JPH08154877A - Vacuum cleaner - Google Patents

Abstract

PURPOSE: To dispense with an exclusive rotating speed detecting means, and reduce cost by arranging plural areas different in reflectance of the light in a rotary part as rotating speed detecting means of a motor-driven air blower, detecting rotating speed by a difference in its reflectance, and controlling voltage to be impressed on the motor-driven air blower on the basis of the detected rotating speed. CONSTITUTION: Black painting is applied to a part of a fan 5 fixed to an electric motor part, and a light emitting element 8 and a light receiving element 9 are arranged in one side part of this fan 5. The light emitting element 8 is connected to electric power supply through a resistor 14, and a connecting point between a collector of the light receiving element 9 and a resistor 15 is connected to a reversible input terminal of an operation amplifier 20, and an output signal of the amplifier 20 at fan rotating time is inputted to a CPU, and a pulse number is counted. Since time when the light receiving element 9 is turned on and off is equal to time when the fan 5 rotates by half, a vacuum cleaner is constituted so as to count its time, and rotating speed of a motor- driven air blower is detected, and impression voltage is controlled on the basis of this, and feedback control of the rotating speed is performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric vacuum cleaner, and more particularly, to an improvement of an electric vacuum cleaner which detects the rotational speed of an electric blower incorporated in a main body case and controls suction force.

[0002]

2. Description of the Related Art As one of conventional vacuum cleaners, the power consumption or rotation speed of an electric blower incorporated in a main body case is changed to adjust the degree of clogging of a dust collecting filter and the surface to be cleaned. Change the suction power of the vacuum cleaner,
There is one that adjusts to an appropriate suction force.

As an example, there is one in which the user manually adjusts the suction force in several steps or steplessly, but since it is set according to the user's feeling, the suction force is not always appropriate.

On the other hand, by detecting the negative pressure in the vacuum cleaner and controlling the electric blower so that the power consumption or the rotation speed is preset according to the detected negative pressure,
An electric vacuum cleaner has been previously proposed that controls the suction force to a set suction force even if the dust collecting filter is clogged.

On the other hand, a technique for detecting the rotational speed of an electric blower to control the suction force of a vacuum cleaner is disclosed in, for example, Japanese Patent Laid-Open No. 5-220.
No. 078, JP-A-4-197230, JP-A-4-21
It is described in Japanese Patent No. 0034, etc.

[0006]

However, among the above-mentioned conventional techniques, the electric blower detects the negative pressure in the vacuum cleaner and sets the power consumption or the rotation speed that is preset according to the detected negative pressure. In the case of controlling the suction force, that is, controlling the suction air volume by detecting the pressure difference between the dust collection chamber and the atmospheric pressure, the error in the pressure detection means, and the airtightness of the cleaner body, Due to the variation in the aerodynamic output of the electric blower, the difference between the suction force estimated by the processing of the microcomputer based on the detected pressure and the actual suction force was large.

Further, in the case of controlling the suction force of the vacuum cleaner by detecting the number of rotations of the electric blower, the above-mentioned Japanese Patent Laid-Open No. 5-22007.
In Japanese Patent Laid-Open No. 8-1972, a disk with a slit is provided coaxially with the rotation axis of the electric blower, and the number of rotations of the electric blower is detected without transmitting light through the slit.
No. 30, a rotation speed sensor is attached to the side surface of the motor, and in JP-A No. 4-210034, a rotation speed dedicated to the magnetic pole position of the rotor incorporated in the brushless motor is detected by a hall element. The detection means is used.

An object of the present invention is to detect a negative pressure in a vacuum cleaner and to control the electric blower so that the power consumption or the rotation speed is preset according to the detected negative pressure. The suction force control is not affected by the error of the detection means, the airtightness of the vacuum cleaner body and the variation of the aerodynamic output of the electric blower. It is an object of the present invention to provide an improved electric vacuum cleaner which can effectively use an existing device as a rotation speed detection means without using a dedicated rotation speed detection means when controlling.

[0009]

The above object is to provide a vacuum cleaner having a main body case, an electric blower incorporated therein, and a control circuit for controlling electric power or rotation speed of the electric blower. As the number detecting means, a plurality of regions having different light reflectances are provided on the rotating portion of the electric blower, for example, the fan surface portion and the end surface of the rotating shaft, and the rotation number of the electric blower is detected by the difference in the reflectances. This is achieved by controlling the voltage applied to the electric blower based on the rotational speed and performing feedback control of the rotational speed.

[0010]

[Operation] When the fan rotates due to the rotation of the electric blower,
The light emitted from the light emitting element is reflected by the rotating portion to reach the light receiving element or does not reach the light receiving element without being reflected repeatedly due to the difference in light reflectance of the rotating portion of the electric blower.

Since the light receiving element has a characteristic that it is turned on when exposed to light, the light receiving element repeats turning on and off according to the light reflectance of the rotating portion of the electric blower.

