JP3253474B2 - microwave - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave oven having a heating plate and a motor on the lower surface of a bottom plate of a cooking chamber.

[0002]

2. Description of the Related Art Conventionally, as a microwave oven, a turntable is rotatably provided at an inner bottom portion of a cooking chamber, and a heating plate is provided on a lower surface of a bottom plate of the cooking chamber. Some are provided with a motor for rotating the motor. The heating plate is for heating the cooking chamber, but inevitably radiates heat also to the motor side. Therefore, conventionally, a heat shield plate is interposed between the heating panel and the motor so that the motor is not affected by heat. The rotating shaft of the motor protrudes into the cooking chamber through the heat shield plate, the heating plate, and the bottom plate of the cooking chamber, and connects the turntable.

[0003] FIG. 7 shows a conventional rotary shaft insertion portion of the bottom plate of the cooking chamber. Bottom plate 2 of cooking chamber 1
, The shaft insertion tube 3 is attached so as to protrude downward. A heating plate 4 is attached to the lower surface of the bottom plate 2. The heating panel 4 is configured by disposing a heat insulating material 4b and a planar heater 4c in a receiver 4a. The planar heater 4
c is in thermal contact with the bottom plate 2. The heat shield plate 5 is attached to the lower surface of the heating panel 4 and has a motor 6
Is attached to the lower surface side of the heat shield plate 5.

Accordingly, the heat of the motor 6 is shielded by the heat shield plate 5. The rotating shaft 8 of the motor 6 protrudes into the cooking chamber 1 through the shaft insertion tube 3. A turntable (not shown) is connected to and supported by the protruding end. A metal ring member 9 is provided between the heat shield plate 5 and the lower end of the shaft insertion tube 3 so as to contact with both.
The ring member 9 suppresses microwave leakage.

[0005]

However, in the above-mentioned conventional structure, the ring member 9 which is a small part must be incorporated when the heating panel 4, the heat shield plate 5 and the motor 6 are attached, and the assembling operation is troublesome. And the ring member 9
Parts management is troublesome. Further, there is a possibility that the assembling of the ring member 9 may be forgotten. Therefore, it is always necessary to confirm the assembling of the ring member 9, and there has been a problem that the efficiency of the assembling work cannot be generally improved.

In addition, since the dimensions of each component must be made fairly accurate so that no gap is formed between the shaft insertion tube 3 and the ring member 9, there is a problem that the price of the entire product increases accordingly.

The present invention has been made in view of the above circumstances, and has as its object to not only prevent microwave leakage, but also to improve the efficiency of assembly work and to simplify parts management. To provide a microwave oven that can be.

[0008]

A first means comprises a main body in which a cooking chamber is formed, a shaft insertion tube attached to a bottom plate of the cooking chamber so as to protrude downward, and a shaft insertion tube. A heating plate attached to the lower surface of the bottom plate in a state where the hole portion is loosely fitted to the outer periphery of the shaft insertion tube;
A motor for rotating a turntable, which is attached to the lower surface side of the heating plate and has a rotating shaft protruding into the cooking chamber through the shaft insertion tube, and at least covers the motor between the lower surface of the heating plate and the motor. A heat shield plate made of a metal plate integrally formed in a form elastically supported by a contact portion that is provided so as to be interposed with a width and that is in contact with the entire periphery of the lower end of the shaft insertion cylinder. (The invention of claim 1).

The second means is characterized in that, in the first means, the contact portion of the heat shield plate is formed to have a tapered shape (the invention of claim 2). Third
The means according to the first means, wherein the contact portion has a substantially circular shape.
None, supported by elastic arms at three places around
It has a feature where it exists (the invention of claim 3). Fourth
In the first means, a slit for draining water is formed at an end on the motor side in the contact portion of the heat shield plate, and the width of the slit is １ ／ of the wavelength λ of the microwave.
It has the following features (the invention of claim 4).

The fifth means is that, in the first means, a convex portion is formed on one of the heating panel and the heat shield plate, and a concave portion is formed on the other, which is fitted with the convex portion. The present invention is characterized in that the heat shield plate is positioned with respect to the panel (the invention of claim 5). The sixth means is characterized in that, in the first means, a weight sensor is provided together with a motor on the lower surface side of the heating panel, and a heat shield plate is provided facing the weight sensor and the motor from above. (Invention of claim 6).

