JPS6352439B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a high-frequency heating device that supplies radio waves generated from a high-frequency oscillator into a heating chamber from the bottom of the heating chamber.

Conventional configuration and its problems Conventionally, in a high-frequency heating device that supplies radio waves generated from a high-frequency oscillator into the heating chamber from the bottom of the heating chamber through a waveguide, as shown in FIG. A power supply port 2 is provided approximately in the center of the power supply port 2, and a coupling rod 4 that connects the heating chamber 1 and the waveguide 3 in a high frequency manner is rotatably attached to the power supply port 2 by a motor 5 or the like. is box-shaped so as to cover the power supply port 2, and has an interval _lh between it and the bottom surface of the heating chamber 1, and an internal waveguide 6 having an opening 6a facing the heating chamber 1 at its end is attached. Incidentally, 7 is a table on which the object to be heated is placed. With the above configuration, the radio waves emitted from the high frequency oscillator 8 are excited by the coupling rod 4 through the waveguide 3 and guided to the internal waveguide 6 from the power feed port 2. Most of the guided radio waves pass through the opening 6a of the internal waveguide 6, are radiated into the heating chamber 1 via the table 7 made of dielectric material, and heat the object to be heated. In order to efficiently guide the radio waves to the heating chamber 1 and evenly heat the object to be heated, l _B , l _F ,
Adjust and determine the dimensions of l and _h by experiment. Generally, when radio waves are supplied from the bottom of the heating chamber, the center bottom of the object to be heated tends to be heated strongly, but this can be resolved by reducing the interval dimension l _h and increasing the dimension l _F. However, when the dimension l _F becomes large, the balance with the coupling rod 4 as a fulcrum is lost, and the internal waveguide 6
may be tilted, and an unbalanced force may be applied to the axis of the motor 5, causing the motor 5 to stop rotating, or the heating chamber 1 may be tilted.
Sparks were generated between the bottom surface and the end surface of the internal waveguide 6, which adversely affected uneven heating and output.

Therefore, it is conceivable to attach a roller 9 to the internal waveguide 6 and rotate it while maintaining the distance l _h between the internal waveguide 6 and the bottom surface of the heating chamber 1, as shown in FIG.
If the boiling liquid from the food overflows and flows from the table 7 to the bottom of the heating chamber 1 and the rotating part of the roller 9 gets dirty, the rotation of the roller 9 will stop, causing the above-mentioned problem, or the motor 5 will be forcibly locked. There were also safety issues, such as the coil heating up and burning out.

OBJECTS OF THE INVENTION The present invention solves the above-mentioned conventional drawbacks, and aims to provide a high-frequency heating device with less uneven heating and high heating efficiency.

Structure of the Invention In order to achieve the above object, the high-frequency heating device of the present invention transmits radio waves generated from a high-frequency oscillator via a waveguide to a power supply port provided at approximately the center of the bottom of the heating chamber, and is rotatably mounted by a motor or the like. In this method, the radio waves are supplied into the heating chamber by a coupling rod, and the internal waveguide provided at the tip of the coupling rod on the heating chamber side is rotated to make the distribution of radio waves uniform. It has a box shape that covers the power supply port and has an opening at the end. In addition, on the bottom of the heating chamber,
An annular protrusion (distance maintaining means) made of a resin with excellent lubricity and high frequency characteristics such as Teflon, which maintains a substantially constant distance between the internal waveguide and the bottom surface of the heating chamber.
Since the internal waveguide rotates around the power supply port while partially contacting the annular protrusion, it can always maintain a substantially constant distance from the bottom surface of the heating chamber, thereby preventing sparks. There are no abnormal phenomena such as, and variations in output performance and uniform heating performance can be made extremely small. Furthermore, since no biased force is applied to the motor shaft, it also has the effect of improving the reliability of the motor.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In Fig. 4, 1 is a heating chamber, 2 is a high-frequency oscillator such as a magnetron that generates radio waves, 3 is a waveguide for guiding the radio waves generated from the high-frequency oscillator 2 to the heating chamber 1, and 4 is the bottom of the heating chamber 1. A power feeding port is provided almost in the center of
One side of the coupling rod 5 is detachably attached to the shaft of the motor 6, and the other side is box-shaped so as to cover the power supply port 4, with a distance l _h between it and the bottom of the heating chamber 1, and a heating element is attached to the end. An internal waveguide 7 having an opening 7a facing the chamber 1 is secured by means such as an eye. Reference numeral 8 denotes an annular protrusion (spacing means) made of a resin with excellent lubricity and high frequency properties such as Teflon, and is attached to the bottom of the heating chamber 1 at a position in contact with a part of the internal waveguide 7. 9 is a table on which the heated object is placed. Incidentally, FIG. 5 shows an embodiment of the shape of the annular protrusion 8 and the method of attaching it. The annular protrusion 8 is made of a resin with good lubricity and high frequency characteristics, such as Teflon, and has a height l _h as shown in Fig. 6.
Then, it is formed into a sheet shape having claw portions 8a. As shown in FIG. 7, the bottom of the heating chamber 1 is provided with a mounting hole 1a that is concentric with the power supply port 4 and has an angle α to the tangent of the circle, and the claw portion 8a of the annular protrusion 8
Insert and install.

