JPH04245192A - High frequency heater - Google Patents

Abstract

PURPOSE:To elevate the oven heating efficiently and make the heating strength of an oven selectivity and stabilize the microwave oscillating operation of a magnetron when heating by heater the oven and microwaves is performed at the same time. CONSTITUTION:This has a table 4, which is provided capably in vertical motion inside a heating chamber 1 so as to place heating load 10, a lifer 16, which raises and lowers the table 4, an oven heater 3, which is attached to the upper part of the heating chamber 1, a wave guide 7, which introduce the microwaves generated by a magnetron 2 into the heating chamber 1, a stub 12, which is attached capably in adjustment of insertion depth and position to the waveguide 7, and adjusting mechanism 13, 14, and 15, which adjust the insertion depth and the position of the stub 12 inside the waveguide 7.

Description

[Detailed description of the invention]

[Object of the invention]

0002

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-frequency heating device for dielectric heating, and more particularly to a high-frequency heating device capable of simultaneously performing microwave heating and oven heating.

0003

[Prior Art] High-frequency heating devices have been proposed from single-function types that only perform microwave heating, to multi-function types that have an electric heating device such as an oven heater built into the refrigerator, and which can heat microwaves and ovens simultaneously. It has become possible to cook food faster and more precisely.

FIGS. 10 and 11 show such a conventional high frequency heating device. In these figures, power from a commercial power supply is converted into power necessary to drive the magnetron 2 by a power supply circuit 9 including a high voltage transformer 8. The microwave oscillated from the magnetron 2 passes through the waveguide 7
is radiated into the oven chamber 1, which is the heating chamber, through the RT
A heating load 10 on a turntable 4 rotating at low speed is dielectrically heated by a motor 11. The stub 12 in the waveguide 7 is adjusted so that the reflected power from the heating load 10 side is minimized, that is, the standing wave ratio of the radio wave is adjusted to be as close to 1 as possible in a well-balanced manner for various heating loads. After that it has been fixed. This stabilizes the oscillation of the magnetron 2. The cooling fan 5 cools the magnetron 2 and the high voltage transformer 8 in combination with the duct 6. Reference numeral 3 denotes an oven heater for heating the oven, which is provided at the upper part of the oven interior 1.

[0005] With this configuration, by heating the surface of the food using the oven heater 3 and simultaneously heating the inside of the food using microwave heating, a variety of detailed cooking methods are realized.

However, such conventional high frequency heating devices have the following problems.

[0007] Since the distance from the oven heater 3 to the turntable 4 is long, the heating efficiency from the oven heater 3 is poor. In order to improve this problem, it has been considered to lower the position of the oven heater 3. In this method, even if the position of the oven heater 3 is changed, the impedance inside the oven chamber 1 is hardly affected, and even if the stub 12 is fixed, the oscillation of the magnetron 2 is stable. However, since the movement mechanism of the oven heater 3 is attached to the oven side plate, radio waves may leak through the large diameter slot required for movement, and if the movement is repeated many times, the heater surface that contacts the oven side plate may be scraped. , there is a problem that electric field concentration tends to occur there.

On the other hand, instead of lowering the position of the oven heater 3, a method can be considered to raise the position of the turntable 4. However, this method causes a large change in oven impedance, which increases the standing wave ratio and reduces the microwave output radiated into the oven interior 1.
Depending on the heating load 10, the magnetron 2 is likely to cause unstable oscillations such as moding. If moding or the like occurs, the life of the magnetron 2 will be significantly shortened. For this reason,
When performing simultaneous heating using oven and microwave, it is difficult to raise the position of turntable 4.

[0009]

[Problems to be Solved by the Invention] In the conventional high-frequency heating device, when performing simultaneous heating using oven and microwave, it is difficult to raise the position of the turntable 4 because the magnetron tends to cause unstable oscillation. For this reason, the oven heating efficiency was poor and a satisfactory oven heating intensity could not be obtained.

[0010] Therefore, the present invention provides a high-frequency heating device that improves oven heating efficiency, provides selectivity to oven heating intensity, and provides stable microwave oscillation when performing simultaneous heating using oven and microwave. The purpose is to provide

[Configuration of the invention]

0012

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention includes a heating chamber, a table provided vertically movably in the heating chamber and on which a heating load is placed, and a table for raising and lowering the table. an oven heater attached to the upper part of the heating chamber; a magnetron that generates microwaves; a waveguide that guides the microwaves generated by the magnetron to the heating chamber; and an insertion depth into the waveguide. The gist of the present invention is to include a stub attached to the waveguide so that its depth and position can be adjusted, and an adjustment mechanism that adjusts the insertion depth and position of the stub within the waveguide.

