JPH0258534B2 - - Google Patents

Description

[Detailed Description of the Invention] <Technical Field> The present invention relates to a heater such as a microwave oven with a heater, and particularly to a heater for automatically setting and controlling the height of a heater according to the height of an object to be heated. This relates to heater position control.

<Prior art> Conventionally, in a microwave oven equipped with a heater, when performing grill heating (the menu for browning fish, gratin, etc. is generally referred to as grill heating), the heater is manually raised and lowered, or the heater 1 is turned off as shown in Fig. 10. By changing the voltage of the electric motor 2A connected to the electric motor 2A or by changing the polarity, the user can move the heater position according to the height of the object to be heated 7 on the mounting plate 3 in the heating chamber 5. The heater position was set appropriately. However, since the user sets the heater position, the user may forget to bring the heater 1 close to the object to be heated 7 and the object to be heated 7 may not be scorched, or the heater position may be inappropriate and the object to be heated 7 may be burnt due to overheating. The finished product of the object to be heated 7 was highly inconsistent as it became brown or too burnt, and the operation of setting the heater position was troublesome.

Further, as shown in FIG. 9, in a heater of the type in which the heater 1 is rotatably installed inside the rear wall of the heating chamber 5, even if the height of the heated object 7 is the same, It becomes important where the object 7 is placed on the placing plate 3 or the cooking grid 3A.
For example, as shown by the solid line in FIG. 9, if the object to be heated 7 is located at the center of the placing plate 3, the heater 1 needs to move lower, and the object to be heated 7 is placed around the placing plate 3. In this case, if the heater 1 is lowered and moved in the same way as when the object 7 to be heated is placed in the center, it will collide with the objects to be heated (imaginary line in FIG. 9) placed in the periphery. For this reason, the heater 1 cannot be lowered very much for the objects to be heated 7 placed in the vicinity. In this way, even if the height of the heated object 7 is the same, the heater position cannot be set properly unless the position is adjusted depending on whether the heated object 7 is at the center or around the mounting plate 3.

<Purpose> In view of the above, the present invention detects the position of an object to be heated on a mounting plate by capturing temporal changes in the output of a position detection sensor,
We aim to provide a heater that corrects the amount of movement of the heater so that the heater is always set slightly above the object to be heated, regardless of the position of the object, and can perform appropriate finish control. It is something to do.

<Example> An example of the present invention will be described below with reference to FIGS. 1 to 9.

FIG. 1 is a front view showing a schematic structure of a microwave oven which is an embodiment of the present invention. In this microwave oven with a heater, a heater 1 is rotatably installed in a heating chamber 5, and the heater 1 is heated by having its heat generating part 1a eccentrically arranged with respect to the rotation axis 1b. The height of the heater 1 is adjustable, and an adjustment drive device 2 is provided to adjust the height of the heater 1. It is equipped with a rotatable interior,
A rotational drive device 9 for rotationally driving the mounting plate 3
, a control device 10 for controlling the adjustment drive device 2 and the rotation drive device 9, and a position detection sensor 11 for detecting the height position and placement position of the object to be heated 7 in the heating chamber 5. A plurality of control devices 10 are arranged in the vertical direction on the wall of the heating chamber 5.
The rotation driving device 9 is driven to rotate the mounting plate 3 once (180 degrees or more), and the height position and the mounting position of the object to be heated 7 are determined based on the temporal change in the output signal of the position detection sensor 11. It has a function of detecting and outputting a signal for controlling the adjustment drive device 2.

As shown in FIGS. 2 and 9, the heater 1 has rotation shafts 1b at both ends supported by the rear lower part of the side wall of the heating chamber 5,
Further, the heat generating portion 1a is formed in a meandering manner as shown in FIG.

The position detection sensor 11 is an optical sensor, and consists of a light emitting element 12 and a light receiving element 13.
12 is interposed between one side wall of the heating chamber 5 and the heater main body 14 that houses the heating chamber 5, and is arranged in the vertical direction, and is located at the same position as the light emitting element 12.
A plurality of small holes 15 are formed in the side wall of. Further, the light receiving element 13 is arranged on the outside of the other side wall of the heating chamber 5 facing the light emitting element 12, corresponding to the position (height) of the light emitting element 12, and a small hole 16 is formed in the side wall of the heating chamber 5. has been done.

FIG. 2 is a schematic plan view of the microwave oven, and the light receiving element 13 and the light emitting element 12 are connected to the rotating shaft 8 of the mounting tray
are arranged opposite to each other in point-symmetrical positions with respect to the axis A of the two. As the light emitting element 12, an oven lamp or a light emitting diode is used. As shown in FIG. 3, the light-receiving elements 13 are composed of phototransistors (a photodiode or the like can also be used), and the emitter side of each light-receiving element 13 is connected to the base side of a transistor 18. When light enters the light-receiving element 13, the transistor 18 is ON, transistor 1
The collector voltage of the transistor 8 is at L level (OV), and when no light enters, the collector voltage of transistor 18 is connected to be at H level (+Vc). The signal level of each transistor 18 is then sent to the interface 22 of the main control circuit 21 of the control device 10.