[0011]

In the first means, since the contact portion formed on the heat shield plate made of metal is in contact with the entire lower end of the shaft insertion cylinder, microwave leakage is prevented. In addition, since the contact portion is formed integrally with the heat shield plate, the contact portion is arranged at a predetermined portion (a portion in contact with the entire lower end of the shaft insertion cylinder) with the attachment of the heat shield plate. And the assembling work is simplified, and the assembling work of the leak prevention member is not required, so that the efficiency of the assembling work can be improved. Also, parts management is simplified. Furthermore, since the heat shield plate has at least an area covering the motor, the heat shield effect for the motor is not impaired. Furthermore, the contact part of the heat shield plate is elastic
Is supported on the lower end of the shaft insertion tube.
No displacement with respect to the entire circumference, and contact in pressure contact
And this also helps prevent microwave leakage
Is further improved.

In the second means, since the contact portion of the heat shield plate is formed to have a tapered shape, the contact portion is naturally guided around the entire lower end of the shaft insertion cylinder, and can be guided by the entire periphery. In such a case, the microwave leakage can be further improved.

[0013]

In the third means, since the contact portion has a substantially circular shape and is supported by elastic arms at three locations around the contact portion, the contact portion is elastically supported while the contact portion is in the supporting posture state. Is stabilized, and the contact portion comes into uniform pressure contact with the entire periphery of the lower end of the shaft insertion cylinder, thereby further improving the microwave leakage prevention effect. By the way, when the contact portion is supported at two places around, the support posture of the contact portion is not stable, and there is a possibility that the contact portion may be in a one-side contact state with respect to the shaft insertion cylinder.

In the fourth means, since a slit for draining water is formed at the end of the contact portion on the motor side, liquid such as water or broth flows from the cooking chamber through the shaft insertion cylinder. Even if it flows down to the abutting portion, it flows out of the slit and does not accumulate at the end of the corresponding portion. In addition, the width of the slit is one of the wavelength λ of the microwave.
Since the ratio is set to / 4 or less, microwaves do not leak from this slit.

In the fifth means, a convex portion is formed on one of the heating plate and the heat shield plate, and a concave portion is formed on the other of the heat plate and the heat shield plate. With the configuration that performs the positioning of the heat shield plate is accurately positioned with respect to the heating plate, and as a result,
The mounting position of the motor, which is to be mounted in a predetermined correspondence with the heat shield plate, is naturally determined with respect to the heating plate and the heat shield plate. Thereby, assemblability is improved.

In the sixth means, a weight sensor is provided together with the motor on the lower surface side of the heating panel, and the heat shield plate is provided so as to face the weight sensor and the motor from above. In addition, the weight sensor can sufficiently shield the heat.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. First, FIG. 2 shows a schematic configuration of a microwave oven. The main body 11 is configured by disposing an inner box 13 inside an outer box 12, and the inside of the inner box 13 is a cooking chamber 14. This cooking room 1
A reflection plate 15 and an upper heater 16 are provided on the upper plate 4, and a magnetron 17 and a waveguide 18 are provided on the side plates. Further, a turntable 19 is provided at the inner bottom of the cooking chamber 14 so as to be rotatable. The upper heater 16 is used at the time of grill cooking. The magnetron 17 outputs microwaves, as is well known, and is used for cooking in a microwave oven.

On the lower surface side of the bottom plate 14a of the cooking chamber 14, a heating plate 20, a heat shield plate 21, a motor 22 and a weight sensor 23 are mounted. Hereinafter, the configuration of this portion will be described in detail. As shown in FIGS. 1, 3 and 6, a circular shaft insertion tube 24 is joined to the central portion of the bottom plate 14 a of the cooking chamber 14 by, for example, welding so as to project downward from the bottom plate 14 a. And the bottom plate 1
On the outer surface of 4a, for example, four mounting pieces 25 for mounting the heating panel 20 are mounted by welding, and three mounting pieces 26 for mounting the motor 22 and the heat shield plate 21 are mounted, for example, by welding. ing. The mounting pieces 25 and 26 include
Each has a screw hole.

