JP2000279354A - Dust sensor for vacuum cleaner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low-priced and highly sensitive dust sensor that fully unnecessary to align each of the optic axes of a floodlight and an optical receiver, that does not require great precision in material processing and assembling, and that stably obtains constant sensitivity in dust detection, not relying on a product. SOLUTION: A floodlight 2 illuminates the inside of pipe 1 for dust suction in a vacuum cleaner, while an optical receiver 3 detects brightness inside the pipe 1, which is illuminated with the floodlight 2. The floodlight 2 and the optical receiver 3 are arranged on an even part parallel to a central axis in the longitudinal direction of the pipe 1, as the floodlight 2 and the optical receiver 3 are separated a little and are parallel to each optic axis. As dust 10a, 10b pass through the pipe 1, a beam of light from the floodlight 2 is blocked off by the dust 10a and is reflected diffusely by the dust 10b. Because of this, the brightness of relevant part inside the pipe 1 relatively declines or rises, and an output value of the optical receiver 3 also decreases or increases. Therefore, the presence of dust is detected by detecting a change in the increase or decrease of this output value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dust sensor provided in a dust suction path in a vacuum cleaner and detecting whether dust is present in the air sucked through the suction path.

[0002]

2. Description of the Related Art As a dust sensor of this type, as shown in a schematic cross-sectional view of FIG. 3, in a dust suction path (usually a pipe having an inner diameter of approximately 30 mm in diameter), a diameter direction of the pipe 1 is considered. , A light emitter (for example, an infrared LED) 2 is arranged on one side, and a light receiver (for example, a photodiode) 3 is arranged on the other side such that the respective optical axes are completely coincident on the same straight line.

[0003] In this dust sensor, dust 10 is pipe 1
When the light does not pass through, the light from the light projector 2 directly enters the light receiver 3 and the amount of light received by the light receiver 3 is constant.
However, when the garbage 10 passes through the pipe 1,
Since part of the light beam is blocked by the dust 10, the amount of light received by the light receiver 3 decreases. Therefore, the presence or absence of dust 10 is detected based on whether or not the output value of the light receiver 3 decreases, and if there is dust, it is displayed on a display (eg, LED).

On the other hand, as another dust sensor, as shown in a schematic longitudinal sectional view in FIG. 4, a light projecting device 2 and a light receiving device 3 are slightly obliquely arranged on a straight line parallel to the central axis of the pipe 1 in a longitudinal direction. In some arrangements, the optical axis of the light projector 2 and the optical axis of the light receiver 3 are made to coincide with each other, and at least the inner surface of the pipe 1 facing the light projector 2 and the light receiver 3 is made light-reflective. In this dust sensor, when the dust 10 does not pass through the pipe 1, the light beam from the projector 2 is reflected by the opposite surface of the pipe 1 and
And the amount of received light is constant. Garbage 10 is pipe 1
, The amount of reflected light received by the light receiver 3 decreases. Therefore, similarly, the presence or absence of the dust 10 is detected based on whether or not the output value of the light receiver 3 decreases, and the presence or absence of the dust is notified on the display.

[0005]

In any of the conventional dust sensors shown in FIGS. 3 and 4, the light emitter 2 and the light receiver 3 are positioned so that their optical axes are completely coincident on the same straight line. Therefore, high precision is required for the holes for mounting the light projector 2 and the light receiver 3 formed in the pipe 1 and for mounting the light projector 2 and the light receiver 3 to these holes, and the processing and assembly of the parts can be performed with high accuracy. Otherwise, the quality will vary. However, in mass production usually performed with this kind of vacuum cleaner, it is difficult to make dust detection sensitivity uniform for each product, and conversely, trying to make dust detection sensitivity as constant as possible increases costs. .

Accordingly, the present invention has been made in view of such a problem, and has a low cost even though there is no need to match the optical axis of the projector and the optical axis of the light receiver with high accuracy. An object of the present invention is to provide a dust sensor for a vacuum cleaner that can easily stabilize the detection sensitivity of dust.

