JPH0620768A - Power cutoff device for high-frequency heating device - Google Patents

Abstract

(57) [Summary] [Purpose] To electrically realize a magnetron oscillation stop device when the door is opened, and to eliminate the need for the conventional door member pin member and the corresponding operating lever. A high-frequency heating device main body having a heating chamber, a door provided in the heating chamber opening of the high-frequency heating device main body for opening and closing the heating chamber opening, and a heating target in the heating chamber by microwave output. A high-frequency oscillator that heats things,
In a high-frequency heating device comprising a power-supply cutoff means for cutting off power supply to the high-frequency oscillator in response to an opening operation of the door, the power-cutoff means is turned on by the proximity of a metal portion on the back surface of the door. , A proximity switch that is turned off by separating the metal parts.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power cutoff device for stopping oscillation of a high frequency heating device such as a microwave oven.

[0002]

2. Description of the Related Art Generally, a high-frequency heating device such as a microwave oven has a high-voltage power supply circuit of several thousand volts, so that various strict requirements are imposed by the Electrical Appliance and Material Control Law.

As one of them, for example, it is required that the oscillating operation of the magnetron, which is a high frequency oscillator, be stopped when the door is opened, and moreover, it is surely linked with the opening and closing of the door. Power off
It is a requirement to realize it by using at least two or more series of open / close switches which can be F / ON and are electrically independent from each other.

Therefore, in order to satisfy the requirement, two sets of switches, which are conventionally a latch switch provided at the periphery of the opening of the heating chamber and a door switch related to a hinge lever for guiding opening and closing of the door, are provided. There is.

Now, there are two of the latch switch and the door switch.
The mechanical structure of a conventional high-frequency heating device having a pair of switches is shown in FIGS. 5 to 7, and the electrical structure is shown in FIG.

First, FIG. 5 shows the overall structure (housing structure) of the high-frequency heating apparatus 1, in which a heating chamber (food storage) 2 is provided inside the housing.

At the bottom of the heating chamber 2, a turntable 3 for placing food is rotatably installed. The latch switch 62 is operated as shown in FIGS. 6 and 7 by inserting a pressing pin 81 on the door 16 side, which will be described later, above the right side portion of the housing front plate 1a around the front opening 19 of the heating chamber 2. End of operation lever 61 (upper end)
An opening 82 for pressing 61a is provided. Further, a door 16 having a finder portion 17 is attached to the opening portion 19 so as to be supported by a hinge 68 and a hinge lever 69 so that it can be opened and closed in the vertical direction. A push pin 81 for pushing the operating end of the latch switch 62 actuating lever 61 is provided on the metal frame surface 16b on the back side of the main body portion corresponding to the opening 82 on the housing side of the door 16. Reference numeral 16a is the door 1
6 shows a handle portion.

On the other hand, in the space 70 on the right side of the housing, for example, as shown in FIGS. 6 and 7, the latch switch actuation lever 61 and the latch switch actuated by the latch switch actuation lever 61 are turned on and off. 62, a hinge lever 69, and a door switch 91 that is turned on / off by the hinge lever 69.

First, the latch switch operating lever 61
Is arranged behind the front plate 1a at the peripheral edge of the housing opening 19 and is arranged in the up-down direction.
Is rotatably supported in the directions of arrows (a), (c) or (b), (d), and the coil spring 64 always causes the arrow (a) and (c) directions, that is, the working end 61b thereof. The latch switch 62 is urged in a rotating direction to turn off the switch portion without pressing the operation button 62a.
Therefore, in the state of FIG. 5 in which the door 16 is opened in the direction of the arrow (e) using the handle 16a, the operating end 61a of the latch switch actuating lever 61 is located in the opening 82 of the front plate 1a. While being held in a state of abutting against the back surface and closing the opening 82, the operating end 61b thereof is held at the rearmost position of the imaginary line shown in the drawing, which is out of the operation button 62a of the latch switch 62. As a result, in this state, the operation button 6 of the latch switch 62 is
2a projects upward by the action of the internal biasing spring, and turns off (opens) the contact portion of the latch switch 62.

