JPH0552350A - Door of high frequency heating device - Google Patents

Abstract

PURPOSE:To make it possible to monitor a heated article in a heating chamber more clearly from the front of a door of a high frequency heating device and find a finished state of the heated article more distinctly. CONSTITUTION:There are installed an illumination lamp 6 which illuminates a heating chamber 4 in a high frequency heating device and a choke section 15a which cuts off radio waves around the heating chamber. There are installed a door frame 15 having an opening shape virtually identical to the front opening section of the heating chamber 4 and a screen 16 comprising a 0.2mm thick-steel plate which is welded to the peripheral edge of the opening section of the door frame 15 from the outside of the hating chamber 4 where 0.7mmsized punch holes are bored at a vertical pitch of 1.86mm and a horizontal pitch of 1.6mm in a zigzag manner and what is more, the front side of the door is projected. This construction makes it possible to embody a door which cuts off the penetration of the radio waves and allows the heated article to be seen more distinctly through a transparent door front section 18 and a thermally sealed glass 19 on the rear side of the screen door 16.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art In recent years, with the advancement of high-frequency heating devices, it is required that the object to be heated can be seen more clearly in order to confirm the quality of the object to be heated from the door surface while heating the object to be heated in the heating chamber. Came.

A conventional example will be described below with reference to FIGS. As shown in FIG. 1, the door 2 of the high-frequency heating device 1 serves to move the object 3 into and out of the heated object 3 and to prevent the radio waves in the heating chamber 4 from leaking to the outside, as shown in FIG.
A radio choke 5a is provided on the outer circumference of the.

The front surface of the door 2 is a lighting lamp 6 for illuminating the inside of the heating chamber 4 so that the object 3 to be heated in the heating chamber 4 can be seen from the front surface.
And the heating chamber 4 through the punch holes 7 in the screen portion provided with a large number of punch holes 7 integrally formed with the door frame 5.
The object 3 to be heated can be seen through the front surface of the door 2 and the leakage of radio waves is prevented.

[0005]

However, in this structure, since the punch hole 7 is made of a steel plate and is integrally formed with the door frame 5 by press working, the strength and the drawing required for the structure of the door frame 5 are reduced. Since it requires processing, the plate thickness needed to exceed a certain limit. Therefore, the diameter and the number of punch holes for processing this steel plate are naturally restricted in relation to the plate thickness. Conventionally, the screen portion is provided with about 30 punch holes / cm ² having a diameter of 1.4 mm. ..
Therefore, due to the material between the punch holes 7 and the insufficient number of punch holes 7, the object to be heated could not be clearly seen even when passing through a large number of punch holes 7, and it was vague.

An object of the present invention is to solve the above-mentioned problems and to provide a door of a high-frequency heating device capable of clearly seeing an object to be heated in a heating chamber of the high-frequency heating device through the front surface of the door.

[0007]

In order to achieve the above-mentioned object, the present invention has an illumination lamp for illuminating a heating chamber, a heating chamber to which radio waves are supplied, and a choke portion for shutting off the radio waves, and a door frame. A screen obtained by performing a convex drawing process on a punching sheet having a large number of openings in a thinner steel plate was welded from the outer surface side of the heating chamber of the door frame by processing the steel plate having an opening of substantially the same shape as the front part of the heating chamber. It consists of a door.

[0008]

According to the present invention, with the above-described structure, a screen having a large number of small holes which are thinner than the thickness of the steel plate of the door frame body and whose surface is convex outward is provided on the outer side of the heating chamber of the door frame body. Because it is welded more, there is no end face of the thin plate screen in the heating chamber, and even if there is heat distortion during welding or deformation of the end face due to handling, there is no fear of abnormal heat generation etc. Through the large number of small holes provided, the object to be heated in the heating chamber can be seen through in a wide angle, and the object to be heated can be seen clearly. Further, by forming the screen in a convex shape toward the outside of the door, distortion of the material during punching and thermal deformation of the screen due to heat from the heating chamber are absorbed.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1, 2 and 3. As shown in FIG. 1, the door 2 of the high-frequency heating device opens and closes the object to be heated 3 into the heating chamber 4 each time it is heated. The radio wave emitted into the heating chamber 4 is configured so as not to leak outside through the door 2. That is, as shown in FIG. 2, the door frame 15 constituting the outer frame of the door 2 is made of steel plate and has a choke portion 15a on the outer periphery of the door frame 15, and the front surface has an opening shape substantially the same as the opening portion of the heating chamber 4. Have

2 and 3, small holes 17 having a diameter of 0.7 mm are formed in a 0.2 mm steel plate at a longitudinal pitch of 0.93 in the opening.
A screen in which steel plates having a staggered arrangement with a horizontal pitch of 0.8 mm are welded to the edge of the front opening of the door frame 15 from the outer surface side of the heating chamber 4 and drawn to the door outer surface side substantially parallel to the welded part. It has 16.

The front side of the door frame 15 is transparent, the front side of the door 18 is transparent, the rear side of the screen 16 is covered with a transparent heat-sealing glass 19, and the back side of the door 2 covers the choke portion 15a of the door frame 15. The door cover 20 has a frame shape. A masking portion 18a is provided on the outer periphery of the transparent door front surface portion 18 so that unnecessary structural portions are hidden and only the inside of the heating chamber 4 is visible.

