JPH04267095A - Heater - Google Patents

Abstract

PURPOSE:To sufficiently attenuate a high frequency leaked in the vicinity of a heater by disposing partition plates having reflectiveness in positions separated by 1/4 wavelength of a high frequency radiated from a high frequency heat source, inside a reflection plate. CONSTITUTION:A plurality of holes 7 are bored in the central portion of a top plate 6 of a heating chamber 1. A portion of the top plate 6 having the bored holes 7 and a heat radiating portion of an upper heater 5 are covered with a metal reflection plate 8, which reflects an infrared ray radiated from the upper heater 5 toward the heating chamber 1. In positions corresponding to 1/4 wavelength of a high frequency beyond the lower ends of both side plates of the reflection plate 8, partition plates 81 having the same shape as those of the side plates are formed integrally with the reflection plate 8 and parallel to the side plates. A part of the high frequency leaked from the heating chamber 1 is leaked outward through the partition plates 81. Meanwhile, the high frequency leaked between the partition plates 81 and the side plates of the reflection plate 8 is canceled by the high frequency having an opposite phase reflected by the side plates separated by 1/4 wavelength from the partition plates 81, thus minimizing leakage of an electric wave.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high frequency heating device having a heater heating function.

0002

2. Description of the Related Art FIG. 6 is a partially exploded sectional view showing the structure of a conventional high-frequency heating device having a heater heating function, disclosed in Japanese Utility Model Application No. 2-4106. In the figure, 1 is a heating chamber, and a turntable 3 on which food 2 to be heated is placed is arranged at the bottom of the heating chamber 1, and a turntable 3 for rotating the turntable 3 is placed below the heating chamber 1. A table motor 4 is provided. Above the heating chamber 1, a heater wire 5 having a diameter considerably smaller than the inner diameter of the tube 51 is placed in an infrared transparent tube 51.
A plurality of upper heaters 5 such as lamp heaters, quartz tube heaters, etc., each of which is inserted into the heater wire 2 and emits infrared rays, are arranged, and the heater wire 52 is held in the tube 51 by a plurality of holding members 53 arranged at appropriate positions. ing. In the center of the top plate 6 of the heating chamber 1, infrared rays emitted by the upper heater 5 pass through, while 245
A plurality of holes 7 with a diameter of 3.0 to 5.0 mm are provided to keep the leakage amount of 0 MHz microwaves within legal standards. The region of the top plate 6 in which the hole 7 is provided and the heat dissipation part of the upper heater 5 are covered with a reflector plate 8, and the reflector plate 8 reflects infrared rays emitted by the upper heater 7 toward the heating chamber 1. A plate 10 made of ultra-heat-resistant crystallized glass that easily transmits infrared rays is attached to the lower surface of the area where the hole 7 is provided by a metal frame 11. Further, on the side of the heating chamber 1, an operation panel 9 is provided, which includes heating time, heating temperature, heating type settings, start/stop switches, and a display section that displays the elapsed time and setting contents. There is a built-in microcomputer in the back that controls heating time, heating temperature, etc. according to setting data.

[0003]Heating operation by the heating device configured as above will be explained. When the heating time, heating temperature, heating type, etc. are set on the operation panel 9 and the start switch is pressed,
A turntable 3 on which food 2 is placed rotates. When heater heating is set, the upper heater 5 emits infrared rays,
The reflector plate 8 reflects the infrared rays radiated upward toward the heating chamber 1, and the reflected infrared rays and the infrared rays radiated downward pass through the hole 7 in the top plate 6 and pass through the plate 10 to the food 2.
and the food 2 is heated. Furthermore, when high-frequency heating is set, the microwaves emitted from the high-frequency heat source into the heating chamber 1 are reflected by the inner wall of the heating chamber 1 and
It is scattered inside and absorbed into the food 2, and the food 2 is heated. Microwaves leaking from the holes 7 in the top plate 6 are attenuated by the holes 7.

