooker provided with the first, second or third means, the cooling air is provided on the hinge unit side of the bottom member constituting the bottom of the rice cooker body. On the other hand, a cooling air exhaust port can also be formed on the anti-hinge unit side of the bottom member, and in this case, the cooling air flow direction is determined by the hinge in the rice cooker body. The flow from the unit side to the anti-hinge unit side can be achieved, and the cooling efficiency in the rice cooker body can be improved.

  As in the fifth means of the present invention, in the electric rice cooker provided with the first, second, third or fourth means, cooling air from the cooling space is supplied to the insulating cover and the control board cover. It is also possible to form an outlet hole serving as an outlet of the air outlet, and in such a case, a sufficient amount of cooling air flowing in the cooling space can be ensured, and the cooling efficiency of the control board can be improved. it can.

  Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

  In this electric rice cooker, as shown in FIG. 1, for example, a pot made of a non-metallic material (for example, an earthen pot, a ceramic pot, a charcoal pot, etc.) is adopted as the inner pot 3 for storing rice and water. It is comprised by the rice cooker main body 1 comprised so that the pan 3 could be set arbitrarily, and the cover body 2 provided in the upper part of this rice cooker main body 1 so that opening and closing was possible.

  The rice cooker main body 1 constitutes the inner peripheral surface of the rice cooker main body 1 and has an inner case 4 made of a synthetic resin having a bottomed cylindrical shape formed so that the inner pot 3 can be set arbitrarily. A cylindrical steel plate case 5 constituting the outer surface of the rice cooker body 1, an annular synthetic resin shoulder member 6 for connecting the upper end of the steel plate case 1 and the upper end of the inner case 4, and the outer The bottom member 7 is made of a dish-shaped synthetic resin that closes the lower end opening of the case 5.

  The inner pot 3 includes a bottom portion 8 and a cylindrical portion 9 that stands upright from the bottom portion 8. In this way, the outermost diameter dimension of the induction heating element G provided on the lower surface of the bottom 8 and the inner diameter dimension of the inner pot 3 can be made substantially the same, and the heat generated by the induction heating element G can be reduced. Go to every corner of rice in pot 3.

  An annular support leg 10 is integrally projected on the outer peripheral part of the bottom part 8, and the support leg 10 is disposed on the outer periphery of the bottom part of the inner case 4 at equal intervals in the circumferential direction. The inner pot 3 is housed and supported in the inner case 4 by coming into contact with three support bases 11, 11, 11 made of (for example, silicon rubber).

  On the other hand, the inner case 4 includes a bottom portion 4a, a cylindrical portion 4b that stands upright from the outer periphery of the bottom portion 4a, and a flange portion 4c that is integrally formed at the upper end of the cylindrical portion 4b. A warming heater 12 is disposed on the outer peripheral side of the heater. Reference numeral 13 denotes a heat insulating material that blocks heat radiation from the heat retaining heater 12 to the outside.

  On the lower surface of the bottom portion 8 of the inner pot 3 (that is, on the inner peripheral side of the support leg 10), a metal induction heating element G such as a silver paste capable of self-heating by an eddy current induced therein is used. Is pasted. By the way, a metal spraying heat generating layer acting as an induction heating element may be formed on the inner surface or inner and outer surfaces of the inner pot 3. In some cases, a metal spray heat transfer layer continuous with the metal spray heat generation layer may be formed. In addition, aluminum or an aluminum alloy can also be used as the metal spray heat generating layer and the metal spray heat transfer layer. Furthermore, as the induction heating element G, a metal plate other than a silver paste or a metal sprayed layer can be adopted, and the induction heating element G may be embedded in the inner pot 3.

  A coil cover 14 is provided below the bottom wall portion (bottom portion) 4a of the inner case 4, a ferrite core is disposed at the lower portion thereof, and the lower surface side of the bottom portion 8 of the inner pot 3 is disposed at the upper portion thereof. Corresponding to the position of the induction heating element G, an electromagnetic induction coil (hereinafter referred to as a work coil) C in which litz wires are concentrically wound is provided, whereby the induction heating element of the inner pot 3 is energized. An eddy current is induced in G to indirectly heat the inner pot 3.

  At the center of the dish-shaped bottom 4a of the inner case 4, there is formed a sensor part fitting port of the center sensor CS acting as a temperature detecting means, and a donut-shaped upper surface on the outer peripheral side of the sensor part fitting port. A heat shield plate 16 is provided.

  By making the thickness of the lower part of the side surface corresponding to the outside of the support leg 10 in the inner pot 3 (that is, the support leg 10) thinner than the thickness of the upper part of the side surface, relatively large air is present between the part and the inner case 4. The layer K will be formed and the heat insulation effect can be ensured.

