JPS61141338A - Electric cleaner - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a vacuum cleaner, and particularly to a delay circuit for outputting a dust detection electric signal, which is suitable for stably and automatically controlling the motor of the vacuum cleaner.

[Background of the invention]

In vacuum cleaners, sensors accurately detect the material condition of the floor surface such as carpets and tatami mats, as well as the clogging condition of the dust filter, and automatically control the current and rotation speed of the blower motor. Various techniques are known for always maintaining an appropriate suction force.

As for the type of sensor, for example, a semiconductor pressure sensor that detects the pressure difference between the floor surface and the suction port is disclosed in Japanese Patent Application Laid-Open No. 56-66228.

Japanese Patent Application Laid-Open No. 146332/1983 is an example of detecting the clogging state of a dust filter by using a movable plate and a bridge circuit based on the pressure difference before and after the filter.

However, in the above-mentioned conventional technology, the vacuum cleaner does not care about the amount or presence of dust on the floor.

From the point of view of power saving, since it is constantly being operated,
Further improvements were desired.

In particular, in the case of so-called self-propelled vacuum cleaners that use batteries as a power source, it goes without saying that it is necessary to maximize power savings and extend the operating time. Only when it is necessary to increase the suction power.

As a sensor for detecting the amount and presence of dust, it is possible to use the semiconductor pressure sensor described above, an optical sensor, or the like. However, even if these means are used, if a method is used in which the motor control directly responds to the output of the sensor,
The rotation of the blower motor pulsates in response to the detection output that is generated in pulses depending on the presence or absence of dust, resulting in unstable operation. The pulsed current that rushes into the blower motor due to the pulsation has caused problems such as shortening the lifespan of the carbon brushes used in the blower motor.

[Purpose of the invention]

The present invention has been made in order to solve the problems of the prior art described above. 1. The purpose of the present invention is to provide a blower motor that can be stably and efficiently controlled regardless of the amount of dust or the presence or absence of dust. Our goal is to provide vacuum cleaners with a high level of functionality.

[Summary of the invention]

In a voltage vacuum cleaner comprising a dust detection sensor, an amplification circuit that amplifies the electrical signal output of the dust detection sensor, a motor, and a control circuit that controls the rotation speed of the motor, The electrical signal output of the detection sensor is
Depending on the amount and presence of dust, there are generally very irregular,
Moreover, it becomes a pulse with a narrow width.

The present invention provides a delay circuit between the dust detection sensor and the motor, and delays the falling timing of the pulsed electric signal by a certain period of time, thereby combining consecutive pulse groups and increasing the width of the pulse. Convert to wide square wave.

This allows the motor to rotate stably.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described in detail using one drawing. FIG. 2 is a vertical cross-sectional view of a vacuum cleaner according to an embodiment of the present invention. In FIG. mechanically connected. Reference numeral 4 denotes a suction blower, which is driven and rotated by a motor 5. 6 is a dust case 1 that collects dust 8, and 7 is a dust detection sensor. Further, arrows indicate air flow paths.

FIG. 1 shows a block diagram according to an embodiment of the present invention.

In the figure, 7 is the above-mentioned dust detection sensor,
Generally, for hard dust such as sand, a piezoelectric element or the like is used which generates electricity due to the so-called piezo effect in response to impact pressure caused by suction.

In addition, light emitting diodes, photodiodes, and the like are used for light-weight and relatively large-volume dust such as one piece of paper and two pieces of lint.

Further, depending on the nature of the dust, the piezoelectric element described above may be used in combination with a light emitting diode, a photodiode, or other appropriate sensor.

Reference numeral 9 denotes an amplifier circuit that amplifies the electric signal output of, for example, about 1 volt from the dust detection sensor 7, and drives the delay circuit 10 at the next stage. Furthermore, if necessary, a waveform shaping circuit such as a clipper or a noise limiter for the amplitude of the pulsed electric signal is provided.

Reference numeral 10 denotes a delay circuit, which is a so-called CR delay circuit composed of a resistor R and a capacitor C (not shown), and a simple logic operation element for controlling the delay time is added.

