JP2741951B2 - Electric vacuum cleaner - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a vacuum cleaner having a sound deadening function.

2. Description of the Related Art In recent years, many vacuum cleaners having a large suction capacity have increased noise in proportion to the suction power, and therefore it has been desired to reduce noise.

Conventionally, this type of vacuum cleaner generally has a configuration as shown in FIG.

Hereinafter, the configuration will be described with reference to the drawings.

As shown in the figure, an electric blower 1 for sucking air includes an impeller (not shown) having a plurality of blades, and an air guide (not shown) installed on the outer periphery of the impeller.
And a fan case 2 (not shown) enclosing them, and a motor 5 for driving the impeller. The fan case has an intake hole 6 protruding in the center.
A ring-shaped anti-vibration rubber and seal 7 is attached to this portion. A rectangular anti-vibration rubber 8 is attached to a rear portion of the electric motor 5. The electric blower 1 is supported by the main body motor room 11 through the vibration isolating rubbers 7 and 8.

A main body dust collecting chamber 10 containing a paper bag 4 as a dust collecting filter and a main body motor chamber 11 containing an electric blower 1 have a communication hole at the center.
It is partitioned by a partition plate 12 having 14. The front end portion 13 of the vibration-proof rubber / seal 7 abuts around the communication hole 14 of the partition plate 12 to seal the intake and exhaust air.

In addition, a code reel chamber 15 containing the code reel 3 is installed in parallel with the main body motor room 11, and between the main body motor room 11 and the code reel room 15 so that exhaust does not flow into the code reel 3 side. Is provided with a partition wall.

Problems to be Solved by the Invention In such a conventional vacuum cleaner, there is a problem that various noises generated from the electric blower 1 are transmitted together with exhaust gas from an exhaust outlet hole at a rear portion of the main motor room 11, so that noise is high. . In order to reduce these noises, noise is devised by a sound absorbing material 16 attached along the exhaust passage 17, but noise of a relatively low frequency such as that caused by the rotational imbalance of the electric blower 1 is reduced. At present, almost no sound is absorbed, and the sound is directly transmitted through the exhaust outlet hole.

In addition, the sound of pressure vibration generated by the impeller blades, that is, the noise having a frequency obtained by multiplying the number of rotations by the number of blades, is often transmitted directly from the exhaust outlet hole. These are electric blower 1
This is the noise synchronized with the rotation speed and rotation position of.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problem, and an object of the present invention is to provide a vacuum cleaner capable of effectively silencing noise synchronized with the rotation speed and reducing unpleasant noise.

Means for Solving the Problems In order to achieve the above object, the present invention provides an electric blower provided in a main body, an exhaust path that guides air exhausted by the electric blower and mutes noise, and discharge of the exhaust path. A rotation position detector that has an exhaust hole corresponding to a section and detects the number of rotations of the electric blower, a converter that receives a signal from the rotation position detector and generates a frequency that is an integral multiple of the number of rotations, An amplifier that is connected to the output and adjusts the output and phase based on the rotation signal; a speaker connected to the output side of the amplifier and provided on the wall of the exhaust path; and a monitoring microphone provided near the exhaust hole. The circuit is configured by an arithmetic circuit that inputs a signal from the microphone, monitors noise of an integral multiple of the number of revolutions, and adjusts the phase and level of the amplifier so that this value is minimized.

Operation In the above-described configuration, the phase and level of the interference sound generated from the speaker are adjusted so that the sound pressure detected by the monitor microphone is minimized, thereby canceling out the sound generated from the speaker.

Embodiment An embodiment of the present invention will be described below with reference to FIG. 1 and FIG. In this embodiment, the same components as those of the conventional example are denoted by the same reference numerals, and description thereof will be omitted.

As shown in the figure, the electric blower 1 has an exhaust hole 21, and an exhaust passage 22 is provided inside the main body, so that the exhaust of the electric blower 1 is guided to the main body exhaust hole 23 while silencing the exhaust. . Reference numeral 24 denotes an optical or electromagnetic rotational position detector, which outputs a pulse proportional to the number of rotations. Depending on the system, a sine wave signal having the same frequency as the rotation speed can be output. A speaker 25 is provided on a wall surface of the exhaust passage 22, and a microphone 26 for monitoring is provided at a position near the main body exhaust hole 23 of the exhaust passage 22. The output from the rotational position detector 24 is converted into a sine wave by the converter 30 and applied to the speaker 25 via the amplifier 27 capable of changing the phase and level. The sound detected by the monitoring microphone 26 is fed back to the amplifier 27 via the arithmetic circuit 31. Reference numeral 28 denotes a filter having a center frequency synchronized with the rotation speed. The converter 30 can output a sine wave signal having a frequency that is an integral multiple of the input pulse by designating an arbitrary integer.

