JP2009097836A - Heating cooker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heating cooker, improved in reliability of operation when the operation of the heating cooker is controlled by a plurality of control means including a microcomputer. <P>SOLUTION: A power supply interruption circuit 118 is provided in a power supply line given to a slave microcomputer 112. The operation of the power supply interruption circuit 118 is performed by the main microcomputer 111. In communication between the main microcomputer 111 and the slave microcomputer 112, when the slave microcomputer 112 receives abnormal data and such receipt is discriminated by the main microcomputer 111, the power supply interruption circuit 118 is operated by the main microcomputer 111, thereby temporarily suspending the supply of power to the slave microcomputer 112 to reset and initialize the slave microcomputer. The slave microcomputer 112 is a control part for administering the control over a display part 10A and key dials 10B, 10C, 10D, and even if the slave microcomputer 112 is reset and initialized, failure in cooking is not caused. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a cooking device such as a microwave oven, a microwave oven, and a steam microwave oven.

Most household appliances in recent years have their operations controlled by a microcomputer (hereinafter abbreviated as “microcomputer”). For example, in a fully automatic washing machine, in order to reduce costs and the like, a plurality of, for example, two microcomputers (one-chip microcomputer) are provided and functions are assigned to them.
In a fully automatic washing machine, when controlling the operation with multiple microcomputers (main microcomputer and sub-microcomputer), both microcomputers are connected by a communication line, and when the power supply rises and falls (when the power switch is on) And a reset circuit for resetting each microcomputer at the time of off).

In addition, a reset circuit is provided in common for a plurality of microcomputers for simplification, and when a reset signal is output from one of the microcomputers, each microcomputer is reset simultaneously. A configuration in which reset terminals are directly connected by a reset signal line has also been proposed (see paragraph [0007] of Patent Document 1).
Furthermore, as another configuration that incorporates multiple microcomputers into home appliances, only one microcomputer is provided with a reset signal generation circuit that generates a reset signal when the power supply rises and falls, and this microcomputer resets the other microcomputer Has also been proposed. (For example, Patent Document 2)
JP 2000-70590 A JP-A-11-134308

  In home appliances that control operation with a microcomputer, when multiple microcomputers are provided, it is common to connect the microcomputers via a communication line and communicate with each other to control the operation of the device. (For example, see paragraphs [0002] to [0003] of Patent Document 1). For this reason, when the printed circuit board on which the microcomputer is mounted is divided into a plurality of boards instead of a single board, it is necessary to provide a power supply line for each board, and between the printed boards. Must be connected by reset signal line and communication line.

  By the way, each microcomputer is usually provided with a reset input terminal, and is reset by the rising and falling of the power supply. A pulse signal with a width of several microseconds is applied to the reset input terminal of each microcomputer. When given, the microcomputer is reset. Therefore, if external noise passes through the power supply line and gets on the reset signal line, an undesired (unexpected) reset signal is given to the reset input terminal, and as a result, the microcomputer is initialized. become.

For this reason, when trying to introduce a configuration that controls the operation by a plurality of microcomputers into an electronically controlled heating cooker, the microcomputer may be reset due to pulse noise caused by the high voltage generated by the magnetron. There was a problem that cooking could be a failure.
In addition, a heating cooker that radiates and heats microwaves has been proposed to emit microwaves from a rotating antenna so that the microwaves are evenly radiated into the heating chamber. In such a configuration, it is desirable to detect the angular position of the rotating antenna that radiates microwaves to detect the radiation direction of the microwaves in order to control the heating cooker well.

However, if the angular position of the rotating antenna that radiates microwaves is always detected, the sensor for the detection must have a longer life, and the problem of increasing the component price and the number of components is encountered.
The present invention has been made based on such a background, and in the case where the operation of the cooking device is controlled by a plurality of control means including a microcomputer, the cooking device with improved operation reliability is provided. The main purpose is to provide.

Another object of the present invention is to provide a cooking device equipped with a rotating antenna for radiating microwaves into a heating chamber, wherein the angular position of the rotating antenna can be controlled as necessary, and has a long life and reliability. It is to provide a cooking device that has the characteristics.
Still another object of the present invention is to provide a long-life cooking device with improved control operation reliability.

