JPS6066714A - Rice cooker - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a rice cooker for general household use that is equipped with a timer device for setting an operation start time.

Conventional configuration and its problems Traditionally, electric rice cookers used in general households are equipped with a timer device such as a motor timer, and if the bed and water are set the night before, they will automatically start cooking the next morning. There was something to do. The conventional timer-equipped rice cooker as described above will be described below with reference to the drawings.

FIG. 1 shows page 2 of the electric circuit of a conventional rice cooker with a timer. In FIG. 1, reference numeral 1 denotes a timer device such as a motor timer, in which a contact 2 opens when a user sets a time, and closes when the set time elapses.

Reference numeral 3 denotes an electric heating element, which generates heat when energized and performs a heating operation. 4 is a thermo switch for detecting the completion of rice cooking, which automatically turns off when the rice cooking is completed. 6 and 6 are resistors and neon tubes connected in series to display the timer operation. 7
．． 8 is a resistor and a neon tube that displays the rice cooking operation.

9 is a temperature fuse for preventing excessive temperature rise, and 1o is a power plug.

The operation of the timer-equipped rice cooker configured as above will be explained below.

When you set rice and water in a pot, connect the power plug 1o to the power source, and turn on the thermo switch 4, the timer device 1 starts.
If it is time 0, start cooking rice. If you now set the timer device 1 to a predetermined time, the contact point 2 will open, and current will flow through the path of the electric heating element 3, the timer device 1, and the thermoswitch 4, and the tie 3 beige motor will operate, causing the timer to operate. A neon lamp 6 for display lights up. When the set time has elapsed, the contact 2 closes and the electric heating element 3 is energized to start heating. After that, when the rice is cooked, the water evaporates and the temperature drops.
When the temperature rises, the thermo switch 4 shuts off.

However, the above configuration has the following drawbacks.

First, rice and water are left in a pot without being heated for a certain period of time using timer device 1, but if water is added instead of hot water, the rice will absorb water significantly before starting cooking. When I cooked the rice after this, I ended up with soggy rice. Figure 2 shows the water absorption characteristics of rice using water temperature as a parameter. When the water temperature is 60°C, it absorbs water more significantly after 20 minutes than at other water temperatures, and
As time passes, the water absorption rate reaches 60%, and as seen from Figure 2, the maximum amount of time that 60°C hot water and rice can coexist is 2.
It can be said that it takes about 30 minutes. Therefore, if you have a rice cooker with a timer, you cannot set it for a longer time than this.
When set, there was a problem that the finished rice would be soggy.

Next, when the room temperature is high, such as in the summer, if you put water at about 15 to 25 degrees Celsius in a pot with rice, if a long time passes, the rice will deteriorate and an odor will occur and the rice will not cook afterward. However, the finished rice has a bad odor,
When the room temperature is approximately 30° C., the above-mentioned problem occurs when the time exceeds 6 hours.

Purpose of the Invention In view of the above drawbacks, the present invention automatically shortens the timer setting time when the temperature inside the pot or the room temperature is high.
This invention relates to a rice cooker that can prevent rice from rapidly reabsorbing water or deteriorating its quality.

Structure of the Invention In order to achieve the above object, the rice cooker of the present invention uses a temperature detection device in the pot, a room temperature detection device, or both, and a set time based on the output of these temperature detection devices. , and a timer device for shortening the time. By doing this, when hot water and rice are placed in the pot, the timer will automatically shorten the set time when the room temperature is high in summer, preventing significant water absorption and deterioration of the rice. This is to be prevented.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 3 is a block diagram showing the electrical configuration of the timer-equipped rice cooker in the first embodiment of the present invention.

In FIG. 3, 11 is a temperature detection device inside the pot, and 12 is a room temperature detection device, each of which detects the water temperature in the pot and the room temperature by replacing them with electrical signals. 13 is a control circuit for the timer device 14, and 14 is the timer device. The start and end times of the timer device 14 are shortened by the control circuit 13.