For example, when the back surface of the fan of the electric blower is divided into two, half of which has a high reflectance surface and the other half of which has a low reflectance surface, when the fan makes one rotation, the light receiving element is turned on and off respectively. Since it is repeated once, the number of rotations can be detected by counting this.

Further, since the time during which the light receiving element is on or off is the time during which the fan makes 1/2 rotation,
The rotation speed can be obtained by measuring this time.

Then, the voltage applied to the electric blower is controlled based on the rotation speed detected as described above, and feedback control of the rotation speed is performed.

[0015]

FIG. 2 shows the appearance of an electric vacuum cleaner. An electric blower 2 built in a main body case 1 is fixed to an electric motor part 3 and a rotary shaft 4 of the electric motor part 3 as shown in FIG. The fan 5 and the diffuser 6 located on the rear side of the fan 5 for rectifying the air flow generated by the rotation of the fan 5 and the casing 7 covering the fan 5 and the diffuser 6 emit light to the diffuser 7. Element 8 and light receiving element 9
Are fixed via the holder 10.

The fan 5 is painted black in the shaded area in FIG. 3, and the painted surface has a lower reflectance than the unpainted surface.

The light emitting element 8 and the light receiving element 9 are electrically connected to the circuit shown in FIG. 4 via lead wires 11 to 13.

The circuit shown in FIG. 4 comprises resistors 14 to 19 and an operational amplifier 20, the light emitting element 8 is connected to a power source through the resistor 14, and the collector of the light receiving element 9 and the resistor 15 are connected. Comparator operational amplifier 20 whose connection point is composed of resistors 16 to 19 and operational amplifier 20
It is connected to the inverting input terminal of.

The voltage divided by the resistors 17 and 18 is input to the non-inverting input terminal of the operational amplifier 20.

When the collector voltage of the light receiving element 9 changes due to the ON / OFF of the light receiving element 9, the voltage of the inverting input terminal of the operational amplifier 20 connected via the resistor 16 also changes.

When the light receiving element 9 is turned on and the voltage at the inverting input terminal of the operational amplifier 20 becomes lower than the voltage at the non-inverting input terminal, the output of the operational amplifier 20 becomes High, and when the light receiving element 9 is turned off, the operation is performed. Since the voltage of the inverting input terminal of the amplifier 20 becomes higher than the voltage of the non-inverting input terminal, the output of the operational amplifier 20 becomes Low.

When the fan 5 rotates, the output of the operational amplifier 20 has a waveform as shown in FIG.

When the electric blower 2 is energized, the fan 5 also rotates.

When the fan 5 rotates, the light emitted from the light emitting element 8 is reflected by the unpainted surface having a high reflectance as shown by the arrow in FIG. 6 and reaches the light receiving element 9, so that the light receiving element 9 is turned on. However, the light receiving element 9 is repeatedly turned off without being reflected by the coated surface having a low reflectance.

A signal detected by the light emitting element 8 and the light receiving element 9 and output from the circuit of FIG. 4 according to the rotation speed of the fan 5 is a microcomputer 21, a power supply circuit 22, and a bidirectional semiconductor shown in FIG. It is input to the microcomputer 21 of a circuit configured by the element drive circuit 23, the bidirectional semiconductor element 24, the electric blower 2, and the rotation speed detection circuit 25 shown in FIG.

When the fan 5 is painted as shown in FIG. 3, the light-receiving element 9 has one turn each in the ON state and the OFF state, so that the microcomputer 21 counts the number of pulses within a certain period of time, or receives light. Since the time during which the element 9 is on or off is equal to the time during which the fan 5 makes 1/2 rotation, the electric blower 2 can be measured by measuring the time.
The rotation speed of can be detected.

The relationship between the rotational speed of the electric blower 2 and the suction force is as shown in FIG. 8. Since the suction force can be obtained by detecting the rotational speed of the electric blower 2, the microcomputer 21 Based on this, the OU is adjusted so that the suction force is set by the user using the hand operation unit 26.
The bidirectional semiconductor element drive circuit 2 receives the trigger signal from the T terminal.
3 to the G terminal of the bidirectional semiconductor element 24.

The relationship between the terminal voltage applied to the electric blower 2 and the trigger signal is as shown in FIG. 9, and the voltage applied to the electric blower 2 changes depending on the output timing of the trigger signal.

Therefore, the current can be changed and the power consumption can be changed (this control method is generally called AC phase control, t / T is an AC phase control angle θ), and the suction force is always set. The electric blower 2 can be controlled so that

When it is detected that the rotation speed of the electric blower 2 exceeds the allowable rotation speed of the electric blower 2, the microcomputer 21 increases the phase control angle θ of the bidirectional semiconductor element 24 to increase the electric blower. It is also possible to protect the electric blower 2 by reducing the voltage applied to the electric blower 2 and controlling the rotation speed of the electric blower 2 to be equal to or lower than the allowable rotation speed.