FIG. 7 is a partially exploded perspective view of the main parts of a conventional high-frequency heating device. Both ends of the two upper heaters 5 , 5 protrude to the outside from holes provided in a side plate 82 of the reflecting plate 8 , and the reflecting plate 8 and the top plate 6 are fastened together with screws 13 . FIG. 8 is an enlarged sectional view of the fastening portion. The top plate 6 is welded to a cavity main body 12 forming the heating chamber 1, and the top plate 6, the cavity main body 12, and the reflection plate 8 are fastened with screws 13.

[0005]

[Problems to be Solved by the Invention] In order to increase the thermal efficiency of the upper heater in the high-frequency heating device configured as described above, it is necessary to
It is better to increase the diameter of the hole 7 provided in the hole 7. However, if the diameter of the hole 7 is increased, high frequency waves will leak. Therefore,
The hole diameter that satisfies both improvements in thermal efficiency and prevention of high-frequency leakage is the maximum hole diameter (approximately 5.0 mm) that can maintain the amount of high-frequency leakage within the legal standard, but this hole diameter does not allow leakage. High frequency attenuation is not perfect, 1~2mW/cm2
High frequencies leak.

[0006] Also, the high frequency waves leaked from the hole 7 of the top plate 6 are transmitted to the side plate 8 of the reflector plate 8 through which the upper heater 5 is inserted and held.
It further leaks to the outside through the hole No. 2 and the heater wire 52 of the upper heater 5. Therefore, in a heating device equipped with a microcomputer, there is a risk that the microcomputer may malfunction due to the influence of leaked high frequency waves, leading to an accident.

Furthermore, since there is a trend toward lower product prices by using thinner materials, for example, as shown in FIG. It must be fastened using the incompletely threaded portion 13c in which no thread is formed. Therefore, the threaded shaft portion 13b does not come into contact with the thread groove, and the screw 13 is rendered useless. Furthermore, if the screw is stopped at a position where the thread is in contact with the thread groove, the tightening torque will be insufficient, and the parts will not be fastened together enough, causing high frequency waves to leak to the outside of the heating chamber.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a heating device that can sufficiently attenuate high frequency waves leaking into the vicinity of the upper heater to prevent accidents from occurring.

[0009]

[Means for Solving the Problems] A heating device according to a first aspect of the present invention has a high frequency heat source and a heater arranged outside a heating chamber in which an article is stored, and heats the side where the heater is arranged. A reflecting plate is provided that covers a plurality of through holes drilled in the wall of the chamber and the heat radiation portion of the heater to reflect radiant heat from the heater toward the heating chamber, and both ends of the heater are connected to the reflecting plate. In a heating device that projects outward from a side wall surface, 1/1/2 of the high frequency wavelength that the high frequency heat source radiates from the side wall surface of the reflecting plate into the space formed by the reflector and the wall surface of the heating chamber. The present invention is characterized in that a reflective partition plate is provided substantially parallel to the side wall surface of the reflector to partition the space, at a position spaced apart by a distance equivalent to 4 times. Further, in the heating device according to the second aspect of the present invention, a high frequency heat source and a heater are arranged outside the heating chamber in which the article is stored, and a high frequency heat source and a heater are provided in the wall surface of the heating chamber on the side where the heater is arranged. A reflecting plate is provided to cover the plurality of through holes and the heat radiation portion of the heater and reflect radiant heat from the heater toward the heating chamber, and both ends of the heater are made to protrude outside from a side wall surface of the reflecting plate. In the heating device, the heating element of the heater is fixed, and the heating element is arranged substantially perpendicularly to the end of the heating element at intervals corresponding to a length of 1/4 of the high frequency wavelength emitted by the high frequency heat source. It is characterized by comprising a reflective member. Further, in the heating device according to the third aspect of the present invention, a high-frequency heat source and a heater are arranged outside the heating chamber in which the article is stored, and a high-frequency heat source and a heater are provided on the wall surface of the heating chamber on the side where the heater is arranged. A heating device comprising: a reflecting plate that covers a plurality of through holes and a heat radiation portion of the heater and reflects radiant heat from the heater toward a heating chamber; and the reflecting plate is fastened to the heating chamber with screws. A flange is provided on the periphery of the screw hole into which the screw is screwed, the height being greater than the height of the portion of the screw between the screw head and the screw shaft where no thread is formed. Features.