15 is an electrical contact of the timer device 14; during timer setting, the contact 16b and the contact 150 are connected, and the 0
At the time limit, contact 15a and contact 150 are connected to each other. 16 is a thermo switch for detecting the end of rice cooking;
Automatically shuts off when cooking is complete.

17 is an electric heating element for heating, 18.19 is a resistor and neon lamp connected in series for displaying rice cooking, 20.21
22 is a DC power source for the circuit, 23 is a temperature fuse to prevent excessive temperature rise,
Reference numeral 24 indicates a power plug.

The operation of the timer-equipped rice cooker configured as above will be described below.

First, put the specified amount of rice and water in the pot, and plug the power plug 2.
4 and turn on the thermo switch 16. When the timer is not operated, the timer device 14 is set to 0 time, and the contacts 15a and 150 are connected, so that the electric heating element 1 is energized and rice cooking starts immediately.

When the timer is still activated, the timer device 14 is set to a predetermined time. At this time, contact 15b and contact 15c
Neon lamp 21 for displaying timer operation
is lit, and the electric heating element 17 is not energized.

During the timer operation, if either the pot internal temperature detection device 11 or the room temperature detection device 12 detects that the set temperature has been exceeded and an output is generated, an input is sent to the control circuit 13 of the timer device 14. The setting time of the timer is shortened. In this case, the temperature detection device 11 in the pot is 5
Since the temperature is set at about 0° C., the setting time of the timer is shortened when significant water absorption as shown in FIG. 2 occurs. Since the room temperature detection device 12 is set to a temperature between 25° C. and above and 30° C. and below, the setting time of the timer can be shortened when the summer room temperature becomes high.

When the timer operation ends and the O time period is reached, the contacts 15a and 15C are connected to energize the electric heating element 17 and start cooking rice.

FIG. 4 is an electric circuit diagram of a rice cooker with a timer according to the second embodiment when applied to a jar rice cooker.

In FIG. 4, 30 is a negative characteristic thermistor provided to detect the temperature inside the pot, and together with resistors 31° and 32.33, it constitutes a bridge circuit, and the output of this bridge circuit is connected to the input terminal of a voltage comparator 34. It is connected. The output of the voltage comparator 34 will be at a low level if the temperature inside the pot is lower than the set value, and will be at a high level if it is higher. The output of the voltage comparator 34 is connected to an NPN transistor 35 via a resistor 36. 37 is a base resistor, 38 is a resistor for supplying base current to the transistor 35, and the transistor 35 is turned on and off according to the output of the voltage comparator 34. Reference numeral 39 denotes a reed relay winding. When the transistor 35 is turned on, the winding 39 is energized and the reed relay contact 40 is opened.

Reference numeral 41 denotes a negative characteristic thermistor provided to detect the room temperature, which together with resistors 42, 43 & 44 constitutes a bridge circuit, and the output of the bridge circuit is connected to the input terminal of a voltage comparator 45.

The output of the voltage comparator 45 will be at a low level if the room temperature is lower than the set value, and will be at a high level if the room temperature is higher than the set value.

9 Page 46 is a reed relay winding, and voltage comparator 46 conducts current to close contact 79 when the voltage is at a low level. Voltage comparator 45
The output of is connected to an NPN transistor 48 via a resistor 47.
It is connected to and turns on and off according to the output of the voltage comparator 45. 49 is a base resistance.

5Q, 51.52 are variable resistors and capacitors connected in series to set the operating frequency of the oscillation circuit, the oscillation frequency is changed by the variable resistor 60, and the contact 40
When the capacitor 62 is short-circuited, the oscillation frequency increases.

A timer circuit 53 divides the oscillation frequency one by one using a flip-flop to obtain a timer set time, and energizes the relay coil 54 when the set time elapses. 56 is a diode for absorbing back electromotive force generated in the coil.

56 is a switch that operates in conjunction with the variable resistor 50;
When the timer is set and the timer is to be started immediately, when the switch 66 is turned on, the relay coil 54 is energized.