The heating plate 20 is used together with the upper heater 16 during oven cooking or toast cooking, and is constituted by disposing a heat insulating material 28 and a sheet heater 29 in a receiver 27 made of a thin metal plate. ing. A relief recess 30 for inserting the mounting piece 25 and a recessed recess 31 for inserting the mounting piece 26 are formed in the planar heater 29 and the heat insulating material 28 of the heating plate 20. Further, a hole 32 is formed to allow the shaft insertion tube 24 to be inserted in a loosely fitted state.
As shown in FIG. 4, rectangular bulges 27a and 27b are formed in the receiver 27 corresponding to the bottom of each of the escape recesses 30 and 31, and screw bulges 27c are formed in the bulges 27a and 27b. Are formed. A circular recess 33 for positioning is formed on the lower surface of the heating platen 20.

The heat shield plate 21 is made of a thin metal plate, and its upper and lower surfaces are finished with relatively high surface accuracy, are silver or mirror-like, and are formed so as to obtain high reflection efficiency. ing. The heat shield plate 21 is formed with a rectangular hole 34 at a portion corresponding to the bulging portion 27b, and a hole 33
Is formed by cutting and raising.

As shown in FIG. 5, a contact portion 36 is formed integrally with the heat shield plate 21. The abutment portion 36 has a substantially circular donut shape in plan view, and is elastically supported at three locations around it by an elongated arm portion 37 which is also integrally formed. Thereby, the contact part 36 can be displaced in the up-down direction and the left-right direction.
The contact portion 36 has a tapered shape, in this case, a funnel-shaped tapered shape that tapers downward. And
A flared portion 36a is formed at the upper edge of the contact portion 36, and a number of slits 38 are formed in the flared portion 36a. Among the slits 38, the slit 38 at the connecting portion of the arm portion 37 is the widest, and the width H (see FIG. 5) of the slit 38 is set to 1/4 (30.6 mm) or less of the wavelength λ of the microwave. It is set to be.

Next, the motor 22 and the weight sensor 23
Is mounted on a metal mounting plate 39, and the rotation of the motor 22 is transmitted to the rotation shaft 40 via a gear mechanism. The rotating shaft 40 projects upward from the mounting plate 39. The rotating shaft 40 is vertically displaced in accordance with the weight applied thereto, and the displacement is transmitted to the movable electrode of the capacitor of the weight sensor 23. It is supposed to be. The weight sensor 23 outputs a weight detection signal based on the capacitance of the capacitor that changes according to the vertical displacement of the rotating shaft 40. As shown in FIG. 3, at three places on the periphery of the mounting plate 39,
A screw mounting seat 41 is formed at a higher position,
The screw mounting seat 41 is attached to the mounting piece 26 on the lower surface of the bottom plate 14a.
It corresponds to.

The mounting procedure will now be described.
The escape recesses 30 and 31 of the heating plate 20 are
a After fitting to the mounting pieces 25 and 26 on the lower surface,
(See FIG. 3) is screwed to the mounting piece 25, and the heating panel 20 is mounted on the lower surface of the bottom plate 14a. In this case, as shown in FIG.
And the sheet heater 29 is attached to the bottom plate 1.
4a in heat conductive contact.

Next, the convex portion 35 of the heat shield plate 21 is
In the state where the heat shield plate 21 is positioned on the lower surface of the heating plate 20 by fitting into the concave portion 33 of the
The rotation shaft 40 is inserted into the shaft insertion tube 24, the screw mounting seat 41 corresponds to the hole 34 of the heat shield plate 21, and the screw 43 is screwed to the mounting piece 26 of the bottom plate 14 a. Thus, the heat shield plate 21, the mounting plate 39, and furthermore, the motor 22 and the weight sensor 23 are mounted on the lower surface side of the heating panel 20.

In this case, the heat shield plate 21 is configured to face and cover the motor 22 and the weight sensor 23 from above. Further, in the above-described mounting state, the heat shield plate 2
As shown in FIG. 1, the contact portion 36 in FIG. 1 contacts the entire lower end of the shaft insertion tube 24. In this case, since the contact portion 36 of the heat shield plate 21 is formed to have a tapered shape, the contact portion 36 is naturally guided around the entire lower end of the shaft insertion tube 24 and is closely contacted over the entire peripheral region. Comes into contact with

According to the present embodiment, the abutting portion 36 formed on the heat shield plate 21 made of metal is
Abuts on the entire periphery of the lower end of the device, so that microwave leakage can be prevented. Moreover, since the abutting portion 36 is formed integrally with the heat shield plate 21, the abutting portion 36 is provided at a predetermined portion (a portion in contact with the entire lower end of the shaft insertion tube 24) with the attachment of the heat shield plate 21. As a result, the assembling work becomes simpler, and unlike the related art, it is not necessary to check the assembling of the leak prevention member, and the efficiency of the assembling work can be improved. Also, parts management is simplified.

