JPH0475638B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a door device for a high frequency heating device such as a microwave oven.

Conventional technology In general, high-frequency heating devices such as microwave ovens are provided with a door that can be opened and closed to close the opening through which objects to be heated are taken in and out of the heating chamber, and the area around the door prevents high-frequency waves from leaking to the outside. A high frequency attenuation device is provided.

Many proposals have been made for this high-frequency attenuation device, and one of the most widely used is the chi-yoke method. This method has a chiyoke groove, and the effective depth from the chiyoke groove opening to the chiyoke groove end is 1/1/2 of the wavelength of the high frequency used.
4 (for example, US Pat. No. 3,182,164 and the drawings).

In addition, as shown in Fig. 5, there is a device that uses double chiyok grooves to further enhance the damping effect (PCT Patent International Publication No. W084/01083). In the figure, a partition wall 3 is provided between the outer wall surface 1 and the inner wall surface 2 of the chiyoke groove,
The partition wall 3 has cutouts 4 at equal intervals,
Further, square holes 5 are provided alternately with the notches 4.
The partition wall 3 has a ceiling part 6 that partially closes the opening on the groove opening side, and a partition part 7 that is parallel to the inner wall surface 2 and extends to the middle thereof.

When looking at the cross section of the chiyoke groove, the inner wall surface 2
The groove between the partition 7 and the partition 7 parallel thereto becomes a high-frequency introduction line, and the width of this groove becomes wider beyond the end of the partition 7, changing the characteristic impedance of the high-frequency line.

By optimizing the combination of characteristic impedances of the narrow groove and wide groove as described above, it is possible to make the depth of the chiyoke groove shorter than 1/4 wavelength. The groove between the partition wall 3 and the outer wall surface 1 can also be called a second yoke groove, and further enhances the damping effect of the first yoke groove. Further, the cutout portion 4 of the partition wall 3 is provided to provide a blocking effect of high frequency waves propagating in the longitudinal direction of the partition wall 3.

Problems to be Solved by the Invention In the chiyoke groove configured as described above, the positional accuracy of the partition wall 3 is an extremely important factor for high frequency attenuation performance. That is, if the mounting position of the partition wall 3 changes, the width of the high frequency introduction line changes, thereby changing the value of the characteristic impedance, and significantly worsening the damping effect. Usually, the partition wall 3 is often joined to the bottom of the yoke groove by a method such as spot welding, but there are problems in that positioning during welding is difficult and it is difficult to improve dimensional accuracy. Further, when the partition wall 3 and the bottom of the groove are joined by spot welding, there is a problem in that if there is even a slight gap between the partition wall and the bottom of the groove due to inadequate welding conditions, leakage radio waves will increase. In addition, the rising portion of the partition wall 3 is essentially only the remaining portion excluding the cutout portion 4 and the square hole portion 5, and the strength as a structure is extremely low, and even if welding is completed, it will not be possible to process the partition wall 3. Since the bending angle easily changes depending on handling during transportation and transportation, the groove width tends to change as a result. In order to compensate for the decrease in damping effect due to these problems, the second chiyoke groove may be made larger, a complex shape effect may be added to this part, or a radio wave absorber such as ferrite may be provided. method is taken, but as a result, the dimensions of the surrounding frame of the door are increased,
There was a problem in that it was disadvantageous in terms of weight and cost.

The present invention solves these conventional problems and provides an excellent door device that has a simple and compact configuration and does not reduce the high frequency attenuation effect.

Means for Solving the Problems The door device of the high-frequency heating device of the present invention is a metal door that can be opened and closed to close an entrance opening of a heating chamber, and the door has a wall on the four sides around the heating chamber. A metal having an opening corresponding to the front plate of the heating chamber extending around the periphery of the opening, and a groove having a bottom on the opposite side thereof, and having a plurality of protrusions joined to the bottom surface of the groove and formed by cutouts. an outer wall surface extending in a direction perpendicular to the joint surface joined to the groove bottom surface, a ceiling surface perpendicular to the outer wall surface and parallel to the joint surface, and a ceiling surface parallel to the joint surface; It consists of a partition part perpendicular to the ceiling surface and extending toward the bottom surface of the groove. The joining surface of the metal element is joined to the groove bottom surface such that the bottom side of the metal element is at the same position as the tip of the outer surface of the heating chamber side of the plate of the door groove or closer to the heating chamber front plate side. That is.

In addition, partitions forming grooves, ceilings, outer walls,
The groove bottom surface and the inner wall surface are integrally formed by bending a single metal plate.

Effect The outer wall surface of the chiyoke groove around the door according to the present invention is
A metal element having a plurality of protrusions formed by a notch connects the protrusions in the side direction of the periphery of the door, thereby having high frequency blocking characteristics in the longitudinal direction of the groove,
In addition, since the root part of the outer wall surface has at least a continuous metal part, it has high strength and does not easily change the bending angle, and it is easy to achieve relative positional accuracy with respect to the inner wall surface, so the dimensions of the high frequency introduction line can be maintained with extremely high precision, improving the external high-frequency blocking characteristics, and thus providing a second
There is no need to provide a yoke groove, and the size is accordingly smaller and less material is used.

