JPS6235020B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heating device capable of measuring the weight of an object to be heated in a heating chamber.

Many methods have already been proposed for heating devices, particularly high-frequency heating devices using microwaves, in which the weight of the object to be heated is detected and the heating time is calculated based on this. In particular, it would be ideal to be able to detect the weight of an object to be heated at the same time it is placed in the heating chamber using a table for placing the object to be heated, and various inventions and ideas have been focused on this point, but none of them have been put to practical use. has not yet been reached.

Among such conventional inventions, there are many that attempt to detect the weight of the object to be heated using a rotary mounting table (such as Japanese Patent Application Laid-open No. 31648/1982).

FIG. 1 is a sectional view schematically showing an example of such a conventional device. A magnetron 2 serving as a heating means is coupled to the heating chamber 1, and a rotary table 4 for rotating an object to be heated 3 is provided within the heating chamber 1. This turntable 4
is rotated by a drive shaft 7 connected to a motor 5 serving as a drive source and a gear 6. A rotating mounting plate 8 made of glass, ceramic, or the like is installed on the rotating table 4. The object to be heated 3 is placed on this rotary placing tray 8, and the drips etc. that spill out from the object 3 are placed thereon to keep the inside of the heating chamber clean. The rotating table 4 and the rotating mounting plate 8 are often constructed integrally, and in this case, they are engaged with the drive shaft 7 by a gear made of plastic.

Now, this rotary table 4 can freely move in the thrust direction of the drive shaft 7, and is supported at the bottom by a bearing 9 and a support table 10. The load sensor 11 is attached to this support base 10.
It measures the weight of the object to be heated 3 and inputs the data to the control section 12. The control unit 12 controls the magnetron 2 based on this data to perform optimal heating. Reference numeral 13 denotes a door body provided at the opening of the heating chamber so as to be openable and closable.

However, this conventional configuration has one serious drawback. That is, the load sensor 11 is connected to the heated object 3.
In addition, the total weight including the weight of all sliding components such as the rotary table 4, drive shaft 7, support table 10, and rotary mounting table 8 is detected. However, if the rotary mounting table 8 alone is made of heat-resistant glass, it usually exceeds 1 kg. On the other hand, the object to be heated 3 may be light, weighing from several tens of grams to several grams, and therefore cannot be measured very accurately.

Further, the configuration of the drive shaft 7, gear 6, bearing 9, support stand 10, etc. is also large-scale, and is very impractical from the standpoint of reliability and cost.

In view of this background, the present invention aims to realize a device in which the weight of the object to be heated can be accurately measured within the heating chamber, and the structure of the movable part is simple, highly reliable, and inexpensive. Hereinafter, the configuration of the present invention will be explained according to the drawings.

FIG. 2 is a sectional view showing an embodiment of the present invention. Components that are the same as those in FIG. 1 are indicated by the same numbers (the same applies to FIGS. 3 and subsequent figures).

Now, compared to the conventional example, in this embodiment, the rotary table 4, drive shaft 7, rotary mounting table 8, etc. are fixed in the thrust direction and do not slide. In place of these, a tray 14 for the object to be heated is newly provided so as to be slidable up and down. This saucer 14 has a saucer shaft 1 at its center.
5 is formed and extends out of the heating chamber 1 through the drive shaft 7 . Its tip is supported by a leaf spring 16, and the leaf spring 16 is elastically displaced according to the weight of the object to be heated 3. A strain gauge is fixed to this leaf spring 16 as a load sensor 11. The control unit 12 controls the magnetron 2 based on the data input from this strain gauge to perform optimal heating.

If the saucer 14 is made of plastic (such as polypropylene) with low dielectric loss, the total weight including the saucer shaft 15 can be kept extremely low. Furthermore, in this embodiment, a large number of large grooves 17 are provided, so that the drips of the heated object 3 fall onto the mounting table 8, thereby preventing the heated object from boiling, and further reducing the weight of the saucer. There is also no need to worry about radio wave leakage or sparks.

By configuring the saucer 14 to be lightweight in this way (reduced to several tens of grams), the amount of displacement of the strain gauge 11 due to the weight of the object to be heated can be largely changed, allowing accurate measurement.

A protrusion 18 is provided at the center of the rotary mounting table 8,
It engages with the projecting piece 19 of the saucer 14 during rotation. That is, once heating is started, the rotary mounting table 8 is moved to the saucer 14.
``Hold on'' and rotate.

Figure 3 shows a strain gauge that is a load sensor. The strain gauge measures the strain of the leaf spring 16, that is, the weight of the object to be heated 3, by utilizing the fact that the resistance foil 21 printed on the base 20 changes its resistance value as it expands and contracts. The resistance foil 21 is covered with a protective sheet 22 such as a laminate film. This strain gauge is fixed to the back surface of the leaf spring 16 with adhesive. With this configuration, the load sensor has a simple configuration and is covered with the protective sheet 22 and adhesive, so it has excellent moisture resistance and is inexpensive. Particularly in the case of heating devices, its good moisture resistance is noteworthy.

FIG. 4 shows another embodiment of the invention. The rotary mounting table is formed integrally with the rotary table 4, and the driving force of the motor 5 is transmitted to the side by a gear 6. saucer shaft 15
is provided at the center of rotation of the saucer 14, and is located at a completely different position from the drive section. 22 is a roller. The protrusion 18 of the rotary table 4 is a protrusion 19 provided on the outer periphery of the saucer 14.
and engages during rotation. This embodiment has a much simpler configuration than the example shown in FIG. 2, and can further improve the reliability of the movable part, radio wave leakage, cost, etc.

As described above, according to the present invention, the weight of the object to be heated in the heating chamber can be accurately detected, the configuration is simple, and it is possible to realize a highly reliable and inexpensive apparatus, which is highly practical.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view schematically showing a conventional example, Fig. 2 is a cross-sectional view showing an embodiment of the present invention, Fig. 3 is a strain gauge as a load sensor, and Fig. 4 is another embodiment of the present invention. FIG. DESCRIPTION OF SYMBOLS 1... Heating chamber, 2... Heating means (magnetron), 3... Heated object, 4... Rotating table, 5... Drive source (motor), 7... Drive shaft, 11... Load sensor (strain gauge), 12... control section, 14
...Saucer, 15...Saucer shaft.

Claims (1)

[Claims] 1. A heating chamber that accommodates an object to be heated, a heating means coupled to this heating chamber, a rotating table that rotates the object to be heated, a drive source that drives this rotating table, and this driving source and the rotating table. a drive shaft that connects the objects, a tray that places the object to be heated, a tray shaft that supports the tray and extends outside the heating chamber, a load sensor that is elastically connected to the tray shaft, and a The rotary table and the drive shaft are fixed in the thrust direction, the saucer and the saucer shaft are configured to slide in the thrust direction, and the load sensor measures the weight of the heated object. A heating device characterized in that the weight of the object to be heated and the saucer is detected via the saucer shaft, and the rotary table and the saucer are fitted together at least when the rotary table rotates.