JPH0278182A - High frequency heating device - Google Patents

Abstract

PURPOSE:To obtain a heating device easy to use by automatically discriminating the frequency of the used power source, and based on the information, by controlling the time of high frequency oscillation, which are to be started by predetermined two switches. CONSTITUTION:Power source current is input from a consent 7 via a low pressure transformer 23 of an electric circuit 19, separated into two directions of a DC source circuit 35 and a source frequency discrimination circuit 36, to a microcomputer 34. The source frequency discrimination circuit 36 is functioned prior to all of the other cooking operation to convert a wave shape of the source voltage to a rectangular wave, and to discriminate the frequency via a base clock. Based on the information of discriminated high frequency, the acting time of a high frequency oscillator is controlled by the microcomputer 34. The oscillation of the high frequency oscillator is executed by turning on both switches for the menu selection and for the timer by which the acting time is controlled. Even when the source frequency differs between the two, operation can thus be done easily.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to speed switching means for a timer mode of a high frequency heating device used in both 50 Hz and 60 Hz regions.

2. Description of the Related Art A conventional high-frequency heating device shown in FIG. 7, for example, includes a heating chamber (1) in a main body, a high-frequency oscillator (magnetron) and a heating chamber (1) for sending high-frequency waves to the heating chamber (1), There is a door (3) that closes the front opening of the heating chamber (1), an operation section (4), and the like. The operation unit (4) includes a menu selection switch (5) for selecting a menu, for example, switching to "microwave high" or "microwave low", a timer (6) for controlling the cooking time for cooking food, and the like.

Then, put the food in the heating chamber (1), close the door (3), set the menu selection switch (5) to "Microwave low", and turn the timer (6) knob to set the cooking time. Figure 7 shows a perspective view of the external appearance immediately after cooking starts at 5 minutes J, and Figure 8 shows the electrical circuit in that state.
As shown in the figure. The electrical circuit diagram will be explained.

A heating chamber (
1) Temperature switch (8) that detects abnormal temperature and turns off the power; ONL when door (3) closes; Door open/close interlock switch (9) that turns off when door (3) opens; The timer switch 00) that is turned off, the timer motor 01), the turntable motor 02) that rotates with the food placed there, the fan motor that cools the magnetron (2), and the interior that lights the heating chamber (1). Lighting light 04)
, and magnetron (2) and capacitor O9 on the secondary side.
and diode 06) are connected to the power transformer Q'7
) is connected to the primary side of the Also, the outlet (7)
On the other side, there is a power fuse 08) that turns off the power when an overcurrent flows through the power supply, a door opening/closing interlock switch B09),
A power on/off switch that cuts off the power that is intermittent due to the rotation of the timer motor (II), the turntable motor θ, the fan motor 03), the interior lighting light 04), and the turntable motor 02) and sets it to a "weak output" l2 (Il, when cooking, select "strong output" or "weak output", and when "strong output" is selected, the switch turns on and the power on/off switch Q
(When D is shorted and the output is a little less than 1, the switch turns OFF and the power on/off switch C!ω is activated.) It is connected to the menu selection switch (5) and the primary side of the power transformer 0'7). .

Problem to be Solved by the Invention However, in such a high frequency heating device shown in FIG.
When trying to use a device in both 0Hz and 60Hz regions, the timer and power supply parts (power transformer, capacitor), etc. had to be replaced to match the power frequency. With the recent rise in labor costs and lower product prices, it has become more economical to buy new products than to call in service personnel. Therefore, there was a demand in the market for a device that could be used immediately after being moved and installed in both 50 Hz and 60 Hz regions without the need for service personnel. However, current technology does this by using an inverter as the power source, or by automatically switching the capacity of the capacitor on the secondary side of the power transformer using frequency discrimination means that automatically discriminates the power frequency of the microcomputer. Moreover, in both cases, since there was a microcomputer, a display tube and keyboard were installed, as shown in the operation section in Figure 1.

