JPH01314818A - High frequency heater - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a kneading container equipped with an internal stirring blade for kneading cooking ingredients, and a turntable for rotating objects to be heated to eliminate uneven heating. This invention relates to a high-frequency heating device, generally called a microwave oven, which can be selectively installed in a heating cabinet.

<Conventional technology> Conventionally, in order to eliminate uneven heating of the object, it has been common practice to place the object on a turntable and heat the object while rotating the turntable. ing. Furthermore, in recent years, a cooking function has been introduced in which a kneading container equipped with an internal stirring blade is installed in the heating chamber, and the cooking ingredients contained in the kneading container are kneaded by the rotation of the stirring blade.
A high-frequency heating device has been proposed that has a function of kneading flour, water, sugar, butter, yeast, etc. with a stirring blade, and then fermenting and baking the mixture to make bread.

This type of conventional high-frequency heating device will be explained with reference to FIGS. 8 and 9. A passive boolean U 4 is integrated into the bottom of a heating chamber 3 into which microwaves are introduced from a magnetron 1 through a waveguide 2. The cylindrical transmission shaft 5 and this transmission shaft 5
A drive shaft 6 inserted therein is rotatably held. The rotation of the high-speed drive motor 7 is transmitted to the transmission shaft 5 via a belt 9 wrapped around the motor pulley 8 and the passive pulley 4, while the drive shaft 6 is directly connected to the low-speed drive motor 10. ing.

As shown in FIG. 8, a kneading vessel 13 has a stirring blade 12 fitted to a connecting shaft 11 rotatably installed at the bottom.
When placed in the heating chamber 3, the connecting shaft 11 is fitted and connected to the transmission shaft 5, and the stirring blade 12 is rotationally driven by the high-speed drive motor 7 at a rotation speed of several tens to hundreds of revolutions per minute. .

On the other hand, as shown in FIG.
It is driven to rotate at a rotational speed of several revolutions per minute.

The reason why different motors 7 and 10 are used to drive the stirring blades 12 and the turntable 14 is that, when making bread dough, the stirring blades 12 for kneading are generally used to drive the stirring blades 12 and the turntable 14, as described above. It is necessary to rotate the turntable 14 ~ several hundred times, but if the turntable 14 were to be rotated at the same rotational speed as described above, the object to be heated on the turntable 14 would scatter, and sometimes the container containing the cooked food that was the object to be heated would be damaged. This is because it is extremely dangerous as it may break.

<Problems to be Solved by the Invention> In recent years, there has been a demand for high-frequency heating devices of this type that are small, inexpensive, and easy to use. However, as mentioned above, the use of separate motors 7 and 10 to drive each of the stirring blades 12 and the turntable 14 makes the motors large and expensive, which is a factor that hinders the achievement of the above-mentioned requirements. There is.

The present invention has been made in view of these conventional problems, and provides a high-frequency heating device that can be miniaturized and cost-reduced in a type in which a kneading container and a turntable can be selectively attached. The technical challenge is to provide the following.

Means for Solving the Problems> In the present invention, as a technical means for achieving the above-mentioned problems, a high-frequency heating device is configured as follows. That is, a kneading container rotatably equipped with stirring blades for kneading cooking ingredients and a turntable for rotating the heated object placed therein can be selectively installed in the heating chamber. In the high-frequency heating apparatus, a single drive motor as a rotational drive source for the kneading container and the turntable installed in the heating chamber, and a detection means for the kneading container and the turntable installed in the heating chamber. and rotational speed switching means for switching the rotational speed of the drive motor based on the detection result of the detection means.

Further, it is preferable to use a drive motor having a rated rotation speed corresponding to the required rotation speed of the stirring blade, and in that case, the rotation speed detection means of the drive motor and the detection means are connected to the turntable. and rotational speed control means for performing feedback control of the drive motor to a predetermined rotational speed based on the rotational speed detected by the rotational speed detection means when detecting the rotational speed.

<Operation> When the kneading container is set in the heating chamber, the kneading container is detected by the detection means, and the rotation speed switching means switches so that the rotation of the drive motor is directly transmitted via the transmission mechanism. In this case, since a drive motor with a rated rotation speed corresponding to the required rotation speed of the stirring blade is used, no problem occurs when controlling the rotation of the stirring blade.

On the other hand, when the turntable is set in the heating chamber, this is detected by the detection means, and the rotational speed of the drive motor is adjusted by the rotational speed switching means to correspond to the required rotational speed of the turntable, which is lower than the rated rotational speed of the turntable. Can be switched to rotation speed.

In this case, since the load side torque accompanying the rotation of the turntable is not constant, the rotation speed becomes unstable, but the rotation speed control means drives the drive motor in response to fluctuations in the rotation speed of the drive motor detected by the rotation speed detection means. The rotation of the motor is feedback-controlled so that it rotates stably at a rotation speed corresponding to the required rotation speed of the turntable. In this way, by being able to drive the kneading container and the turntable with a single drive morph, it is possible to achieve significant downsizing and cost reduction compared to conventional devices.