  The invention according to claim 1 is a heating cooker having control means including a microcomputer, the operation of which is controlled by the control means. The control means communicates with the main control means and the main control means. A power cut-off means for shutting off the power supplied to the sub-control means, which is connected by a line and includes a sub-control means for controlling the operation of a predetermined part of the cooking device, and is controlled by the main control means It is a heating cooker characterized by being provided with the power-supply-cut-off means.

The invention according to claim 2 is characterized in that the sub control means has means for discriminating normality and abnormality of data communicated from the main control means through a communication line. Is transmitted to the main control means. The heating cooker according to claim 1, wherein
According to a third aspect of the present invention, in response to the reception of the data abnormality from the slave control unit, the main control unit temporarily operates the power shut-off unit to interrupt power supply to the slave control unit. And after that, power supply is restarted, It is a heating cooker of Claim 2 characterized by the above-mentioned.

  According to a fourth aspect of the present invention, there is provided a heating chamber for containing the food to be cooked, a rotating antenna for radiating microwaves into the heating chamber, and a detecting means for detecting an angular position of rotation of the rotating antenna. A heating cooker including a disabling means for disabling the detection operation of the detection means in a cooking mode in which it is not necessary to detect the angular position of the rotating antenna. It is a heating cooker.

  According to a fifth aspect of the present invention, the detection means includes a contact that switches between a contact state and a non-contact state according to the angular position of the rotating antenna, and the immobilization means determines the angular position of the rotating antenna. 5. The cooking device according to claim 4, wherein the contact point is not energized in a cooking mode that does not need to be detected.

  According to the first aspect of the present invention, the power shut-off means controlled by the main control means is provided, and the power supply to the slave control means can be temporarily shut down as needed by the power shut-off means. That is, when it is necessary to reset the sub control means, the main control means does so, so there is no need to provide a reset signal line sensitive to noise, and it is possible to prevent an undesired reset from occurring in the sub control means. . Further, since the reset signal line is not necessary, the configuration can be simplified and the cost can be reduced.

  In the configuration in which the main control means operates the power shut-off means to reset the slave control means, as described in claim 2 or 3, when the slave control means determines an abnormality in the data being communicated, The data abnormality is notified to the main control means. When the main control means receives the data abnormality, it is desirable to temporarily shut off the power supply of the slave control means and reset the slave control means.

According to a second aspect of the present invention, the slave control means discriminates whether the data received by the slave control means is normal or abnormal, and when it is abnormal data, the master control means transmits the data to the master control means. It is possible to grasp at once whether or not it is necessary to reset. Then, the slave control means that has received the abnormal data can be reset as necessary.
According to the fourth aspect of the present invention, in the heating cooker including the rotating antenna for radiating the microwave into the heating chamber and the detecting means for detecting the angular position (rotating position) of the rotating antenna, The life of the means can be extended. This is because the rotating antenna for radiating microwaves is normally rotated in order to radiate microwaves uniformly into the heating chamber in the cooking mode. If the detection means always detects the rotation of the rotating antenna, the detection means is likely to deteriorate with time, and it is difficult to extend the life of the detection means. Therefore, as described in claim 4, when it is not necessary to detect the angular position of the rotating antenna, it is possible to realize a longer life of the detecting means by disabling the detecting operation of the detecting means. .

  In particular, as described in claim 5, when the detection means includes a contact that switches between a contact state and a non-contact state, if the detection means does not need to detect the angular position of the rotating antenna, The detection means is disabled so as not to energize. As a result, the contact of the detection means is merely mechanically opened / closed with the rotation of the rotating antenna, and it is possible to eliminate the problem that an arc or the like occurs due to the opening / closing of the contact in the energized state, and the contact wears and wears. . As a result, the life of the detection means can be extended.

Hereinafter, as an embodiment of the present invention, a microwave oven (microwave oven steam range) will be described as an example, but the present invention can also be applied to a cooking device other than a microwave oven.
FIG. 1 is a front right perspective view of a microwave oven 1 according to an embodiment of the present invention. FIG. 2 shows a state in which the door 2 is opened in FIG. FIG. 3 is a bottom view of the microwave oven 1. FIG. 4 is a front upper perspective view of the casing 4 in a state in which the door 2 and the decorative plate 3 (outer cover plate) are removed. FIG. 5 is a plan view of the recess 16 that is the bottom of the heating chamber 11 and shows the arrangement and shape of the rotating antennas 20A and 20B. FIG. 6A is an image view of microwave radiation in the diffusion mode, and FIG. 6B is an image view of microwave radiation in the concentrated mode.