On the other hand, when we investigate the actual purchasers of low-priced models, we find that they are ``single people,'' ``university students,'' and ``single people'' in their 50s to 60s. For those people, the 7th model is better than the model with a display tube as shown in Figure 9.
It is less cumbersome to set the time by turning the timer knob as shown in the figure (you need to press several keys to set the time, and there was no start button in Figure 7, but Figure 9) There is a start button, which increases the number of operations for one account, and the keyboard feels complicated just by looking at it.Also, when setting the time, you need to operate the keys on the keyboard to select the menu. It is said by the market that searching for and operating keys on the same keyboard is particularly troublesome for the silver generation.) It is said to be easy.

However, a synchronous motor is used as a timer for high-frequency heating devices that require high time accuracy.

In the case of a synchronous motor, there are dedicated timers for 50 Hz and 60 Hz, so it was necessary to replace the timers in accordance with each power frequency.

On the other hand, as an example of solving these problems, JP-A-52-309
Publication No. 45 includes a description of "a high-frequency heating device equipped with a frequency converter in a timer", but it is unclear what the frequency converter is.

Therefore, the equipment can be used in both 507 and 60Hz FIii areas without the need for service personnel, and
There was a problem in that it was impossible to create a high-frequency heating device (without a start button) that only oscillated when the menu selection switch and timer switch were turned on.

Means for Solving the Problems In order to achieve the above object, the high frequency heating device of the present invention includes:
A main body, a heating chamber for storing food in the main body, a high frequency oscillator for supplying high frequency output to the heating chamber, a timer for controlling the oscillation time of the high frequency oscillator, and a timer for controlling the opening and closing of the power supply of the motor of the timer. a frequency determining means for automatically determining a power supply frequency; a control unit controlling the opening/closing switch based on information of the frequency determining means; and a menu selection for selecting a menu when cooking food. The frequency determining means functions with priority over all other cooking operations when the power is turned on, and the control section operates the open/close selector switch intermittently at a certain power supply frequency based on the information, and Both the menu selection switch and the timer switch are configured to function as a start switch so that both the menu selection switch and the timer switch are turned on and the high frequency oscillator oscillates.

Function Since the high-frequency heating device of the present invention has the above-described configuration, the time can be set by turning the r① knob, which is the advantage of the conventional example. ■No need to press the start button. ■When you look at the operation panel, the ``switch to select the menu'' and ``timer knob to set the time'' are obvious and easy to understand. ” while still maintaining 50Hz.
This has the advantage that it can be used at the rear of a mobile installation without calling a service person in both the 60Hz and 60Hz power frequency regions.

EXAMPLE Hereinafter, an example of the present invention will be described based on the drawings. Components that are the same as the conventional example are given the same numbers. FIG. 1 is a control circuit diagram for implementing the present invention.

On one side of the power outlet (7), there is a temperature switch (8) that detects abnormal temperature in the heating chamber (1) and turns off the power.
ONL when the door (3) is closed; door opening/closing interlock switch A (9) that turns off when the door (3) opens; and timer motor (11) that has a built-in timer switch (00) that turns off the circuit when the cooking set time has passed. , a turntable motor that rotates with food loaded thereon (02), an oscillator (magnetron) (
2), a power supply connected to a fan motor (13) that cools the heating chamber (1), and an interior lighting lamp that illuminates the heating chamber (1) (magnetron (2), capacitor 05), and diode 06 on the 1st option and secondary side). It is connected to the primary side of the transformer θ'r).

Moreover, the other side of the outlet (7) is equipped with a power fuse 08) that turns off the power when an overcurrent flows through the power supply.

Turn on the power of the motor 01) of the timer (6) by the electronic circuit 09) equipped with a microcomputer (when the power frequency is 507)
Alternatively, turn on relay Q■, turntable motor 02), fan motor (13), and refrigerator interior light 0 gradient for intermittent operation (when the power frequency is 607: described later) using electronic circuit 09) equipped with a microcomputer. Relay (21), microcomputer-equipped electronic circuit 09) enables ONL at "strong output"
It is connected to a relay (22) that switches on and off for "weak output" and the like, and to the primary side of the power transformer. Further, a low voltage transformer (23) for power supply for the electronic circuit 09) equipped with a microcomputer is connected in parallel with the outlet (7).