FIG. 3 is a diagram showing the configuration of a control device, and the control device 10 includes a main control circuit 2 that controls the heater heating device B, the high frequency heating device C, and the rotation drive device
1 (microcomputer) and the main control circuit 2
1, a selection key 23A for selecting microwave heating, oven heating, and grill heating, and a cooking start key 2
The setting device 23 (operation panel) outputs signals such as 3B, and the setting device 23 and the main control circuit 21 are connected via an interface 22.

The adjustment drive device 2 is composed of a DC motor 24 and a motor control circuit (IC) 25 that controls the motor to rotate, reverse, and stop, and signals for forward/reverse rotation and stop are sent via the interface 22. is output from the main control circuit 21.

The rotation drive device 9 is a mounting plate drive motor 26.
, a relay switch 27a that turns on/off the motor 26, a relay coil 27b that operates the relay switch 27a, and a transistor 28 that drives the relay coil 27b with the output signal of the main control circuit 21. The relay switch 27a is connected to a power plug 30 via a door switch 29.

The heater heating device B includes a heater 1 and a relay switch 31a that controls ON/OFF of the heater 1.
, a relay coil 31b that operates the relay switch 31a, and a transistor 32 that drives the relay coil 31b by the output signal of the main control circuit 21.
1a connects the power plug 30 via the door switch 29
It is connected to the.

The high-frequency heating device C also includes an oscillation circuit 36 including a magnetron 4, a resonant capacitor 33, a diode 34, a transformer 35, etc., a relay switch 37a that conducts to the oscillation circuit, and a relay coil 37b that operates the relay switch 37a.
and a transistor 38 that drives the relay coil 37b by the output signal of the main control circuit 21, and the primary side of the transformer 35 and the relay switch 3
7a is the power plug 30 via the door switch 29
It is connected to the.

The cooking net 3A shown in FIGS. 4 and 5 is a special accessory used to drain the oil when grilling fish during grill heating.

Next, the operation will be explained. First, press the grill key among the selection keys 23A of the setting device 23, select the menu, and then press the heating start key 23B.The main control circuit 21 operates the mounting plate drive relay coil 31b, closes the relay switch 27a, and then Rotate the tray 3.

Next, if the light emitting element 12 is made to emit light and there are a plurality of outputs from the transistors 18 that change according to the input to the light receiving element 13, that many "L" or "H" level signals will be sent. , read into the main control circuit 21.

Figures 4 and 5 are schematic diagrams when the object to be heated 7 is actually placed on the cooking grid 3A and operated (each figure a).
and a diagram (each diagram b) showing the output of the transistor 18 at that time. As shown in FIG. 4, the object to be heated 7 reaches the light receiving element 13 without blocking the light from the light emitting element 12, so the output of the transistor 18 becomes "L" level. As shown in FIG. 5, when the height of the object to be heated 7 is high, the light does not reach the light receiving element 13, and the output of the transistor 18 in the shaded portion becomes "H" level. As the mounting plate 3 rotates, the light is emitted and sometimes it is not emitted, so the output often changes between the "L" and "H" levels as shown in FIG. 5B.

Therefore, the main control circuit 21 reads the output of the light receiving element 13 until the mounting plate 3 rotates 180 degrees. Then, it is checked which of the plurality of light receiving elements 13 has reached the "H" level at least once, and if there is a light receiving element 13 that has reached the "H" level at least once, the height of that light receiving element 13 is determined. indicates that the object to be heated 7 is at a corresponding height. Therefore, if the heater 2 is lowered to the position of the light receiving element 13 that has reached the "H" level, the heater 2 will hit the object to be heated 7, so it is necessary to lower the heater 2 to the position of the light receiving element 13 directly above it. The control circuit 21 is
A signal is sent to the control circuit 25 of the adjustment drive device 2 to rotate the DC motor 24 and lower the heater 2.
However, at this time, since the amount of rotation of the heater 1 varies depending on the placement position of the object to be heated 7 as shown in FIG. 9, the control circuit 21 performs control as shown in the flowchart of FIG. That is, the mounting plate 3 is rotated, the output of the light receiving element 13 is read until the control circuit 21 rotates once, and the time when it is in the shadow of the object to be heated 7, that is, the time when the transistor 18 is at the "H" level, is calculated as follows.
As shown in FIG. 7, this To is obtained as To, and the control circuit 21 stores it in memory. Then, find the total time (ΣTo) during which the output is at "H" in one rotation,
The amount by which the heater descends (moves) is corrected in accordance with this sum total. That is, if the time for descending (for the motor to rotate) is t, then t=a·f(ΣTo). As To increases, the object to be heated 7 is located in the center of the mounting plate 3, so the heater 1 must be moved and lowered more than in the periphery. The constant a of the formula and the calculation formula f(ΣTo) are determined in advance through cooking experiments, etc., so that when placed in the vicinity, ΣTo is small and t is short, and the descending time of the heater 1 is short and the descending amount is also correspondingly small. When the heater height reaches the height set by detection and correction, the main control circuit 21 outputs a stop signal to the control circuit 25 in the same manner as above.
Stop the motor 24.

