JP2002071143A - Cooker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem of a cooker that power consumption of means for driving a load is high when a high current load is turned on because the capacity of a control power supply is low and since the voltage of the control power supply decreases, the level for extracting a drive timing signal from a commercial power supply is varied to cause variation of the drive timing. SOLUTION: A control means alters a drive command to a cooling fan such that the volume of supply air of a cooling fan when a heater relay is turned on in order to drive a heater is substantially equal to the volume of supply air of the cooling fan when the heater relay is turned off.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooking device provided with cooling means.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Patent Application Laid-Open No. 9-60888
No. in the official gazette.

[0003] In a cooker in which food is heated by a magnetron or a heater serving as a heating source, a cooling fan motor is connected in series with a switching component, and an ON signal is given from the control means to the switching component to drive the cooling fan motor. A switching component that is turned off every time the voltage waveform of the commercial power supply passes through the zero-cross point is used.

[0004] Further, the control means, based on the zero cross point of the commercial power supply voltage waveform as a reference, in order to rotate the cooling fan motor at a desired rotation speed therefrom, to the switching component after a delay time delay corresponding to the rotation speed, that is, the blowing amount. By giving an ON signal, the number of revolutions of the cooling fan motor was controlled.

More specifically, as shown in FIG. 5, a voltage waveform m (see FIG. 5A) of a commercial power supply is subjected to full-wave rectification to obtain a pulsating waveform n (see FIG. 5B). Then, a pseudo zero-cross point is detected by comparing with a predetermined value x, and a drive timing signal p (see FIG. 5C) is obtained. The ON signal q is given to the switching component after a delay time α corresponding to the amount of blown air from the falling of the drive timing signal p. So-called phase control is performed.

[0006]

Generally, the control power supply is
This control power is supplied to switching components generated from the commercial power supply and for controlling the control means and the cooling fan motor to be turned on. The capacity of this control power supply is designed to be able to absorb even a slight change in the power consumption of the supply destination. However, in recent years, the capacity has been designed to be small for reasons such as cost reduction of products.

However, since a large current flows through a heating source such as a heater, the withstand voltage of the switching component is increased, and the ON power for driving the switching component is correspondingly large. Therefore, the DC output of the control power supply fluctuates when the switching component is on and off. Specifically, the output voltage of the control power supply decreases.

On the other hand, the control means detects a zero-cross point of the AC power supply voltage waveform by comparing a predetermined value generated from the control power supply with the AC power supply voltage waveform. As described above, when the control power supply output voltage decreases, the predetermined value also decreases, so that the output timing of the drive timing signal also shifts.

Specifically, as shown in FIG. 6, a predetermined value x to be compared with the pulsating waveform n is generated from the control power supply because the output voltage of the control power supply decreases when the switching component is turned on. The predetermined value x decreases as x ′. Due to this decrease, the width of the drive timing signal P is widened by Y, so that the start point of counting the delay time α for outputting the ON signal of the switching component is delayed by β time.

[0010] Even if the count start time of the delay time α is delayed, the off time of the switching component does not change, so that the energizing time to the cooling means is shortened, the rotation speed of the fan motor is reduced, and the predetermined air flow rate is reduced. May not be obtained.

The present invention is to solve such a problem.

[0012]

A cooker according to the present invention is driven by turning on and off a heating chamber for storing food, a heating source for heating the food in the heating chamber, and a connection between the heating source and a commercial power supply. Heating source driving means for controlling, control means for controlling the heating source driving means, cooling means for blowing at least cooling air to the control means, and the control means for obtaining a desired air flow from the cooling means. Cooling drive control means for controlling the drive based on instructions, control power supply means for supplying a control power generated from the commercial power to the heating source drive means, the control means and the cooling drive control means, The control unit is configured such that, when driving the heating source driving unit, the blowing amount of the cooling unit when driving the heating source driving unit is the blowing amount of the cooling unit when driving of the heating source driving unit is stopped. Compared to To be the same, characterized by an indication of the drive control to the cooling drive control means.

Further, the apparatus further comprises a zero-crossing detecting means for detecting a zero-crossing point from a voltage waveform of the commercial power supply and outputting a driving timing signal, wherein the control means drives the cooling driving control means based on the driving timing signal. The control is instructed.

