JP2672095B2 - Dust detection device for vacuum cleaner - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dust detector for a vacuum cleaner that detects dust passing through an air passage of the vacuum cleaner. 2. Description of the Related Art Generally, a conventional dust detection device for an electric vacuum cleaner has a configuration as shown in FIGS. 4 and 5. 4 and 5, a light emitting diode 2 is provided in a suction passage 1 extending from a floor suction port of an electric vacuum cleaner to a suction port of a cleaner body, and a photodiode 3 is provided facing the light emitting diode 2. The light from the light emitting diode 2 was received. When a large amount of dust 5 is contained in the suction airflow 4 flowing through the suction passage 1 during the cleaning work of the photodiode 3, the light from the light emitting diode 2 is blocked by the dust 5, and the amount of light received by the photodiode 3 is reduced. The output decreases as the amount decreases. As a result, the transistor 6 having the photodiode 3 connected to the base is turned off. As a result, the transistor 7 at the next stage is turned off, the transistors 8 and 9 are turned on, and the light emitting diode 10 serving as a display unit is turned on. This indicates that the light-emitting diode 10 is sucking dust while the light-emitting diode 10 is on, and the worker continues the cleaning work. On the other hand, when dust in the intake air flow disappears, the amount of light received by the photodiode 3 increases and the output increases, so that the transistors 6 and 7 are turned on, whereby the transistors 8 and 9 are turned off and the light emitting diode 10 is turned off. .
Since turning off the light emitting diode 10 means that there is no dust to be sucked, the worker finishes the cleaning work. DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, in the dust detection device for the conventional vacuum cleaner described above, the light emitting diode 2 and the photodiode 3 are provided as detectors that only optically detect dust regardless of the size of the intake air volume. ing. However, since the amount of light received by the photodiode 3 differs depending on the speed at which dust passes between the detectors, even if dust of the same size is sucked in, the level of display of the light emitting diode 10 depends on the speed at which the dust passes through, that is, the amount of sucked air. There was a problem that (brightness) was different. The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a dust detection device for an electric vacuum cleaner in which the display level of the light emitting diode does not change depending on the amount of intake air. Means for Solving the Problems In order to solve the above-mentioned conventional problems, the dust detection device for an electric vacuum cleaner of the present invention includes a light emitting unit that emits light into an air passage through which dust flows, and a light emitted from the light emitting unit. A light-receiving unit that receives light and outputs a signal according to the amount of received light, an amplification unit that amplifies the signal from this light-receiving unit, a power control unit that controls the intake air volume, and a power control that detects the set level of the intake air volume. A level detection unit, and an amplification degree setting unit that sets the amplification degree of the amplification unit based on an output signal from the power control level detection unit,
And a display unit that changes the display level according to the output signal of the amplification unit. Action With the above configuration, the output signal of the light receiving unit is conventionally small when the suction air volume of the vacuum cleaner is large, and conversely the output signal of the light receiving unit is large when the suction air volume is small. Is large and the amplification degree is changed so that the amplification degree is reduced when the intake air volume is small, the output signal from the light receiving unit changes depending on the intake air volume for dust of the same size. However, the influence of the suctioned air volume is compensated by that amount, and the output signal from the amplifying unit is always almost constant, and it is possible to display at the same level. An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a dust detection device for an electric vacuum cleaner showing an embodiment of the present invention. In FIG. 1, reference numeral 21 denotes a light emitting unit that emits light into an air passage through which dust flows, and 22 denotes a light receiving unit that receives light from the light emitting unit 21 and outputs a signal according to the amount of received light. It is provided so as to face the light emitting unit 21. The output signal V _S from the light receiving unit 22 is amplified by the amplification unit 23, and then the output signal V _d is output to the display unit 24. A power control unit 25 controls the suction air volume of dust by controlling the rotation speed of the motor 26, and the set level for setting the suction air volume is detected by the power control level detection unit. The amplification degree setting unit 28 sets the amplification degree of the amplification unit 23 based on the setting level detection signal detected by the unit 27. 29 is a power supply. In the above configuration, in the air passage through which dust flows, if the suction air volume is large, the dust flows fast, and in the opposite case, the dust flows slowly and passes through the passage. The output signal V _S is small, and conversely, when the intake air volume is small, the output signal V _S is large. On the other hand, the operation of the amplification degree setting unit 28 is reversed, that is,
If the amount of intake air is large, the amplification degree is large, and if the amount of intake air is small, the amplification degree is set small, so that the output signal V _d from the amplification unit 23 can be at a constant level regardless of the amount of intake air. . 2 (a) to 2 (c) show waveforms of each part of the power control unit 25 for controlling the rotation speed of the motor 26, and FIG.
