JPS5947806B2 - Microwave oven with heater - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a microwave oven with a heater that has a browner function in addition to a microwave heating function.

Microwave ovens perform dielectric heating by irradiating the food with microwaves, so it is possible to obtain a heating effect over almost the entire food. I can't attach it.

This lack of fish marks on the surface of the food results in inferior appearance and flavor, depending on the type of food being cooked, compared to conventional cooking methods, and has been a major problem with microwave ovens.

In order to compensate for the above-mentioned drawbacks of microwave heating, devices have been developed in which a radiant heater, such as an electric heater, gas heater, or infrared heater, is installed in an oven, which is a heating chamber.

However, even in an apparatus equipped with such a radiant heater, it is difficult to form an appropriate fish pattern depending on the type of food, and it has not been possible to obtain a uniform fish pattern.

In response, the applicant installed an infrared radiation type so-called browner heater in the oven, supported it so that it could move up and down in the oven, and made it possible to adjust the distance between the food surface and the heater surface by external operation. We have already applied for a microwave oven with a heater in Japanese Patent Application No. 59028/1983.

The present invention is an improved configuration in which the Browner heater in the microwave oven with a heater is moved up and down by a manual lever so that it is driven by a motor, and will be described below with reference to the drawings.

FIG. 1 is a diagram showing the external appearance of a microwave oven with a heater, which is an embodiment of the present invention. A turntable 2 is provided at the inner bottom of the oven 1, which is a heating chamber, and a browner heater, which will be described later, is provided at the top. 3 is provided.

An operation panel 5 is provided on the front surface of the main body along with a door 4 that can freely open and close the opening of the oven 1, and a keyboard 6 and a digital display device 7 are provided with keys to be described later.

This heater-type microwave oven has a microcomputer installed in the control circuit section, and by operating each key arranged on the keyboard 6, a cooking program suitable for the type of food can be created.

The key arrangement is shown in FIG. 2, for example.

Here, 60a is a group of keys consisting of keys for selecting and setting the heating method; for example, the m key is a key to set microwave output of 30% for low heat, and the Th key is a key for setting microwave output of 100% for high heat. The 2 key and 2 key are keys for operating the browner heater 3, and the loco key is a key for instructing which position in the oven the heater 3 is to be moved.

Further, 60b is a group of keys with a numeric keypad configuration for setting the cooking time and heater position, and 60c is a group of keys for setting the start (low key) or stop (low key) of cooking.

Now, as an example, a cooking program to be set up when cooking frozen meat for steak will be explained.

This cooking program consists of the following three steps.

Stage 1: As a thawing operation, heating is carried out for 4 minutes using a microwave output of 30%.

2nd stage 100% microwave output for normal cooking work
Heat it over high heat for 2 minutes and 30 seconds.

The 3rd stage Browner browning process involves moving the heater to heater position "3" in the oven and heating it for 7 minutes.

Incidentally, in the focusing process, the position of the browner heater in the oven may be selected to suit the user's preference.

In order to automatically switch between such three-stage cooking sequences, the following keys are selected and operated in advance.

l four mouths Key operation procedure W (Defrost) Rororo (Full Power) [M] Rolo m decoy 1 (Heater Location) mouth [ When the last m key is operated, the electronic Nji starts cooking.

FIG. 3 is an internal configuration diagram seen from the front of the microwave oven with heater shown in FIG. 1, mainly showing the vertical drive and support mechanism of the Brauner heater 3.

A magnetron (not shown) is provided outside the oven 1, and when it is in operation, it projects 2450 MHz microwaves into the oven 1, while when the heater 3 is in operation, it projects the radiant heat onto the food on the turntable 2. Irradiate it to create fish eyes.

The turntable 2 is located at the inner bottom of the oven, is rotatably supported at its center bottom, and is connected to a drive shaft of a motor 8 mounted outside the oven 1 to rotate.

As the turntable 2 rotates, the relative position of the food in the oven changes, and not only the microwave irradiation conditions but also the radiant heat irradiation conditions from the heater 3 are made almost uniform regardless of the location of the food, resulting in even heating and cooking. can be done.

The heater 3 consists of a back plate 31 and a heat generating part 32. The back plate 31 is made of a mirror-finished metal plate or a heat-resistant ceramic plate on the surface facing the heat generating part 32, and emits radiation toward the oven ceiling. radiant heat is reflected towards the food.

