JPS5940015B2 - Rotary cooker rotation speed detection device - Google Patents

Description

[Detailed Description of the Invention] The present invention is a rotating household rotary cooker that integrates a juicer, mixer, kneader, speed cutter, etc., and allows one machine to be used for these multipurposes by replacing attachments. It concerns a number detection device.

In such complex machines, it is necessary to produce a rotational speed commensurate with the attachment, and when the reduction ratio is kept constant,
The load ratio will be significantly different. In order to accurately control the rotation speed of such a cooking device, it is necessary to accurately detect the speed or rotation speed. An object of the present invention is to provide a device that can quickly and accurately detect the rotational speed and is suitable for use for such purposes. FIG. 1 shows an embodiment of the rotation speed detection device of the present invention.

In the figure, 1 is a rotary cooker electric motor, 2 is a transformer connected to an AC commercial power source, and the transformer 2 is connected to a resistor 3, a diode 4, and a transistor 5, and the output of the transistor 5 is a rectangular wave synchronized with the power frequency. is obtained. This rectangular wave is connected to the interrupt input terminal IRQ of the microcomputer T. On the other hand, the electric motor 1 is provided with a magnet 8 that rotates in conjunction with the magnet 8, which generates a pulse signal at a frequency proportional to the number of rotations of the electric motor in the Hall IC 9, and this pulse signal is sent to the counter input terminal T of the microcomputer T.
Connected to C. The magnet 8 is, for example, as shown in FIG.
As shown in Figure 2, increasing the pulse frequency by providing multiple poles is convenient for detecting the rotational speed in a short time.

As is well known, the Hall IC 9 is an element that detects a Hall voltage using the Hall effect. Now, if we take the multi-pole magnet 8 as shown in Fig. 2a as an example, the NS poles are magnetized alternately along the circumferential surface, and there are 8 NS poles each, for a total of 16 poles, so this magnet 8 An alternating magnetic field is applied on the surface of the Hall IC 9 by the rotation of , and eight pulses are obtained per rotation. Instead of the rotating magnet and Hall IC, a similar pulse signal can be obtained by rotating a disk 12 having a slit 13 in conjunction with the motor 1 as shown in FIG. can. Next, the rotation speed detection operation will be explained with reference to FIG.

At the fall of the rectangular wave IT synchronized with the power supply waveform 16 obtained from the transistor 5, the microcomputer 7 is interrupted to obtain a time base, and during that time the T from the Hall IC 9 is
Count the number of pulses of the C input signal 18. For example, if the AC frequency of the power supply is 60 Hz and the microcomputer counter counts 10 pulses of the input signal 18, then
The rotation speed N of the electric motor 1 is determined by the microcomputer 7 (where f is the power supply frequency, PO is the number of pulses per rotation, and P
n is the number of pulses counted).

The number of rotations N counted in this way is displayed on the display 11. In this way, the number of revolutions can be known without counting the number of pulses per second, and control operation can be started immediately in the next cycle, making it possible to detect the number of revolutions with a quick response. The quantization error in the above example is as follows, and although it is difficult to precisely detect the rotational speed with about 16 poles, it is practically sufficient for detecting the rotational speed of something like a rotary cooker.

In order to further increase the accuracy of rotation speed detection, magnet 8
Just increase the number of magnetic poles. For example, if a magnet with 100 poles is used, 50 pulses can be obtained per revolution, so the quantization error is 181 υυ difference is N=? = 1 = 1.2 rps, and the detection accuracy can be improved.

Also, if a diode bridge is inserted after the transformer 2 in Fig. 1 to obtain pulses through full-wave rectification, the voltage will be 1/2 f.
It goes without saying that it is also possible to detect the rotational speed between the two. FIG. 4 shows a flowchart of the detection device. In this way, according to the rotation speed detecting device of the present invention, the rotation speed of the electric motor can be quickly detected and controlled, or it can be digitally displayed.

[Brief explanation of drawings]

1 is a circuit diagram of an embodiment of the present invention, FIG. 2 is a plan view a of a rotating magnet, and an example b of an optical pulse generator replacing it. FIG. 3 is an explanatory diagram of the operation of FIG. 1, and FIG. The figure is a flowchart of the detection device of the present invention. 1...Electric motor, 2...Transformer, 5...
...Transistor, 7...Microcomputer, 8...Rotating magnet, 9...
・Hall ICllll...Indicator.

Claims (1)

[Claims] 1 A device that generates a pulse signal with a frequency proportional to the rotation speed of the electric motor in conjunction with a cooking electric motor, and a pulse generated by the pulse signal generator between 1/f or 1/2 f of the time base frequency f. A rotational speed detection device for a rotary cooker, comprising: a device for counting the number of pulses; and a device for detecting the rotational speed per second of the electric motor from the number of pulses counted by the counting device and a time base frequency.