On the other hand, on the contrary, as shown by the solid line in FIGS. 6 and 7, when the door 16 is completely closed, the pressing pin 81 on the door 16 side is inserted into the housing through the opening 82. When the latch switch operating lever 61 is inserted and pushes the operating end 61a of the latch switch operating lever 61 in the direction of arrow (b), the operating end 61b of the latch switch operating lever 61 rotates in the direction of arrow (d) shown in the drawing to move the latch switch 62. Operation button 62
By pressing a, the contact portion of the latch switch 62 is turned on (closed).

On the other hand, the door switch 91 is provided above the rear end of the hinge lever 69 for guiding the opening and closing of the door 16 as shown in detail in FIG. The arrow (f), (h) or (g), (d) of the door switch actuating lever 95 that is pivotally operated by the door switch operating piece 87 of the hinge lever 69 that moves as shown by the locus of the phantom line in the figure. The operation button 91a is operated by the turning operation in the direction to be turned ON / OFF.

That is, as in the case described above, first the door 16
Is released in the direction of the arrow (e), the hinge lever 69 is also sequentially pulled out as shown by the phantom line in FIG. 7, and the door switch operation piece 87 is operated at the initial stage of opening the door 16. The operating end 95a of the door switch actuating lever 95 is rotated in the arrow (f) direction.

As a result, the operating end 95b of the door switch operating lever 95 rotates in the direction of the arrow (g) to release the pressed state of the operation button 91a of the door switch 91, and the contact portion of the door switch 91 turns off ( Open).

On the other hand, when the door 16 is closed in the state shown by the solid line in the figure, the hinge lever 69 moves in the direction opposite to the above, and the door switch actuating lever 95 is moved in the directions indicated by arrows (h) and (h). The door switch 91 is rotated in the direction to press the operation button 91a of the door switch 91 to turn on (close) the switch portion of the door switch 91.

The latch switch 62 and the door switch 91 are incorporated in series between a power source (AC 100 V) and the magnetron 13 together with a thermo switch and other switches, as shown in the circuit of FIG.
(See below).

On the other hand, in front of the right side space 70 of the opening 19 of the heating chamber 2 on the front side of the housing, an operation panel section 26 for operating and controlling various functions of the high frequency heating apparatus is installed. Has been done. On the operation panel unit 26, as shown in detail in FIG. 5, for example, from the upper side to the lower side, a display unit (liquid crystal display unit) 34, a heating time setting key for a manual menu (27a for 5 minutes ,, 27b for 1 minute, 1
It consists of two keys of 27c for 0 seconds), manual heating key group
(Raw thaw, toaster, pizza heating, rice porridge 4 keys) 29, automatic heating key group (liquor can, toast, frozen toast, rice cooking 4 keys) 30,
A manual menu designating key 41, an auto menu designating key 42, a start key 43, a cancel key 44, a finish adjusting key 45, etc. are appropriately arranged with good operability.

The display section 3 of the operation panel section 26 is
For example, when various operation keys described above are turned on, various selection setting states are displayed at 4.

The operation panel section 26 is connected to a control unit 20 (see FIG. 8) for controlling a microwave oven mainly composed of a computer via a data bus and a control bus to freely send and receive input / output signals. You can do it.

Further, the inside of the housing of the high-frequency heating device 1 is heated by causing the object 40 to be heated on the cooking plate 5 placed on the turntable 3 in the heating chamber 2 to radiate and absorb microwaves. A magnetron 13, upper and lower heaters H ₁ and H ₂ and a heater circuit for heating an object to be heated in the heating chamber 2 by irradiating infrared rays as needed, and a ventilation fan and a fan motor 12 are installed. Has been done. A turntable motor drive circuit is provided between the control unit 20 and the turntable motor 4, and the control unit 20 and the fan motor 1 are also provided.
A fan motor drive circuit is provided between the control unit 20 and the magnetron 13, and a magnetron drive unit is provided between the control unit 20 and the magnetron 13.

The electrical circuit diagram of the high-frequency heating apparatus constructed as described above is shown in FIG. 8, for example.