The heat generating portion 32 of the heater 3 is a sheathed heater, and a heat generating resistance wire that generates heat when energized is inserted into the interior of a highly conductive tubular sheath.

A heat-resistant insulating material such as magnesia is filled between the tubular sheath and the resistance wire.

Further, the heat generating portions 32 meander in order to increase the heat generating area on the surface facing the back plate 31, and are fixed to each other by fixtures 33 on both side walls of the back plate 31.

In the heater 3, the sheath covering the heat generating resistance wire extends further from the attachment end of the back plate 31 and is integrally provided with a long support pipe 34 that penetrates both side walls of the oven and supports the heater 3. It has become.

A lead wire is inserted through the support pipe 34, and an electrical connection is made to the resistance wire near where the support pipe 34 passes through the side wall of the back plate 31 to connect the heater 3 to a power supply circuit located outside the oven. electrically connected.

Note that the support pipe 34 can be formed integrally with the sheath of the heat generating part 32 from a conductor, but in consideration of the process of assembling the microwave oven, the sheath of the heat generating part and the support pipe made of a conductor may be formed separately. and may be electrically connected using a coupling means such as a joint.

Further, since the lead wires inserted into the support pipe 34 are covered with a pipe made of a conductive material, there is no possibility that the microwaves projected into the oven will ride on the lead wires and leak to the outside of the oven.

The side wall of the oven where the support pipes 35 and 34 on both sides are located is provided with a recess 9 that protrudes to the outside in order to avoid a reduction in the internal volume of the oven. has been derived.

A cylindrical radio wave shielding means 11 having a choke structure is attached to the bottom wall 10 in order to shield microwaves from leaking to the outside from the penetrating portion of the support pipe 34.

A vertical movement driving and supporting mechanism for the heater 8 as shown in FIGS. 3 to 5 is provided outside the oven 1.

First, place L-shaped support plates 1 on both sides of the top plate 101 of the oven 1.
2 and 12 are attached, and rotatably supports a shaft 14 that fixes the boo IJs 13 and 13 at both ends, and L-shaped support plates 16 and 16 are provided on both sides of the bottom plate 150 of the cabinet 15, which forms the outer casing of the microwave oven. attached to the shaft 17,
Boo IJ 1B, 1B which can be rotated freely with 17
A timing belt 19, 19 is suspended, supporting the upper and lower boots IJ 13 and 18.

A transmission gear 22 is fixed to the right end of the shaft 14, and meshes with a drive gear 21 that is rotationally driven by a motor 20 to transmit rotation.

The motor 20 is attached to a support plate 23 on the top plate 101 of the oven 1.
It can be installed with.

Furthermore, as shown in an enlarged view in FIG. 5, the timing belt 1
9, the belt fixing fitting 25 is attached to the support pipe 34 of the heater 3.
Heater fixing fittings 26 are attached to the inner fittings 25 and 26 by screws 24 and 28, respectively, and inner fittings 25 and 26 are connected by springs 27.

The spring 27 has one end attached to the belt fixing metal fitting 25 and the other end attached to a fixed piece 260 bent and raised from the heater fixing metal fitting 26, and normally transmits the movement of the belt 19 to the heater 3 by its tensile force, and both are integrated. It is configured so that it can be exercised.

If the heater 3 touches the food or tableware placed on the turntable 2 during its descent, the heater 3 will stop at that position, but the belt 19 will be further driven by the motor 20 until the dashed line 25' The belt fixing fitting 25, which was at the position , is lowered to the position indicated by the solid line in FIG. 5 against the tensile force of the spring 27.

Along with this, the actuator of the food detection switch 29 is pressed and the food detection switch 29 is closed.

This food detection switch 29 is attached to the heater fixture 26 and is assembled as a means for reversing the motor 20 in conjunction with its closing operation, as will be described later.

A switch operation plate 40 is attached to one surface of the left side of the heater fixture 26, and has three vertical rows of protrusions 40a to 40h.

As shown in a perspective view in FIG. 6 and in a side view in FIG. Switch 4 faces the switches 42, 43, 44.
The protrusions of each row are positioned on the respective actuators, such that the switch 43 is in the second row, the switch 44 is in the third row, and so on.

Incidentally, the protrusions 40a to 40d of the first column are treated as position marks, and the protrusions 40e to 40h of the second and third columns are treated as sensing marks, and therefore face the protrusions of the first column. The switch 42 operates as a position mark readout switch, and the switches 43 and 44 facing the second and third protrusions operate as sensing mark readout switches, and the sensing mark is formed longer than the position mark.

