JPS6021479B2 - High frequency heating device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a probe for detecting the internal temperature of the object to be heated in the heating chamber to enable good cooking. This invention relates to a high frequency heating device that effectively improves radio wave seals.

FIG. 1 shows an overview of a high-frequency heating device 10, a so-called microwave oven, in which a heating chamber with a front entrance is formed in a bonito body 12.

A door 14 is pivotally supported at the opening of the heating chamber so as to be openable and closable. As shown in FIG. 2, this heating chamber 16 is surrounded by a metal wall 16a, and a high frequency generator 18 is provided on the ceiling plate 16b of the heating chamber 16. Microwaves generated by (24
5) is connected to the heating chamber 1 via the output antenna 20.
6 and is diffusely reflected by the rotation of the stirrer fan 22. On the other hand, on the bottom plate 16c of the heating chamber 16,
Turn table 2 rotated by a drive device 24
6 is provided, and a heated object 30 is placed on a shelf board 28 disposed on this turntable 26. The three objects to be heated are irradiated with the microwave and cooked. At this time, knowing the internal temperature of the object to be heated 30 during heating is necessary for good cooking. For this reason, a probe 34 having a heat-sensitive section 32 at its tip is sometimes used. This probe 34 consists of the heat sensing section 32 and a cable 36 that leads to the outside an electrical signal that changes depending on the temperature detected by the heat sensing section 32. A plug 40 is provided to connect to a socket 38 provided on the outer wall 16a. FIG. 3 shows a state in which a plug is inserted into a conventional socket 38, in which a cylindrical body 42 serving as a protector with one end closed is placed so that the closed surface of the cylindrical body 42 is placed against the outer wall 16a of the heating chamber 16. The pin 44 is coaxially attached and fixed with a screw to a hole 46 provided for insertion. A cylindrical contact body 48 that receives the piston 44 is disposed inside this cylindrical body 42, and a first contact portion 44a of the pin 44 and a first contact portion 44a of the pin 44 are arranged coaxially therewith. The first contact piece 48a and the second contact piece 48b are arranged so that the second contact piece 44M can be connected to the first contact piece 48a.
are made of resilient metal and are each attached in place. Pin 4 provided on plug 40 of probe 34
4 is the heating chamber 1 in order to derive a temperature measurement signal to the outside.
The contact piece 48 of the socket 38 is inserted through the hole 46 of No. 6, and the contact pieces 48a and 48b' are brought into contact and electrically coupled.

With such a structure, as described above, the high frequency generator 1
When microwaves are radiated from 8 into the heating chamber 16, the pin 44 acts as an antenna, and there is a risk that the microwaves will leak outside through the hole 46 provided in the heating chamber 16. In order to prevent this microwave leakage, in the high frequency heating device ID which does not have the turntable 26, the pin 44 is inserted into the periphery of the hole 46 provided in the heating chamber 16 so that it comes into close contact with the periphery of the hole 46. Radio wave sealing was performed by attaching a contact metal 50 and grounding the contact metal 50. However, in the high-frequency heating device 10' having the turntable 26, the heat-sensitive section 3-2, that is, the probe 34, needs to rotate together with the rotating heated object 30, and therefore the plug 40 is also inserted into the socket 38. It rotates in the same position.