  On the other hand, the lid body 2 is composed of a synthetic resin outer cover 20 that forms an outer peripheral surface of the lid body 2 and that includes a pressure adjusting pipe 19 at the center, and a synthetic resin that is fitted and integrated inside the outer cover 20. A resin inner frame 21, a packing 22a and a metal heat dissipating plate 23 disposed in the inner opening of the inner frame 21, a lid heater 24 provided on the upper surface of the heat dissipating plate 23, and the heat dissipating plate 23 And an inner lid 25 made of metal, which can be opened and closed via a hinge unit 26 with respect to one side of the upper portion of the rice cooker body 1 (ie, the shoulder member 6). It is pivotally supported. The lid 2 is held in a closed state via a lock mechanism 27 on the opposite side of the hinge unit 26. Reference numeral 28 denotes a lock release lever for releasing the lock state of the lock mechanism 26.

  Further, packings 22a and 22b are respectively provided below the outer peripheral edge of the heat radiating plate 23 and below the outer peripheral edge of the inner lid 25, and the inner lid 25 is connected to the flange of the inner pot 3 via the packing 22b. It is made to contact the upper surface part of the part 3a. The inner pot flange portion 3 a has substantially the same thickness as the cylindrical portion 9, and a flat portion on which the packing 22 b is pressed when the lid body 2 is closed is formed on the upper surface thereof. Reference numeral 29 denotes a pressure regulating valve in the pressure regulating pipe 19, 30 denotes a lower side cap, and 31 denotes a pressure regulating ball.

  By the way, in the case of the electric rice cooker of the said structure, since the flange part 3a of the inner pot 3 is easy to cool, the annular shoulder heater 32 is arrange | positioned between the flange part 4c of the inner case 4, and the shoulder member 6, and this shoulder The inner pot flange portion 3 a is heated by the heater 32. In this case, in order to effectively receive the upward heat from the shoulder heater 32, it is desirable to extend the inner pot flange portion 3 a to a position covering the upper side of the shoulder heater 32.

  In the case of the present embodiment, an operation panel unit 33 having various keys and a liquid crystal display device is provided on the side surface on the side opposite to the hinge unit in the rice cooker body 1. The operation board 34 is disposed. On the other hand, a control board cover made of synthetic resin for attaching a control board 36 provided with various electronic components (for example, IGBT, diode bridge, etc.) on the hinge unit 26 side in the space 35 in the rice cooker body 1. 37 is disposed. A cooling fan 39 is attached to the lower end of the control board 36 via a heat sink 40.

  Although the rice cooker body 1 can be made compact with the above configuration, the control board 36 provided with various electronic components (for example, IGBT, diode bridge, etc.) and the outer surface of the rice cooker body 1 are configured. There is a risk of electric leakage from the control board 36 side to the steel plate case 5 side because the distance from the steel plate case 5 to be performed becomes too short. Therefore, in the present embodiment, an insulating cover 38 made of an electrically insulating material is disposed on the inner surface side of the steel plate case 5.

  In the present embodiment, the insulating cover 38 and the control board cover 37 form a cooling space S as a path for cooling air from the cooling fan 39. In other words, in the space 41 on the hinge unit 26 side in the rice cooker body 1, the cooling space whose lower side is opened by the control board cover 37 positioned on the inner pot 3 side and the insulating cover 38 positioned on the steel plate case 5 side. A substrate holder 42 having S is formed (see FIGS. 3 to 6). A hanging wall 38a that covers up to half of the vertical height of the cooling fan 39 is integrally extended at the lower end of the insulating cover 38 in order to stabilize the air volume of the cooling fan 39 by the orifice effect.

  Then, engaging protrusions 43, 43,... Integrally projectingly provided on the upper end portion and both side portions of the control board cover 37 are engaged with engaging holes 44, 44,. The control board cover 37 and the insulating cover 38 are integrated with each other by being fitted to each other, and can be easily assembled.

  The insulating cover 38 is disposed along the inner surface of the steel plate case 5 in a state where a predetermined interval is maintained between the insulating cover 38 and the inner surface of the steel plate case 5. A number of outlet holes 45, 45,... Serving as outlets for cooling air passing through the cooling space S are formed. The outlet holes 45, 45,. It is formed to avoid. The reason why this is done is that the portion where the hinge unit 26 is formed in the rice cooker body 1 is susceptible to dripping or steam dripping, so the inside of the substrate holder 42 (in other words, through the outlet holes 45, 45... In other words, it prevents the steam from entering the cooling space S).

  In addition, a plurality of outlet holes 46, 46... Serving as outlets for cooling air passing from the cooling fan 39 through the cooling space S are formed in the upper part of the control board cover 37. 46... Is formed in a portion where the control board 36 is not disposed. In this way, the cooling air from the cooling fan 39 is exhausted from the outlet holes 46, 46... Without being obstructed by the control board 36.

  By configuring as described above, the cooling air from the cooling fan 39 passes through the cooling space S and is discharged from the outlet holes 45, 45... And 46, 46. In the process, the control board 36 (including attached electronic components) is cooled. That is, it is possible to form a cooling space S that becomes a passage of cooling air for cooling the control board 36 using the insulating cover 38 disposed on the inner surface side of the steel plate case 5, and the shape of the rice cooker main body 1 is changed. The control board 36 can be efficiently cooled while being kept compact.