This is the switch 43.4 for reading sensing marks.
This arrangement is designed so that the position mark readout switch 42 is operated after the position mark reading switch 42 is operated reliably.

These switches 42 to 44 are assembled together with the food detection switch 29 into an electric circuit shown in FIG. 9, which will be described later.

FIG. 8 shows an electric circuit installed in the above-mentioned microwave oven with heater.

According to this, the control circuit section 50 (shown by a dashed line).

), five relays RL1~ connect the power to each load as appropriate.
RL5, a keyboard 6 on which the above-described key groups 60a to 60c are arranged, a display device 7, and a microcomputer 5 that stores a cooking program input by key operations on the keyboard 6 and executes cooking according to the program.
1 is set.

This microcomputer 51 has relays RL, ~RL
, are connected to amplifiers 52-56.

Further, 57 is a constant voltage power supply that supplies DC voltage to each device of the control circuit section 50.

Relay RL1 opens and closes switch 61 to control energization of fan motor 60 that rotates the magnetron cooling fan, and relay RL2 opens and closes switch 64 to control energization of high voltage generation circuit 63 to generate microwaves from magnetron 62. output.

Relay RL3 opens and closes switch 65 to control energization of Brauner heater 3, and relay RL4 opens and closes switch 66 to control energization of motor 20 that moves heater 3 up and down.

The other Q-RL is a relay that, when activated, switches the heater vertical movement changeover switch 67, which is connected in series with the previous switch 66 and is normally at the normally closed contact NC, to the normally open contact NO.

The motor 20 rotates in the reverse direction by switching the heater vertical movement changeover switch 67.

Now, a vertical movement control circuit for the heater 3 shown in FIG. 9 is installed in the microcomputer 51.

Roughly speaking, among the group of keys arranged on the keyboard 6 shown in FIG. 2, the heater 3 can be stopped in advance by operating a hidden key for specifying the heater position and then operating a numeric key, for example, a country key. The location can be memorized.

Then, when cooking starts with the operation of the > key,
The heater 3 is controlled to be automatically moved to the set heater position "4" in synchronization with the heat generation operation.

According to FIG. 9, reference numeral 6 indicates a keyboard provided on the operation panel 5 shown in FIG. 2, including a key group 60a for setting the heating method and a key group 60b for setting the cooking time and heater position.
As described above, it is comprised of the key group 60c for setting the start or stop of cooking.

The output of each key is code-converted by the encoder 70 into a code signal consisting of binary numbers 0'' and 1'' handled by the microcomputer, and sent to the central processing unit (CPU) 71.

Here, the numerical information of the cooking time and heater position input by operating the four to four number keys of the numeric keypad arranged in the key group 60b is transferred to the storage device (RAM) 73 and stored therein.

Further, when the 2nd key of the key group 60c is operated, a cooking start signal is generated from the central processing unit (CPU) 71.

According to the example of cooking frozen meat for steak described above, the numerical information of the cooking time and heater position of each stage is stored in the storage device (RAM) 73 according to key operations according to the procedure, and is stored in the storage device (RAM) 73 when the cooking start signal is generated. The missing cooking time information is sequentially transferred to the counter 74, while the heater position information is transferred to the temporary storage register 75.

When the cooking program is set and the key is operated, a cooking start signal is generated and the first step, the thawing operation, begins.

At this stage, microcomputer 51 generates a signal to intermittently drive relay RL2 with a duty of 3/10 based on a control command read from fixed storage device (ROM) 72.

Therefore, the high voltage generation circuit 63 is continuously driven and the magtoron 6
2, the microwave output is 30% oscillated to perform repeated heating suitable for defrosting frozen foods.

At this time, relay RL1 operates simultaneously and turntable 2
and rotate the magnetron cooling fan.

Further, the digital display device 7 sequentially counts down the set cooking (defrosting) time by 4 minutes.

When this display reaches zero, the process moves to the second step.

The microcomputer 51 is a fixed storage device (ROM) 7
Relay R based on the second stage control command read from 2.
Outputs a signal that continuously activates L2.

Therefore, in this stage, high flame heating with 100% microwave output is performed.

The fan motor 0 and the turntable motor 8 remain in operation, while the display device 7 sequentially counts down the set cooking time of 2 minutes and 30 seconds.