Further, the zero-crossing detecting means detects the zero-crossing point by comparing a predetermined voltage generated from a control power supply from the control power supply means with a voltage waveform of the commercial power supply.

The cooling means is connected in series with a cooling fan having a fan section for rotating and sending cooling air and a fan motor for rotating the fan section; A switching component that is turned off every time the voltage waveform of the commercial power supply passes through the zero-cross point; and the control unit controls the cooling drive control unit after a delay time delay according to the air flow rate of the cooling unit from the drive timing signal. An on signal is transmitted to the switching component via the switching component.

Further, the control means changes the delay time when the heating source is being driven or stopped.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, reference numeral 1 denotes a microwave oven as an embodiment of the cooking device of the present invention, 2 denotes a heating chamber for storing foods, 3 denotes a door for opening and closing a front opening of the heating chamber 2, 4
Is an operation panel provided with a key input unit and the like, and a control means to be described later is arranged on the back surface.
It is an electrical equipment room located on the side of.

Reference numeral 6 denotes a magnetron for supplying microwaves to the heating chamber, 7 a high-voltage transformer for supplying a high voltage to the magnetron, 8 a heater for heating food in the heating chamber 2 by infrared rays, and 9 a heater at least in the electrical equipment chamber 5. This is a cooling fan for cooling the magnetron 6, the high-voltage transformer 7 and the control means arranged.

The magnetron 6 comprises an anode 6a and a sword 6b. The high-voltage transformer 7 includes a primary winding 7a, a secondary winding 7b, and a heater winding 7
c. Further, the cooling fan 9 includes a fan unit for sending cooling air and a fan motor constituting the fan unit.

The magnetron 6 and the heater 8 correspond to a heating source according to the present invention.

In FIG. 2, 10 is a commercial power supply, 11 is a door switch which is linked with opening and closing of the door 3 and is turned off when the door 3 is opened, and turned on when the door 3 is closed, and L1 and L2 are commercial switches via the door switch 11. A commercial power line of the microwave oven 1 connected to the power supply 10, a fuse 12 connected between the commercial power supply 10 and the door switch 11, 13 linked with opening and closing of the door 3, and turned on and closed when the door 3 is opened. This is a monitor switch that turns off when the monitor is turned off.

Reference numeral 14 denotes a fan motor of the cooling fan 9;
Are connected in series with the fan motor 14, and the power lines L1 and L
2, a lamp 16 for lighting the inside of the heating chamber 2, a lamp relay 17 connected in series with the lamp 16, and a lamp relay connected between the power lines L1 and L2, and a heater 18 8 is connected in series with the power lines L1 and L2, and 19 is an MQ relay connected in series with the primary winding 7a of the high-voltage transformer 7 and connected between the power lines L1 and L2. It is a relay.

The triac 15 controls the number of revolutions of the fan motor 14 by turning on and off. Each of the relays 17, 18, and 19 is for driving and controlling the connection load by turning on and off. The triac 14 corresponds to a switching component of the present invention, and the cooling fan 9, the fan motor 14, and the triac 15 correspond to a cooling unit of the present invention.

Reference numeral 20 denotes one end of the secondary winding 7 of the high-voltage transformer 7.
b and the other end to the cathode 6 of the magnetron 6
b, a high-voltage capacitor 21;
0 is a high voltage diode connected between the other end of the high voltage transformer 7 and the other end of the secondary winding 7b of the high voltage transformer 7. The magnetron 6
Is connected to the heater winding 7c of the high-voltage transformer 7.

A control power supply means 22 rectifies and smoothes the commercial power supply 10 to generate a control power supply of, for example, 5 VDC.
Numeral 3 denotes a zero-crossing detecting means for generating a predetermined value from the control power supply from the control power supply means 22, detecting a zero-crossing point by comparing with a commercial power supply voltage waveform, and outputting a drive timing signal.

As shown in FIGS. 3 and 5, the zero-cross detecting means includes a full-wave rectifier 30 for full-wave rectifying the AC voltage waveform m of the commercial power supply 10 into a pulsating waveform n, and a predetermined value x from the control power supply. , And a comparator 32 that compares the pulsating waveform n with a predetermined value x and outputs a drive timing signal p.