For this reason, when the frictional resistance between the pin 44 and the contact metal 50 is large, if the pin 44 is rotated forcibly, sparks will be generated in the contact area and an abnormal temperature rise will occur, causing the probe 3
There were drawbacks such as damage to No. 4. This invention was made in view of the above-mentioned drawbacks, and when the probe inserted into the object to be heated simultaneously rotates due to the rotation of the turntable, the pin of the plug part of the probe does not come into contact with the side wall of the heating chamber. It is an object of the present invention to provide a high-frequency heating device equipped with a fin wave shield that can reliably prevent leakage of microwaves.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 4 shows the plug 40 portion of the probe 34 taken out, and a radio wave shielding cap 52 is provided in the side wall 16a of the heating chamber 16 coaxially with the hole 46 into which the pin 44 of the plug 40 is inserted. Figure 5 shows the above radio wave shield.
The cap 52 is shown taken out, and has a bottomed cylindrical main body 54, and a flange 56 extending outward is formed at the entrance of the main body 54. The flange 56 has a plurality of screw holes 56a, 56b, which pass through screws for attachment to the side wall 16a of the heating chamber 16. ... are provided as appropriate. On the other hand, a throttle hole 60 is provided in the center of the bottom plate 58 of the cylindrical main body 54 coaxially with the main body 54 .
This throttle hole 60' is constituted by a cylindrical body 62 extending inward from the surface of the bottom plate 58 so that the pin 44 of the plug 40 passes through the cylindrical body 62 of this throttle hole 60 and is inserted into the socket 38. Then, the plug 40 is inserted into the cylindrical body 62.
This type of radio wave shield cap 52 is integrally constructed by pressing a thin metal plate as appropriate. Here, when the radio wave shield cap 52 is attached to the inner wall 16a of the heating chamber 16 (see FIG. 4), the inner wall 16a of the heating chamber 16
A space 66 is formed between the radio wave shield cap 52 and the radio wave shield cap 52 .

As shown by the broken line in FIG. 5A, this space 66 has a length that is 1/1/2 of the wavelength of the microwave (approximately 245 mm) from the edge of the entrance of the cylindrical main body 54 to the opening edge of the aperture hole 60. If the length is set to correspond to the length of 4 (1'4^:^: wavelength), it will function as a choke capacitance section. In other words, the microwaves that are guided and radiated into the space 66 forming this choke cavity using the pin 44 of the plug 40 as an antenna are attenuated and disappear here. Here, the set position of this radio wave shield cap 42, that is, the insertion position of the plug 40 is
It is desirable to set the position so that it does not interfere with the rotation of the Therefore, as shown in FIG. 6 when viewed from above, the heating chamber 16 may be set at a position that is off the top of the turntable 26. That is, avoid the vicinity of the center of the side wall 16a of the heating chamber 16, and set it at a position near the entrance or at a deep position, so that even if the object to be heated 30 rotates, it will rotate smoothly without colliding with the radio wave shield cap 52. The insertion position of the plug 40 may be determined at a position where the plug 40 can be inserted. In FIG. 4, the same parts as those in FIG. 3 are given the same reference numerals, and the explanation thereof will be omitted.

That is, the high frequency heating device 10 configured as described above
At the same time, when cooking is started and microwaves are irradiated into the heating chamber 16, the turntable 26 rotates, and the object to be heated 30 on the turntable 26 rotates as the turntable 26 rotates. Then, the probe 34 inserted and held within the object to be heated 30 to detect the internal temperature of the object to be heated 30 during heating is rotated as the object to be heated 30 rotates. This rotation of the probe 34 causes the plug 40 inserted into the socket 38 to rotate. At this time, since the grip part 64 of the plug 40 is inserted in a twill manner against the aperture hole 601 of the radio wave shield cap 52, the plug 40 of the probe 34 can be rotated without difficulty. Even if the pin 44 serves as an antenna and guides the microwaves radiated into the heating chamber 16, the microwaves introduced by the pin 44 pass through the aperture hole 60 of the radio wave shield cap 52. The microwaves are radiated into a space 66 that serves as a choke cavity, and as described above, the radiated microwaves are attenuated and annihilated in this space 66.

In this case, it has been experimentally revealed that the inner diameter ◇ of the aperture hole 60 and the length L of the cylindrical body 62 forming the aperture hole 60 are related to each other to prevent the penetration of microwaves.
FIG. 7 is a graph showing the relationship between the length L of the cylindrical body 62 and the strength of microwave leakage, that is, the leakage value (during no-load oscillation) when the inner diameter ◇ of the aperture hole 60 is kept constant. So, the inner diameter is 0
When L is on the 14th side, the leakage is the minimum when the length L is 14th, and the inner diameter? It was found that when the length L is 18 skins, the leakage value is the minimum.