Reference numeral 11 denotes a control circuit for controlling the rotation of the motor; 1 usually includes a bidirectional three-terminal semiconductor element that turns on and off the voltage or current of the power supply applied to the motor 5; and the bidirectional three-terminal semiconductor element described above. It is composed of a gate trigger circuit, etc. that controls turn-on/off of the element.

Next, the operation shown in FIG. 1 will be explained using the motor control explanatory diagram shown in FIG. 3.

In FIG. 2, dust 8 sucked through the dust suction port 2 is detected by a dust detection sensor 7 provided in the suction path.

As mentioned above, as a dust detection sensor.

When a piezoelectric element is used, the piezoelectric effect caused by the collision of dust such as sand causes a pulse width of, for example, 0.5 ms and a maximum peak voltage of around 1 volt.

Pulse groups with many variations are shown in (a) and (b) of the sensor output characteristic diagram in FIG. 3(a).

As shown in (c) and (d), it occurs extremely irregularly depending on the presence and amount of dust.

Also, when using one light emitting diode and a phototransistor to detect threads, paper scraps, etc., the amount of passing dust is detected as the amount of light received by the phototransistor, and similarly,
A pulsed output signal is generated.

FIG. 3(b) shows a motor rotation characteristic diagram according to the prior art corresponding to FIG. 3(a).

In the figure, H indicates the steady overall rotation of the motor 5, and L indicates a low speed light load circuit.

As shown in the figure, the motor 5 does not completely follow the pulsed electrical signal output shown in FIG. It is controlled in response to each period in which there is no group, and enters a pulsating state as shown in (E), (E), and (G) in the figure.

FIG. 3(Q) shows a motor rotation characteristic diagram according to the present invention. In this case, by providing the above-mentioned delay circuit 10, the fall of each pulse shown in FIG. 3(a) is delayed for several seconds, and as a result, the pulse group (b) shown in FIG. ,
(C) and (D) act as a series of rectangular waves (H) to drive the motor 5 via the control circuit 11. motor 5
is a pulse group (
Through the periods of b), (c), and (d), like (ch),
High speed rotation and, for relatively long dust-free periods, low speed rotation can be safely performed.

A preferred embodiment of the present invention has been described above with reference to the drawings. However, the constituent circuits, constituent elements, their characteristics, relative arrangement, etc. described in this example are not intended to limit the scope of this invention to only those, unless specifically stated. This is just an illustrative example, and
The delay circuit may be provided between the control circuit and the motor.
Furthermore, there are various methods for controlling the motor, such as voltage, current, and phase, but in the gist of the present invention, they are collectively referred to as power control. 1 [Effects of the Invention] According to the present invention, by providing a delay circuit between the dust detection sensor and the motor, the above-mentioned information can be stably detected even by the dust detection output signal generated in a pulsed manner. The motor can be controlled with.

It has the following effects.

Since the power of the motor can be stably controlled depending on the amount and presence of dust on the floor, it is possible to significantly save power, and this is particularly effective for self-propelled vacuum cleaners that use batteries.

It is possible to prevent unpleasant pulsating operation noise caused by unstable operation caused by conventional control techniques.

Eliminating pulsed inrush current extends the life of the motor's carbon brushes and other parts.

It can be constructed from simple and inexpensive parts.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a block diagram of an embodiment of the present invention.
A vertical cross-sectional view of the vacuum cleaner, FIG. 3 is a motor control explanatory diagram, and (a) is a sensor output characteristic diagram. (b) is a conventional motor rotation speed characteristic diagram, and (c) is a motor rotation characteristic diagram of the present invention. 1... Vacuum cleaner body, 2... Dust suction port, 3...
...Pipe, 5...Motor, 6...Dust case,
9... Amplification circuit, 10... Delay circuit, 11... Control circuit.

Claims (1)

[Claims] 1. In a vacuum cleaner comprising a dust detection sensor, an amplifier circuit that amplifies the electrical signal output of the dust detection sensor, a motor, and a control circuit that controls electric power applied to the motor. . A vacuum cleaner, characterized in that a delay circuit is provided between the dust detection sensor and the motor.