[0013]

[Operation] When heating the oven and microwave simultaneously, the table is raised by the elevating mechanism to bring the heating load closer to the oven heater, increasing oven heating efficiency. By approaching the table stepwise or continuously, it is possible to provide selectivity to the heating intensity of the oven. At the same time, the adjustment mechanism adjusts the stub to a preset optimal insertion depth and position into the waveguide according to the height of the table. This allows stable microwave oscillation to be obtained from the magnetron.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the drawings.

1 to 3 are diagrams showing a first embodiment of the present invention.

In FIGS. 1, 2, and the figures showing the second and third embodiments described later, the same or equivalent parts as those in FIGS. 10 and 11 are designated by the same reference numerals. , and redundant explanation will be omitted.

In FIGS. 1 and 2, reference numeral 12 denotes a long transmission shaft that serves as a lifting mechanism for raising and lowering the turntable 4.
It is used when increasing the heating intensity from the oven heater 3. That is, this is assembled into the shaft of the RT motor 11 and the turntable 4 is raised to the position A in FIG.
The heating load 10 is brought close to the oven heater 3. 13 is a transmission bar; 14 is a stepping motor for driving and adjusting the stub 12 to a position parallel to the tube axis within the waveguide 7; 15;
is a stepping motor for driving and adjusting the stub 12 in the depth direction within the waveguide 7. These transmission bars 13
And by both stepping motors 14 and 15, the waveguide 7
An adjustment mechanism is configured to adjust the insertion depth and position of the stub 12 within. If it is determined that the long transmission shaft 16 is to be used, the stub 12 is controlled to the position a in FIG. 2 by the adjustment mechanism. Note that the position a is set in advance so that the microwave heating is most optimal when the height of the turntable 4 is A.

Next, the operation of the high frequency heating device constructed as described above will be explained using the flowchart shown in FIG.

When the user selects simultaneous oven and microwave heating on the operation panel (step 31), an instruction appears asking whether to use the long transmission shaft (step 32).
). If NO here, the heating load 10 is placed in the oven chamber 1, the heating time is set, and the heating is started (step 33). If YES, the stub 12 is moved to position a by the adjustment mechanisms 13, 14, and 15, and the user is notified of the completion of the movement (step 34). And the long transmission shaft 16
is assembled into the shaft of the RT motor 11, the turntable 4 is raised to the position A, the heating load 10 is placed on the turntable 4, the heating time is set, and the heating time is started. By the above operations, it is possible to increase the oven heating efficiency during simultaneous heating using oven and microwave, and at the same time obtain stable microwave oscillation.

Next, FIGS. 4 to 6 show a second embodiment of the present invention.

In FIGS. 4 and 5, reference numeral 17 is an RT motor having a long transmission shaft, and when this motor is moved up and down, the position of the turntable 4 is changed upward or downward. 1
8 is a high torque motor, 19 is a support rod, 20 is a column, 21
is a spring and is in its natural state when the turntable 4 is in the standard position. In this embodiment, the high torque motor 18, the support rod 19, the column 20, and the spring 21 constitute a lifting mechanism. This elevating mechanism allows the height of the turntable 4 to be changed to three levels: the top level A, the middle level B, and the standard position, thereby providing selectivity to the heating intensity of the oven. That is, A is strong, B is medium, and the standard position is weak. The stub 12 is controlled by an adjustment mechanism in conjunction with each height of the turntable 4, as shown in FIG. The positions a and b in this case are also set in advance as described above.

Next, the operation of the above-mentioned high frequency heating device will be explained using the flowchart shown in FIG.

[0023] When the user selects simultaneous oven and microwave heating on the operation panel (step 41), the user is prompted to ``raise the height of the table'' (step 42).
. If NO here, put the heating load 10 into the oven chamber 1, set the heating time, and start it (Step 4
6). If YES, an instruction is issued asking whether to set the height of the table to A (step 43). If YES, the turntable 1 will be raised to the position A by the lifting mechanisms 18, 19, 20, 21, and the stub 12 will also be raised by the adjustment mechanisms 13, 14, 15.
is adjusted to the position a (step 44). If NO, the positions are adjusted to B and b, respectively (step 45).
). After informing the user that the adjustment has been completed, the user places the heating load 10 into the oven interior 1, sets the heating time, and starts the heating (step 46). Through the above operations, it is possible to improve the heating efficiency of the oven, adjust the oven heating intensity in stages by adjusting the height of the turntable 4, and at the same time obtain stable microwave oscillation.

7 to 9 show a third embodiment of the present invention.