<Example> Hereinafter, a preferred example of the present invention will be described in detail with reference to the drawings.

FIGS. 1 and 2 show an embodiment of the present invention, and FIGS. 1 and 2 correspond to FIGS. 8 and 9, respectively, for clear comparison with conventional devices. This is an indication. In these figures, the same or equivalent parts as in FIGS. 8 and 9 will be given the same reference numerals and their explanations will be omitted, and only the structures that are different from those in FIGS. 8 and 9 will be explained. The low-speed drive motor 10 of the conventional device is excluded, and a drive shaft 15 equivalent to the drive shaft 6 of the conventional device is directly connected to the passive pulley 4.
5 is inserted into the heating chamber 3 from the bottom and is held rotatably. Accordingly, the drive shaft 1 is attached to the kneading container 13.
A connecting shaft 16 is provided which is attached to the connecting shaft 5, and a stirring blade 12 is fixed to this connecting shaft 16. In addition, heating chamber 3
A detection rod 17 is inserted into the interior from the bottom so as to be movable up and down, and a coil spring 1 biases the detection rod 17 upward.
8, and a detection mechanism (not shown) for determining whether it is the kneading container 13 or the turntable 14 that is attached to the heating chamber 3 based on the vertical position of the detection rod 17. It is being Further, although not shown, a rotational speed switching means is provided for switching the rotational speed of the high-speed drive motor 7 based on a detection signal from the detection means.

Since the drive motor 7 is a high-speed drive motor 7 for driving the stirring blade 12, this rotational speed switching means may include voltage control, phase control, frequency control, intermittent control, etc., which are known only when driving the turntable 14. The rotational speed control means may be driven to reduce the rotational speed of the turntable 14 to a required speed. In order to perform feedback control of the drive motor 7 by the rotation speed control means (not shown) to the rotation speed switched by the rotation speed switching means, the rotation speed detection means 1 of the drive motor 7
9 is provided.

Next, the operation of the above embodiment will be explained with reference to FIGS. 3 to 7. First, as shown in FIG. 1, when the kneading container 13 is set in the heating chamber 3, the connecting shaft 16 is connected to the drive shaft 15, and at this time, the kneading container 13
The detection rod 17 is pushed down against the biasing force of the coil spring 18, and the detection mechanism detects that the kneading container 13 is attached based on the lowered position. The rotational speed switching means switches the rotational speed of the drive motor 7 based on the detection signal of the detection means. That is, in this case, the stirring blade 12 corresponds to the rated rotational speed of the high-speed drive motor 7.
, the high-speed drive motor 7 is normally supplied with power and rotated at the rated rotational speed, and is set to be decelerated to the required rotational speed of the rotary blade l113 according to the pulley diameter ratio of the motor pulley 8 and the passive pulley 4. There is.

As shown in FIG. 2, when the turntable 14 is set in the heating chamber 3, the bottom surface of the turntable 14 in this set state is located above the detection rod 17, and the detection rod 17 is By not being pushed down, the detection means detects that it is the turntable 14, and the rotation speed switching means changes the rotational speed to 1 for the kneading container 13.
/1° rotation speed. Here, the relationship between the torque and the rotational speed of the high-speed drive motor 7 is shown in FIG.
The characteristic curve is as shown in (a), and the load torque is (d).
T shown by the line. Then, both lines (A).

The rotation speed NA at point A at the intersection of (d) is turntable 1
The rotation speed N at point B is the rotation speed corresponding to the required rotation speed of 4.
, is the rotation speed corresponding to the required rotation speed of the kneading vessel 13. Therefore, when operating at point B, the high-speed drive motor 7 rotates stably because it is at its rated rotational speed.
When operating at point A, the load torque accompanying the rotation of the turntable 14 is not constant, for example, T as shown by the line (e). ', it becomes very unstable, and with this load variation, it either accelerates along the characteristic curve (a) and operates at point B, or stops rotating at point H. Therefore, the rotational speed of the high-speed drive motor 7 is detected by the aforementioned rotational speed detection means 19, and the rotational speed of the high-speed drive motor 7 is feedback-controlled by the rotational speed control means based on the detected rotational speed. To explain the structure and operation of this device, first, as the rotational speed detection means 19, as shown in FIGS. 5 and 6, a detection disk 21 is fixed concentrically to the motor shaft 20 of the high-speed drive motor 7. At the same time, a photo ink club 22 is fixed to the high speed drive motor 7 with a part of the detection disk 21 sandwiched therebetween. Further, the detection disk 21 is shown in FIG. 6(a) showing its plane and front view, respectively.
As shown in (b), a plurality of slits 23 are arranged at equal intervals along the circumferential edge. Therefore, when a signal as shown in FIG. 7(a) is inputted to the photo ink club 22, the output signal is changed as the detection disk 210 rotates together with the high-speed drive motor 7 (see FIG. 7(b). ) The pulse waveform will be as shown in (). The part of this pulse waveform shown as ``corresponds to the slit 23'', and the cycle of this pulse waveform becomes shorter as the rotation speed increases, and conversely becomes longer as the rotation speed becomes lower (lower rotation speed). The rotation speed is detected by reading the number of output pulses using an LSI (not shown).