In addition, in order to receive various signals, the electronic circuit 09) equipped with a microcomputer includes signals from the menu selection key (25) on the keyboard (24) fixed to the operation unit (4), and a door opening/closing interlocking switch (9). ), the signal of the door open/close interlock signal switch (26), the low voltage transformer (23) is connected to the electronic circuit 0.
9), it is built in the timer (6), and when the user operates the timer (6), it also provides ON information and the motor (11) of the timer (6).
Various switches are provided in order to input various signals to the microcomputer, such as information on the timer switch θ0) which is turned off by the timer (6) itself after the timer (6) has been driven for a set time. In addition, the output signals of the microcomputer include relay 09, relay (21), relay (22), relay (27) that switches the capacitance of the capacitor surface depending on the power frequency, and LED (28) for displaying menu selection on the operation unit (4). is driving.

FIG. 2 is an external perspective view of the high-frequency heating device according to the present invention. Inside the main body, there is a heating chamber (1) for storing food, and at the front opening of the heating chamber (1) there is a closed door (3) which is pivotally supported so as to be openable and closable. An operating section (4) is located near the door (3). On the operation panel (4), the name of the menu to be selected is written, and near the menu name there are a menu selection key (25) and an LED (28) for menu selection display.
), there is a keyboard (24) with visible parts, and a knob (29) for the timer (6), with a setting time scale "
5 minutes" is shown.

Next, the power supply frequency discrimination circuit will be explained based on FIG. This power supply frequency discrimination circuit (36) includes a waveform shaping circuit (30) that converts a commercial voltage waveform into a rectangular wave, and a
A basic clock generation circuit (31) that generates a basic clock of 00 kHz; a binary counter (32) that counts the period of the rectangular wave from the waveform shaping circuit (30) based on this basic clock; Binary counter (
32) Among the output terminals, it is composed of an AND circuit (33) that takes an AND between the QIO port, which is the output terminal when the 210 pulse force is counted, and the Q13 port, which is the output terminal when the 213 pulse force is counted. This AND circuit (33
) is input to the microcomputer (34) as information on power supply frequencies of 50 Hz and 60 Hz.

Next, the operation of this power supply frequency discrimination circuit (36) will be explained. The commercial power waveform input to the waveform shaping circuit (30) is
The rHj state is converted to a TI rectangular wave, and the "L" state is converted to a T2 rectangular wave. In the case of this implementation, the duty is 50%, and in the case of 60 Hz, TI, T2 - 8.3 m5ec, and in the case of 50Hz, T1, T2 = 10 m5ec. This square wave is the R of the binary counter (32).
input to the ESET port. This binary counter (3
2) is the CL of the binary counter (32) during T2, the period when the input terminal level to the RESET boat is in the "L" state.
The number of clocks of the basic clock signal input to the OCK port is counted, and the counted number is output to output ports from Ql to Ql4. Q1 boat changes its output state every time one pulse of basic tarok is input.
The output state of the Q4 boat changes every time 23 pulses are input. Below, the basic clock frequency division output is output in the same way, for example, the QIO port changes depending on its output state every 512 pulses, and the Q13 port changes every 512 pulses.
The state changes every pulse.

Therefore, when the power frequency is 60Hz, the binary counter (3
The output state of 2) is T I = 8.3 m5 ec, and the 500 kHz (period: 2 μ5 ec) clock is counted 4150 pulses. At this time, the Q13 port is at the rH level, while the QIO port is at the “L” level.
” level. As a result, the output of the AND circuit (33) that takes the AND between the QIO port and the Q13 port is “L”.
” signal and is input to the input port, K port, of the microcomputer (34). On the other hand, if the power supply frequency is 50Hz,
T 1 =10 msecd, and the number of basic clocks counted during this period is 500 pulses.