In FIGS. 7 and 8, reference numeral 22 denotes a red semiconductor laser unit with good directivity, from which red light emitted horizontally is monitored by a light detection unit 23 such as a photodiode. The red light from the laser unit 22 passes over the center of the turntable 4, and the laser unit 22 and the light detection unit 23 are both movable in the vertical direction in conjunction with each other.
23 constitutes a surface position detection system that detects the surface of the heating load 10. Both stepping motors 14,1
5 and the high torque motor 18 have finer steps than those of the second embodiment. In the high-frequency heating device of this embodiment, the optimal height of the turntable 4 is selected based on the heating load 10 conditions input by the user into a control unit such as a microcomputer (not shown), and automatic cooking is performed.

Next, the operation of the above-mentioned high-frequency heating device will be explained using the flowchart shown in FIG.

[0027] The user selects simultaneous oven and microwave heating on the operation panel (step 51), and heats load 1.
0 on the turntable 4, and input conditions such as the type and weight of the heating load 10 (step 52). From this, the stub 12 control set in advance for each heating load condition is selected (step 53). That is, a locus of the optimal stub 12 position on the waveguide that differs for each heating load condition is selected. Next, an instruction appears asking "Do you want to use automatic cooking?" (step 54). If NO here, a further instruction is given asking whether to change the height of the table (step 55). NO
If so, select the microwave strength, set the heating time, and start (step 57). If YES, the turntable 4 is manually moved to a position desired by the user (step 56). The rest is the same as in the case of NO. If the selection in step 54 is YES, the surface position, microwave strength, and heating time of the heating load 10 set in advance are selected based on the heating load conditions (step 58), and the surface position detection systems 22 and 23 of the heating load are selected. The system is moved to the position A in FIG. 8, and the systems 22 and 23 are turned on (step 59). Next, the turntable 4 is gradually raised and stopped at the moment when the laser beam is no longer detected by the heating load 10 (step 60). During this time, the turntable 4 is rotated so that the above effect can be obtained regardless of the position of the heating load 10. After this, the surface position detection system 22
, 23 and start heating (step 61
). The above operations improve the heating efficiency of the oven, and by continuously changing the height of the turntable 4, the oven heating intensity can be continuously adjusted, and at the same time it becomes possible to obtain stable microwave oscillation.

[0028]

[Effects of the Invention] As explained above, according to the present invention,
When heating the oven and the microwave simultaneously, the table can be raised by the elevating mechanism to bring the heating load closer to the oven heater, thereby improving oven heating efficiency. Furthermore, the table can be changed stepwise or continuously, allowing for selectivity in the oven heating intensity. Furthermore, the adjustment mechanism allows the stub to be adjusted to the optimum insertion depth and position within the waveguide in accordance with the height position control of the table, thereby stabilizing the microwave oscillation operation of the magnetron.

[Brief explanation of the drawing]

FIG. 1 is a front view of the internal configuration of a first embodiment of a high-frequency heating device according to the present invention.

FIG. 2 is a side view of the internal configuration of the high-frequency heating device shown in FIG. 1;

FIG. 3 is a flowchart for explaining the operation of the first embodiment.

FIG. 4 is a front view of the internal configuration of a second embodiment of the present invention.

FIG. 5 is a side view of the internal configuration of the high-frequency heating device shown in FIG. 4;

FIG. 6 is a flowchart for explaining the operation of the second embodiment.

FIG. 7 is a front view of the internal configuration of a third embodiment of the present invention.

8 is a side view of the internal configuration of the high-frequency heating device shown in FIG. 7. FIG.

FIG. 9 is a flowchart for explaining the operation of the third embodiment.

FIG. 10 is a front view of the internal configuration of a conventional high-frequency heating device.

11 is a side view of the internal configuration of the high-frequency heating device of FIG. 10. FIG.

[Explanation of symbols]

1 Oven interior (heating chamber) 2 Magnetron 3 Oven heater 4 Turntable 7 Waveguide 10 Heating load 12 Stub 13 Transmission bar 14 Stepping motor 15 that constitutes an adjustment mechanism together with the transmission bar Stepping motor that constitutes an adjustment mechanism together with the transmission bar 16 Long transmission shaft 18 that becomes the lifting mechanism High torque motor 19 Support rod 20 Pillar 21 Spring that constitutes the lifting mechanism together with the high torque motor, support rod and pillar

Claims (1)

[Claims] 1. A heating chamber, a table provided vertically movably in the heating chamber and on which a heating load is placed, a lifting mechanism for raising and lowering the table, and an oven heater attached to the upper part of the heating chamber. a magnetron that generates microwaves, a waveguide that guides the microwaves generated by the magnetron to the heating chamber, a stub that is attached to the waveguide so that its insertion depth and position can be adjusted, and the waveguide. A high-frequency heating device comprising: an adjustment mechanism that adjusts the insertion depth and position of the stub in a pipe.