Further, the contact portion 36 of the heat shield plate 21
Is formed so as to form a tapered shape, so that the abutting portion 36 is naturally guided on the entire lower periphery of the shaft insertion tube 24 and comes into close contact with the entire peripheral region, thereby preventing microwave leakage. The effect is further improved. In particular, since the contact portion 36 is formed in a funnel-shaped tapered shape, the shaft insertion cylinder 2
Even if water or the like (including boiled juice and the like) flows from the inside of the heating cooking chamber 14 between the 4 and the abutting portion 36, this does not accumulate. By the way, if the contact portion 36 is formed in a reverse funnel-shaped taper shape, there is a possibility that water or the like may be accumulated between the shaft insertion tube 24 and the contact portion 36, but this is not the case in the present embodiment.

Further, according to the present embodiment, since the contact portion 36 of the heat shield plate 21 is elastically supported,
The contact portion 36 does not shift with respect to the entire circumference of the lower end of the shaft insertion tube 24, and comes into contact with the press-contact state, thereby further improving the microwave leakage prevention effect.

In particular, since the contact portion 36 has a substantially circular shape and is configured to be supported by elastic arms 37 at three locations around the contact portion 36, the support posture state is stable while the contact portion 36 is elastically supported. However, the abutting portion 36 uniformly comes into pressure contact with the entire periphery of the lower end of the shaft insertion tube 24, thereby further improving the microwave leakage prevention effect. Incidentally, if the contact portion 36 is supported at two locations around the support portion, the supporting posture of the contact portion 36 may not be stable, and the contact portion 36 may be in a one-sided contact state with respect to the shaft insertion tube 24. As a member for elastically supporting the contact portion 36, a fin portion 38a (see FIG. 5) located between the slits 38 has the function in addition to the arm portion 37 described above.

Further, since a slit 38 for draining water is formed at the end of the contact portion 36 on the side of the motor 22, water or the like flows down from the heating cooking chamber 14 to the contact portion 36 via the shaft insertion tube 24. However, since it flows out of the slit 38, it does not accumulate at the end of the corresponding portion 36. In addition, since the width of the slit 38 is set to be equal to or less than 1/4 of the wavelength λ of the microwave, it is possible to reliably prevent the microwave from leaking from the slit 38.

Further, since the concave portion 33 is formed in the heating plate 20, the convex portion 35 is formed in the heat shield plate 21, and the heat shield plate 21 is positioned with respect to the heating plate 20 by fitting them. The heat shield plate 21 is accurately positioned with respect to the panel 20, and as a result, the motor 22, which is mounted in a predetermined correspondence relationship with the heat shield plate 21, also has a mounting position with respect to the heating panel 20 and the heat shield plate 21. Will be able to decide naturally. Thereby, assemblability is improved, and the position where the heat is shielded from the motor 22 by the heat shield plate 21 is always an appropriate position. The concave portion 33 is provided on the heat shield plate 21 and the convex portion 3
5 may be provided on the heating platen 20.

On the lower surface of the heating platen 20, a motor 22
In addition, since the weight sensor 23 is provided and the heat shield plate 21 is provided to face the weight sensor 23 and the motor 22 from above, not only the motor 22 but also the weight sensor 23 can sufficiently shield the heat. In the case of a configuration that does not include a weight sensor, the heat shield plate may be configured to have at least an area that covers the motor, and the heat shielding effect on the motor is not impaired.

[0034]

As apparent from the above description, the present invention has the following effects. According to the first aspect of the present invention, since the contact portion formed on the metal heat shield plate abuts on the entire lower end of the shaft insertion cylinder, microwave leakage can be reliably prevented. In addition, since the contact portion is formed integrally with the heat shield plate, the contact portion is arranged at a predetermined portion along with the attachment of the heat shield plate, so that the assembling work is simplified, and further, assembling of the conventional leak prevention member is performed. Confirmation is not required, the efficiency of assembly work can be improved, and parts management can be simplified. In addition, the contact part of the heat shield plate is elastically supported
So that the abutment is positioned with respect to the entire circumference of the lower end of the shaft insertion tube.
There is no misalignment and it comes into contact with the pressure contact state.
This further improves the microwave leakage prevention effect
Can be made.