In FIG. 8, reference numeral ST is a thermostat switch for preventing heating, RS ₁ is a relay contact which is turned on in conjunction with turning on the start key 43 on the operation panel 26 side, and L ₁ is the relay contact RS ₁ The internal lamps, RS ₂ and RS ₃ excited by the ON of the above, are turned ON in response to the ON operation of the operation keys corresponding to the oven or toast menu, and the upper and lower heaters H ₁ and H ₂ are relay contacts for heating, RS ₄ Is a magnetron OFF relay contact, RS ₅ is a high voltage relay contact, RS ₆ is a range / oven switching relay contact, TR
Is a high-voltage transformer, and MS is a monitor switch for blowing a fuse.

The control unit 20 includes the control board 5
0 is provided via a power supply circuit (constant voltage power supply circuit) 53, and a door signal switch DS _{1 that} is turned on / off in conjunction with the above-mentioned latch switch 62 is externally attached in order to obtain a door opening / closing signal. ing.

Therefore, in this structure, when the door 16 is opened as described above, the latch switch 6 described above is surely opened.
Both the door switch 91 and the door switch 91 are turned off, so that the heaters H ₁ and H ₂ , the fan motor 12, the turntable motor 4, and the magnetron 13 are surely cut off from energization.

[0024]

However, in the structure of the conventional power cutoff device, a pin member for pressing the actuating lever for actuating the latch switch is required on the door side, and the pin member is the peripheral edge of the door. It has a drawback that it looks very bad because it protrudes at the part, and it also becomes a hindrance during the operation of moving food in and out. In order to improve the drawback, it is conceivable to project an ON / OFF pin on the front side of the housing, but doing so is not preferable because it may be pushed by a finger.

In addition, the above-mentioned conventional structure requires an operating lever for operating the latch switch, which is mechanically complicated, and the switch side O for opening and closing the door.
There are problems such as poor responsiveness of N / OFF operation.

[0026]

The present invention has been made for the purpose of solving the above-mentioned conventional problems, and is constructed as follows.

That is, the power cutoff device for the high-frequency heating device of the present invention comprises a high-frequency heating device main body having a heating chamber,
A door provided at the opening of the heating chamber of the main body of the high-frequency heating device to open and close the opening of the heating chamber, a high-frequency oscillator for heating an object to be heated in the heating chamber by microwave output, and an opening operation of the door. In a high-frequency heating device comprising a power-supply cutoff means for cutting off the power supply to the high-frequency oscillator, the power-supply cutoff means is turned on by the proximity of the metal portion on the back surface of the door, It is composed of a proximity switch that is turned off by separation.

[0028]

The power cutoff device for the high-frequency heating device according to the present invention is
As described above, a high-frequency heating device body having a heating chamber,
A door provided at the opening of the heating chamber of the main body of the high-frequency heating device to open and close the opening of the heating chamber, a high-frequency oscillator for heating an object to be heated in the heating chamber by microwave output, and an opening operation of the door. In a high-frequency heating device comprising a power-supply cutoff means for cutting off the power supply to the high-frequency oscillator, the power-supply cutoff means is turned on by the proximity of the metal portion on the back surface of the door, Since the proximity switch is turned off by being separated from the power source, it is possible to cut off the power supply with high responsiveness without requiring a mechanical operating member or an interlocking mechanism for opening and closing the power supply.

[0029]

Therefore, unlike the prior art, it is not necessary to provide a convex portion such as a pin member on the door and a mechanical interlocking mechanism such as an actuating lever is not required, and the appearance and operability of the door portion are improved. At the same time, the space factor inside the housing is greatly improved.

[0030]

1 to 4 show the construction of a high-frequency heating apparatus equipped with a power interruption device according to an embodiment of the present invention.

First, FIG. 1 shows the entire structure (housing structure) of the high-frequency heating apparatus 1, and a heating chamber (cooking product storage) 2 is provided inside the housing.

At the bottom of the heating chamber 2, a turntable 3 for placing food is rotatably installed. A latch switch 18 to be described later is provided on the housing front plate 1a above the front opening 19 of the heating chamber 2 at the peripheral right side.
An opening portion 35 for fitting the sensing surface 18a is provided. A latch switch 18 is attached to the back side of the opening 35 as described later.

Further, in the lower portion of the space 70 on the right side of the housing, for example, a hinge lever 69 similar to the conventional one shown in FIG. 7 and ON / OFF by the hinge lever 69.
A door switch 91 to be operated is similarly provided (not shown).