[0007]

To achieve the above object, a dust sensor for a vacuum cleaner according to the present invention is a dust sensor provided in a dust suction path in a vacuum cleaner, wherein the dust sensor is provided in a dust path. When there is dust for a constant value signal output from this receiver, which does not change when there is no dust, and a light emitter for illuminating the inside, a light receiver for detecting the brightness in the suction path illuminated by this light emitter, and In the dust sensor provided with processing means for detecting the presence or absence of dust due to the variation of the signal, the light emitter and the light receiver are slightly separated from each other on a straight line portion substantially parallel to the longitudinal center axis of the suction path, and each light beam It is characterized in that the axes are arranged substantially parallel.

In this dust sensor, when dust does not pass through the suction path, the relevant portion in the suction path (particularly, the surrounding area of the light receiver) is kept at a constant brightness by the illumination of the light projector, and the brightness is adjusted to the light receiver. And the electrical signal from the light receiver is also kept at a constant value. When dust is sucked into the atmosphere having a constant brightness, in some cases, the amount of light emitted from the light emitter is blocked by the dust and decreases. The value of the electrical signal output from the vessel decreases in response to low levels of brightness. Also, in some cases, depending on the location of the dust in an atmosphere of constant brightness, the light beam from the projector is irregularly reflected on the surface of the dust, and the brightness detected by the light receiver is due to the scattered light due to the irregular reflection. Relatively increasing, the value of the electrical signal output from the light receiver increases corresponding to the high level of brightness.

That is, the dust sensor of the present invention does not detect a decrease in the absolute value of the amount of light radiated from the light emitter and reaches the light receiver, but detects a certain brightness due to the presence of dust in an atmosphere of a certain brightness. Is detected, and the presence or absence of dust and the amount of dust are detected by detecting a change in which the brightness relatively increases or decreases. Therefore, according to the present invention, there is no need to exactly align the optical axes of the light emitter and the light receiver on the same straight line, and high precision is not required for processing or assembling parts, and is constant regardless of the product. Not only can the dust detection sensitivity be obtained stably, but also a highly sensitive dust sensor can be provided at low cost.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described based on embodiments. The configuration of the dust sensor for a vacuum cleaner according to the embodiment is shown in a schematic longitudinal sectional view in FIG. In this embodiment, the light emitter (for example, infrared LED) 2 and the light receiver (for example, photodiode) 3 are a dust suction path in a vacuum cleaner (a pipe having an inner diameter of about 30 mm).
1 are arranged slightly apart from each other on a straight line parallel to the central axis in the longitudinal direction, and are arranged so that each optical axis is parallel. That is, the straight line connecting the light projector 2 and the light receiver 3 is parallel to the central axis of the pipe 1 in the longitudinal direction, and the optical axes of the light projector 2 and the light receiver 3 match the diameter direction of the pipe 1 and are parallel. ing.

However, the optical axes of the light projecting device 2 and the light receiving device 3 do not necessarily have to be parallel with high accuracy, and the relevant portion in the pipe 1 illuminated by the light beam from the light projecting device 2 (particularly, the peripheral portion of the light receiving device 3). If the brightness can be detected by the light receiving device 3, it is sufficient if the brightness is substantially parallel. According to this dust sensor, the light beam from the light projector 2 is irradiated toward the opposite side of the pipe 1, and the atmosphere in the portion inside the pipe 1 becomes bright, and the brightness is received by the light receiver 3.
Output an electrical signal. When dust does not pass through the pipe 1, the brightness of the atmosphere in the pipe 1 is constant, so that the output signal from the light receiver 3 is kept at a constant value.

When the dusts 10a and 10b pass through the pipe 1, the light rays from the projector 2 are affected by the dusts 10a and 10b, but there are two ways of the influence. First, when the dust 10a blocks the light beam, the brightness of the corresponding portion in the pipe 1 is relatively reduced.
The output value from is also reduced. On the other hand, when the dust 10b irregularly reflects the light beam, the scattered light due to the irregular reflection relatively increases the brightness of the portion in the pipe 1, so that the output value from the light receiver 3 also increases. Accordingly, when dust passes through the pipe 1, the output value from the light receiver 3 decreases or increases. If there is a change in the increase or decrease, it is determined that dust is present, and the fact is indicated by the indicator 27 of the following processing means. Be informed.