According to the second aspect of the present invention, since the contact portion of the heat shield plate is formed to have a tapered shape, this contact portion is naturally guided around the entire lower end of the shaft insertion cylinder, and the entire peripheral region is formed. , So that the microwave leakage preventing effect is further improved.

[0036]

According to the third aspect of the present invention, since the contact portion has a substantially circular shape and is configured to be supported by elastic arms at three locations around the contact portion, the contact portion is supported while being elastically supported. The posture state can be stabilized, whereby the microwave leakage prevention effect can be further improved.

According to the fourth aspect of the present invention, since a slit for draining water is formed at the end of the contact portion on the motor side, water or the like flows down from the heating cooking chamber to the contact portion via the shaft insertion tube. However, since it flows out of the slit, it is possible to eliminate the accumulation at the end of the corresponding portion. In addition, since the width of the slit is set to 1/4 or less of the wavelength λ of the microwave, the microwave does not leak from the slit.

According to the fifth aspect of the present invention, one of the heating plate and the heat shield plate has a convex portion, and the other has a concave portion fitted with the convex portion. Since the heat shield plate is configured to be positioned, the heat shield plate can be accurately positioned with respect to the heating plate. As a result, the motor that can be mounted in a predetermined correspondence relationship with the heat shield plate also has the same structure. The mounting position is automatically determined with respect to the hot plate. Thereby, assemblability is improved. According to the sixth aspect of the present invention, the weight sensor is provided together with the motor on the lower surface side of the heating panel, and the heat shield plate is provided so as to face the weight sensor and the motor from above. The heat can be shielded.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a main part showing one embodiment of the present invention.

FIG. 2 is a longitudinal sectional front view of a microwave oven.

FIG. 3 is an exploded perspective view.

FIG. 4 is a perspective view of the lower surface side of the heating plate;

FIG. 5 is a partial perspective view of a contact portion.

FIG. 6 is an exploded side view.

FIG. 7 shows a conventional example and is equivalent to FIG.

[Explanation of symbols]

11 is a main body, 14 is a cooking chamber, 16 is an upper heater, 17
Is a magnetron, 19 is a turntable, 20 is a heating plate, 21 is a heat shield plate, 22 is a motor, 23 is a weight sensor,
24 is a shaft insertion tube, 29 is a planar heater, 33 is a concave portion, 35
Denotes a convex portion, 36 denotes a contact portion, 37 denotes an arm portion, 38 denotes a slit, 39 denotes a mounting plate, and 40 denotes a rotation axis.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-6-281159 (JP, A) JP-A-7-113529 (JP, A) JP-A-3-129814 (JP, U) (58) Survey Field (Int.Cl. ⁷ , DB name) F24C 15/16 F24C 7/02 551 F24C 15/34

Claims (6)

(57) [Claims] 1. A main body having a heating chamber formed therein, a shaft insertion cylinder attached to a bottom plate of the heating cooking chamber so as to protrude downward, and a hole for loosely fitting into the shaft insertion cylinder. A heating plate attached to the lower surface of the bottom plate in a state where the hole portion is loosely fitted to the outer periphery of the shaft insertion tube; and a rotating shaft attached to the lower surface side of the heating plate and the rotation shaft is inserted into the cooking chamber through the shaft insertion tube. A projecting turntable rotation motor, provided between the lower surface of the heating panel and the motor with a space covering at least the motor, and the entire lower end of the shaft insertion cylinder. Elastic support for abutting parts
And a heat shield made of a metal plate integrally formed in the above-described form. 2. The microwave oven according to claim 1, wherein the contact portion of the heat shield plate is formed to have a tapered shape. 3. The contact portion has a substantially circular shape and has three peripheral portions.
2. The microwave oven according to claim 1, wherein the microwave oven is supported by an elastic arm . 4. A motor side at a contact portion of the heat shield plate.
A slit for draining water is formed at the end of
2. The microwave oven according to claim 1 , wherein the width of the cut is not more than 1/4 of the wavelength [lambda] of the microwave. 5. A projection on one of a heating plate and a heat shield plate.
Is formed, and the other side is formed with a concave portion to be fitted with the convex portion.
Positioning of the heat shield plate with respect to the heating board by fitting
The microwave oven according to claim 1, wherein the microwave oven has a configuration. 6. A weight sensor together with a motor is provided on the lower side of the heating plate.
A heat shield is provided for the weight sensor and the motor.
The microwave oven according to claim 1, wherein the microwave oven is provided so as to face the heater from above.