The case where phase control is used as the rotation speed control means will be explained with reference to the flowchart in FIG. 3 and the characteristic diagram in FIG. [Step (3)
1)) and this rotational speed is compared with a predetermined rotational speed [step (S2)), and if the detected rotational speed and the predetermined rotational speed are equal, for example, point A of the characteristic curve wc (a) in FIG. The motor torque and load torque match at To, but the load torque is T. To becomes smaller in Figure 4
', the operating point of the drive motor 7 moves from point A to point 0 along the characteristic curve &1 (a), and the rotational speed detection means 19 detects that the rotational speed has become too high. , the rotational speed control means performs feedback control [step (S4)) to reduce the conduction angle, so that the operating point becomes point D of the characteristic curve (c) in FIG. 4.

At point D, the load torque T0' becomes larger than the motor torque of the drive motor 7, so the rotational speed of the drive motor 7 decreases and moves toward point E along the characteristic curve (c). When the rotational speed decreases to this point E, this step (
In step S2), it is determined that the conduction angle has decreased too much, and the conduction angle is controlled to increase (step (S3)), and F of the characteristic curve (b) is
At point F, the load torque is T. Since the motor torque is larger than ', it moves towards point G along the characteristic curve (b). Thereafter, the same operation is repeated to form a loop between points DG, and as a result, the rotational speed of the high-speed drive motor 7 is controlled to the required rotational speed of the turntable 14 indicated by NA.

It should be noted that the present invention is not limited only to the above description and illustrated examples, but may include various modifications without departing from the scope of the claims. For example, the rotational speed detecting means is not limited to the optical means shown in the illustrated example, and any known means such as an encoder may be used.

<Effects of the Invention> As detailed above, according to the high frequency heating device of the present invention,
By using a single drive morph, the kneading container and turntable, which each have different drive rotational speeds, are rotated by switching the rotational speed of the drive motor, so the configuration can be simplified while reducing the number of parts. It is possible to significantly simplify the structure and achieve considerable size reduction and cost reduction.

In addition, as a single drive motor, one with a rated rotation speed corresponding to the required rotation speed of the stirring blade of the kneading vessel on the lower rotation speed side is used. Since the rotation speed of the drive motor is feedback-controlled by detecting the rotation speed of the drive motor, low-speed rotation by the high-speed drive motor can be performed extremely stably. The drive body can be rotationally driven by a single drive motor without any problems.

[Brief explanation of the drawing]

Figures 1 to 7 each show an embodiment of the present invention, Figure 1 is a schematic longitudinal cross-sectional view of a state in which a kneading container is set, and Figure 2 is a schematic longitudinal cross-sectional view of a part of a state in which a turntable is set. 3 is a flowchart of the rotation speed control means, FIG. 4 is a characteristic diagram showing the relationship between rotation speed and motor torque to explain the rotation speed control according to FIG. 3, and FIG. 5 is a rotation speed detection diagram. Partially cutaway front view of the means, Figure 6 (
a) and (b) are respectively a plan view and a front view of the detection disk in Fig. 5, Fig. 7 (a) and (b) are waveform diagrams of the input signal and output signal in Fig. 5, respectively, Fig. 8 and FIG. 9 are a schematic vertical cross-sectional view of a conventional apparatus in which a kneading container is set and a part of a conventional apparatus in which a turntable is set. 3 - Heating chamber 7 - Drive motor 12 - Stirring blade 13 - Kneading container 14 - Turntable 15 - Drive shaft 17 - Detection rod (detection means) 19 - Single rotation speed detection means Patent applicant Sharp Corporation Company agent Patent attorney Nishi 1) New construction 1 drawing 2 Fig. 3 Fig. 5'#47 drawing

Claims (2)

[Claims] (1) A kneading container rotatably equipped with stirring blades inside for kneading cooking ingredients and a turntable for rotating the heated object placed therein can be selectively installed in the heating chamber. In the high-frequency heating device, a single drive motor is used as a rotational drive source for the kneading container and the turntable installed in the heating chamber, and detection of the kneading container and the turntable installed in the heating chamber. 1. A high-frequency heating device comprising: a rotational speed switching means for switching the rotational speed of the drive motor based on a detection result of the detection means. (2) As the drive motor, one having a rated rotation speed corresponding to the required rotation speed of the stirring blade is used, and when the rotation speed detection means of the drive motor and the detection means detects the turntable, 2. The high-frequency heating apparatus according to claim 1, further comprising rotational speed control means for feedback-controlling the drive motor to a predetermined rotational speed based on the rotational speed detected by the rotational speed detection means.