3, a specific configuration example of the amplification degree setting unit 28 and the power control level detection unit 27 will be shown, and a method of setting the output signal V _d from the amplification unit 23 to a constant level regardless of the intake air amount will be described in more detail. Conventionally, phase control has been used as a method of controlling the power of the motor 26. That is, a triangular wave V _c is generated as shown in FIG. 2 (c), and a trigger pulse is generated as shown in FIG. 2 (b) when the set level V _r is reached. Then, the trigger pulse causes the motor 26, which has been stopped until then, to start rotating as shown in FIG. 2 (a), but when the power supply voltage becomes 0 volt, the power supply to the motor 26 is stopped and the next Wait for the trigger pulse to occur. In other words, due to the phase shift of the trigger pulse, the motor 26
Controls the number of revolutions of, and determines the size of the intake air volume by the number of revolutions. In FIGS. 2A to 2C, the case where the intake air amount is small is shown by a solid line and the case where the intake air amount is large is drawn by a broken line, but this difference is due to the set level V _r . That is, the set level V _r
When is set low, a large power is input to the motor 26 by the phase control of the power supply voltage, and conversely, when the set level V _r is set high, a small power is input to the motor 26. It controls the rotation speed of 26. Therefore, it can be seen that this set level V _r should be investigated in order to detect the amount of intake air that changes depending on the rotation speed of the motor. In FIG. 3, the power control level detection unit 27 includes a comparator 30 to which the set level V _r is input from the power control unit 25, and a comparison voltage 31 for checking the magnitude of the set level V _r ,
The output of the comparator 30 is the switching element 32 of the amplification degree setting unit 28.
Is input to The amplification degree setting unit 28 includes resistors 33, 34, and 35 for setting the amplification degree of the amplification unit 23, and the amplification unit 23
In the amplifier 36, these resistors 33, 34 and 35 are connected to the input / output terminals to form an inverting amplifier circuit, and the amplification degree is selected by using, for example, an analog switch as a switching element. In FIG. 3, when the set level V _r is large (the amount of intake air is small), the output level of the comparator 30 becomes “H” and the switching element 32 is turned on. Therefore, the feedback resistance value of the amplifier 36 is resistance. 34 and 35 are the values connected in parallel, and the degree of amplification is small. However, when the set level V _r is small (the intake air volume is large), the output level of the comparator 30 becomes “L” and the switching element 32 becomes OFF,
As the feedback resistance value, only the value of the resistor 35 is obtained, and the amplification degree becomes large. Therefore, the output signal V _d from the amplification unit 23 can be kept at a constant level regardless of the intake air volume. EFFECTS OF THE INVENTION As described above, according to the present invention, a power control level detection unit that detects the set level of the intake air volume, and an amplification degree setting that sets the amplification degree of the amplification unit by the output signal from this power control level detection unit. Since the gain setting unit compensates for the change in the output signal from the light receiving unit due to the intake air volume, the output signal of the amplification unit becomes almost constant regardless of the intake air volume, and the display at the same level is provided. It will be possible.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a dust detection device for an electric vacuum cleaner showing an embodiment of the present invention, FIG. 2 is an operation waveform diagram of a power control unit in the dust detection device, and FIG. FIG. 4 is a circuit diagram showing a specific configuration of an amplification unit, an amplification degree setting unit and a power control level detection unit in the dust detection device, FIG. 4 is a circuit diagram of a dust detection device of a conventional vacuum cleaner, and FIG. It is a principal part sectional drawing of the electric vacuum cleaner which attached the light-emitting device and the light-receiving device in the conventional dust detection apparatus. 21 ...... emitting unit, 22 ...... light receiving unit, 23 ...... amplification unit, 24 ...... Display unit, 25 ...... power control unit, 27 ...... power control level detecting unit, 28 ...... amplification degree setting unit, V _S ...... Output signal of light receiving part,
V _d …… Amplifier output signal, V _r …… Set level.

Claims (1)

(57) [Claims] A light emitting unit that emits light into an air passage through which dust flows, a light receiving unit that receives the light from the light emitting unit and outputs a signal according to the amount of received light, and an amplification unit that amplifies the signal from the light receiving unit, A power control unit for controlling the intake air amount, a power control level detection unit for detecting the set level of the intake air amount, and an amplification degree setting unit for setting the amplification degree of the amplification unit by an output signal from the power control level detection unit. A dust detection device for an electric vacuum cleaner, the display unit changing a display level according to an output signal of the amplification unit.