When this display reaches zero, the third and final stage of focusing shifts to the work process.

This focus is because the work process is related to the gist of the invention.
This will be explained in detail with reference to FIG.

That is, when the second stage process is completed, the storage device (RAM)
From 73, cooking (focusing) time information is transferred to counter 74 as in the previous stage, while heater position information is transferred to temporary storage register 75.

In addition, the heater drive instruction signal ■ is sent to the central processing unit (CPU).
) 72 and sets the flip-flop 76.

This setting causes the Q terminal of the flip-flop 76 to go high.
high, the amplifier 54 is operated and the switch 65 is closed by the relay RL3.

The Browner heater 3 starts to be energized by this,
Radiant heat is projected onto the food from the heat generating unit 32, and at the same time, the work of transporting the food to the heater position "3" in the oven 1, which has been programmed in advance in the cooking program, begins.

The heater position "3" is encoded by the encoder 70 as a code signal 110 as shown in Table 1, and is temporarily stored in the register 75. However, upon generation of the heater drive instruction signal (■), the three MOS transistors 76 to 78 are becomes conductive and is transferred to register 79.

In Table-1, tl I II is switch closure, 0
′” corresponds to the open state of the switch.

Therefore, for example, when the heater is in position "2", switch 4
2 is closed, switch 43 is open, and switch 44 is closed.

The register 80 is a device that stores heater position information corresponding to the actual position of the heater 3.

The heater 3 is always placed at the top stage in the oven 1 (
(near the top plate 101), which corresponds to heater position "1".

Therefore, the heater position "1" is preset in the register 80.
” is stored.

Here, the register 80 is connected to the switch 42 shown in FIG.
Since the code signal is set and input through 44, the heater position "1" means that the switch operation board 4
0 is located at the top of the vertical movement range, and only the actuator of the switch 42 is closed by being pressed by the protrusion 40d.

Numbers are written on the right end of the switch operation panel 40 in FIG. 6 at locations corresponding to heater positions "1" to "4".

A comparator 81 connects both registers 79 and 80, compares the magnitude of the code signals stored in both, and holds A>B until they match.
The terminal is in a high state.

Assuming that the code signal stored in the register 71 is A and the code signal stored in the register 80 is B, A>B at the time when the heater drive instruction signal ■ is generated and the third stage process is started. The comparator 81 makes the A>B terminal H.
A signal is output to the amplifier 55 via the OR gate 82 in the high state.

Relay RL4 operates accordingly, and is a relay that operates motor 20 as shown in FIG.
begins to fall.

Since the lowering of the heater 3 is accompanied by the lowering of the switch operation plate 40 at the same time, the protrusions 40a to 40h selectively open and close the switches 42 to 44 in sequence.

That is, the register 80 stores code signals io1.corresponding to each heater position. iio.

111 are input in sequence.

When the heater reaches position "3" while descending, register 8
Since the code signal of 110 is input to 0, the comparator 81
detects A=B and inverts the A>B terminal output to the Low state.

As a result, relay RL4 is cut off, and therefore heater 3
stops descending and is held in that position for 7 minutes to brown the food.

However, the heater 3 may hit food or tableware during its descent.

Of course, this does not always happen, and if you happen to lower the device to the intended heater level, the food may be larger than expected.

In this case, as explained in FIG. 5, the heater 3 and the switch operation plate 40 stop at the position where they hit the food due to the expansion of the spring 27, but the belt 19 continues to move until the food detection switch 29 is closed.

Switch 29 assembled in FIG. 9 represents this food detection switch, and when closed, resets flip-flops 84 and 85 through OR gate 83.

Accordingly, the contents of the lower 2 bits of register 79 are '0'
”, and the code signal is switched to 100.

That is, when A>B hits the food, the condition A>B switches to A<B, and the comparator 81 immediately puts the A<B terminal in the High state and sends the relay RL4. Activate RL5.

As described above, the relay RL is a relay that switches the heater vertical movement changeover switch 67 to the normally open contact NO and causes the motor 20 to reverse rotation.

When the heater 3 returns to the top stage, which is the heater position "1", only the switch 42 is in the closed state and the code signal 100 is input to the register 80.

From this point on, the comparator 81 detects A=B, inverts the A<B terminal to a Low state, and shuts off relay RL4°RL.