0010

[Operation] In the heating device according to the first aspect of the present invention, the high frequency waves leaking from the heating chamber through the hole to the vicinity of the heater are partially prevented from leaking by the partition plate, and are separated from the hole holding the heater by the partition plate. The high frequency waves leaking to the outside of the plate cancel out the high frequency waves of the opposite phase reflected by the side plate of the reflector plate, which is separated by a length equivalent to 1/4 of the wavelength of the high frequency wave, and finally the high frequency waves leaking to the outside of the reflector plate are sufficiently attenuated. Therefore, it does not cause malfunction of the microcomputer, for example. Further, in the heating device according to the second aspect of the present invention, the member provided to grip the heating element of the heater is formed of a reflective material, and the heating element is arranged at intervals equivalent to 1/4 of the high frequency emitted by the high frequency heat source. arrangement,
The high frequency waves leaking through the heating element are partially reflected and attenuated by this member, and finally the high frequency waves leaking to the outside of the reflecting plate are sufficiently attenuated so that, for example, a microcomputer does not malfunction. Further, in the heating device according to the third aspect of the present invention, when the reflection plate is fastened to the wall surface of the heating chamber with screws, the flange provided at the periphery of the screw hole prevents the screw thread from being formed near the screw head. The fully threaded portion stops above the screw hole, and the shaft portion of the screw on which the thread is formed comes into contact with the thread groove portion of the screw hole. The screw head is pressed against the end of the flange to provide sufficient tightening torque.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained below based on drawings showing embodiments thereof. FIG. 1 is a partially fragmented sectional view showing the configuration of a high-frequency heating device having a heater heating function according to the present invention, and FIG.
is an exploded view of its main parts. In the figure, 1 is a heating chamber, and a turntable 3 on which food 2 to be heated is placed is arranged at the bottom of the heating chamber 1, and a turntable 3 for rotating the turntable 3 is placed below the heating chamber 1. A table motor 4 is provided. Above the heating chamber 1, a heater wire 5 having a diameter considerably smaller than the inner diameter of the tube 51 is placed in an infrared transparent tube 51.
A plurality of upper heaters 5 such as lamp heaters, quartz tube heaters, etc., each of which is inserted into the heater wire 2 and emits infrared rays, are arranged, and the heater wire 52 is held in the tube 51 by a plurality of holding members 53 arranged at appropriate positions. ing. The top plate 6 of the heating chamber 1 is welded to a cavity main body 12, which has a plurality of small holes on both side walls that transmit microwaves from a high-frequency heat source.
A plurality of holes 7 each having a diameter of 5.0 mm are provided in the center of the top plate 6 to allow infrared rays emitted by the upper heater 5 to pass through while keeping the amount of leakage of 2450 MHz microwaves within legal standards. The region of the top plate 6 in which the hole 7 is provided and the heat dissipation part of the upper heater 5 are covered with a metallic reflector plate 8, and the reflector plate 8 reflects infrared rays emitted by the upper heater 7 toward the heating chamber 1.

[0012] The upper heater 5 is inserted into and held in a hole provided in a side plate on the side surface of the reflector plate 8, and is held at a distance corresponding to 1/4 of the wavelength (λ) of the high frequency from the lower end of both side plates of the reflector plate 8. 3
A partition plate 81 that is formed integrally with the reflection plate 8 and has the same shape and is parallel to the side plate is erected 0 mm inside. Top plate 6
The plurality of holes 7 are provided within a range partitioned by both partition plates 81.

Further, on the side of the heating chamber 1, a heating time,
An operation panel 9 is provided that includes heating temperature, heating type settings, start/stop switches, and a display section that displays time elapsed and settings. Behind the operation panel 9, heating time, heating temperature, etc. are controlled according to the setting data. It has a built-in microcomputer. As mentioned above, in this embodiment, since the partition plate 81 is integrally formed with the reflection plate 8,
The number of parts does not increase.

