JPH06241470A - High-frequency heating device - Google Patents

Abstract

PURPOSE:To miniaturize and reduce the weight of the title device by shallowing the depth of a choke groove formed along the whole periphery of the circumference of a door. CONSTITUTION:A conductive member 5, covering the opening section of a groove 3b provided along the whole periphery of the peripheral rim section of a door 1, formed between an inside plate 2d in the L-shape bent section 2a of a door frame 2 and the side peripheral piece 3a of a door cover 3, is provided. A supporting piece 5c, having a hight arriving at the bottom of the groove 3b and continued along the whole periphery of the peripheral rim section of the door 1, is provided at one side of the width direction of the conductive member 5.

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 for a microwave oven or the like, which is capable of preventing electric wave leakage from the peripheral portion of a rectangular door provided at the opening of a heating chamber.

[0002]

2. Description of the Related Art FIG. 4 is a partial sectional view showing a peripheral portion of a heating chamber door in a conventional microwave oven, in which 31 is a door and 32 is a door.
Is a door frame, and 33 is a door cover. The door 31 is formed in a rectangular shape in conformity with a rectangular opening in the front surface of a heating chamber of a microwave oven (not shown), and is pivotally supported by a body frame (not shown) around the opening so as to open laterally or upward.

The door frame 32 is formed of punching metal 32a at its center, and its peripheral portion is surrounded by a front plate 32b and an outer plate 32a.
The c-side inner plate 32d is formed with an L-shaped bent portion 32a having an L-shaped cross section that bulges outward. The door cover 33 is provided with a side peripheral plate 33a formed by bending the door cover 33 at a right angle, and the door frame 32 is positioned inside the side peripheral plate 33a and integrally formed with the side peripheral plate 33a. Fixed, this side plate
A groove 33b is formed over the entire circumference of the door 31 between 33a and the inner plate 32d of the L-shaped bent portion 32a. And the door frame 32
Along the inside of the front plate 32b of the L-shaped bent portion 32a of the
A periodic structure 34 (only one is shown in the drawing) is attached so as to extend over substantially the entire length of each side of 31.

In the periodic structure 34, one side of an elongated rectangular fixed piece 34a is bent at a right angle to form a rising piece 34b,
The rising piece 34b is formed by alternately forming U-shaped metal portions and slit portions along the longitudinal direction. Each U-shaped metal part is configured such that the upper end of the rising piece 34b is parallel to the fixing piece 34a and is bent to the opposite side to form a covering piece 34e, and has a U-shaped cross section as a whole. There is. On the other hand, in the slit portion, this is cut off at a position about 1/3 the height of the rising piece 34b.

In such a periodic structure 34, a cover piece 34e is provided in the inner plate of the L-shaped bent portion 32a at the center of the inner surface of the front plate 32b constituting the L-shaped bent portion 32a of the door frame 32 in the width direction. The fixing piece 34a is integrally fixed to the front plate 32b by spot welding while facing the 32d and with a predetermined gap therebetween, and is electrically connected to the fixing piece 34a. is there.

The side peripheral plate 33a of the door cover 33 and the door frame
Dielectric member covering the opening between 32 and inner plate 32d
35 is provided all around the periphery of the door 31. The dielectric member 35 is formed by bending one side in the width direction of the elongated plate-shaped main body portion 35a covering the opening at a right angle to form a bent piece 35b, and is formed on the covering piece 34e of the periodic structure 34. Body part 35a
And the bent piece 35b is attached to the opening in such a manner that the bent piece 35b extends along the inside of the side peripheral plate 33a of the door cover 33. The bent pieces 35a are provided with holes 35c at appropriate intervals.
The dielectric member 35 is fixed to the door cover 33 so as not to come off by engaging the locking claw 33c provided on the side peripheral plate 33a of the door cover 33 with the door 35c.

In such a conventional microwave oven, a front plate 32b and an outer plate 32c which form the L-shaped bent portion 32a of the door frame 32.
And a space A surrounded by the U-shaped metal portion 34c in the periodic structure 34 is formed, and the electric wave propagating to the peripheral portion of the door 31 is confined and attenuated to prevent leakage to the outside. There is.

