JPH05253143A - Dust detection device for vacuum cleaner - Google Patents

Abstract

(57) [Abstract] [Purpose] A dust detection device for an electric vacuum cleaner is connected in parallel with a sensitivity setting unit 110 for setting the dust detection sensitivity and an amplification degree setting unit 112 for setting the amplification degree of the amplification unit 105. Set the amplification degree. [Configuration] Sensitivity setting unit 110 for setting dust detection sensitivity
Since the switch 111 is not directly connected to the OP amplifier 109 having high input impedance, it is strong against hum and does not malfunction due to the influence of the wiring length.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dust detector for an electric vacuum cleaner which detects dust passing through an air passage of the electric vacuum cleaner.

[0002]

2. Description of the Related Art Conventionally, the structure of a dust detection device for an electric vacuum cleaner of this type has generally been as shown in FIGS. The configuration will be described below.

As shown in the figure, a light emitting diode 4 is provided in a suction passage 3 extending from a floor suction port 1 of an electric vacuum cleaner to a suction port 2 of a cleaner body, and a phototransistor 5 is provided facing the light emitting diode 4. For receiving light from the light emitting diode 4. When dust is included in the suction airflow flowing through the suction passage 3 during the cleaning work of the phototransistor 5, the light from the light emitting diode 4 is blocked by the dust, and the amount of light received by the phototransistor 5 decreases and the phototransistor 5 outputs. The voltage increases. As a result, the output voltage of the amplification unit 10 including the resistors 6 and 7, the capacitor 8 and the OP amplifier 9 once decreases and then increases. Here, the amplification degree of the amplification unit 10 is set by (resistance value R7) / (resistance value R6). Then, the processing time setting unit 11 receives the output of the amplifying unit 10 and after the discharging time set by the values of the resistor 12 and the capacitor 14, the resistor 13 and the capacitor 14 are discharged.
The charging process is performed for the time set by the value of. Therefore, the output voltage of the comparison unit 18 including the resistors 15 and 16 and the OP amplifier 17 is 5 V in a steady state, but decreases to an arbitrary voltage determined by the discharge time each time dust passes. After that, the operation of returning to 5V again after an arbitrary charging time is repeated. The output of the comparison unit 18 sets the drive time of the fan motor 19 and the display unit 20. The fan motor 19 is powered up for an arbitrary time, and the display element provided in the display unit 20 is turned on to generate dust. Notifying the detection.

The dust detection sensitivity is set to a variable resistor as the resistor 6 in the amplifying section 10 so that it can be widely applied from fine sensitivity setting to general sensitivity, and further to sensitivity setting of a carpet with a lot of waste hair. I am using.

[0005]

However, in such a conventional configuration in which the variable resistor is used as the resistor 6 in the amplifying portion 10 in order to set the dust detection sensitivity, the OP amplifier 9 having a high impedance input is used. Since the variable resistor is connected in series, there is a problem that due to the mounting of the control circuit, a malfunction due to a hum easily occurs due to an increase in the wiring length between the variable resistor and the OP amplifier.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a dust detection device for an electric vacuum cleaner which is excellent in usability and operability.

[0007]

In order to achieve the above object, the present invention provides a light emitting section which emits light in an air passage through which dust flows, and a light receiving section which receives the light of the light emitting section and outputs a signal corresponding to the amount of received light. A light receiving unit for outputting, an amplification unit for amplifying an output signal of the light receiving unit, and an amplification degree setting unit for setting the amplification degree of the amplification unit, and a sensitivity setting unit for setting the detection sensitivity of dust and the amplification degree. The first problem solving means is to connect the setting unit in parallel and set the amplification degree.

Further, in the above structure, a shorting circuit is provided in the sensitivity setting section as a second means for solving the problem.

[0009]

According to the present invention, since the sensitivity setting unit for setting the dust detection sensitivity is not directly connected to the OP amplifier having a high input impedance by the first problem solving means, the wiring length is affected by the mounting of the control circuit. It will not be done.

Further, by the second means for solving the problem, it is possible to always select the amplification degree before or after the amplification degree switching even when the amplification degree is switched.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG.