Table 1 shows the measurement results and average values of the amount of radio wave leakage at each distance when the distance between the reflection plate 8 and the partition plate 81 is changed, and FIG. 3 shows the measurement results for each distance and the radio wave leakage. It is a graph showing the relationship between the amount and the average value. From Table 1 and the graph, the distance between the reflector 8 and the partition plate 81 is 3
It is clear that the amount of radio wave leakage is the smallest when the distance is 0 mm (equivalent to 1/4 of the high frequency wavelength emitted by the high frequency heat source).

[0015]

[Table 1]

The high frequency waves leaked from the heating chamber 1 are removed by the partition plate 8.
1 suppresses leakage to the outside to some extent, but some of it leaks to the outside from the partition plate 81. However, the partition plate 81
Since the high frequency waves leaking between the side plate and the side plate of the reflecting plate 8 cancel out the high frequency wave of the opposite phase reflected by the side plate 1/4λ away from the partition plate 81, the partition plate 81 is provided at a distance equivalent to 1/4λ. Radio wave leakage is minimized when That is, a choke structure is formed between the side plate of the reflector plate 8 and the partition plate 81, and the high frequency waves that eventually leak to the outside from the hole for holding the upper heater 5 provided in the side plate of the reflector plate 8 cause a malfunction of the microcomputer. It is attenuated to the extent that it does not induce

FIG. 4 is a schematic cross-sectional view showing the structure of the upper heater 5 in a second embodiment of the high-frequency heating device according to the present invention. The coiled heater wire 52 is housed in the tube 51, and metal holding members 53 arranged at intervals of 1/4λ hold the heater wire 52, which has a coil diameter considerably smaller than the diameter of the tube 51, into the tube. The heater wire 51 is held at the center of the heater wire 51, and a portion of the high frequency waves leaking through the heater wire 52 is reflected. The leaked high frequency wave cancels out the reflected high frequency wave of opposite phase every 1/4λ, and when it finally exits from the reflection plate 8, it is sufficiently attenuated to the extent that it does not cause malfunction of the microcomputer.

FIG. 5 shows the third example of the high frequency heating device according to the present invention.
FIG. 3 is an enlarged cross-sectional view of the main part of the embodiment. The cavity body 12 is provided with an upward flange 12a on the periphery of the screw hole, which is higher than the thickness of the top plate 6, and the top plate 6 is provided with a screw hole with a diameter slightly larger than the outer diameter of the flange 12a. . The flange 12a is used for positioning the top plate 6 when welding it to the cavity main body 12 and for the reflection plate 8 when screwing it to the top plate 6.
It can also be used for positioning, improving work efficiency. The reflecting plate 8 is a flange 12 provided on the cavity body 12.
It has a screw hole with an inner diameter slightly larger than the outer diameter of a, and an upward flange 8a that is higher than the dimension of the incompletely threaded portion 13c of the screw 13 is provided on the periphery of the screw hole.

In the high-frequency heating device configured as described above, the screw hole becomes deeper than the thickness of the member due to the flange 8a of the reflection plate 8 having a height greater than the dimension of the incompletely threaded portion 13c of the screw 13, so that the shaft portion 13b is brought into sufficient contact with the screw groove, and the end of the flange 8a is pressed against the screw head 13a, so that sufficient tightening torque can be obtained. In this embodiment, the case where the flange is provided facing upward has been described, but even when the flange is provided facing downward, the same effect as in this embodiment can be obtained.

[0020]