[0008]

By the way, in such a conventional door 31, there is no particular inconvenience in the radio wave confining function, but there is a problem that the dielectric member 35 is easily detached. Further, when it is attempted to reduce the size and weight of the whole while keeping the volume of the heating chamber as it is in recent years, it is required to make the door 31 thin. However, in order to efficiently attenuate the radio waves traveling to the peripheral portion of the door 31 in the space A in the U-shaped metal portion, it is necessary to appropriately determine the U-shaped metal portion, the length of the slit portion, and the overhanging width of the cover piece 34e. Of course, there is a close relationship with the depth of the space A, for example, the door 31.
If the thickness of the choke groove is made thinner and the depth of the choke groove is made shallower than 1/4 wavelength of the radio wave of frequency 2450MHz, there is a problem that sufficient attenuation effect is not obtained and it causes radio wave leakage.

The present invention has been made in view of the above circumstances, and an object thereof is to make it possible to reduce the door thickness without sacrificing the radio wave attenuation effect in the U-shaped metal portion. In order to provide a high-frequency heating device according to the present invention.

[0010]

A high frequency heating apparatus according to the present invention is provided with a choke groove along the periphery of a rectangular door provided in an opening of a heating chamber, and a choke corresponding to each side of the door. In each of the grooves, a periodic structure in which a U-shaped metal portion having a U-shaped cross section with respect to the longitudinal direction and a slit portion are alternately formed, and the opening side of the U-shaped metal section in the U-shaped metal portion is located at the central portion side of the door. In a high frequency heating device in which a dielectric member is fixed in such a manner that the dielectric member is fixed toward the opening of the choke groove and the dielectric member is fixed to the opening of the choke groove. A support piece having a height in contact with the groove bottom of the choke groove is continuously provided along the inner wall of the door over the entire circumference of the peripheral portion of the door.

[0011]

According to the present invention, by arranging the supporting piece of the dielectric member in the choke groove at the peripheral edge of the door over the entire circumference, the same effect as deepening the choke groove can be obtained. The choke groove has a small depth, in other words, the door can be made thin.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings showing the embodiments thereof. FIG. 1 is a sectional view showing a peripheral portion of a door in a high-frequency heating apparatus according to the present invention, in which 1 is a door, 2 is a door frame of the door 1, 3 is a door cover, 4 is a periodic structure,
Reference numeral 5 indicates a dielectric member. The door 1 is formed in a rectangular shape in conformity with a rectangular opening on the front surface of the heating chamber of the apparatus main body (not shown), and is attached to the apparatus main body so that it can be opened and closed in an upward opening type or a lateral opening type.

The door frame 2 is similar to the conventional door frame shown in FIG.
Front plate by bending the peripheral edge into an L-shaped section that bulges to the front side
An L-shaped bent portion 2a composed of b, the outer side plate 2c and the inner side plate 2d is formed, and the central portion is connected to the punching metal 2e.
The door cover 3 is bent along its entire circumference at a right angle to form a side peripheral piece 3a. An L-shaped bent portion 2a is provided inside the side peripheral piece 3a, and a front plate 2b is provided. The door frame 2 is integrally fixed with the door cover 3 in contact with the door cover 3, whereby a groove extending over the entire circumference of the door 1 is provided between the side peripheral piece 3a and the inner side plate 2d of the L-shaped bent portion 2a. 3b is formed. The periodic structure 4 (only one is shown in the drawing) is fixed to the inner surface of the front plate 2b of the L-shaped bent portion 2a corresponding to each side of the door 1 in the groove 3b.

FIG. 2 is a perspective view of the periodic structure 4. In the periodic structure 4, one side of the fixed piece 4a is vertically raised to form a rising piece 4b, and the U-shaped metal portion 4c and the slit portion 4d are alternately arranged on the rising piece 4b so as to extend over the entire length in the longitudinal direction. It is formed and configured. As shown in FIG. 2, each U-shaped metal portion 4c is formed by bending the upper end of the rising piece 4b toward the same side as the fixing piece 4a and bending it in parallel to form a covering piece 4e. It is configured to have a letter shape. On the other hand, in the slit portion 4d, the rising piece 4b is cut off at a side higher than the position approximately 1/3 of the entire height.

Such a periodic structure 4 has an L-shaped bent portion 2a.
At the center of the front plate 2b in the width direction, the cover piece 4e is directed toward the inner plate 2d side of the L-shaped bent portion 2a, and is arranged at a predetermined distance from the cover piece 4e, and the fixing piece 4a is provided. The front plate 2b is integrally fixed to the front plate 2b by spot welding and is electrically connected to the front plate 2b. As a result, a space B surrounded by the L-shaped bent portion 2a and the periodic structure 4 is formed, and the radio waves traveling to the peripheral portion of the door 1 are confined and attenuated therein.