Embodiment Hereinafter, a door device for a high-frequency heating device according to an embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 1 (first embodiment), an inner wall surface 8, a chiyoke groove bottom surface 9, and an outer portion 10 are formed of a single metal plate on the four sides around the door body, and the groove bottom surface 9 is placed so that it corresponds to the front side of the door. That is, it is located on the opposite side to the heating chamber front plate extending around the periphery of the heating chamber entrance opening. A metal element is joined to the groove bottom surface 9 by means such as spot welding,
This metal element has a plurality of protrusions formed by cutouts 12. The protrusion has an outer wall surface 11 extending in a direction perpendicular to the joint surface joined to the groove bottom surface 9;
Furthermore, a ceiling surface 14 that is perpendicular to the outer wall surface 11 and parallel to the joint surface, and a partition section 1 that is perpendicular to the ceiling surface 14 and extends toward the groove bottom surface.
It consists of 5. A square hole portion 13 is provided in the outer wall surface 11, and a protruding end 15a of the partition portion 15 near the groove bottom surface 9 is substantially parallel to an upper side 13b of the square hole 13. That is, the partition portion 15 ends on the way toward the groove bottom surface 9. Bottom side 12a of notch 12
The lower end side 13a of the square hole portion 13 is located slightly above the bottom surface 9, and is located approximately at the same level as or slightly above the tip of the outer surface 10 of the groove, that is, on the front plate side of the heating chamber. Furthermore, the edges of the notch 12 and the square hole 13 have slight arcs. Furthermore, a circular arc is provided at the bent portion that is the intersection of the bottom surface 9 and the outer portion 10, and a corresponding circular arc portion is also provided at the root portion of the outer wall surface 11. That is, the metal element has a structure in which protrusions having square holes 13 are alternately and periodically formed on the outer wall surface 11 with cutouts 12 interposed in the flow direction.

When looking at the cross section of the configuration shown in the figure, the narrow groove formed by the inner wall surface 8 and the partition part 15 opens on the front plate side of the heating chamber, and becomes a high frequency introduction line, and the width of this groove is the same as that of the partition part 15. After passing the tip 15a of the portion 15, the groove becomes wider and becomes the groove width between the inner wall surface 8 and the outer wall surface 11. When spot welding a metal element to the groove bottom surface, the ceiling surface 14 of the plurality of protrusions hides most of the joint surface, so the spot electrode is inserted aiming at the gap between the notches 12. Welding position is L
The closer the groove is to the outer surface 10, that is, the closer it is to the outside, the more advantageous it is in terms of strength. but,
When the outer wall surface 10 is bent at an acute angle than a right angle, the outer wall surface 11 of the metal element and the tip of the outer wall surface 10 of the groove first come into contact, causing a shunt of the welding current,
There is a risk that the welding will be incomplete. Therefore, the groove outer wall surface 10 facing the position of the notch 12 into which the welding electrode is inserted is partially bulged outward.

FIG. 2 shows a cross section of a door having the above-mentioned chiyoke groove. A cover 16 made of a material such as resin is provided on the open side of the chiyoke groove, and a transparent cover 17 is attached to the front surface. There is. A large number of small holes 20 are provided in the center of the door for looking into the heating chamber 19.

In this way, the attachment position of the outer wall surface 11 to the door body is at the L of the groove bottom surface 9 and the partial outer part 10.
Since it is pressed tightly against the corner of the letter, it can be positioned with extremely high precision even when welding or other joining means are used. In addition, since the tip of the outer part 10 is aligned with the bottom side 12a of the notch 12 of the outer wall surface 11 and the lower end side 13a of the square hole section 13, it is easy to prevent the outer wall surface from lifting up during joining processing such as welding. becomes.

Further, the outer wall surface 11 has a metal portion continuous in the longitudinal direction at its rising root portion, and has a circular arc portion at its bent portion, so that it has high strength against bending from the bent portion. In particular, due to the double structure with the outer portion 10, the position does not easily change in response to an external force applied in an outward direction. On the other hand, even if the root portion is strengthened, the bases of the square hole portion 13 and the notch portion 12 become relatively weak, but the lack of strength is compensated for by the slight radius of the corner provided during each processing. As is visually clear in this cross-sectional view, the partition part 15 of the metal element is located approximately in the middle between the inner wall surface 8 and the outer wall surface 11 of the metal element, and moreover, the partition part 15 of the metal element is located approximately in the middle of the groove of the tip 15a (in the depth direction of the groove of the door). (equivalent to the front-to-back direction). In actual design, the dimensions are set to be approximately in the middle. In other words, the width of the groove is approximately 1/2 as a high frequency introduction line, and the area where the characteristic impedance changes is also approximately 1/2 in the high frequency propagation direction. In order to reduce the groove dimensions as a whole, it is necessary to increase the impedance change and therefore the width dimension change of the high frequency introduction line, but if the width of the introduction line is too small, the high frequency will pass through it. and leaks to the outside. A configuration that optimally satisfies these conditions is one in which the width and depth are each reduced to 1/2 as described above. The high frequency waves propagating in the longitudinal direction of the metal element are blocked by the structure in which the protrusions and notches 12 are arranged alternately.