On the other hand, on the right side of the opening 19 of the heating chamber 2 on the front side of the housing (in front of the right space 70), various functions of the high-frequency heating apparatus are provided as in the conventional case described above. An operation panel unit 26 for operating / controlling is installed. As shown in detail in FIG. 1, for example, the operation panel unit 26 is provided with a display unit from the upper side to the lower side.
(Liquid crystal display) 34, heating time setting key for manual menu (composed of two keys 27a for 5 minutes, 27b for 1 minute, 27c for 10 seconds), manual heating key group (defrosting raw food, toaster, It consists of 4 keys: pizza heating and porridge) 2
9, automatic heating key group (consisting of four keys of liquor can, toast, frozen toast, and rice) 30, manual menu designation key 41, auto menu designation key 42, start key 43, cancel key 44, finishing adjustment key 45 Are properly arranged with good operability.

The display section 3 of the operation panel section 26
For example, when various operation keys described above are turned on, various selection setting states are displayed at 4.

The operation panel section 26 is connected to the control unit 20 for controlling the microwave oven, which is mainly composed of a computer, via a data bus and a control bus so that input / output signals can be freely transmitted and received. ing.

Further, inside the housing of the high-frequency heating device 1, as in the prior art, the object to be heated 40 on the cooking plate 5 placed on the turntable 3 in the heating chamber 2 radiates and absorbs microwaves. Magnetron 13 heated by
And upper and lower heaters H ₁ and H ₂ and a heater circuit for heating an object to be heated in the heating chamber 2 by irradiating infrared rays as necessary, a ventilation fan and a fan motor 12
And are installed respectively. Then, the control unit 2
0 and the turntable motor 4, a turntable motor drive circuit, a fan motor drive circuit between the control unit 20 and the fan motor 12, and a control circuit between the control unit 20 and the magnetron 13. Magnetron drive units are provided between them.

By the way, the latch switch 18 of the present embodiment detects that a metal (magnetic metal such as iron or nickel) approaches the front side sensing surface 18a, as shown in FIGS. 2 and 3, for example. It is turned on when the metal is separated, and is turned off when the metal is separated.
It does not require a mechanical actuation stroke for F.

That is, the latch switch 18 has the pin insertion opening 82 for operating the above-mentioned conventional latch switch.
The cylindrical switch portion main body, which is resin-molded, behind the large-diameter opening 35 formed at substantially the same position as the mounting bracket 24 and the attachment nut 25 having two nut portions. It is attached to and installed on the front plate 1a of the housing via the intermediary of the housing. The front side sensing surface portion 18a faces the opening 35 of the housing front plate 1a, and the finder portion 17 of the door 16 is exposed.
The ON / OFF operation is performed by magnetically detecting the proximity or separation of the peripheral magnetic metal frame surface 16b. The latch switch 18 is connected to a latch opening / closing control circuit 71 newly provided on the control board 50 for the control unit 20 shown in FIG. 4, for example, via a connection terminal 18b provided on the rear end side. ing.

FIG. 4 is an electric circuit diagram showing the configuration of the high-frequency heating apparatus of the present embodiment constructed as described above.

In FIG. 4, the conventional circuit described above (of FIG. 8).
Similarly, first, ST is a thermostat switch for preventing heating, RS ₁ is a relay contact that is turned on in conjunction with the start key being turned on, L ₁ is an internal lamp that is excited by turning on the relay contact RS ₁ , and RS ₂ and RS ₃ are relay contacts for heating the upper and lower heaters, which are turned ON in response to ON operation of an operation key corresponding to the oven or toast menu, RS ₄
Is a relay contact for turning off the magnetron, RS ₅ is a high-voltage relay contact, RS ₆ is a range / oven switching relay contact, TR is a high-voltage transformer, and MS is a monitor switch for blowing a fuse.

The control unit 20 includes the control board 5
0 is also provided via the power supply circuit 53.

However, in the present embodiment, unlike the conventional circuit configuration shown in FIG. 8, the conventional latch switch 62 is composed of a relay contact (a contact) RS ₇ , which is electrically ON / OFF. It is supposed to do.