As another embodiment, the light emitting element 8 and the light receiving element 9 are installed on the rear surface of the electric motor section 3 by using the holder 27 and the fixing plate 28 as shown in FIG. It is divided into two parts in the diametrical direction, and black coating is applied as shown by the hatched portion in FIG.

In the above structure, when the electric motor section 3 rotates, the rotary shaft 4 also rotates, and the light emitted from the light emitting element 8 is emitted as shown in FIG.
As indicated by the arrow in 2, the uncoated surface having a high reflectance reflects and reaches the light receiving element 9, the light receiving element 9 turns on, and the coated surface having a low reflectance does not reflect, and the light receiving element 9 turns off.

That is, when the rotary shaft 4 is painted as shown in FIG. 11, since one turn is made for each ON state and OFF state of the light receiving element 9, the number of pulses within a fixed time is counted.
Alternatively, the number of revolutions of the electric blower 2 can be detected by measuring the time of turning on or off, and the same control as in the previous embodiment can be performed.

[0034]

According to the present invention, as in the case of detecting the negative pressure in the vacuum cleaner and controlling the electric blower so that the power consumption or the rotation speed is set in advance in accordance with the detected negative pressure. The suction force control is not affected by the error of the pressure detection means, the airtightness of the vacuum cleaner body and the variation of the aerodynamic output of the electric blower, and the rotation speed of the electric blower is detected to suck the vacuum cleaner. When controlling force, it is possible to effectively use existing equipment as a rotation speed detection means for a vacuum cleaner without using a dedicated rotation speed detection means, and satisfy both performance and price at the same time. it can.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of an electric blower 2 showing an embodiment of an electric vacuum cleaner according to the present invention.

FIG. 2 is an external perspective view of the electric vacuum cleaner.

FIG. 3 is a view as seen from the arrow A of FIG. 1 (FIG. 1) in which the fan shown by reference numeral 5 in FIG. 1 is coated.

FIG. 4 is a detailed diagram of a rotation speed detection circuit indicated by reference numeral 25 in FIG.

5 is an output waveform diagram of a rotation speed detection circuit 25. FIG.

6 is a partially enlarged view of FIG.

FIG. 7 is the overall control circuit of the vacuum cleaner.

FIG. 8 is a characteristic diagram showing the relationship between the rotational speed of the electric blower 2 and the suction force.

9 is a diagram showing a relationship between an electric blower terminal voltage and a trigger signal when the bidirectional semiconductor element indicated by reference numeral 24 in FIG. 7 is used.

FIG. 10 is a partial cross-sectional view of the electric blower 2, showing another embodiment of the electric vacuum cleaner according to the present invention.

11 is a view taken in the direction of arrow B in FIG. 10 (FIG. 10) in which coating is applied to the rotary shaft indicated by reference numeral 4 in FIG.

12 is a partially enlarged view of FIG.

[Explanation of symbols]

2 ... Electric blower, 4 ... Rotating shaft, 5 ... Fan, 8 ... Light emitting element, 9 ... Light receiving element.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masataka Kaji 1-1-1 Higashitaga-cho, Hitachi-shi, Ibaraki Hiritsu Taga Technology Co., Ltd.

Claims (4)

[Claims] 1. A body case, an electric blower built therein, and a control circuit for controlling the electric power or the rotation speed of the electric blower, wherein the rotating portion of the electric blower serves as a rotation speed detecting means of the electric blower. A plurality of areas with different light reflectances are provided in the sensor, the number of rotations of the electric blower is detected based on the difference in the reflectances, and the voltage applied to the electric blower is controlled based on the detected number of rotations. An electric vacuum cleaner characterized by being configured to perform feedback control of the number. 2. A body case, an electric blower incorporated therein, and a control circuit for controlling electric power or rotation speed of the electric blower, wherein a fan surface portion of the electric blower serves as rotation speed detection means of the electric blower. A plurality of areas with different light reflectances are provided in the sensor, the number of rotations of the electric blower is detected based on the difference in the reflectances, and the voltage applied to the electric blower is controlled based on the detected number of rotations. An electric vacuum cleaner characterized by being configured to perform feedback control of the number. 3. A body case, an electric blower built therein, and a control circuit for controlling electric power or rotation speed of the electric blower, wherein a rotation shaft of the electric blower serves as a rotation speed detection unit of the electric blower. Provide a plurality of regions with different light reflectance on the end face, detect the rotation speed of the electric blower by the difference in the reflectance, and control the voltage applied to the electric blower based on this detected rotation speed, An electric vacuum cleaner characterized by being configured to perform feedback control of rotation speed. 4. The method according to claim 1, wherein
An electric vacuum cleaner also provided with means for detecting when the rotation speed of an electric blower exceeds an allowable rotation speed and controlling the rotation speed to be equal to or lower than the allowable rotation speed.