Therefore, the output signal at this time is QIO becomes rH" level, Ql3 also becomes "H" level, and as a result, the output of the AND circuit (33) becomes an "H" signal, and the microcomputer (34)
is input to the port. The above is the operation of the power supply frequency discrimination circuit (36), which outputs the rH signal when the frequency is 50 Hz, and outputs the rl and J signals when the frequency is 60 Hz.

Next, the electronic circuit side of the present high-frequency heating device will be explained based on FIG. This circuit consists of a low-voltage transformer (23) that steps down the commercial power supply voltage, a power supply circuit (35) that generates the DC power necessary for the electronic circuit Q9 from the AC output of this low-voltage transformer (23), and the aforementioned power frequency discrimination circuit. (36)
, a microcomputer (34) that controls the input and output according to a pre-stored program, a basic clock generation circuit (31) to the microcomputer (34), and an electronic circuit in the operating section (4) of the high-frequency heating device. 09), the door opening/closing interlocking signal switch A (26), the timer (6) switch aω, which sends a signal indicating that the timer (6) is ON or OFF. A display device (menu selection display LED (28)) that displays operation input information and cooking information;
It is composed of a relay drive circuit (37) that drives the relay 09), the relay (21), the relay (22), and the relay (27) according to an output signal from the microcomputer (34).

For example, when cooking with this high-frequency heating device in an area where the power supply frequency is 60Hz, the output signal "L" level of the power supply frequency discrimination circuit (36) is detected by the microcomputer (34).
By reading this power supply frequency information, the microcomputer (34) recognizes that the frequency is 60Hz and activates relay D (
The output port R3 of the microcomputer (34) outputs an LJ level control signal to the relay drive circuit (37) that drives the microcomputer (37).
4) Output port R3 outputs rH and level control signals.

Next, based on FIG. 1, switching of the capacitance of the capacitor 05) of the high voltage power supply for supplying high voltage to the magnetron (2) will be explained.

For use at 60Hz, operate with relay (27) open, i.e. with low capacitance, and at 50Hz
When used in a capacitance state of 60 Hz, the current flowing through the secondary circuit decreases, so the capacitance switching relay (27) is closed to increase the capacitance. Therefore, whether operating at 60Hz or 507Hz, the output of the magnetron (2) remains constant.

Next, the circuit of the motor (II) of the timer (6) will be explained.

When using at 50Hz, relay AI2Φ is turned on by the power frequency discrimination circuit (36) mentioned above, and when the set time is reached, the switch 0ω built in the timer (6) is turned on.
is set to 0FFL by the cam etc. built into the timer (6).
, the signal is taken into the microcomputer (34), and the microcomputer (34) outputs an OFF signal to relay 80. In the case of 60 Hz, a synchronous motor is used to ensure accuracy of the set time, so it rotates faster than in the case of 50 Hz, so it is only necessary to turn the motor (11) on and off during that time. For example, turn on for 10 seconds and turn off for 2 seconds. If you are concerned about the OFF time, use relay AC.
Although it is necessary to assume that the intermittent durability life of 2Φ is not a problem, it is sufficient to turn it on for 5 seconds and turn off for 1 second.

Next, the overall operation of the high frequency heating device of the present invention will be explained based on FIG. When the outlet (7) is connected to a commercial power source, the power frequency determination circuit (36) described above determines whether the power frequency is 50 Hz or 60 Hz. According to this power frequency discrimination information, relay C
! Controls the opening and closing of contacts between Φ and relay (27). If the power supply frequency is 60 Hz, the contacts of the relay (27) remain open, so the capacitor q9 operates with only the capacitance of C1 connected, and C2 does not participate in the circuit function at all. Also, the time is set by a pre-stored program and the switch qO of the timer (6) is turned OFF.
After N, relay Q (D is on/off according to the programmed duty. On the other hand, when the power frequency is 50Hz, the contact of relay (27) is closed and the capacitor 09
C1 and 02 are connected in parallel, and the capacitor capacitance value becomes CI+C2. In addition, after the time is set by the pre-stored program and the switch 00 of the timer (6) is ONL, the relay Q, 0
turns on.