Hereinafter, for convenience of explanation, the direction in which the door 2 is provided in FIG. 1 is defined as the front (front side), and the direction of the microwave oven 1 is specified with reference to the time when the microwave oven 1 is viewed from the front side (the illustrated direction arrow). reference). The left-right direction is synonymous with the width direction.
The microwave oven 1 has a casing 4 that forms an outer shell thereof. As shown in FIG. 2, the casing 4 has a metal frame 12 in the shape of a hollow box whose front surface is open (this portion is referred to as an opening 8), and the outside (left and right outer surfaces and upper and outer surfaces) of the frame 12. ) And a decorative board 3 (outer cover board). A heating chamber 11 is formed by the frame 12. The heating chamber 11 is a horizontally long, substantially rectangular parallelepiped space defined by the left and right side walls, the top wall, the bottom wall, and the rear wall of the frame 12, and has an opening 8 on the front surface. The bottom wall forms a recess 16 that is recessed over substantially the entire area (see FIG. 4). The flat bottom plate 6 is placed so as to close the recess 16 from above. That is, the bottom surface of the heating chamber 11 has a double structure of the bottom plate 6 on which the food to be cooked is placed and the concave portion 16 recessed below.

A plurality of rails 24 extending in the front-rear direction are provided on each inner surface of the left and right side walls (three in this embodiment) at regular intervals in the vertical direction. The rail 24 slightly protrudes into the heating chamber 11. With the left rail 24 and the right rail 24 facing the rail 24, the tray-shaped square dish can be held in a state of floating from the bottom plate 6.
A door 2 that opens and closes the opening 8 is provided on the front surface of the casing 4. The door 2 rises around the rotation shaft extending in the width direction at the lower end thereof (see FIG. 1), and the door 2 tilts forward from the closed position to open the opening 8 to open the door 2. Is rotated between an open position (see FIG. 2) where the inner surface of the plate is substantially flush with the bottom plate 6.

As shown in FIG. 1, a handle 9 is provided at the upper end and an operation panel 10 is provided at the lower end on the front of the door 2. By grasping the handle 9, the door 2 can be rotated between the open position and the closed position described above.
The operation panel 10 includes a display unit 10A for displaying setting contents and cooking status, and a plurality of (eight in the figure) press keys 10B and two rotary dials 10C for setting cooking conditions and instructing cooking start. And a cancel key 10D.

  As shown in FIG. 3, a magnetron 13 that generates a microwave and a waveguide 14 (branch waveguide) that guides the microwave are provided on the bottom surface of the casing 4. The magnetron 13 is disposed in the vicinity of the heating chamber 11 in the center in the width direction of the rear end portion of the bottom surface of the casing 4 (frame 12). The waveguide 14 accommodates the antenna 29 of the magnetron 13 and has a T-shape in a bottom view that extends from the magnetron 13 to the front and then branches to the left and right. Note that the left and right branch portions of the waveguide 14 are each referred to as a shunt 18. The microwave radiated from the magnetron 13 is guided to each shunt 18 by the waveguide 14. On the inner wall surface of the waveguide 14, a hemispherical protrusion 28 that bulges into the waveguide 14 is formed at a branch position. The microwave that has reached the branching position of the waveguide 14 from the antenna 29 of the magnetron 13 hits the protrusion 28 and is hardly reflected to the magnetron 13 side, and smoothly flows to each shunt 18 as shown by the arrows in the figure. To be distributed. That is, by providing the hemispherical projection 28 at the branching position of the waveguide 14, the impedance matching of the microwave at the branching position is improved, and the microwave output from the magnetron 13 is reflected to the magnetron 13 side. Can be suppressed. Thereby, when the microwave generated in the magnetron 13 is guided to each shunt 18 through the waveguide 14, the microwave in the waveguide 14 is favorably sent to each shunt 18 (antenna portion 15 described later). Can be guided to. As a result, it is possible to prevent problems such as that the microwave reflected toward the magnetron 13 causes discharge in the vicinity of the antenna 29 of the magnetron 13 or the like.