That is, in the high-frequency heating apparatus of this embodiment, the mechanical contact of the latch switch is not directly incorporated in the power supply circuit as in the conventional case, but, for example, as shown in detail in FIG. Opening / closing control circuit 7 for the latch
Incorporate only the relay contact RS ₇ relayed controlled by a door 16 of the latch switch 18 to the relay contact RS ₇ is constituted by a proximity switch, as described above
Indirectly corresponding to ON / OFF operation accompanying opening / closing of
-It is configured to control OFF. The output of the latch opening / closing control circuit 71 is input to the microcomputer-side control unit 20 on the same control board 50 as a door opening / closing state display signal indicating the door opening / closing state.

The latch opening / closing control circuit 71 divides the power supply voltage (+ Vb) of the latch switch 18 by resistors r ₂ and r _3.
Using the divided voltage V _{2 obtained} by {[r ₃ / (r ₂ + r ₃ )] · Vb} as a reference voltage, compare the output voltage V ₁ between the detection resistors r ₁ generated according to ON / OFF of the latch switch 18. It is configured to have a comparator 51 for voltage.

In the comparator 51, the door 16 is closed and the latch switch 18 is turned on as shown by the phantom line in the figure, and the comparison voltage V ₁ on the latch switch output side is higher than the reference voltage V _2. Is higher,
The base circuit of the transistor Tr consisting of the resistors r ₄ and r ₅ has H
(High) Outputs the same switching transistor Tr
Is turned on to excite the relay coil RL.

As a result, the latch relay contact RS _{7 of the} power supply circuit is turned on, and power can be supplied to the upper and lower heaters H ₁ and H ₂ and the magnetron 13 side.

On the other hand, at the same time, the comparator output V ₃ divided by the resistors r ₆ and r ₇ is further input to the control unit 20 as a door closed state display signal.

On the other hand, contrary to the above case, when the door 16 is opened, the output of the comparator 51 becomes L (low) output, and the relay coil RL is not excited. RS ₇ is OFF
Therefore, the supply of power to the upper and lower heaters H ₁ and H ₂ and the magnetron 13 is surely cut off. Further, the door open / closed state display signal V ₃ also becomes an L (low) output to form a door opened state display signal.

As described above, according to the configuration of this embodiment,
Since the latch switch 18 is configured by the proximity switch, it is not necessary to provide a pin member on the back surface of the door 16 as in the conventional case, and a mechanical actuation mechanism such as a latch switch actuation lever is not required in the housing. Space factor is improved. Further, since the output of the comparator 51 can form a signal indicating the open / closed state of the door 16 in the control board 50, the conventional external door signal switch DS ₁ becomes unnecessary.

[Brief description of drawings]

FIG. 1 is a perspective view showing a housing structure of a high frequency heating apparatus according to an embodiment of the present invention.

FIG. 2 is a partially cutaway side view showing a structure of a door of the housing and a latch switch part corresponding to the door.

FIG. 3 is a partially cutaway plan view showing a structure of a door of the housing and a latch switch part corresponding to the door.

FIG. 4 is an electric circuit diagram of the same high-frequency heating device.

FIG. 5 is a perspective view showing a housing structure of a conventional high-frequency heating device.

FIG. 6 is a partially cutaway side view showing a structure of a door of the housing and a latch switch part corresponding to the door.

FIG. 7 is a partially cutaway side view showing a structure of a door hinge lever of the housing and a door switch unit corresponding to the hinge lever.

FIG. 8 is an electric circuit diagram of the conventional high-frequency heating device.

[Explanation of symbols]

1a is a front plate of the housing, 13 is a magnetron, 16
Is a door, 16a is a handle, 16b is a metal frame, 1
8 is a latch switch, 20 is a control unit, 35 is an opening, 51 is a comparator, RL is a relay coil, RS ₇
Is a relay contact for latch.

Claims (1)

[Claims] 1. A high-frequency heating apparatus main body having a heating chamber,
A door provided at the opening of the heating chamber of the main body of the high-frequency heating device to open and close the opening of the heating chamber, a high-frequency oscillator for heating an object to be heated in the heating chamber by microwave output, and an opening operation of the door. In a high-frequency heating device comprising a power-supply cutoff means for cutting off the power supply to the high-frequency oscillator, the power-supply cutoff means is turned on by the proximity of the metal portion on the back surface of the door, A power cutoff device for a high-frequency heating device, comprising a proximity switch which is turned off by being separated.