That is, it has been experimentally confirmed that the microwave leakage value is minimized when the length L matches the inner diameter. Therefore, first, the shape of the radio wave shield cap 52 should be adjusted to the inner diameter as shown above. By defining the length L and the length L to be the same, it is possible to prevent microwaves from entering the aperture hole 60 of the radio wave shield cap 52 as much as possible. Then, the microwaves that have passed through the aperture hole 60 without being blocked are guided to the space 66 that serves as the aforementioned choke cavity, where they are repeatedly reflected, attenuated, and disappear. In general, the material of the grip portion 64 of the plug 40 of the probe 34 is made of metal, and the material of the radio wave shield cap 52 is also made of metal, as described above.

Therefore, when the probe 34 rotates, the plug 40
If it undergoes an eccentric movement under some force, it will come into contact with the radio wave shield cap 52, and sparks will be generated at this contact portion, which may cause an abnormal temperature rise. Therefore, it goes without saying that in order to prevent this, it is sufficient to prevent one of these from being made of metal. For example, the grip portion 64 of the plug 40 of the probe 34 may be made of resin. In addition, the aperture hole 6 of the radio wave shield cap 52
A resin coating may be provided inside the cylindrical body 62, or a cylindrical body made of resin may be inserted into the cylindrical body 62. In this way, even if the plug 40 of the probe 34 comes into contact with the radio wave shield cap 52, not only will sparks not be generated, but the radio wave shield cap 52
Since the gap between the throttle hole 60 and the plug 40 can be made sufficiently narrow, the cylindrical body 62 of the throttle hole 60 can also function as a guide body that can prevent eccentric D movement when the plug 40 rotates. It becomes like this. Here, examples of the resin material include polypropylene, polyphenylene sulfide, etc., but it goes without saying that any material can be used as long as it can achieve the intended function.

As detailed above, according to the present invention, even when the object to be heated is attached to the side wall of the heating chamber so that the probe plug can rotate smoothly as the turntable rotates, the radio waves It is possible to provide a safe high-frequency heating device that can reliably prevent leakage of radio waves using the shield cap.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing the external appearance of a conventional high-frequency heating device, Fig. 2 is a cross-sectional view showing the heating chamber of the above device, and Fig. 3 is a perspective view showing the appearance of a conventional high-frequency heating device.
The figure is a sectional view showing how the plug of the heating chamber is inserted.
FIG. 4 is a diagram explaining the plug insertion part of a high-frequency heating device according to an embodiment of the present invention, FIG. 5 is a diagram showing the structure of the fin wave shield cap in the above embodiment, and A is a side sectional view; B is a front view, FIG. 6 is a diagram illustrating the insertion position of the plug of the above embodiment, and FIG. 7 is a diagram illustrating the microwave leak-like device according to the shape of the radio wave shield cap. DESCRIPTION OF SYMBOLS 10... High frequency heating device, 16... Heating chamber, 28... Shelf board, 30... Heated object, 32... Heat sensitive part, 34... Probe, 36... Cable, 38... Socket, 40... Plug, 46 ...Through hole provided in the heating chamber, 52...Radio wave shield cap, 54...Main body, 58...Bottom plate,
60... Throttle hole, 62... Cylindrical body. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7

Claims (1)

[Scope of Claims] 1. A heating chamber, a probe provided in the heating chamber and having a heat-sensitive part inserted and held in the object to be heated at its tip and extracting a heat-sensitive signal via a plug, and a probe provided on the side wall of the heating chamber. a socket provided on the outside into which the plug is inserted through a through hole formed in the side wall; and a radio wave shield cap attached to the inner side wall of the heating chamber corresponding to the through hole of the heating chamber into which the plug is inserted. This radio wave shielding cap has a bottomed cylindrical body made of a thin metal plate with its opening facing the side wall of the heating chamber, and a hole formed coaxially with the through hole in the side wall in the center of the bottom plate of the body. The length of the cylinder and the inner diameter thereof are set to be equal, while the length of the cylinder is set equal to the inner diameter of the cylinder. A high frequency heating device characterized by the following. 2. The socket into which the plug of the probe is inserted is set at the upper end of the side wall of the heating chamber, and the radio wave shield cap is set at a position that is removed from the upper side of the heating cooking section. The device described.