Regarding the length X of the U-shaped metal portion 4c, the length Y of the slit portion 4d, and the width Z of the cover piece 4e in the periodic structure 4 shown in FIG. 2, a radio wave propagating along the opening of the heating chamber ( For example, it may be set appropriately so that (2450 MHz) can be effectively attenuated. At the opening of the groove 3b between the side peripheral piece 3a of the door cover 3 and the inner side plate 2d of the L-shaped bent portion 2a of the door frame 2,
Dielectric member 5 is installed in such a manner that it covers the entire circumference of door 1.

FIG. 3 is a perspective view of the dielectric member 5. The dielectric member 5 is formed by bending one end in the width direction of the main body portion 5a covering the opening of the groove 3b at a right angle to form a short bending piece 5b. Further, the other end is also bent to the same side to continuously form the support pieces 5c each having a length reaching the inner surface of the door frame 2 over the entire length of the main body portion 5a, in other words, the entire circumference of the door 1. There is. The bent piece
Holes 5d are opened in the body portion 5a at a predetermined interval in the longitudinal direction of the main body portion 5a, and when the dielectric member 5 is mounted in the opening portion of the groove 3b, it is provided so as to project on the inner surface of the side peripheral piece 3a of the door cover 3. The locking claw 3c is adapted to engage with this.

The dielectric member 5 has a main body portion 5a.
Is brought into contact with the upper surface of the cover piece 4e of the periodic structure 4, the bending piece 5b is inside the side peripheral piece 3a of the door cover 3, and the supporting piece 5c is inside the inner plate 2d of the L-shaped bent portion 2a. The dielectric members 5 are positioned so as to be in contact with each other, and the locking claws 3c are engaged with the holes 5d of the bent pieces 5b to prevent the dielectric member 5 from slipping off and being fixed in the grooves 3b. Although not shown in the drawing, the thickness of the support piece 5c of the dielectric member 5 located in the corner of the door 1 and in the vicinity of the corner is thicker than the thickness d at the peripheral portion, and has a damping effect on radio waves. Is designed to be large.

In such an embodiment, the dielectric member 5, especially the supporting piece 5c thereof, effectively attenuates the radio wave traveling to the peripheral portion of the door 1, so that the periodic structure 4 and L are formed.
The same damping effect can be obtained as when the depth h of the space B formed between the bent portion 2a and the character-shaped bent portion 2a is substantially lengthened. That is, the depth h of the space B is 1/1 of the frequency of 2450MHz
Even if the wavelength is substantially shorter than 4 wavelengths, the same attenuation effect as if the substantial depth h is set to 1/4 wavelength by continuously providing the supporting piece 5c of the dielectric member 5 over the entire circumference of the door 1. Will be obtained.

[0020]

As described above, in the high frequency heating apparatus according to the present invention, the dielectric member is provided with the supporting piece having a length in contact with the groove bottom along the side wall forming the choke groove over the entire circumference of the door. Since it is provided in the present invention, even if the choke groove is shallow, a large attenuation effect on radio waves can be obtained, and the door itself can be made thinner accordingly, and the door itself can be further reduced in size and weight. Play.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view showing a peripheral portion of a door provided at an opening in front of a heating chamber of a high-frequency heating device according to the present invention.

FIG. 2 is a perspective view of the periodic structure shown in FIG.

FIG. 3 is a perspective view of the dielectric member shown in FIG.

FIG. 4 is a partial sectional view showing a peripheral portion of a door of another conventional microwave oven.

[Explanation of symbols]

 1 Door 2 Door frame 2a L-shaped bent portion 3 Door cover 3a Side peripheral piece 3b Groove 3c Locking claw 4 Periodic structure 4a Fixed piece 4b Start-up piece 4c U-shaped metal part 4d Slit part 4e Cover piece 5 Dielectric member 5a Body part 5b Bent piece 5c Support piece 5d Hole

Claims (1)

[Claims] 1. A choke groove is provided along the periphery of a rectangular door provided in an opening of a heating chamber, and each choke groove corresponding to each side of the door has a U-shaped cross section in the longitudinal direction. A periodic structure in which a U-shaped metal portion and a slit portion are alternately formed is fixed so that the opening side of the U-shaped metal portion having a U-shaped cross section faces toward the central portion side of the door, and the opening portion of the choke groove. In a high-frequency heating device in which a dielectric member is fixed so as to close it, the dielectric member is in contact with the groove bottom of the choke groove along an inner wall forming a choke groove in a main body portion covering the opening of the choke groove. A high-frequency heating device, characterized in that a supporting piece of height is continuously provided over the entire circumference of the peripheral part of the door.