JPH0638912A - Dust detecting device for vacuum cleaner - Google Patents

Abstract

PURPOSE:To obtain a device for constantly detecting dust by calculating the amount of dust with collision frequency of dust by the use of a piezoelectric element. CONSTITUTION:A dust sensor 4 made of piezoelectric element is embedded in a nozzle 2 and covered with a flexible protective plate 6. Numeral 5 is a signal producing circuit from the sensor. With a cleaner is on, a suction air current flows through the nozzle. Dust in the air current hits against the protective plate 6 at a bent. Then the plate 6 deforms and the dust sensor 4 also deforms locally to produce an output signal. That is, there is a correlation between the amount of dust and the strength and frequency of the output signal, and the amount of dust is calculated by the processing of signal of the sensor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention uses a piezoelectric element,
The present invention relates to a detection device that detects the amount of passing dust and a cleaner using the detection device.

[0002]

2. Description of the Related Art In recent years, there has been an increasing demand for high-value-added vacuum cleaners that control suction force according to the amount of dust and judge and display the state of dirt in a room. To detect the amount of dust for that purpose, a photocoupler or the like which is a combination of a light emitting diode and a phototransistor is used, and a method of optically detecting the amount of dust that crosses the optical axis is generally used.

[0003]

In the case of the optical type,
The initial measurement accuracy is high, but as a result of suctioning various dusts during long-term use, dust adheres to the windows of both the light emitting part and the light receiving part, and the light intensity is significantly impaired. There was a drawback that it decreased.
Possible causes of dust adhesion include dust adhesion due to friction and dust due to charging effect of photocoupler window material, and dirt on the window due to dust containing liquid at the time of suction. Methods such as cleaning at intervals and coating the window with an antistatic agent have been adopted, but they are insufficient and there is a problem that the dust detection accuracy decreases.

The present invention solves the above-mentioned problems, and provides a dust detection device of low cost and high reliability, and a cleaner using the dust detection device.

[0005]

In order to solve the above-mentioned problems, the present invention uses a piezoelectric element having electrodes on both sides of a piezoelectric body as a dust detection device. Further, the dust detector is arranged at an arbitrary position of the dust suction path, detects dust passing through the dust suction path, and controls driving according to the detected amount.

[0006]

With the above-described structure, the present invention uses the piezoelectric element for detecting the dust passing through the dust suction path, and thus enables stable dust detection that is not affected by dirt on the window material. .

Further, it is possible to provide a vacuum cleaner of high precision drive control in which drive control is performed according to the detected amount of dust passing through the dust suction path.

[0008]

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

FIG. 1 is a diagram showing a schematic structure of a vacuum cleaner according to an embodiment of the present invention. A vacuum cleaner body 3 is provided with a suction nozzle 2 and a dust sensor 1 is provided at a bent portion of the nozzle. Install.

(First Embodiment) A more detailed description will be given with reference to FIG. A dust sensor 4 made of a piezoelectric element is embedded in the nozzle 2 and covered with a flexible and flexible protective plate 6. Reference numeral 5 is a signal line from the sensor. Now, when the vacuum cleaner is turned on, a suction airflow flows in the nozzle, and if dust is contained in the airflow, the suction airflow collides with the protection plate 6 of the bent portion. At this time, the protective plate 6 is deformed, and the dust sensor 4 is also locally deformed, so that an output signal is obtained. That is, there is a correlation between the dust amount and the intensity and frequency of occurrence of the output signal, and the dust amount can be inferred by the signal processing of the sensor.

FIG. 3 shows an example of sensor signal output in actual cleaning. As shown in (a) in the figure, after starting suction,
While the dust is being sucked, the output voltage from the sensor is high, and the output decreases as the dust decreases. now,
When output values above a certain level were sampled by signal processing, the results shown in (b) in the figure were obtained, and it was found that the dust amount can be calculated from the intensity and frequency of occurrence of the output signal. For signal processing, a method of obtaining a membership function related to the dust type according to the signal intensity and the dust amount according to the signal generation frequency and inferring it by fuzzy inference was also effective.

As described above, the dust detection device can be realized by processing the output signal from the dust sensor using the piezoelectric body.

It has been found that the dust sensor functions as a dust detection device as long as the air flow hits the wall surface even if only a part of the dust sensor is installed.

(Example 2) As a result of examining various piezoelectric sensors as a dust sensor, polyvinyl fluoride or
It was found that a sensor using a film-shaped organic piezoelectric material made of polyvinylidene fluoride can be used with good flexibility.

FIG. 4 shows a schematic view of this sensor section. This sensor preferably has a structure in which electrodes 8 and 9 made of metal such as aluminum are provided on both surfaces of the organic piezoelectric body 7. In the figure, 10 is a lead wire of the electrode, and 11 is a connecting portion for electrically connecting the lead wire and the electrode. Although not shown in the drawing, it is usually preferable to coat the electrodes with an organic material in order to improve reliability.

In addition to the above-mentioned organic piezoelectric material, a piezoelectric element made of an inorganic piezoelectric material such as barium titanate, lead titanate, lithium tantalate, lithium niobate, etc. was used. It could be used as a sensor.

(Embodiment 3) The dust sensor made of the organic piezoelectric material shown in Embodiment 2 may be subject to electromagnetic noise in an indoor environment, but the dust sensor shown in FIG.
By adopting a structure in which one electrode connected to the ground side covers the entire outside and the other electrode is back-to-back inside, a dust detection device that is not affected by external electromagnetic noise was possible.

(Embodiment 4) The following vacuum cleaner control was performed based on the signal processing information of the dust detection device. (1) The room cleanliness level is displayed according to the amount of dust and the type of dust. (2) Automatic suction force control is performed to increase the suction force when the dust amount is large or when the dust amount is heavy in accordance with the amount of dust and the type of dust. (3) Floor brush drive control is performed when the amount of dust is large or the amount of heavy dust is large in accordance with the amount of dust and the type of dust. By performing the above control, a higher performance energy-saving vacuum cleaner was realized.

[0019]

As is apparent from the above description, the present invention uses the piezoelectric element as the dust sensor and calculates the dust amount from the change in the electric signal of the sensor. Therefore, the present invention is dependent on the dust adhering to the detecting portion. It is possible to indirectly and accurately detect the amount of dust over a long period of use without any need.

[Brief description of drawings]

FIG. 1 is a schematic view of a vacuum cleaner according to an embodiment of the present invention.

FIG. 2 is an external view of a mounting portion of a dust detection device according to an embodiment of the present invention.

FIG. 3 is an explanatory diagram of signal processing of dust detection according to an embodiment of the present invention (a) shows a sensor output, and (b) shows an output from a signal processing unit.

FIG. 4 is a perspective view showing a cross-sectional structure of a dust sensor according to an embodiment of the present invention.

[Explanation of symbols]

 2 Nozzle 4 Dust sensor 5 Signal line 6 Protection plate

Claims (4)

[Claims] 1. A dust detecting device using a piezoelectric element for a dust detecting portion. 2. The piezoelectric element is film-shaped, and a foil-shaped first electrode and a second electrode are provided on both surfaces of the piezoelectric element, and the surface is covered with a protective film. The dust detection device described. 3. The dust detection device according to claim 2, wherein the film-shaped piezoelectric element has a double structure, and the outer electrode covers the inner electrode. 4. A dust detection device comprising a piezoelectric element is provided, and any one or any two or all of the dust amount display, suction force control, and floor brush drive control according to the detected amount can be performed. Characteristic vacuum cleaner.