JP2001126858A - Microwave oven - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve problems that in a microwave oven having a power saving function of prior art, the oven sends its total current into a relay for saving power because a switching circuit for controlling the power saving operation is arranged in series with a control circuit and a heater and so it needs a rating to accept a very large current, raising the cost of production. SOLUTION: A microwave oven according to the invention connects a heating part 3 with a relay for heating 7 in series and connects a control circuit 2 with a switching circuit 11 in series and connects a control circuit 2 and the switching circuit 11, and the heater 3 and the relay for heating 7, in parallel with a utility power supply 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave oven having a function of reducing power consumption when the apparatus is not operated, ie, a so-called power saving function.

[0002]

2. Description of the Related Art FIG. 1 is a circuit diagram showing a configuration example of a conventional microwave oven having a power saving function. This microwave oven
The circuit configuration is such that the control circuit unit 2 and the heating unit 3 are connected in parallel to the commercial power supply 1. The control circuit unit 2 includes a microcomputer and performs various controls such as a heating operation and a power saving operation of the microwave oven. The heating unit 3
Is a load 4 that is not directly related to the heating operation, such as an oven lamp for illuminating the inside of the microwave oven during heating, and a turntable for rotating the object to be heated so that the heating is performed uniformly, and an object to be heated. And a magnetron 5 that oscillates microwaves for heating. The energization of the magnetron 5 is controlled by a magnetron relay 6 controlled to be opened and closed by the control circuit 2. The magnetron relay 6 includes a relay coil 6a and a relay switch 6b.

[0003] As shown in the figure, a heating relay 7 and a door switch 8 are provided as means for controlling the energization of the heating unit 2. The heating relay 7 is controlled to be opened and closed by the control circuit unit 2, and includes a relay coil 7a and a relay switch 7b. The door switch 8 is controlled to open and close in conjunction with an opening and closing operation of a door (not shown) for separating the inside of the microwave oven from the outside of the apparatus. That is, when the door is open, the door switch 8 is also opened, and when the door is closed, the door switch 8 is also closed. in this way,
By providing a means for stopping the current supply to the heating unit 2, in other words, a means for stopping the oscillation of the magnetron 5, a highly safe product compliant with the Electrical Appliance and Material Control Law is provided. Can be.

Here, in order to realize a function of reducing power consumption when the apparatus is not operated, that is, a so-called power saving function, in a conventional microwave oven, a start switch 9 controlled to be opened and closed by a user's operation; As shown in the figure, a switching circuit 11 connected in parallel to a power saving relay 10 that is opened and closed by the control circuit 2 is connected in series to both the control circuit 2 and the heating unit 3 as shown in the figure. It is provided at a position where The start switch 9 is a switch that closes while the user presses the button and opens when the user releases the hand. The power saving relay 10 includes a relay coil 10a and a relay switch 10b.

The operation of the switching circuit section 11 will be described. When starting the microwave oven, the user presses the start switch 9 to supply power to the control circuit unit 2. The control circuit unit 2 started by receiving power supply from the commercial power supply 1 immediately starts the power saving relay 10.
Of the relay coil 10a that constitutes the control circuit, and control is performed so as to close the relay switch 10b. This allows
Even if the user releases his / her hand from the start switch 9, the power supply to the control circuit unit 2 is continued.

Thereafter, the control circuit section 2 performs various controls such as a heating operation of the microwave oven, and on the other hand, monitors an operation state of the microwave oven to control a power saving operation. Here, when there is no input operation by the user and the heating unit 3 is also stopped, that is, when the microwave oven is not operated for a predetermined time, the control circuit unit 2 configures the power saving relay 10. The power supply to the relay coil 10a is stopped, and the relay switch 10b is opened. This allows
The power supply to all the circuits including the control circuit unit 2 is cut off, and the power consumption of the microwave oven can be completely reduced to zero. It is economical.

[0007]

However, in the conventional microwave oven, the switching circuit section 11 is provided at a position where it is connected in series to both the control circuit section 2 and the heating section 3. Therefore, the total current necessary for driving the entire device flows through the power saving relay 10. Therefore, as the power saving relay 10,
There is a problem in cost because a rating that can accept a very large current value is required.

In view of the above problems, an object of the present invention is to provide a microwave oven capable of reducing the capacity of a power saving relay.

[0009]

In order to achieve the above object, in a microwave oven according to the present invention, a control circuit section for controlling the microwave oven; a heating section for heating an object to be heated; A microwave oven comprising: a switching circuit section in which an activation switch that is controlled to be opened and closed by the operation of and a power saving relay that is controlled to be opened and closed by the control circuit section are connected in parallel; and a heating relay that is controlled to be opened and closed by the control circuit section. In, while connecting the control circuit unit and the switching circuit unit in series, connecting the heating unit and the heating relay in series, for commercial power, the control circuit unit and the switching circuit unit, , The heating unit and the heating relay are connected in parallel.