  Each shunt 18 of the waveguide 14 is provided with an antenna unit 15 that radiates the microwave guided by the waveguide 14 into the heating chamber 11. These two antenna portions 15 form a pair and are arranged on the left and right sides so as to be symmetrical in the width direction with respect to the branching position of the waveguide 14 (the projection 28 and further the central portion in the left-right direction of the heating chamber 11). ing. The antenna unit 15 includes antenna motors 19A and 19B and rotating antennas 20A and 20B (see FIG. 4) for radiating microwaves. The antenna motors 19A and 19B are attached to the shunt 18 from below. As shown in FIG. 4, the rotation shafts of the antenna motors 19A and 19B are coupled to the rotation shafts 21A and 21B of the rotation antennas 20A and 20B, and the rotation shafts 21A and 21B are recessed in the shunt 18 upward. 16 extends into the interior. The left and right rotating shafts 21A and 21B are arranged so as to be symmetrical in the width direction with respect to a branching position (a reference plane X described later) of the waveguide 14. The rotary antennas 20A and 20B are attached to the rotary shafts 21A and 21B in the recess 16. The rotary antennas 20A and 20B are in the form of an elongated rectangular thin plate in the figure, and are attached to the rotary shafts 21A and 21B at positions away from the center in the longitudinal direction. The rotating antennas 20A and 20B are not limited to the shapes described above, and may be substantially disk-shaped and project asymmetrically horizontally with respect to the rotating shafts 21A and 21B, as will be described later. The rotating antennas 20A and 20B receive the driving force of the antenna motors 19A and 19B, respectively, and rotate along the lower surface of the bottom plate 6 around the rotating shafts 21A and 21B.

  The microwaves guided to each shunt 18 (see FIG. 3) by the waveguide 14 reach the rotating antennas 20A and 20B via the rotating shafts 21A and 21B of the rotating antennas 20A and 20B in the pair of left and right antenna portions 15. Then, it is radiated from the rotating antennas 20A and 20B that rotate. Then, this microwave passes through the bottom plate 6 shown in FIG. 2 and is supplied into the heating chamber 11. The bottom plate 6 is formed of a material that transmits microwaves, such as a ceramic plate. Microwave operation is performed by radiating microwaves into the heating chamber 11 by the antenna unit 15, and the food to be cooked in the heating chamber 11 is cooked by microwave heating (dielectric heating). The pair of antenna portions 15 can be installed, for example, so as to radiate microwaves from the left and right side surfaces of the heating chamber 11. Therefore, microwave heating can be performed satisfactorily. In addition, by using the rotating antennas 20A and 20B, microwaves can be radiated and stirred almost uniformly into the heating chamber 11.

The rotating antennas 20A and 20B may be the rotating antennas 20A and 20B shown in FIG. 5 instead of the one shown in FIG.
Rotating antennas 20A and 20B shown in FIG. 5 are large flat antennas that are formed of thin metal plates and have the same planar shape. That is, the rotating antennas 20A and 20B respectively have a wide rectangular projecting portion 211 projecting from the rotation shafts 21A and 21B in a predetermined angular direction, and a pair of narrow rectangular sub projecting portions 212 and 213 projecting on both sides thereof. And a semi-ring-shaped projecting portion 214 projecting in an angle direction opposite to the projecting direction of the rectangular asserting projecting portion 211, and a hook-shaped projecting portion 215 formed inside the semi-ring-shaped projecting portion 214.

By adopting such a large W antenna structure that includes a pair of large flat antennas on the left and right, the microwave oven 1 can be made to perform the following microwave heating.
In the embodiment of FIG. 5, the rotating antenna 20A is rotated by a rotating shaft 21A, and the rotating shaft 21A is rotated by an antenna motor 19A. A cam 101A is attached to the rotating shaft 21A. The cam 101A has an arcuate circumferential surface and has a protrusion 102 on a part thereof. A micro switch 103A is disposed in the vicinity of the cam 101A. The actuator 104A of the micro switch 103A is displaced according to the rotation of the cam 101A, and the contact points P1 and P2 are switched between a contact state and a non-contact state.

  Similarly, the rotating antenna 20B is rotated by the rotating shaft 21B, and the rotating shaft 21B is rotated by the antenna motor 19B. A cam 101B is attached to the rotating shaft 21B, and the cam 101B is rotated by the rotation of the rotating shaft 21B. The circumferential surface of the cam 101B is a circumferential surface, and a protrusion 102 is provided at a predetermined angular position. A micro switch 103B is disposed in the vicinity of the cam 101B, and the actuator 104B of the micro switch 103B is displaced by the rotation of the cam 101B. Then, the contacts P1 and P2 are switched between a contact state and a non-contact state. The signals of the micro switches 103A and 103B are given to a microcomputer as a control unit described later.