Next, the main control circuit 21 controls the heater relay coil 3
1b is operated, the relay switch 31a is operated, the heater 2 is turned on, and grill heating is performed to scorch the object to be heated 7. Then, after a certain period of time has passed, heating is stopped and heater 1 is automatically returned to its original position (upper).
The main control circuit 21 sends a signal to the motor control circuit 25 to return the motor. As described above, the present invention detects the height of the object to be heated according to the output of the position detection sensor and controls the heater to a predetermined height. However, when moving the heater up and down by rotating the heater, even if the heater is in the same position, if the object to be heated is placed in the center of the mounting plate 3, it may be placed on the periphery. The heater must be turned lower than when it is turned on. The present invention
Since the amount of movement of the heater is corrected based on the output of the position detection sensor, anyone can easily operate it regardless of where the heated object is placed, improving operability and making a difference in the finish. The difference between the center and the periphery of the placing plate can be eliminated, and cooking performance can be improved.

It should be noted that the present invention is not limited to the above embodiments, and it goes without saying that many modifications and changes can be made to the above embodiments within the scope of the present invention. For example, in this embodiment, the sensor is an optical sensor, but a sensor that utilizes reflection of ultrasonic waves or the like may also be used.

<Effects> As is clear from the above description, the present invention has a heater rotatably installed in the heating chamber, and the heating height of the heater is adjusted by placing the heater eccentrically with respect to the rotation axis. In the heating device, the heater is equipped with an adjustment drive device for adjusting the height of the heater, and a mounting plate for placing an object to be heated in the heating chamber is rotatable around a rotation axis. A rotational drive device for rotationally driving the mounting plate is provided, a control device for controlling the adjustment drive device and the rotational drive device is provided, and a control device is provided for controlling the height position and placement of the object to be heated in the heating chamber. A plurality of position detection sensors for detecting positions are arranged vertically on the wall of the heating chamber, and the control device drives the rotation drive device to rotate the mounting plate by 180 degrees or more to detect the position detection sensors. The present invention relates to a heater having a function of detecting the height position and placement position of the object to be heated based on temporal changes in the output signal and outputting a signal for controlling the adjustment drive device. .

Therefore, according to the present invention, even if the heater is moved up and down, it is possible to determine where the object to be heated is placed on the mounting plate by capturing temporal changes in the output of the position detection sensor. This function detects whether the object is heated, corrects the amount of movement of the heater, and always sets the heater slightly above the object to be heated, regardless of the position of the object to be heated, allowing for appropriate finish control. It has excellent effects such as improving operability and cooking performance.

[Brief explanation of drawings]

Fig. 1 is a front view showing a schematic structure of a microwave oven which is an embodiment of the present invention, Fig. 2 is a plan view thereof, Fig. 3 is a diagram showing the configuration of a control device, Figs. 4a and 5. Fig. 4a is a schematic diagram of when the object to be heated is actually put on the cooking grid and operated, Fig. 4b and Fig. 5b are diagrams showing the output of the transistor at that time, and Fig. 6a is the object to be heated. Fig. 6b is a diagram showing the output of the transistor at that time, and Fig. 7a is a sectional view when the object to be heated is placed around the mounting plate. , Fig. 7b is a diagram showing the output of the transistor at that time, Fig. 8 is a control flowchart, Fig. 9 is also an operation explanatory diagram, and Fig. 1
FIG. 0 is a schematic front view of a conventional microwave oven. 1: Heater, 2: Adjustment drive device, 3: Placement plate,
5: heating chamber, 7: object to be heated, 8: rotating shaft, 9: rotational drive device, 10: control device, 11: position detection sensor.

Claims (1)

[Claims] 1. A heater is rotatably installed in the heating chamber, and the heating height of the heater is adjustable by having its heat generating part eccentrically arranged with respect to the rotation axis, and the height of the heater is adjusted. In the heating device, the heating chamber is provided with an adjustment drive device for placing an object to be heated in the heating chamber. A rotation drive device is provided, a control device for controlling the adjustment drive device and the rotation drive device is provided, and a position detection sensor for detecting the height position and placement position of the object to be heated in the heating chamber is installed in the heating chamber. A plurality of units are arranged vertically on the wall, and the control device drives the rotary drive device to rotate the mounting plate by 180 degrees or more, and adjusts the height of the object to be heated based on temporal changes in the output signal of the position detection sensor. 1. A heater having a function of detecting a position and a mounting position and outputting a signal for controlling the adjustment drive device.