Reference numeral 24 denotes a triac driving means for outputting an ON signal to the triac 15; 25, a lamp relay driving means for turning on and off the lamp relay 17; 26, a heater relay driving means for turning on and off the heater relay 18;
MQ relay drive means for turning on / off the Q relay 19. The triac drive means 24 corresponds to the cooling drive control means of the present invention, and the heater relay drive means 26
The MQ relay driving means 27 corresponds to the heating source driving means of the present invention.

Reference numeral 28 denotes a door sensing switch for detecting opening and closing of the door 3. Reference numeral 29 denotes a triac driving unit 24 based on a driving timing signal from the zero-cross detecting unit 23.
And control means for controlling the operation of each of the relay driving means 25, 26 and 27.

The triac driving means 24, each of the relay driving means 25, 26, 27 and the control means 29 are supplied with driving power from the control power supply means.

In the microwave oven having the above-described configuration, the microwave fan 6 supplies microwaves from the magnetron 6 into the heating chamber 2 to heat the food.
Is operated at a high speed to send more cooling air to the magnetron 6 and the high-pressure transformer so as to be cooled as much as possible. At the time of heating the food by the heater 8, at least the rear part of the operation panel 4 Is operated to cool the temperature to a high temperature due to the radiant heat from the heating chamber 2.

However, when the cooling fan is operated at a high speed, (1) the wind noise of the fan unit becomes noise and becomes annoying to the user. (2) During microwave heating, a cooling fan 9 is used to prevent the viewing window of the door 3 from fogging.
When the cooling fan is operated at high speed during heating of the heater,
A large amount of cooling air is sent into the heating material 2, which causes the heater to reduce the efficiency of overheating. There are two problems described above, and it is necessary to reduce the amount of air blown from the cooling fan 9 to the minimum amount of air blow. Therefore, the amount of air blown by the phase control of the cooling fan 9 during heater heating is reduced.

The operation of the control means 29 in such a configuration will be described with reference to FIG.

First, in step S 1, food is stored in the heating chamber 2, and heating conditions are set from the operation panel 4. In step S2, it is determined whether the start key has been operated on the operation panel 4. The process waits until it is determined that the operation has been performed in the step, and when it is determined that the operation has been performed, the process proceeds to step S3.

In step S3, the driving of the magnetron 6 and the heater 8 is started according to the heating conditions set in step S1. In step S4, it is determined whether the start operation in step S3 is heater heating or microwave heating. If microwave heating is performed in this step, the process proceeds to step S5. If heater heating is performed, the process proceeds to step S6.

In the case of microwave heating, in order to rotate the fan portion of the cooling fan 9 at high speed, the zero-cross detecting means 23 is used.
The triac 15 outputs an ON signal from the triac driving unit 24 at the same time when the drive timing signal is obtained from the controller 3 to drive the cooling fan 9. At this time, the magnetron 6 and the high voltage transformer 7 are efficiently cooled.

In the case of heater heating, the process shifts to step S6 to determine whether the heater 8 is currently turned on. If it is determined in this step that the heater is being turned off, the process proceeds to step S7, and a delay time for providing an ON signal to the triac 15 after obtaining the drive timing signal so that power capable of low-speed rotation at a desired rotation speed can be supplied to the delay time is α Set. If the heater 8 is on, the process proceeds from step S6 to step S8, where the delay time is (α−
β) is set.

Here, β to be added in step S8 is
As described above, this is the delay time at the start of counting the delay time α caused by the decrease in the predetermined value x in FIG. To take this time into account, delay time α to β
Time is subtracted.

After execution of step S7 or step S8,
Move to step S9. In step S9, an ON signal is output to the triac 15 after the elapse of the delay time set from the drive timing signal output from the zero-cross detecting means 23, and the cooling fan 9 is driven to rotate at a desired low speed.

In step S10, it is determined whether the heating operation has been completed. For example, it is determined whether the heating time set in step S1 has elapsed. Steps S4 to S10 are repeatedly executed until it is determined in this step that the heating operation is completed.