By rotating the rotating antennas 20A and 20B by the antenna motors 19A and 19B, the diffusion mode and the concentration mode can be performed in the microwave heating cooking mode.
First, as a diffusion mode, microwave heating is performed while rotating the two rotating antennas 20A and 20B in the opposite directions at a constant speed. In the diffusion mode, microwaves are diffused from the large W antennas 20A and 20B, and the microwaves are spread to every corner of the heating chamber 11, and cooking can be performed while suppressing uneven heating of food.

Further, as the concentrated mode, the rotation of the two rotary antennas 20A and 20B is stopped at the position shown in FIG. 5, and microwave heating is performed. The concentration mode is, for example, a speed heating mode that can satisfy the desire to quickly heat a bowl of rice or to quickly heat a dish.
The rectangular asserting portions 211 and 211 of the rotating antennas 20A and 20B are portions that radiate microwaves strongly. When the rotating antennas 20A and 20B are stopped at the position shown in FIG. Microwaves are emitted strongly to the center. Therefore, the food placed in the central portion of the heating chamber 11 can be quickly heated.

FIGS. 6A and 6B are image diagrams of microwave radiation in the diffusion mode and the concentrated mode. FIG. 6A shows the diffusion mode and FIG. 6B shows the concentration mode. By using the rotating antennas 20A and 20B, the diffusion mode and the concentration mode can be switched as necessary.
FIG. 7 is a block diagram showing the configuration of the control unit of the microwave oven 1 according to one embodiment of the present invention.

  As shown in FIG. 7, the control unit of the microwave oven 1 includes two control units including a microcomputer (hereinafter abbreviated as “microcomputer”). That is, it has a main microcomputer 111 and a slave microcomputer 112, and the two are connected by a synchronous clock supply line 113 and communication lines 114 and 115. In this embodiment, the main microcomputer 111 detects the input of the sensor and controls the operation of the heater, magnetron, etc., and the sub-microcomputer 112 displays for displaying the cooking time, cooking status, etc. While controlling the display of the part 10A, the input signals from the pressing key 10B, the two rotary dials 10C and the cancel key 10D are processed.

  A power supply circuit 116 is provided, and the power supply generated by the power supply circuit 116 is supplied to the main microcomputer 111 and also to the main microcomputer 111 via the power-on reset circuit 117. The power supply generated by the power supply circuit 116 is supplied to the slave microcomputer 112 via the power supply cutoff circuit 118 and is supplied to the slave microcomputer 112 via the power supply cutoff circuit 118 and the power-on reset circuit 119. The power-on reset circuits 117 and 119 detect the rise and fall of the power supply supplied from the power supply circuit 116, respectively, and initialize the main microcomputer 111 or the slave microcomputer 112 at each rise and fall timing. It is a circuit that resets to.

  The power cut-off circuit 118 is interposed in a power supply line that is supplied from the power supply circuit 116 to the slave microcomputer 112 and the power-on reset circuit 119, and is controlled by a signal from the main microcomputer 111. . That is, the main microcomputer 111 can turn on / off the power supplied to the slave microcomputer 112 by controlling the power shut-off circuit 118. Thus, the slave microcomputer 112 can be reset and initialized by the main microcomputer 111.

FIG. 8 is a flowchart showing a control operation of the main microcomputer 111 and the sub-microcomputer 112 shown in FIG. 7, in particular, a reset control operation flow associated with a communication abnormality between the main microcomputer 111 and the sub-microcomputer 112.
First, referring to FIG. 8A, when power is supplied to the main microcomputer 111 by the power circuit 116, the power-on reset circuit 117 detects the rise of the power, and the main microcomputer 111 is reset and initialized (step). S1).

  Next, the main microcomputer 111 transmits display data to the sub-microcomputer 112, and is given a key and dial operation status signal based on the operation of the pressing key 10B, the rotary dial 10C, the cancel key 10D, etc. from the sub-microcomputer 112. Wait and receive it when given (step S2). When the operation state is received, it is determined whether or not the received data is normal (step S3). If the received data is not normal, the power cutoff circuit 118 is controlled to turn off the power of the slave microcomputer 112 ( In step S4), the slave microcomputer 112 is turned on after a predetermined time (step S5).