As a result, the accuracy of cooking time, circuit operation, and high frequency output can be maintained at appropriate values at both power supply frequencies of 50Hz and 60Hz.

Next, the operation of the power frequency determining means and the operation timing of the relay (27) by the control section will be explained. First, when the power is turned on for the first time, the power frequency discrimination circuit (36) functions before any other cooking operation and inputs the information to the microcomputer (34).

On the other hand, the microcomputer (34) inputs the output information from the power frequency discrimination circuit (36) according to a procedure stored in advance, and if the result is 50Hz, it immediately switches the contacts of the relay (27). In order to close the output port R3, the signal at the output port R3 is set to "H". This output state is maintained until the power is turned off, and is maintained completely independently of the operation of the other relays (121), relays (21), and relays (22). As shown in the process flowchart in Figure 5, it is clear whether the power supply frequency is 50Hz or 607Hz, and the relay (
The configuration is such that the original microwave cooking is accepted only after the operation 27) is completed. In addition, after the power is turned on, the contact state of the relay (27) is 50 as long as the power is on.
ON if Hz, OFF if 60) (z)
is fixed in one state.

Next, the menu selection operation will be explained.

As shown in the processing flowchart in Figure 6, as in the conventional example,
If you operate either the timer (6) or menu selection key (25) first, the menu selection LED (28
) lights up, and when you operate other items next, the menu selection LED
(28) flashes and cooking begins.

In other words, the timer (6) or the menu selection key (2)
The switch operated after step 5) also serves as the start switch.

You can also use the timer (6) or menu selection key (25).
), we intentionally do not set a priority order for them.

This is because, as in the conventional example (FIG. 7), it goes without saying that it is more convenient to use without prioritizing as much as possible, although this is not limited to the silver generation.

Effects of the Invention As described above, according to the high frequency heating device of the present invention, the following effects can be obtained.

(1) Since the circuit automatically switches according to the power supply frequency, there is no need to divide the frequency of the equipment. Therefore, frequency classification of devices at the shipping stage is no longer necessary, and sometimes due to rapid changes in the market or inaccuracies in production allocation, the frequency of devices must be changed before being shipped or transferred in the market. There is no such troublesome work involved. Also, since only one model is required for 50Hz/60Hz, it is very economical in terms of inventory management.

(2) Even if you move to an area where the power supply frequency is different, there is no need to do any work to switch the frequency of the device, and you can use the device immediately after installation, making it a very easy-to-use device. Also,
It goes without saying that even if you move to an area where the power supply frequency is different, there is no need to change the frequency of the equipment, so there is no need to call a service person, so it is economical.

(3) Since the appropriate frequency of the device is automatically switched, it is possible to prevent the occurrence of danger by forgetting to change the frequency of the device.

(4) According to UL (safety standard in North America), in the user service method (users change the frequency from outside the device), even if they forget to change the frequency,
This is considered a normal state, and in the worst case scenario, the device is operated at 50Hz (large capacity) and operated with a 60Hz power supply, and the temperature rise at this time must be kept within the standard range. According to this method, there is no need for this, and the power transformer can be miniaturized, which is very advantageous in terms of cost and space for installing the transformer, and is very economical.

(5) By performing the relay setting operation when the power is turned on, the effect of the relay's operating sound (the sound when the contact turns 0NeOFF) (which is harsh) is limited to only once when the power is turned on, causing anxiety to the user. It does not cause any discomfort or discomfort.

