JPS6046520B2 - Microwave oven with heater - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a microwave oven equipped with a heater, in which a heater is disposed in an open refrigerator having a cooking chamber.

A microwave oven with a heater is also called a microwave oven with a browner or an open range, and has a heater (sheathed heater) installed above and below or on either side in the open cooking chamber, and can only be used for high-frequency heating cooking at 2450 MH2 that outputs oscillation from a magnetron. First, it is equipped with an open heating cooking function that uses heater heating to heat the oven to the internal atmosphere temperature, or a grill heating cooking function that uses a heater to generate heat at high output and heats cooking over an open flame. Therefore, it is necessary to design the heater penetration part of the open wall so that high frequency waves do not leak outside the open refrigerator. Conventional measures to prevent radio wave leakage at the heater penetration portion have been taken as shown in FIG.

According to this, in the part of the heater 2 that penetrates the open wall 1, a metallic choke 3 is provided on the back surface of the open wall 1 and has a cavity having a depth λ/4 so as to surround the penetrating part of the heater 2. It was installed to capture and absorb high frequency waves that were about to leak outside the open warehouse. In addition, heater 2 and Chiyo...
An insulating material 4 is provided between the inner cylinder 30 of the tank 3 to prevent metal contact between the two. Further, the heater 2 is electrically connected to a control circuit provided outside the open refrigerator through a lead wire 5. Because of this structure, if there were fluctuations or perturbations in the electric field in the open refrigerator during high-frequency heating, the choke 3 would be affected by the resonance Q and frequency obtained as a radio wave trap, and it would not have a sufficient choke function. .

In addition, the outer sheath of the pipe-shaped heater 2 may be covered with oxide, so if you want to make the heater 2 moveable, the inner cylinder 30 that constitutes the choke 3 and the heater 2 should be able to slide smoothly. This is something that could not be obtained. The present invention has been made in view of this point, and it is an object of the present invention to provide a microwave oven with a heater that eliminates the above-mentioned drawbacks by providing a reactance element near the opening of the choke.

FIG. 2 is a cross-sectional view of a main part of an embodiment of the present invention, in which a cavity with a depth of λ/4 is formed on the back surface of an open wall 1 of a pipe-shaped heater 2 so as to surround the penetrating part of the heater 2. It is conventional that the metal choke 3 is attached by welding.

The new structure has a choke 3 in the open wall penetration part of the heater 2.
A reactance element 6 made of metal or dielectric material forming a raised portion 60 having a length 1 of λ/4 or less is fitted into the opening 31 by press-fitting. In this case, if the reactance element 6 is made of metal, the choke 3
An insulating material 4 is disposed between the inner cylinders 30 of. If it is a dielectric material, it is unnecessary as it also serves as an insulating material. Here, the speed of the electromagnetic wave propagating through the reactance element 6 is V, = -3-... (E
OE3 is the dielectric EOεSOμ0PS ratio, μ.

μ8 is magnetic permeability), which has the property of slowing down in inverse proportion to V7, but since the energy velocity of electromagnetic energy per unit time is slower than that of spatial waves, the delay (VO - Vg) P This is a form in which energy is apparently stored, and this shows that the reactance element 6 is equivalent to a capacitor or inductance in a lumped constant circuit. Due to the reactance effect of the reactance element 6, the resonance cavity of the choke 3 can be maintained at an appropriate degree of coupling, and fluctuations such as fluctuations and perturbations of the electric field in the open refrigerator during high-frequency heating can be suppressed. Q and frequency are not affected and sufficient radio wave attenuation (absorption) is obtained.

In addition, the reactance element 6 extends not only to the inner cylinder 30 of the choke 3 but also to the flange portion 10 protruding from the open wall 1, and when the heater 2 is movable, it moves together with the heater 2, and is attached to the insulating material 4 or the choke 3. It serves as a sliding surface for the inner cylinder 30 and the flange. If a metal is selected for the reactance element 6, a soft metal different from that of the heater 2 whose outer sheath of the vibrator is covered with an oxide or a metal with good sliding properties is used in order to improve heat radiation efficiency. FIG. 3 shows another embodiment of the present invention, in which a constriction 61 having a length l of λ/4 or less is formed in a part of the lead wire 5 of the heater 2 at the opening 31 of the choke 3. Alternatively, the reactance element 6 made of a dielectric material is fitted by press-fitting.

An insulating material 4 is provided between the reactance element 6 and the inner cylinder 30 of the choke 3 and between the heater 2 and the flange portion 10. The function of this reactance element 6 is the same as in the previous example. As described above, according to the microwave oven with a heater of the present invention, the leakage radio wave absorption effect in the open wall penetrating portion of the heater is sufficient due to the incorporation of the reactance element, and in the case of a movable heater, smooth sliding is promoted. To obtain a microwave oven with a heater, which functions as a means to improve functions, reduces the number of parts, and improves functions.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of the main part structure showing a conventional example, FIG. 2 is a cross-sectional view of the main part structure showing one embodiment of the present invention, and FIG. 3 is a cross-sectional view of the main part structure showing another embodiment of the present invention. There is. 1...Open wall, 2...Heater, 3
...Choke, 5...Heater lead wire, 6...Reactance element.

Claims (1)

[Scope of Claims] 1. A microwave oven with a heater, comprising: a choke surrounding a radio wave leakage path provided in a heater penetrating portion of an oven wall; and a reactance element having a length of λ/4 or less provided near an opening of the choke. 2. A microwave oven with a heater, in which a choke surrounding a radio wave leakage path is provided in the heater penetration part of the oven wall, and a reactance element having a length of λ/4 or less and thicker or thinner than the outer diameter of the heater is provided near the opening of the choke. .