  As described above, the main microcomputer 111 performs necessary initialization when the power is turned on (step S1), starts communication with the slave microcomputer 112 (step S2), and the received data is received every time data is received from the slave microcomputer. Whether it is normal or abnormal is determined (step S3), and if abnormal, the power cutoff circuit 118 is controlled to reset the slave microcomputer 112. By switching on / off the power to the slave microcomputer 112 using the power cutoff circuit 118, a reset signal can be given to the slave microcomputer 112 via the power-on reset circuit 119 to reset the slave microcomputer 112.

The slave microcomputer 112 controls the display unit 10A, the press key 10B, the rotary dial 10C, the cancel key 10D, etc., and does not control the operation of the heater, magnetron, etc. that directly contribute to cooking. Therefore, even if the slave microcomputer 112 is initialized by resetting during cooking, there is no problem that cooking fails.
Next, the operation of the slave microcomputer 112 will be described with reference to FIG. 8B. In the slave microcomputer 112, when power is supplied from the power supply circuit 116 via the power cutoff circuit 118, the power-on reset circuit 119 performs necessary initialization (step P1). Thereafter, when display data is received from the main microcomputer 111 (step P2), the normality of the received data is determined (step P3). When the received data is determined to be normal, the reception error flag is turned off (step P5). Is determined to be abnormal, the reception error flag is turned on (step P4). Next, the state of the reception error flag is determined (step P6). If the reception error flag is on, abnormal data is transmitted to the main microcomputer 111 (step P7). The key / dial operation state given from 10B, rotary dial 10C, cancel dial 10D, etc. is transmitted (step P8).

  The “abnormal data” in step P7 may be a signal (signal indicating that the data is abnormal) that is determined to be abnormal when the main microcomputer 111 determines the validity of the received data in step S3. Thus, the main microcomputer 111 can detect a communication abnormality with the slave microcomputer 112. If the received data from the slave microcomputer 112 does not return to normal even if the reset initialization of the slave microcomputer 112 is repeated several times, the operation of the device such as forcibly canceling the cooking operation is performed. Will be controlled so as not to be dangerous.

  According to this embodiment, it is not necessary to provide a reset signal line sensitive to noise as a communication line between the main microcomputer 111 and the sub-microcomputer 112. The reset initialization of the slave microcomputer 112 can be performed only when necessary by the main microcomputer 111. In other words, when the main microcomputer 111 detects a communication error with the sub-microcomputer 112, the sub-microcomputer 112 is reset and initialized by turning off and on the sub-microcomputer 112, and the sub-microcomputer 112 communicates normally due to some bug or error. If not, the slave microcomputer 112 can be returned to normal.

FIG. 9 is a configuration block diagram of a control circuit for antenna motors 19A and 19B (see FIG. 5) for rotating the rotating antennas 20A and 20B in the microwave oven 1 according to the embodiment of the present invention.
In FIG. 9, one antenna motor 19, cam 101, and microswitch 103 are shown for convenience of illustration and description. Actually, as described with reference to FIG. Is provided with two rotating antennas 20A and 20B, and for each of the rotating antennas 20A and 20B, antenna motors 19A and 19B, cams 101A and 101B, and micro switches 103A and 103B, respectively, Each antenna motor 19A, 19B and microswitch 103A, 103B are individually controlled.

  In FIG. 9, the microcomputer 111 is the main microcomputer 111 described with reference to FIG. 7, and the rotation of the antenna motor 19 is controlled by the main microcomputer 111, and the antenna motor 19 is controlled by the detection output of the microswitch 103. Stopped at a predetermined angular position. Referring to FIG. 9, based on the AC power supplied from commercial power supply 120, power supply circuit 116 generates a DC power supply of 5 V, for example, necessary for driving microcomputer 111 and supplies it to microcomputer 111. Note that the power-on reset circuit 117 and the slave microcomputer 112 described in FIG. 7 are omitted because they do not need to be touched in the description of this embodiment.

  The microcomputer 111 also drives the antenna motor 19 via the antenna motor control circuit 121. As described with reference to FIG. 5, the rotating shaft of the motor 19 is provided with the cam 101 that rotates together with the rotating shaft. The rotation of the cam 101 switches the micro switch 103 on and off. The micro switch 103 has two contact points P1 and P2, one contact point P2 is grounded, and the other contact point P1 is connected to the port 122 of the microcomputer 111 via the resistor R2. A point A is formed between the resistor R2 and the port 122, and the DC power supply voltage VDD is applied to the point A via the resistor R1.