When it is determined in step S10 that the heating operation has been completed, the process proceeds to step S11. In step S11, the magnetron 6 and the heater 8 are turned off, and the heating operation ends. In step S12, the cooling fan 9 is rotated at a high speed for a predetermined time (for example, 5 minutes) counted in step S13 by the same operation as step S5 to cool the inside of the electrical equipment room 5. When it is determined in step S13 that the predetermined time has elapsed, the process proceeds to step S14, where the ON signal to the triac 15 is stopped, the operation of the cooling fan 9 is stopped, and the process ends.

[0041]

According to the present invention, the amount of air blown by the cooling fan can be prevented from decreasing due to the driving of the heating source, and the required amount of air can be secured even when the cooling fan is operated at a low speed. It is.

[Brief description of the drawings]

FIG. 1 is an external view of a cooker according to the present invention.

FIG. 2 is a control block diagram of the cooking device of the present invention.

FIG. 3 is a detailed block diagram of a zero-cross detection unit in FIG.

FIG. 4 is an operation flowchart of a control unit in FIG. 2;

FIG. 5 is a timing chart for explaining the operation of the zero-cross detecting means. (A) shows a voltage waveform of a commercial power supply, (b) shows a voltage waveform of a pulsating current subjected to full-wave rectification, (c) shows a drive timing signal, and (d) shows an ON signal to the triac 15.

FIG. 6 is a timing chart illustrating a change in a signal when a control power supply voltage is reduced.

[Explanation of symbols]

 Reference Signs List 8 heater 9 cooling fan 23 control power supply means 24 triac drive means 29 control means

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Katsu Noda 2-5-1-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Inventor Satsuo Sakai 2-chome, Keihanhondori, Moriguchi-shi, Osaka No.5-5 Sanyo Electric Co., Ltd. F-term (reference) 3K086 AA05 AA07 AA08 BA02 BA08 BB08 CA04 CB04 CB12 CB13 CC01 CC06 CC07 CD09 CD15 CD19 CD27 DA04 DA14 DB02 DB05 DB15 DB21 DB30 EA04 3L086 AA02 AA04 BA05 BA06 BB05 BD05 CB14 CC03 CC10 CC15 DA06 DA17 DA18 DA26

Claims (5)

[Claims] 1. A heating chamber for storing food, a heating source for heating the food in the heating chamber, a heating source driving means for turning on and off a connection between the heating source and a commercial power supply to control the driving, and the heating source. Control means for controlling the driving means, cooling means for blowing at least cooling air to the control means, and cooling drive control means for controlling the driving based on an instruction from the control means in order to obtain a desired amount of air from the cooling means And a control power supply unit for supplying a control power generated from the commercial power to the heating source driving unit, the control unit, and the cooling drive control unit, and the control unit includes the heating source driving unit. When driving, the cooling unit is configured such that the amount of air blown by the cooling unit when the heating source driving unit is driven is substantially the same as the amount of air blown by the cooling unit when the driving of the heating source driving unit is stopped. Drive control A cooker for instructing a means to drive control. 2. The cooling drive control unit according to claim 2, further comprising: a zero-cross point detecting unit that detects a zero-cross point from a voltage waveform of the commercial power supply and outputs a drive timing signal. The control unit drives the cooling drive control unit based on the drive timing signal. The cooker according to claim 1, wherein control is instructed. 3. The zero-cross point detecting unit detects a zero-cross point by comparing a predetermined voltage generated from a control power supply from the control power supply unit with a voltage waveform of the commercial power supply. 3. The cooker according to 2. 4. The cooling means, comprising: a cooling fan having a fan unit that rotates to send cooling air and a fan motor that rotates the fan unit; and a cooling motor connected in series with the fan motor of the cooling fan. A switching component that is turned off every time the voltage waveform of the commercial power supply passes through the zero-cross point; and the control unit controls the cooling drive control unit after a delay time delay according to the air flow rate of the cooling unit from the drive timing signal. The cooker according to claim 2 or 3, wherein an ON signal is transmitted to the switching component via the switching device. 5. The cooking device according to claim 4, wherein the control unit changes the delay time between when the heating source is being driven and when the heating source is being stopped.