In FIG. 1, reference numeral 101 denotes a light emitting portion that emits light into an air passage through which dust flows, and uses a light emitting diode 102. Reference numeral 103 denotes a light receiving unit that receives light from the light emitting unit 101 and outputs a signal according to the amount of received light, and uses a phototransistor 104. Reference numeral 105 is an amplification unit, which includes resistors 106 and 107, a capacitor 108, and an OP amplifier 10.
It is composed of nine. Reference numeral 110 denotes a sensitivity setting unit for setting the dust detection sensitivity, which is a 3-position switch 11
1 is used and is set to the “H” position when the high sensitivity is set, the “M” position when the medium sensitivity is set, and the “L” position when the low sensitivity is set. Reference numeral 112 denotes an amplification degree setting unit composed of a plurality of resistors 113 and 114, which is connected in parallel with the sensitivity setting unit 110 and has a sensitivity setting unit 11
When the resistance value of the amplification degree setting unit 112 due to 0 is R112, when high sensitivity is set: R112 = 0Ω, when medium sensitivity is set: R11
2 = resistance value R113, low sensitivity setting: R112 = resistance value (R113 + R11
4) In this configuration, since the input impedance of the amplification unit 105 is the resistance value (R106 + R112), the amplification degree at each sensitivity setting is as follows: High sensitivity setting: R107 / R106, Medium sensitivity setting: R107 / (R106 + R113), Low sensitivity setting Time: R107 / (R106 + R113 + R1
14) is given in. At this time, since the switch 111 is not directly connected to the OP amplifier 109 having a high input impedance, even if the distance between the two is slightly increased, the wiring length is not affected.

Now, considering the moment when each sensitivity setting is switched, the switch generally has an infinite resistance value, that is, an open state. Therefore, the sensitivity switching moment is from the infinite resistance value. It is connected to a resistance value and becomes an operating state in which the amplification degree apparently becomes large, and malfunctions as if dust was detected even though dust was not detected. For example, considering the moment of switching from the high sensitivity setting to the medium sensitivity setting, the amplification degree changes as shown below.

R107 / R106 (high sensitivity setting) → R107 / (R106 + R113 + R114) (low sensitivity setting) → R107 / (R106 + R113) (medium sensitivity setting) That is, high sensitivity, low sensitivity, and medium sensitivity are switched.

This problem is solved by the following embodiment, which will be described below with reference to FIGS. 2 and 3. In addition,
In the figure, components that perform the same operations as those in the above-described embodiment are designated by the same reference numerals, and description thereof will be omitted here.

In FIGS. 2 and 3, reference numeral 120 denotes a sensitivity setting unit for setting the dust detection sensitivity, which uses a 3-position switch 121 having a shorting circuit configuration.
Set to'H 'position for high sensitivity setting,' M 'position for medium sensitivity setting, and'L' position for low sensitivity setting. The amplification factor at each sensitivity setting is the same as in the above embodiment, when high sensitivity is set to R107 / R106, when medium sensitivity is set to R107 / (R106 + R113), and when low sensitivity is set to R107 / (R106 + R113 + R1).
14) is given in. In addition, switching of each sensitivity setting, for example,
Considering the instant of switching from the high sensitivity setting to the medium sensitivity setting, the operation of the terminal S is as follows.

Connect only to'H 'position (high sensitivity setting) → Connect to both'H' position and'M 'position (high sensitivity setting) → Connect only to'M' position (medium sensitivity setting) It switches from high to medium sensitivity without going through sensitivity. In the opposite case, the sensitivity does not decrease. That is, even when the amplification degree is switched, the amplification degree before or after the amplification degree can be selected without fail.

[0018]

As is apparent from the above embodiments, according to the present invention, since the sensitivity setting unit for setting the dust detection sensitivity is not directly connected to the OP amplifier having high input impedance, the control circuit is mounted. Stable operation can be obtained without being affected by the wiring length.

Further, by using the switch having the shorting circuit structure, it is possible to select the amplification degree before or after the amplification degree switching without fail, and it is possible to prevent a malfunction at this moment.

[Brief description of drawings]

FIG. 1 is a block circuit diagram of a dust detection device for an electric vacuum cleaner according to an embodiment of the present invention.

FIG. 2 is a block circuit diagram of a dust detection device for an electric vacuum cleaner according to another embodiment of the present invention.

FIG. 3 is an operation explanatory view of a sensitivity setting switch of the dust detection device of the electric vacuum cleaner.

FIG. 4 is a block circuit diagram of a conventional dust detector for an electric vacuum cleaner.

FIG. 5 is a cross-sectional view of the main parts of the dust detection device of the electric vacuum cleaner.

[Explanation of symbols]

 101 light emitting unit 103 light receiving unit 105 amplifying unit 110 sensitivity setting unit 112 amplification degree setting unit 120 sensitivity setting unit

Claims (2)

[Claims] 1. A light emitting unit that emits light into an air passage through which dust flows, a light receiving unit that receives the light of the light emitting unit and outputs a signal according to the amount of received light, and an output signal of the light receiving unit is amplified. An amplification unit and an amplification degree setting unit for setting the amplification degree of the amplification unit are provided, and the sensitivity setting unit for setting the dust detection sensitivity and the amplification degree setting unit are connected in parallel to set the amplification degree. The dust detection device for the electric vacuum cleaner configured in. 2. A shorting circuit is provided in the sensitivity setting section,
2. The dust detection device for an electric vacuum cleaner according to claim 1, wherein the amplification degree is always selected before or after the amplification degree is switched.