The 1o vane 67 is a contact driven by the relay coil 54, and the contact 57b and the contact 57c are connected during the timer setting, and when the timer reaches the O time, the contact 57a and the contact 570 are connected. 58 is a thermo switch for detecting the completion of rice cooking. When rice is being cooked, it is turned on so that contacts 58a and 58c are connected, and when rice cooking is completed, contacts 5ab and 58c are automatically closed.
The connection is switched to contact 58C. 59 is an electric heating element for heating, which connects a transistor 62 having a pace resistor 61 via a resistor 6o, and a base resistor 6 via a resistor 63.
4, the transistor 65 has a thermoswitch 68
Base terminals are connected to the contacts 58b of the base terminals, respectively. Therefore, when the rice cooking is completed, the thermosi Sochi 58 closes the contact point s.
When the connection between sb and contact 58G is switched, the transistor 62 turns on and resets the timer circuit 53.
Transistor 65 is also turned on, energizing relay coil 54, and maintaining contact 67 between contact 57a and contact 57c.

67 and 68 are a resistor and a neon lamp connected in series to display the rice cooking operation, and 69 and 70 are a resistor and a neon lamp connected in series to display the timer 11 page operation. The light is turned on.

71 and 72 are diodes and capacitors connected in series, which act to generate DC power for the circuit.

73, Ryo 4 is an electric heating element installed at the top of the jar rice cooker and the side of the main body, which is heated by being energized during the heat-keeping operation. 75 and 76 are resistors and neon lamps connected in series to indicate heat retention operation, 77 is a two-way three-terminal thyristor, connected in series with electric heating elements 59, 73 and 74, and 2
Direction 3 terminal thyristor 770 on/off electric heating element 59
, 73°74. 78 is a gate resistor, and 79 is a contact of the reed relay 46. During the heat retention operation, the thermoswitch 58 is connected to the contact 5sb and the contact 58c, and is connected to the resistor 43b in parallel to the resistor 43a. Therefore, the negative characteristic thermistor 41 and the resistor 42
, 43a and 43b, the temperature set by 44 is
This is higher than the setting during rice cooking, and is suitable for the operating temperature of about 7oC. The temperature inside the pot is detected by the negative characteristic thermistor 41 during warming as well as during cooking, and this causes the voltage comparator 45 to drive the reed relay 46.
The contact 79 of the gate circuit of the directional 3-terminal thyristor 77 is turned on and off, and the energization of the electric heating elements 59, 73, 74 is controlled by the 2-directional 3-terminal thyristor 77 to perform a heat retention operation.

8o is a temperature fuse for preventing excessive rise, 81 is a power switch, and 82 is a power plug.

FIG. 5 is a sectional view of the main body to which the second embodiment is applied, showing the arrangement of each component.

Reference numeral 82 denotes the main body of the jar rice cooker, and a switch box 84 is provided on the front of this main body 83.

85 is a printed board provided in the switch box 84, on which the negative characteristic thermistor 30.85 shown in FIG. 4 is mounted.
Variable resistor 60. Neon lamps 68 and the like are installed. A knob 86 is attached to the variable resistor 60 so that it can be operated from the outside.

Page 13 87 is a pot housed inside the main body, which is placed on the electric heating element 66 in FIG. 4 or in contact with the side of the pot 87 to detect the temperature inside the pot. is provided.

Electric heating elements 73 and 74 for keeping warm are arranged on the top and sides of the pot 87.

Reference numeral 88 denotes a heat sensitive part of a thermoswitch for detecting the completion of rice cooking, which is placed in contact with the bottom of the pot 87, and the movement of this heat sensitive part is transmitted by a lever 89 to operate the switch 56. 9o is a part of a lever for manual input.

FIG. 6 is a block diagram of the timer circuit.

In FIG. 6, 90 is an oscillation circuit, which oscillates at a frequency determined by a resistor 5o and capacitors 51 and 52. 91, 92...93 are flip-flops that sequentially divide the oscillation frequency. A power supply regulator 94 stabilizes the DC voltage supplied to each circuit. 9
Reference numeral 5 indicates an output circuit, and reference numeral 96 indicates a reset circuit.