In the above configuration, the radio waves generated from the high frequency oscillator 2 pass through the waveguide 3, are excited by the coupling rod 5, and are guided to the internal waveguide 7. Most of the guided radio waves pass through the opening 7a at the end of the internal waveguide 7, are radiated into the heating chamber 1 via the table 9 made of dielectric material, and heat the object to be heated. .

The internal waveguide 7 is connected to the coupling rod 5 by the motor 6.
Since the heating chamber 1 rotates with the heating chamber 1 as a fulcrum while contacting the annular projection 8 provided on the bottom surface of the heating chamber 1, the object to be heated can be heated evenly.

Note that the dimensions l _F , l _B , and l _h are adjusted and determined through experiments in order to efficiently send the radio waves from the high frequency oscillator 2 to the heating chamber 1 and to obtain uniform distribution performance.

As described above, according to this embodiment, the internal waveguide 7 can be rotated by the annular protrusion 8 while maintaining a substantially constant distance from the bottom surface of the heating chamber 1, thereby preventing discharge phenomena such as sparks. l _F , l _B , which does not occur and greatly affects the uniform distribution characteristics and output characteristics.
Since the dimensional accuracy of the positional relationship between l and _h is good, the initial characteristics can be maintained. Furthermore, since no biased force is applied to the shaft of the motor 6, the reliability of the motor 6 can be improved, which is a great effect.

Effects of the Invention As described above, according to the present invention, the following effects can be obtained.

(1) Because the bottom of the heating chamber and the internal waveguide can always maintain a nearly constant distance, abnormal phenomena such as sparks do not occur.

(2) Since the dimensional accuracy of the positional relationship of l _F , l _B , and l _h is improved, the initial characteristics can be maintained. In other words, variations can be reduced.

(3) Since unbalanced force is not applied to the motor, the reliability of the motor can be improved.

(4) Even if food broth etc. overflows and flows from the table to the bottom of the heating chamber, it will not affect the rotation of the internal waveguide and stable rotation performance can be achieved.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of a conventional high-frequency heating device;
The figure is an external perspective view of an internal waveguide used in a conventional high-frequency heating device, FIG. 3 is an external perspective view of a high-frequency heating device that is an embodiment of the present invention, and FIG.
A-A' sectional view in the figure, FIG. 5 is an exploded perspective view of the same essential parts,
FIG. 6 is an enlarged view of the main part of the annular projection, and FIG. 7 is a diagram showing the angle of the mounting hole on the bottom of the heating chamber. DESCRIPTION OF SYMBOLS 1... Heating chamber, 2... High frequency oscillator, 3... Waveguide, 4... Power feeding port, 5... Coupling rod, 7... Internal waveguide, 8... Annular protrusion (space maintaining means).

Claims (1)

[Scope of Claims] 1. A configuration in which radio waves guided by a waveguide are supplied into the heating chamber from the bottom surface of the heating chamber, a rotatable coupling rod is provided at the coupling port between the waveguide and the heating chamber, and the coupling rod An internal waveguide is attached to the inner end of the heating chamber, and a distance maintaining means is provided to maintain a substantially constant distance between the internal waveguide and the bottom surface of the heating chamber during rotation, and the distance maintaining means is made of resin. A high frequency heating device. 2. The high-frequency heating device according to claim 1, wherein an annular projection is provided on the bottom surface of the heating chamber facing the internal waveguide, the surface of which is in contact with a portion of the internal waveguide made of resin.