The operation of the above configuration will be described. The object 3 to be heated is heated in the heating chamber 4, and the door front portion 18 of the door 2 is heated.
An object to be heated 3 which is being heated by an illumination lamp 6 which illuminates the inside of the heating chamber 4 through the screen portion 16 and the heat seal glass 19.
Is seen through from the front of the door.

Although the heat seal glass 19 is transparent except for the masking portion 18a of the door front portion 18, the screen 16 is a steel plate provided with a large number of small holes. Whether the image is clearly visible depends on the number of punch holes 17, that is, the number of pixels, and the thickness of the punch holes 17, that is, the viewing angle. In order to open more punch holes 17 within a certain area, a smaller punch hole 17 is required.
is necessary. In this embodiment, the thickness of the steel plate is 0.8 mm compared to the conventional one.
With the thickness of 0.2 mm, the diameter of the conventional 1.4 mm holes can be increased to 0.7 mm, so that the number of punch holes 17 opened in a certain area is about 30 holes / It is possible to increase from cm ² to about 110 holes / cm ² , that is, as the number of pixels increases and the thickness of the punch hole 17 is changed from 0.8 mm in the conventional case to 0.2 mm, the punch hole 17 is transparent. The viewing angle that can be seen is widened.

Therefore, the front surface 18 of the door, the screen 1
6. The object 3 to be heated becomes clearly visible through the heat seal glass 19.

As described above, in order to make the object to be heated 3 clearly visible, it is necessary to reduce the thickness of the screen 16 and open more punch holes 17 within a certain area.
The more visible it is, the thinner and weaker the screen 16 is.

Therefore, the screen 1 is attached to the door frame 15.
When the screen 16 is welded to the inner surface of the heating chamber 4 of the door frame 15, the end surface of the screen 16 is exposed to a strong electric field in the heating chamber 4 when the 6 is welded. Therefore, there is a possibility of performance problems such as abnormal heat generation. Therefore, by welding the screen 16 of the present invention to the outer surface side of the heating chamber 4 of the door frame 15, handling of the end surface of the screen 16 and deformation during welding,
Even if distortion occurs, it is outside the welded part, so that it is not exposed to the strong electric field in the heating chamber 4, and there is no fear of abnormal heat generation, etc., and there is no concern about safety and stable electromagnetic wave leakage prevention performance can be obtained.
Further, a masking portion 18a is provided on the outer peripheral portion of the transparent door front surface portion 18 so as to be visible only in the heating chamber 4, and the outer peripheral end surface portion of the screen 16 is masked portion 18a.
It can be hidden and it can be finished in good appearance.

Further, the screen 16 is a door frame 15
Since it is drawn along the welded part of the
The distortion of the material due to the processing of a large number of small holes is absorbed, and the deformation due to heating is reduced, so that the visibility of the object to be heated is not impaired.

[0018]

As described above, according to the door of the high-frequency heating apparatus of the present invention, the choke for shielding the radio wave from the screen obtained by drawing the punching sheet having a large number of small holes of the steel plate thinner than the door frame in the outward convex shape. (1) It is possible to weld a thin and weak steel plate by welding from the outer surface side of the heating chamber of the door frame by the steel plate press work having the opening part around and the opening shape substantially the same as the front opening part of the heating chamber. It is possible to realize a door that allows the heated object in the heating chamber to be seen more clearly. (2) Since the thickness of the screen portion having the punched holes is thin, the object to be heated can be seen through a wider range of angles through the punched holes, so that the object can be seen more clearly. (3) Since the plate thickness of the screen is thin, it is lighter than the conventional door having a punched hole structure in which the frame is integrated, and the door can be easily opened and closed. (4) Since the screen is drawn beforehand, uneven heat distortion does not occur in the screen, so that there is little influence on high frequency reflection, power supply is stable, and heating performance is stable.

[Brief description of drawings]

FIG. 1 is a perspective view of a high frequency heating device.

FIG. 2 is a cross-sectional view of a main part of a door of a high frequency heating device according to an embodiment of the present invention.

FIG. 3 is an array diagram of punch holes of the screen.

FIG. 4 is a sectional view of a main part of a door of a conventional high-frequency heating device.

FIG. 5 is an array diagram of punch holes on the screen.

[Explanation of symbols]

 15 Door Frame 16 Screen 17 Punch Hole 18 Door Front 19 Heat Seal Glass 20 Door Cover

Claims (1)

[Claims] 1. A high-frequency heating apparatus for heating an object to be heated, comprising: a heating chamber to which radio waves are supplied; an illumination lamp for illuminating the heating chamber; Door frame having a substantially same opening shape as the opening portion of the door frame, and a convex drawing on a punching sheet having a number of openings welded to the periphery of the opening of the door frame with a steel plate thinner than the door frame. A processed screen, a transparent door front surface that forms the outermost surface of the door, a heat-sealing glass provided on the back side of the screen, and a frame shape that covers the choke portion of the door frame on the back side of the door. The door of the high-frequency heating device, which is formed by welding the screen from the outer side of the heating chamber of the door frame.