The operation in the above configuration will be described. When the vacuum cleaner is operated, noise synchronized with the rotation of the electric blower 1 propagates from the electric blower 1 as a sound source to the exhaust passage 22 and the main body exhaust holes 23
At this time, the noise is detected by the monitor microphone 26 and input to the arithmetic circuit 31. The inputted noise is compared with a reference level in the arithmetic circuit 31. If the inputted noise is equal to or higher than the reference level, a signal having the same frequency as the rotation speed is output from the amplifier 27 to the exhaust passage.
22 In addition to the speaker 25 installed on the wall,
The 25 produces a sound of that frequency and tries to counteract the noise.
That is, the arithmetic circuit 31 is firstly an amplifier added to the speaker 25 so that the noise detected by the monitor microphone is reduced.
The phase of the output signal 27 is changed with reference to the rotation of the electric blower 1, the phase condition that minimizes the phase is determined, and then the level of the output signal is sequentially changed. And a microphone for the monitor
The conditions of the phase and level of the interference sound generated from the speaker 25 are determined so that the noise detected by 26 is minimized. That is, noise synchronized with the number of revolutions generated from the electric blower 1 as the sound source is canceled out by the sound generated from the speaker 25 and is muted.

The same applies to the case where the noise source has a frequency that is an integral multiple of the number of revolutions, and the integer may be specified in the converter 30.

As described above, noise caused by rotational unbalance vibration and noise caused by pressure pulsation by a blade having a frequency obtained by multiplying the number of rotations by the number of blades of the impeller are synchronized with the rotation of the electric blower 1. That is, the waveforms of these noises propagating through the exhaust passage 22 always have a fixed relationship with the rotational position of the electric blower 1, and have the opposite phase with respect to the rotational position signal of the electric blower 1 as in this embodiment. By creating the sound of, the noise synchronized with the number of rotations can be canceled out.

As is clear from the above description of the embodiment, according to the electric vacuum cleaner of the present invention, the electric blower provided in the main body, and the exhaust passage for guiding the air discharged by the electric blower and silencing the air. A rotation position detector for detecting the number of rotations of the electric blower, which is provided with an exhaust hole corresponding to a discharge portion of the other exhaust path, and inputting a signal of the rotation position detector to set a frequency of an integral multiple of the number of rotations. A converter to be made, an amplifier connected to the converter to adjust the output and phase based on the rotation signal,
A speaker connected to the output side of the amplifier and provided on the wall of the exhaust path, a monitoring microphone provided near the exhaust hole, and monitoring the noise of an integral multiple of the number of revolutions by inputting a signal from the microphone. By using an arithmetic circuit that adjusts the phase and level of the amplifier so that this value is minimized, the sound generated by the speaker can be canceled out and muted, and the number of revolutions changes, and the sound source changes over time. Even so, noise can always be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram of a vacuum cleaner according to one embodiment of the present invention,
FIG. 2 is a longitudinal sectional view of the vacuum cleaner, and FIG. 3 is a longitudinal sectional view showing a conventional vacuum cleaner. 1 ... electric blower, 26 ... microphone, 24 ... rotational position detector, 25 ... speaker, 27 ... amplifier, 30 ... converter, 31
…… Operation circuit.

Claims (1)

(57) [Claims] An electric blower provided in a main body, an exhaust passage for guiding air exhausted by the electric blower and silencing the exhaust, and an exhaust hole corresponding to a discharge portion of the exhaust passage are provided. A rotational position detector that detects the rotational speed, a converter that receives the signal of the rotational position detector and generates a frequency that is an integral multiple of the rotational speed, and is connected to the converter and determines the output and phase based on the rotational signal. An amplifier to be adjusted, a speaker connected to the output side of the amplifier and provided on the wall of the exhaust path, a microphone for monitoring provided near the exhaust hole, and an integer of the number of revolutions by inputting a signal from the microphone. Vacuum cleaner consisting of an arithmetic circuit that monitors double noise and adjusts the phase and level of the amplifier to minimize this value.