FIG. 3 (second embodiment) shows the outer wall surface 21 as the groove bottom surface 2.
2 and the inner wall surface 23 from a single metal plate. FIG. 4 shows a developed view before bending. Notch 24 provided in the outer wall surface 21
The square hole portion 25 is the same as in the first embodiment. The position indicated by the broken line in FIG. 4 is the part to be bent. In this way, each part of the chain yoke groove is formed integrally during bending and drawing, making manufacturing much easier and achieving dimensional accuracy compared to when separate parts are joined by means such as welding. It's also easy to take out.

As described above, if the dimensional accuracy of the cheese yoke groove can be maintained, the high-frequency attenuation performance of one cheese yoke groove can be maintained at a high level without variation, and the second groove on the outside is also unnecessary, which can reduce the amount of materials used. This has the advantage of making it possible to make the door smaller and lighter.

Effects of the Invention As described above, the door device of the high frequency heating device of the present invention has an opening on its four sides facing the heating chamber front plate extending around the periphery of the opening of the heating chamber, and a bottom portion on the opposite side. a groove having
The metal element includes a plurality of protrusions formed by notches, and the protrusions of the metal element have an outer wall surface extending perpendicularly to the joint surface joined to the groove bottom surface, and an outer wall surface perpendicular to the outer wall surface. and a ceiling surface that is parallel to the joint surface, and a partition section that is perpendicular to the ceiling surface and extends toward the bottom surface of the groove, and this metal element is arranged at a position close to the outer surface of the groove. , so that one side of the square hole provided in the outer wall surface and the bottom of the partition part are at the same position as the tip of the outer surface of the groove of the door on the heating chamber front plate side, or closer to the heating chamber front plate side. By configuring this, the dimensional position of each part of the groove can be maintained with high precision.
It is possible to eliminate the possibility that the high frequency attenuation effect is reduced due to processing precision, and it is possible to make the door extremely advantageous in making the door smaller and lighter. At the same time, the root portion of the outer wall surface of the metal element and the outer circumferential wall of the groove of the door body overlap, so that the mechanical strength is high and changes due to external forces can be made extremely small.

In addition, partitions forming grooves, ceilings, outer walls,
By forming the groove bottom and inner wall surfaces by bending a single metal plate, manufacturing is much easier and dimensional accuracy is improved compared to when separate parts are joined by means such as welding. It has the effect of being easy to use.

[Brief explanation of the drawing]

FIG. 1 is a perspective view including a cross section of a main part of a chiyoke groove according to a first embodiment of the present invention, FIG. 2 is a cross-sectional view of a main part thereof,
Figure 3 is a sectional view of the chiyoke groove of the second embodiment;
The figure is a developed view of the entire door before processing, and FIG. 5 is a perspective view including a cross section of the main part of a conventional chiyoke groove. 8... Inner wall surface, 9... Groove bottom surface, 11... Outer wall surface, 12... Notch portion, 13... Square hole portion.

Claims (1)

[Scope of Claims] 1. An openable and closable metal door that closes the entrance opening of a heating chamber that heats an object by receiving high frequency waves supplied by a high frequency generator, the door having a A groove having an opening and a bottom on the opposite side is provided facing the front plate of the heating chamber extending around the periphery of the opening of the heating chamber, and a plurality of grooves are joined to the bottom surface of the groove and formed by notches. A metal element having a protrusion is provided, and the protrusion of the metal element extends between an outer wall surface extending in a direction perpendicular to the joint surface joined to the groove bottom surface, and a ceiling perpendicular to the outer wall surface and parallel to the joint surface. and a partition part perpendicular to the ceiling surface and extending toward the bottom surface of the groove; The joining surface of the metal element is aligned so that one side of the hole and the bottom of the notch are at the same position as the tip of the outer surface of the groove of the door on the heating chamber front plate side, or closer to the heating chamber front plate side. A door device for a high-frequency heating device that is configured to be bonded to the bottom of the groove. 2. An openable and closable metal door that closes the entrance opening of a heating chamber that heats objects to be heated by receiving high frequency waves supplied by a high frequency generator; An opening is formed facing the front plate of the heating chamber extending around the periphery of the opening, and a groove having a bottom on the opposite side is formed on an outer wall surface, a groove bottom surface, and an inner wall surface, and the outer wall surface has a groove at one end of the groove bottom surface. a ceiling surface that is perpendicular to the outer wall surface and parallel to the groove bottom surface; a partition section that is perpendicular to the ceiling surface and extends toward the groove bottom surface; The inner wall surface is provided at the other end of the groove bottom surface in parallel with the outer wall surface so as to extend perpendicularly to the groove bottom surface, and the partition section, ceiling surface, outer wall surface, groove bottom surface, and inner wall surface are integrated into one piece. A door device for a high-frequency heating device, which is formed by bending a metal plate, and has a structure in which a plurality of square holes and partitions are alternately formed on the outer wall surface.