  In such a configuration, in this embodiment, the port 122 for the micro switch 103 (antenna position detection switch) provided in the microcomputer 111 is switched to the input state or the output state according to the cooking mode. Normally, when the port 122 is in the input state and the micro switch 103 is on, a voltage obtained by dividing the power supply voltage VDD by the resistors R1 and R2 appears at the point A, and the voltage is read by the microcomputer 111. When the microswitch 103 is off, the power supply voltage VDD is supplied to the port 122. Thereby, the microcomputer 111 detects whether the port 122 is low or high, and determines whether the micro switch 103 is on or off.

On the other hand, when the port 122 is set to the output state, the potential of the port 122 becomes almost the ground potential. For this reason, when viewed from the microswitch 103, the contact P2 is grounded, and the contact P1 is connected to the port 122 that is at the ground potential via the resistor R2, so that the two contacts P1 and P2 of the microswitch 103 are connected. No voltage is applied between them.
In general, even if the contacts P1 and P2 are opened and closed in a state where no voltage is applied, the microswitch 103 is merely mechanically opened and closed and has almost no influence on the life of the microswitch 103. On the other hand, when the contacts P1 and P2 of the microswitch 103 are opened and closed in a state where a voltage is applied between the contacts P1 and P2, an arc or the like due to the applied voltage may occur, and the life of the microswitch 103 may be shortened. That is, there is a possibility that electrical wear of the contacts occurs.

  Therefore, in this embodiment, as shown in FIG. 10, only when the angular position of the rotating antenna 20 needs to be detected, the state of the port 122 of the microcomputer 111 is set to the input state, and otherwise, the state of the port 122 is output. Put it in a state. That is, even in the cooking mode by microwave heating, for example, in the above-described diffusion mode, it is not necessary to detect the rotational positions of the two rotating antennas 20A and 20B, so the port 122 of the microcomputer 111 is in the output state ( (See FIG. 10B). As a result, no energization occurs between the contacts P1 and P2 of the microswitch 103, and the contacts are merely mechanically opened and closed, so that the contacts of the microswitch 103 are hardly worn.

  On the other hand, when it is necessary to stop the rotational positions of the two rotating antennas 20A and 20B at predetermined positions or detect the positions of the rotating antennas 20A and 20B as in the concentrated mode described above, FIG. As shown, the port 122 is temporarily switched from the output state to the input state, and in this state, the potential at the point A is detected to detect the angular positions of the rotating antennas 20A and 20B, respectively.

By doing so, the lifetime of the microswitch 103 can be dramatically improved, and the operation reliability of the microwave oven can be improved.
FIG. 11 shows a specific example of circuit constants of the circuit shown in FIG. 9 when the power supply voltage VDD is 5 V as an example. As shown in the switch contact current of FIG. 11, a contact current of 1.5 mA flows between the contacts P1 and P2, and the minimum value is about 1.0 mA. According to this embodiment, the detection of the antenna position is performed. When the port is not required, the state of the port 122 of the microcomputer 111 is set to the output state, so that the flowing contact current can be eliminated. As a result, the lifetime of the microswitch 103 (103A, 103B) can be extended.

  FIG. 12 is a block diagram illustrating a configuration example of a lock detection circuit for the DC fan motors 124 and 125 in the microwave oven 1. The microwave oven 1 is provided with DC fans, for example, on the inlet side and the outlet side of the magnetron as cooling fans for the magnetron. Furthermore, a DC fan is provided as a cooling fan for the infrared sensor provided to detect the temperature of the food to be heated in the heating chamber. When driving these three DC fans, it is necessary to provide a lock detection circuit for the DC fan to detect a stop due to a failure of the fan. This is because, for example, when a DC fan provided for supplying hot air is not operating due to a lock, unless it is detected quickly, not only hot air is supplied well to the heating chamber, but also the microwave oven is partially abnormal. This is because there is a risk of having heat.

  By the way, the DC fan has a large variation in input current, and the input current varies due to variations in drive current. On the other hand, when a plurality of DC fans are provided and one of the DC fans is not operating due to the lock, if it is not detected promptly, not only heat is not supplied to the heating chamber, but the microwave oven is abnormal. This may cause heat generation or cause the infrared sensor to malfunction.

