JPS64719Y2 - - Google Patents

Description

[Detailed explanation of the idea]

INDUSTRIAL APPLICATION FIELD The present invention relates to a high-frequency heating device in which stirrer blades for stirring radio waves are driven by exhaust air from a fan motor. Conventional structure and its problems Conventionally, in a high-frequency heating device having a stirrer blade for stirring radio waves, a dedicated motor for the stirrer blade is provided as a means for driving the stirrer blade, or a fan motor is rotated to cool the high-frequency oscillator. A means of driving the motor through a speed reduction mechanism or belt was generally adopted. However, with these methods, the former has the drawback that the unit cost of the dedicated motor is high and the external height of the high-frequency heating device is high, while the latter requires an increase in the number of parts such as a reduction mechanism and belt, and the number of man-hours. The disadvantage was that the total cost was high. Therefore, in order to eliminate these drawbacks, a method that can be considered is to introduce the exhaust air from the fan motor that cools the high-frequency oscillator into the heating chamber and apply that air to the stirrer blades to drive them. If the fan motor is used in an area with poor power supply conditions (for example, -10% of the rated voltage must be guaranteed), rotational friction must be minimized as much as possible due to the voltage fluctuation characteristics of the fan motor. This causes a problem in that the stirrer blades do not rotate due to the decrease in air volume. As a result, the radio waves cannot be stirred, which adversely affects the high-frequency oscillator and shortens its lifespan.Also, the distribution of radio waves in the heating chamber becomes uneven, causing uneven heating of the food, and dehydration and carbonization occur from the areas that are strongly hit by the radio waves. There was a risk of fire occurring and even igniting. Purpose of the invention The present invention solves the above-mentioned conventional drawbacks.
The purpose is to obtain highly reliable rotational performance of stirrer blades with a simple configuration. Structure of the Invention In order to achieve the above object, the high-frequency heating device of the present invention fixes a stirrer shaft in a part of the heating chamber, and provides stirrer blades rotatable around the stirrer shaft. A stirrer blade receiver made of resin is inserted into the neck to hold the stirrer blades.In order to reduce the contact area between the stirrer blade receiver and the stirrer shaft, The stirrer blade holder is chamfered or has an annular protrusion on the stirrer blade holder.This reduces the rotational friction between the stirrer shaft and the stirrer blade holder, and is used in areas with poor power supply. The stirrer blades have stable rotational performance even when the rotational speed of the fan motor decreases and the air volume decreases. DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In Fig. 1, 1 is a heating chamber, and the radio waves generated from a high frequency oscillator 2 such as a magnetron are passed through a waveguide 3.
and is sent into the heating chamber through an internal conductor (shaft) 4 made of non-magnetic material such as aluminum or SUS304 that constitutes a coaxial line. Reference numeral 5 denotes a support plate formed integrally with the internal conductor (shaft) 4. A hook portion 5a provided on one side of the support plate is fixed to a hole provided on the top surface of the heating chamber 1, and the other side is made of resin such as polypropylene. It is held with a molded clip 6 and attached to the top of the heating chamber. 7 is a stirrer blade that stirs radio waves, and has a constriction 40 provided in a part of the internal conductor (shaft) 4.
A stirrer blade receiver 8 made of a resin with good lubricity and high frequency characteristics, such as Teflon, is inserted and held rotatably. Reference numeral 9 denotes a fan motor for cooling the high frequency oscillator 2, which sends air after cooling the high frequency oscillator 2 into the heating chamber 1 through an air guide 10 to rotate the stirrer blades 7. still,
Reference numeral 11 denotes a top plate provided to prevent the stirrer blades 7 from being contaminated by oil etc. from food and to prevent them from deforming when touched by the user, and a heating chamber 1 for guiding air so that it hits the stirrer blades 7 smoothly. It also serves as an air guide inside the tank, and is made of resin such as polypropylene. In the above configuration, the internal conductor (shaft) 4 needs to have a certain thickness (diameter) in order to efficiently send radio waves from the high frequency oscillator 2 to the heating chamber 1. Therefore, as shown in FIG. 2, the shape of the constricted portion 4a provided in a part of the internal conductor (shaft) 4 is determined by the diameter a of the contact surface with the stirrer blade receiver 8.
The inner conductor (shaft) 4 may be chamfered to make it smaller than the outer diameter b of the inner conductor (shaft) 4 as shown in Fig. 3.
A protrusion 13 smaller than the outer diameter of the inner conductor (shaft) 4 is provided to reduce the contact area between the inner conductor (shaft) 4 and the stirrer blade receiver 8. Table 1 shows data obtained through experiments, and when N=5, the voltage of the fan motor 9 was lowered, and the voltage (starting voltage) when the stirrer blades 7 rotated was measured between the conventional product and the present invention. This is a comparison of products.

[Table] According to this embodiment, the internal conductor (shaft) 4
The rotational friction at the contact surface between the stirrer blade receiver 8 and the stirrer blade receiver 8 is reduced, and when used in areas with poor power supply conditions, the stirrer blade 7 maintains stable rotational performance even when the rotation speed of the fan motor 9 decreases and the air volume decreases. It has the following. Incidentally, since the internal conductor (shaft) 4 is made of a metal material, in order to obtain the shape of the constricted portion 4a as in the above embodiment, it can be easily processed by shaping the cutting tool into the desired shape. Moreover, it is also possible to prevent burrs that adversely affect the rotation of the stirrer blades 7. Effects of the invention As described above, according to the invention, the following effects can be obtained. (1) It has sufficient rotational performance even when used in areas with poor power supply conditions, and the stirrer blades may stop, reducing the lifespan of components such as the high-frequency oscillator, or causing uneven heating of food. There is no danger of fire or even ignition. (2) It has a simple configuration and can be assembled easily and at low cost. (3) Since the metal shaft is machined, there are no burrs and the stirrer blades rotate stably.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a high-frequency heating device which is an embodiment of the present invention, and FIGS. 2 and 3 are sectional views of the same essential parts of each embodiment. DESCRIPTION OF SYMBOLS 1... Heating chamber, 2... High frequency oscillator, 3... Waveguide, 4... Internal conductor, 4a... Constriction, 7...
... Stirrer blade, 8... Stirrer blade receiver, 9...
...Fan motor, 10...Top plate.

Claims (1)

[Scope of utility model registration request] The stirrer blades are configured to be driven by the force of the wind, the stirrer blades are provided with a metal shaft, the stirrer blades are provided so as to be rotatable around this shaft, and a constricted portion is provided in a part of the shaft, and this constricted portion A sliding shaft having a structure in which a stirrer blade receiver made of resin is inserted to hold the stirrer blade, and the contact surface of the shaft with the stirrer blade receiver is cut to have an area smaller than the horizontal cross-sectional area of the shaft. A high-frequency heating device consisting of a surface.