  Incidentally, when the conventional cooling structure and this embodiment were compared, the results shown in Table 1 below were obtained.

  According to this, it can be seen that in any of the work coil, IGBT, diode bridge, control board atmosphere and operation board atmosphere, the temperature is greatly lowered, and the cooling efficiency is improved. In the case of the conventional cooling structure, a special two-speed switching high-speed rotating fan had to be used as a cooling fan as a countermeasure against temperature rise. The operation sound is quieter than that of an electric rice cooker using a normal pot.

  2, in the case of the electric rice cooker having the above configuration, the cooling air intake ports 47, 47... Are provided on the hinge unit 26 side of the bottom member 7 constituting the bottom of the rice cooker body 1. On the other hand, cooling air exhaust ports 48, 48,... Are formed on the bottom member 7 on the side opposite to the hinge unit. Meanwhile, a pair of support legs 49, 49 and 50, 50 of the rice cooker main body 1 are formed on the bottom unit 7 on the hinge unit 26 side and the anti-hinge unit side. Of the 50 and 50, between the support legs 50 and 50 located on the side opposite to the hinge unit, the warm exhaust discharged from the exhaust ports 48, 48... Short-circuits to the intake ports 47, 47. A windbreak wall 51 is provided to prevent this. If it does in this way, the flow direction of cooling air can be made into the flow from the hinge unit 26 side in the rice cooker main body 1 to the anti-hinge unit side, and the improvement of the cooling efficiency in the rice cooker main body 1 is aimed at. In addition, a short circuit to the intake ports 47, 47... Of the exhaust discharged from the exhaust ports 48, 48... Is prevented, and further improvement in cooling efficiency in the rice cooker body 1 can be achieved. Can be planned. The windbreak wall 51 may be provided between the support legs 49 and 49 on the hinge unit 26 side. However, as in the present embodiment, the windshield wall 51 is provided between the support legs 50 and 50 on the anti-hinge unit side. However, it is effective for improving the cooling efficiency.

  Incidentally, when the change in the cooling efficiency depending on the presence or absence of the windbreak wall 51 was examined, the results shown in Table 2 below were obtained.

  According to this, since the windbreak wall 51 is provided, the temperature is lowered in any of the work coil, the IGBT, the diode bridge, the control board atmosphere, and the operation board atmosphere. It can be seen that the improvement is obtained. In the case of those without windbreak walls, a special two-speed switching high-speed rotating fan had to be used as a cooling fan as a cooling fan for temperature rise countermeasures. The operation sound is quieter than that of an electric rice cooker using a normal pot.

  The invention of the present application is not limited to the above-described embodiment, and it is needless to say that the design can be appropriately changed without departing from the gist of the invention.

It is a longitudinal cross-sectional view of the electric rice cooker concerning embodiment of this invention. It is a bottom view of the electric rice cooker concerning embodiment of this invention. It is a perspective view of the substrate holder in the electric rice cooker concerning embodiment of this invention. It is a disassembled perspective view of the board | substrate holder in the electric rice cooker concerning embodiment of this invention. It is a front view of the board | substrate holder in the electric rice cooker concerning embodiment of this invention. It is a bottom view of the substrate holder in the electric rice cooker concerning embodiment of this invention.

Explanation of symbols

1 is a rice cooker body 2 is a lid 3 is an inner pan 5 is a steel plate case 7 is a bottom member 26 is a hinge unit 36 is a control board 37 is a control board cover 38 is an insulating cover 39 is a cooling fan 45, 46 is an outlet hole 47 Intake port 48 is exhaust port S is cooling space

Claims (5)

  Cools the rice cooker body that detachably accommodates the inner pot, the lid of the rice cooker body, the cylindrical steel plate case constituting the outer peripheral surface of the rice cooker body, and the electronic components attached to the control board An electric rice cooker provided with a cooling fan for disposing an insulating cover made of an electrically insulating material on the inner surface side of the steel plate case, and a control board cover for attaching the insulating cover and the control board The electric rice cooker characterized by forming the cooling space used as the passage of the cooling air from the said cooling fan by.   The electric rice cooker according to claim 1, wherein the cooling fan is attached to the control board.   The electric rice cooker according to claim 2, wherein the cooling fan and the control board are arranged on a side of the rice cooker body on which a hinge unit for pivotal support of the lid is attached.   On the hinge unit side of the bottom member constituting the bottom of the rice cooker body, the cooling air intake port is formed on the anti-hinge unit side of the bottom member, while the cooling air exhaust port is formed on the hinge member side. The electric rice cooker as described in any one of Claims 1, 2, and 3 characterized by the above-mentioned.   5. The electric rice cooker according to claim 1, wherein an outlet hole serving as an outlet for cooling air from the cooling space is formed in the insulating cover and the control board cover. vessel.

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