[Effects of the Invention] In the heating device according to the first aspect of the present invention, the high-frequency waves leaked from the heating chamber to the outside of the partition plate are separated from the partition plate by a length equivalent to 1/4 of the wavelength of the high-frequency wave emitted by the high-frequency heat source. Since it cancels out the high frequency waves of opposite phase reflected by the side wall surface of the reflector, it has the excellent effect of attenuating the high frequency waves that ultimately leak to the outside from the reflector to the extent that they do not cause malfunctions of the microcomputer. . In the heating device according to the second aspect of the present invention, the high frequency waves leaking from the heating chamber through the heater wires are reflected by the heater wires arranged at intervals of a length equivalent to 1/4 of the wavelength of the high frequency waves emitted by the high frequency heat source. Part of the high frequency wave that is partially reflected by the member, and the reflected high frequency wave with the opposite phase and the high frequency wave that leaks through the heater wire cancel each other out, so that the high frequency wave that ultimately leaks from the reflector to the outside,
This has an excellent effect of being sufficiently attenuated so as not to cause malfunction of the microcomputer. Third aspect of the present invention
The heating device according to the invention makes it possible to bring the threads and thread grooves into contact even when thin members are fastened together by using the flange provided at the periphery of the threaded hole and having a height greater than the dimension of the incompletely threaded part. Furthermore, since the screw head is pressed against the flange end and sufficient tightening torque is obtained, it has the excellent effect of suppressing high frequency leakage from the heating chamber to the outside to the extent that it does not cause malfunction of the microcomputer. .

[Brief explanation of the drawing]

FIG. 1 is a partially exploded cross-sectional view showing the configuration of a first embodiment of a high-frequency heating device according to the present invention.

FIG. 2 is an exploded view showing the configuration of main parts of a first embodiment of the high-frequency heating device according to the present invention.

FIG. 3 is a graph showing the relationship between the position of the partition plate and the leakage microwave intensity.

FIG. 4 is a sectional view of an upper heater in a second embodiment of the high-frequency heating device according to the present invention.

FIG. 5 is an enlarged cross-sectional view of a main part of a third embodiment of the high-frequency heating device according to the present invention.

FIG. 6 is a partially exploded cross-sectional view showing the configuration of a conventional high-frequency heating device.

FIG. 7 is a partially exploded perspective view showing the configuration of a conventional high-frequency heating device.

FIG. 8 is an enlarged sectional view of a main part of a conventional high-frequency heating device.

[Explanation of symbols]

1 Heating chamber 5 Upper heater 6 Top plate 7 Hole 8 Reflector 8a Flange 12a Flange 13 Screw 13a Screw head 13c Incomplete threaded part 51 pipe 52 Heater wire 53 Holding member 81 Partition plate 82 Side plate

Claims (4)

[Claims] Claim 1: A high-frequency heat source and a heater are disposed outside a heating chamber in which an article is stored, and a plurality of through holes are formed in the wall of the heating chamber on the side where the heater is disposed, and In the heating device, a reflecting plate is provided to cover a heat dissipating portion and reflect radiant heat from the heater toward the heating chamber, and both ends of the heater are made to protrude outside from a side wall surface of the reflecting plate, wherein the reflecting plate A reflector for partitioning the space is located at a distance equivalent to 1/4 of the high frequency wavelength radiated by the high frequency heat source inward from the side wall surface of the space formed by the reflector and the wall surface of the heating chamber. A heating device comprising a reflective partition plate provided substantially parallel to the side wall surface. 2. The heating device according to claim 1, wherein the partition plate is arranged outside a region of the wall surface of the heating chamber in which the through hole is provided. 3. A high frequency heat source and a heater are disposed outside a heating chamber in which the article is stored, and a plurality of through holes are formed in the wall of the heating chamber on the side where the heater is disposed, and In the heating device, a reflecting plate is provided to cover a heat radiation part and reflect radiant heat from the heater toward the heating chamber, and both ends of the heater are made to protrude outside from a side wall surface of the reflecting plate. The heating element is fixed, and 1/1 of the high frequency wavelength emitted by the high frequency heat source is directed toward the end of the heating element.
A heating device comprising reflective members arranged substantially perpendicular to the direction at intervals of four equivalent lengths. 4. A high-frequency heat source and a heater are arranged outside the heating chamber in which the article is stored, and a plurality of through holes are formed in the wall of the heating chamber on the side where the heater is arranged, and In the heating device, a reflecting plate is provided that covers a heat radiation part and reflects radiant heat from the heater toward a heating chamber, and the reflecting plate is fastened to the heating chamber with a screw, and the screw is screwed together. 1. A heating device characterized in that a flange is provided on the periphery of a screw hole and has a height greater than the height of a portion of the screw between the screw head and the screw shaft where no thread is formed.