Further, when the food detection switch 29 is closed, the flip-flop 86 is reset and the contents of the counter 74 are forced to zero.

Accordingly, the zero detection circuit 87 resets the flip-flop 76.

Therefore, relay RL3 is cut off, cutting off power to heater 3.

At this time, the error is notified by the notification circuit 58 shown in FIG.

The user must therefore reset the heater position and operate the [key] again.

When the heater 3 is brought to the desired position and the grain size work is completed, the display device 7 reaches zero.

The output of the zero detection circuit 87 detects this and becomes High, thereby resetting the flip-flop 76.

At this time, the Q terminal is switched to High, so the flip-flops 84 and 85 are reset, and the contents of the register 79 are forcibly set to 100.

As a result, the comparator 81 sets the half-speed A<B terminal to a High state and operates the relays RL4 and RL5.

Therefore, as described above, the heater 3 is raised until the contents of the register 80 reach 100.

Note that 88 is a count control circuit that counts the power supply frequency of 60 Hz and outputs one pulse per second to cause the counter 74 to count down.

Further, a display body 7a provided at the left end of the display device 7 digitally displays the heater position.

In this way, the predetermined cooking program ends.

At this time, the heater 3 is placed on the top plate 10 as the top shelf in the oven.
Since it is reset to around 1, there is little risk of touching the heater 3 when taking out food.

As described above, according to the present invention, there is provided a heater housed in a heating chamber so as to be movable up and down, a motor for moving the heater upward or downward, a means for setting the height position of the heater, and a code for outputting the output of the setting means. means for converting into a signal, means for storing the converted set position signal, means for detecting the height position of the heater, means for converting the detected height position into a code signal, and the converted detected position signal. means for storing the set position signal and the detected position signal; means for outputting a motor drive signal when the two signals do not match according to the comparison result; and the heater comes into contact with the heated object. and means for resetting the set position signal to a signal corresponding to a position above the height at which the heater made contact, according to the output of the means for detecting contact. With this configuration, you can simply set the desired fish grain in advance, and the heater will automatically move up and down and hold it in place, heating the food on the width side and cooking the desired fish grain. can get things.

In this case, the heater moves up and down automatically, so there is no inconvenience that the user would have to manually move the heater up and down. You can freely get the fish texture you like, down to "weak".

In addition, even if the heater comes into contact with the heated object due to vertical movement of the heater after setting the height of the heater, this contact can be automatically detected and the heater can be returned upwards, making it safe and possible to avoid unnecessary There will be no burning, so you can cook with peace of mind.

[Brief explanation of the drawing]

Fig. 1 is an external perspective view of the microwave oven with a heater of the present invention;
The figure is an enlarged view of the operation panel, Figure 3 is a front view showing the internal structure, Figure 4 is a side view, Figure 5 is an enlarged view of the main parts, Figure 6 is an enlarged perspective view of the switch operation panel, FIG. 7 is a side view thereof, FIG. 8 is an electric circuit diagram assembled into the microwave oven with a heater, and FIG. 9 is an electric circuit diagram showing the control circuit section thereof. 1: Oven, 3: Brauner heater, 6: Keyboard, 13, 17: Pulley, 19: Belt, 20: Motor, 40: Switch operation board, 42 to 44: Switch, 51
: Microcomputer.

Claims (1)

[Scope of Claims] 1. A heater housed in a heating chamber so as to be movable up and down, a motor for moving the heater upward or downward, means for setting the height position of the heater, and an output of the setting means. means for converting the detected height position into a code signal; means for storing the converted setting position signal; means for detecting the height position of the heater; means for converting the detected height position into a code signal; means for storing a position signal; means for comparing the set position signal and the detected position signal; means for outputting a motor drive signal when the two signals do not match according to the comparison result; means for detecting contact with the heater; and means for resetting the set position signal to a signal corresponding to a position above the height at which the heater contacts, in accordance with the output of the contact detecting means. A microwave oven with a heater. 2. The microwave oven with a heater according to claim 1, wherein the microwave oven includes means for notifying that the heater has come into contact with an object to be heated. 3. The heater-equipped microwave oven according to claim 1 or 2, wherein the means for detecting the height position of the heater is a plurality of switches that open and close according to the vertical movement of the heater. 4. The heater-equipped microwave oven according to any one of claims 1 to 3, wherein the setting position signal reset by contact with the heater is a signal corresponding to an initial top position.