[0010]

FIG. 2 is a circuit diagram showing one embodiment of a microwave oven according to the present invention. The microwave oven according to the present invention has a commercial power source 1 similar to the microwave oven shown in the conventional example.
It operates by receiving power supply from. Also, the control circuit unit 2,
It has a heating unit 3, a heating relay 7, a door switch 8, and a switching circuit unit 11, and the heating unit 3 includes a load 4, a magnetron 5, and a magnetron relay 6, and the switching circuit unit 11 Is a parallel connection circuit of a start switch 9 controlled to be opened and closed by a user's operation and a power saving relay 10 controlled to be opened and closed by the control circuit unit 2.

Here, in the microwave oven according to the present invention, the connection position of the switching circuit section 11 is different from the conventional one. In the circuit configuration of the microwave oven according to the present invention, the control circuit unit 2 and the switching circuit unit 11 are connected in series, and the heating unit 3 and the heating relay 7 are connected in series. . The control circuit section 2 and the switching circuit section 11, the heating section 3 and the heating relay 7 are connected in parallel to the commercial power supply 1. With such a circuit configuration, the total current required for driving the entire device does not flow through the power saving relay 10, and only the small current required to drive the control circuit unit 2 flows. become. Therefore,
Without increasing the number of components, the power saving relay 10
Can be reduced in capacity, so that significant cost reduction can be achieved.

Next, the operation of the microwave oven according to the present invention will be described. First, the start switch 9 and the power saving relay 10 constituting the switching circuit 11 are both open, and the power supply to all the circuits including the control circuit 2 is cut off, so that the power consumption becomes zero. Think.
In this state, when the user presses the start switch 9, power is supplied to the control circuit unit 2 to start the microwave oven. At this time, in order to keep the door switch 8 closed,
It is necessary to close a door (not shown) for separating the inside of the microwave oven from the outside of the apparatus.

The control circuit section 2 started by receiving the power supply from the commercial power supply 1 immediately energizes the relay coil 10a constituting the power saving relay 10 and controls the relay switch 10b to close. Thus, even if the user releases his hand from the start switch 9, the power supply to the control circuit unit 2 is continued. At this time, since the heating relay 7 is open, power is not supplied to the heating unit 3.

As described above, in the microwave oven according to the present invention, the small current for driving the control circuit unit 2 is controlled by the power saving relay 10 and the large current for driving the heating unit 3 is Roles such as control by the heating relay 7 are clearly defined. In other words, the heating relay 7 provided in the microwave oven according to the present invention partially plays a role of the conventional power saving relay 10 even though its operation itself is the same as the conventional one. .

In this state, when the user performs a heating operation of the microwave oven, the control circuit section 2 energizes the relay coil 7a constituting the heating relay 7 and controls the relay switch 7b to close. Do. Thus, energization of the load 4 not directly related to a heating operation such as an oven lamp or a turntable starts. Thereafter, the control circuit unit 2 energizes a relay coil 6a constituting the magnetron relay 6, and controls the relay switch 6b to close. Thereby, the magnetron 6
Starts microwave oscillation, and heating of the object to be heated starts. When the heating is completed, the control circuit unit 2 terminates the energization of the relay coil 6a and the relay coil 7a, and stops the operation of the heating unit 3. As a result, the microwave oven returns to a state in which only the control circuit unit 2 is energized again.

Here, as in the prior art, the control circuit unit 2 monitors the operation status of the microwave oven in order to control the power saving operation. In a state where only the control circuit unit 2 is energized, if there is no user input operation, that is, if the microwave oven is not operated for a predetermined time, the control circuit unit 2 turns off the power saving relay 10. The power supply to the relay coil 10a is stopped, and the relay switch 10b is opened. As a result, power supply to all circuits including the control circuit unit 2 is shut off, and the power consumption of the microwave oven can be completely reduced to zero. Very economical without.

[0017]

In the microwave oven according to the present invention, the control circuit unit and the switching circuit unit are connected in series, and the heating unit and the heating relay are connected in series. The circuit unit and the switching circuit unit are connected to the heating unit and the heating relay in parallel. Thereby, a small current for driving the control circuit unit is controlled by the switching circuit unit, and a large current for driving the heating unit is controlled by the heating relay. I have. For this reason, the total current required for driving the entire device does not flow through the power saving relay constituting the switching circuit unit, and only the small current required for driving the control circuit unit flows. Therefore, the rating of the power saving relay can be reduced without increasing the number of components, so that the cost can be significantly reduced.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a configuration example of a conventional microwave oven having a power saving function.

FIG. 2 is a circuit diagram showing one embodiment of a microwave oven according to the present invention.

[Description of Signs] 1 Commercial power supply 2 Control circuit section 3 Heating section 7 Heating relay 8 Door switch 9 Start switch 10 Power saving relay 11 Switching circuit section

Claims (1)

[Claims] A control circuit for controlling a microwave oven;
A heating unit for heating the object to be heated; a switching circuit unit in which a start switch controlled to be opened and closed by a user's operation and a power saving relay controlled to be opened and closed by the control circuit unit are connected in parallel; and the control circuit unit A heating relay that is controlled to open and close by a microwave oven, wherein the control circuit unit and the switching circuit unit are connected in series, the heating unit and the heating relay are connected in series, and On the other hand, a microwave oven, wherein the control circuit section and the switching circuit section are connected in parallel with the heating section and the heating relay.