FIG. 2 is a block diagram showing an example of the circuit configuration of the entire dust sensor including the light projector 2, light receiver 3, processing means, and the like. In the circuit configuration of FIG.
Driven by the current supplied by 0, the amount of light emitted from the projector 2 is stably maintained at a constant value. Receiver 3
Is amplified by an amplifier 21 and further amplified by another amplifier 23. As described above, the brightness is disturbed by the passage of dust through the pipe 1, and the electrical signal from the photodetector 3 exhibits a ± pulse waveform.
The output signal from the signal 3 is converted into a unidirectional pulse signal by the full-wave rectifier 24. The pulse signal is converted into a voltage signal having a certain time constant by the integrator 25, and the voltage signal is converted into a continuously changing current by the V / I converter 26. ) The brightness of 27 changes continuously. In this embodiment, the processing means includes amplifiers 21 and 23, full-wave rectifier 24, integrator 25,
It comprises a V / I converter 26, a display 27 and the like.

The display 27 is turned on, for example, so that its brightness continuously increases or decreases according to the amount of dust. Specifically, for example, when the display 27 is configured with one LED, the brightness of the LED changes according to the amount of dust, or when the plurality of LEDs are arranged, When the amount of dust is large, many LEDs are turned on, and when the amount of dust is small, a small number of LEDs are turned on.

Further, in the circuit configuration of FIG. 2, an automatic gain adjuster 22 is provided. This is to correct a decrease in the output signal of the light receiver 3 due to contamination of the light receiving surface of the light receiver 3 and the like. The signal amplified by the amplifier 21 is fed back by the automatic gain adjuster 22 so that the light reception is performed. The output is kept constant when there is no dust on the light receiver 3 without being affected by surface contamination or the like.

[0016]

According to the dust sensor for a vacuum cleaner of the present invention, as described above, unlike the conventional dust sensor which detects a decrease in the absolute value of the amount of light emitted from the light emitter and reaching the light receiver, the dust sensor is fixed. When the dust passes through the dust sensor attachment part in the suction path maintained at the brightness of, the brightness of the dust is disturbed, and by detecting the fluctuation that the brightness relatively increases or decreases, the presence or absence of the dust is determined. Since it is a detector, there is no need to precisely align the optical axes of the sender and receiver on the same straight line, high precision is not required for parts processing and assembly, and the dust detection sensitivity is constant regardless of the product And an inexpensive and highly sensitive dust detection function can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic vertical sectional view showing a configuration of a dust sensor according to an embodiment.

FIG. 2 is a block diagram illustrating an example of a circuit configuration of the dust sensor according to the embodiment.

FIG. 3 is a schematic cross-sectional view showing a configuration of a dust sensor according to a conventional example.

FIG. 4 is a schematic vertical sectional view showing a configuration of a dust sensor according to another conventional example.

[Explanation of Signs] 1 pipe (suction path) 2 light emitter 3 light receiver 10a, 10b dust

Claims (3)

[Claims] 1. A dust sensor provided in a dust suction path in a vacuum cleaner, comprising: a light emitter for illuminating the inside of the suction path; a light receiver for detecting brightness in the suction path illuminated by the light emitter; A dust sensor comprising a processing unit that detects the presence or absence of dust by a change in a signal when dust is present with respect to a constant value signal that does not change when there is no dust output from the light receiver. A dust sensor for a vacuum cleaner, wherein the dust sensor is disposed at a position slightly apart on a straight line substantially parallel to a central axis in the longitudinal direction of the suction path and with each optical axis substantially parallel. 2. The light receiver detects a change in brightness when dust passes with respect to a certain brightness when there is no dust, and the processing means responds to a change in brightness due to dust. The vacuum cleaner according to claim 1, wherein the presence or absence of dust is detected from an output signal of the light receiver. 3. The processing means according to claim 2, wherein said processing means performs full-wave rectification on a pulse-like output output from the light receiver, and detects the presence or absence of dust and the amount of dust from the rectified signal waveform. A dust sensor for a vacuum cleaner according to claim 1 or 2.