By the way, in the case where a plurality of DC fans are provided, if an attempt is made to use the ports of the microcomputer 111 for lock detection for each DC fan, the number of ports of the microcomputer 111 may be insufficient.
Therefore, in the embodiment shown in FIG. 12, the non-volatile memory 129 stores the total input current of the plurality of DC fan motors 124 and 125, and the input of the plurality of DC fan motors 124 and 125 is corresponding to the value. When the current changes by a certain value or more, it is determined that one of the DC fans is locked and measures such as error notification and output limitation are taken.

  That is, the DC fan motors 124 and 125 are connected in parallel to the power supply voltage VDD. (In this embodiment, two DC fan motors are shown, but three or more DC fan motors may be used.) The switching transistors 126 and 127 of the DC fan motors 124 and 125 are connected to the DC fan motors 124 and 125, respectively. ing. The lock detection input port is connected to the junction of the switching transistors 126 and 127, and detects whether or not the total value of the input current flowing through the DC fan motors 124 and 125 varies. With this configuration, it is possible to absorb variations in input current and drive voltage flowing through the plurality of DC fan motors 124 and 125, and even when a plurality of DC fans are used, only one port of the microcomputer 111 is used for lock detection. The cost can be reduced.

  The present invention is not limited to the embodiment described above, and various modifications can be made within the scope of the claims.

It is a front right perspective view of microwave oven 1 concerning one embodiment of this invention. In FIG. 1, the state which opened the door 2 is shown. 2 is a bottom view of the microwave oven 1. FIG. It is a front upper side perspective view of the casing 4 in the state which removed the door 2 and the decorative board 3 (outer cover board). It is a top view of the recessed part 16 which is the bottom of the heating chamber 11, Comprising: It is a figure which shows arrangement | positioning and shape of rotating antenna 20A, 20B. FIG. 6A is an image view of microwave radiation in the diffusion mode, and FIG. 6B is an image view of microwave radiation in the concentrated mode. It is a block diagram which shows the structure of the control part of the microwave oven 1 which concerns on one Embodiment of this invention. 3 is a flowchart showing a flow of a reset control operation accompanying a communication abnormality between a main microcomputer 111 and a sub microcomputer 112. It is a block diagram of the configuration of a control circuit for antenna motors 19A, 19B for rotating the rotating antennas 20A, 20B in the microwave oven 1 according to one embodiment of the present invention. FIG. 6 is a timing chart showing a relationship between currents flowing through the microswitch 103 by switching the state of the port 122 of the microcomputer 111. FIG. 10 is a diagram illustrating a specific circuit constant example of the circuit illustrated in FIG. 9. It is a block diagram which shows the structural example of the lock | rock detection circuit of a some DC fan motor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Microwave oven 11 Heating chamber 13 Magnetron 15 Antenna part 20A, 20B Rotating antenna 21A, 21B Rotating shaft 101, 101A, 101B Cam 103, 103A, 103B Micro switch 111 Main microcomputer 112 Sub microcomputer 118 Power supply cutoff circuit

Claims (5)

A cooking device having a control means including a microcomputer, the operation of which is controlled by the control means,
The control means includes main control means, and sub control means that is connected to the main control means by a communication line and controls the operation of a predetermined part of the cooking device,
A heating cooker characterized in that a power shut-off means for shutting off the power supplied to the sub-control means is provided, the power shut-off means being controlled by the main control means.   The slave control means has means for determining normality or abnormality of data communicated from the main control means through a communication line, and when data abnormality is determined, transmits the data abnormality to the main control means. The cooking device according to claim 1, wherein:   The main control means, in response to receiving the data abnormality from the slave control means, temporarily operates the power shut-off means to interrupt the power supply to the slave control means, and thereafter the power supply The cooking device according to claim 2, wherein the cooking device is restarted. A heating chamber for containing the food to be cooked;
A rotating antenna for radiating microwaves into the heating chamber;
A cooking device including a detecting means for detecting an angular position of rotation of the rotating antenna,
A cooking device, comprising: a disabling unit that disables the detecting operation of the detecting unit in a cooking mode in which the angular position of the rotating antenna does not need to be detected. The detection means includes a contact that switches between a contact state and a non-contact state according to the angular position of the rotating antenna,
The cooking device according to claim 4, wherein the disabling means does not energize the contact in a cooking mode in which the angular position of the rotating antenna does not need to be detected.