With this configuration, a predetermined set time can be obtained, and the set time can be set using the variable resistor 6014 page. Furthermore, when the contact 40 opens, the oscillation frequency increases and the set time is shortened.

The operation of the timer-equipped rice cooker configured as above will be explained below.

First, rice and water are placed in a pot 87, the power plug 82 is connected to the power source, and the power switch 81 is turned on.

If the timer does not operate, when the variable resistor 6o is set to the 0 time position, the contact 66 is closed and the relay coil 64 is energized, so the contacts 57a and 57a are connected, and the thermoswitch 68 When the rice is turned on, the electric heating element 5e is energized and rice cooking starts.

Next, in the case of timer operation, when the variable resistor 6° is set to a predetermined time and the thermoswitch 58 is turned on, the contact 56 is in an open state and the output terminal C of the timer circuit 53 is also turned off. Therefore, the relay coil 54 is not energized, the contacts 67 are connected to the contacts s7b and 57c, the neon lamp 70 for displaying the timer operation is lit, and the state remains in this state until the predetermined time 154-ji has elapsed. will continue.

During this time, if the negative characteristic thermistor 41, which corresponds to a device that detects the temperature inside the pot, or the negative characteristic thermistor 30, which corresponds to a device that detects room temperature, detects that these temperatures are higher than the set value, the room temperature is changed. In the case of using a detection device, contact 4o is opened to increase the oscillation frequency of capacitor 52 and automatically shorten the timer setting time.

In addition, when using a detection device for the temperature inside the pot, transistor 4
8 is turned on to energize the relay coil 54 and immediately start cooking rice.

As described above, when rice cooking starts and then ends, the thermo switch 58 automatically shuts off the contact 58.
b and contact 58c are connected, and transistor 65 is connected to reset the timer circuit by transistor 62.
The relay coil 54 is energized and the contact 57 is connected to the contact 5.
7& and contact 57c are connected. Furthermore, the bridge circuit of the temperature detection circuit inside the pot includes a resistor a3b and a resistor 43a.
By connecting the two in parallel, the temperature can be switched to keep warm.

In this way, after rice cooking is completed, the contact 79 inserted into the gate circuit of the 2-way 3-terminal thyristor is turned on and off by the pot internal temperature detection device, and the electric heating element 59, 73, 74 is energized and kept warm. can perform actions.

Therefore, by providing at least one of a pot internal temperature detecting device and a room temperature detecting device, and having a timer device that automatically shortens the setting time based on the output of this detecting device, when the timer is set, rice and hot water can be It is possible to prevent rice from deteriorating due to heating or high room temperature, and failure to cook the rice.Furthermore, the pot temperature detection device is configured to be used for control during the warming operation, making it even more effective. It is true.

Effects of the Invention As described above, the present invention includes at least one of a temperature detection device inside the pot or a room temperature detection device, and a timer device whose set time is controlled by the output of these detection devices. When hot water and rice are put in the pot, or when the room temperature is high in summer, the timer can be automatically shortened, so the timer setting time can be automatically shortened. The practical effect of providing a rice cooker that prevents water absorption and deterioration of rice and prevents failure in cooking rice is great.

[Brief explanation of drawings]

Fig. 1 is an electric circuit diagram of a conventional rice cooker with a timer, Fig. 2 is a graph showing how the water absorption rate of rice changes over time depending on water temperature, and Fig. 3 shows a first embodiment of the present invention. A block diagram, FIG. 4 is an electric circuit diagram showing a second embodiment of the present invention, FIG. 5 is a sectional view of a main part of a rice cooker to which the second embodiment is applied, and FIG. 6 is a diagram showing the second embodiment of the same. FIG. 2 is a block diagram of a timer circuit in an example. 11... In-pot temperature detection device, 12...
Room temperature detection device, 13... Control circuit, 1
4... Timer device, 30.41...
Negative characteristic thermistor.

Claims (1)

[Claims] A rice cooker equipped with a timer device whose set time is controlled by the output of a detection device for the temperature inside the pot or the room temperature.