(6) The discharge resistor connected in parallel to the first capacitor ensures that the accumulated charge in the second capacitor is discharged through the contacts of the relay, and the discharge resistor for the second capacitor It is possible to reduce the amount of

(7) Product planning that incorporates a microcomputer so that it can be used after installation in any area with a power frequency (507 or 607) will result in higher costs;
If a microcomputer was to be installed, the idea was to have the microcomputer perform multiple functions.
Moreover, there were many keys on the keyboard. It is true that it is very convenient, but it is useful for people who want a simple and low-priced model (single people, college students, and silver 150-6
(0 years old) was not satisfactory. However, by implementing the present invention, a simple operation section can be realized.

(8) The good thing about the conventional model is that you can set the time by turning the knob, and even if you are away from the device while cooking, you can
Since the knob moves, you can easily see the remaining cooking time by looking at the angle the knob is pointing at. ■No need to press the start button. ■When you look at the operation panel, the ``switch to select the menu'' and ``timer knob to set the time'' are clearly visible and easy to understand. Mobile installation rear, available.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of an embodiment of the present invention, FIG. 2 is an external perspective view of the same, and FIG. 3 is an explanatory diagram of the power frequency discrimination circuit.
Fig. 4 is a block diagram of the electronic circuit, Fig. 5 is a processing flowchart from the time the power is turned on in the electronic circuit, and Fig. 6 shows the menu selection and timer operation of the equipment shown in Fig. 2. Processing flowchart from settings,
FIG. 7 is an external perspective view of a conventional high-frequency heating device;
7 is an electric circuit diagram, and FIG. 9 is a front view of main parts of another conventional high-frequency heating device. (1)...Heating chamber, (2)...High frequency oscillator (magnetron'), (3)...Door,
(4)......Operation unit, (5)...Menu selection switch, (6)...Timer, (7)
...Outlet, (8) ...Temperature switch, (9) ...Door opening/closing interlock switch B, θ0
)......Timer switch, θ1)...
・Timer motor, 02)...Turntable motor, 03)...Fan motor, circle...
...Interior lighting, 05)...Capacitor, 0
ω...Diode, Q71...Power transformer, (18)...Power fuse, 09)
...Electronic circuit, Qω ...Relay, (21
) ・・・・・・Relay, (22) ・・・・・・
Relay, (23)...Low voltage transformer, (2
4)...Keyboard, (25)...Menu selection key, (26)...Door opening/closing interlock signal switch, (27)...Relay, ( 28)...
... Menu selection LED, (29) Timer knob, (30) ... Waveform shaping circuit, (31) ...
...Basic clock generation circuit, (32)...
Binary counter, (33)...A N D times! , (34)...Microcomputer, (35)...
...Power supply circuit, (36)...Power frequency discrimination circuit, (37)...Relay drive circuit, (38)...
... Display tube, (39) ... Cooking time setting key, (40) ... Clock setting key, (41) ...
... Finish adjustment key, (42) ... Start button. Name of agent Patent attorney Shigetaka Awano 1 person + No 〉臥 2 Fig. 5E;'' Fig. 5 Densai OFF Fig. 6 Fig. 7

Claims (2)

[Claims] (1) a main body; a heating chamber for storing food in the main body;
a high-frequency oscillator that supplies high-frequency output to the heating chamber; a timer that controls the oscillation time of the high-frequency oscillator; an on/off switch that opens and closes the power supply to the motor of the timer; and a frequency that automatically determines the power supply frequency. Discrimination means;
The frequency determining means is equipped with a control unit that controls the opening/closing switch based on the information of the frequency determining means, and a menu selection switch that selects a menu when cooking food, and the frequency determining means is configured to control the opening/closing switch based on information from the frequency determining means, and the frequency determining means is configured to control the opening/closing switch based on information from the frequency determining means, and a menu selection switch that selects a menu when cooking food. The high-frequency heating device has a configuration in which the control section operates on and off at a predetermined cycle at a specific power frequency based on the information. (2) The high-frequency heating according to claim 1, wherein both the menu selection switch and the timer switch are configured to double as a start switch so that the high-frequency oscillator oscillates when both the menu selection switch and the timer switch are turned on. Device.