JPH02223700A - Blower - Google Patents

Abstract

PURPOSE:To reduce an amount of noise generated from the air inlet and outlet of a blower by a method wherein a microphone, a speaker, an amplifier, and a control circuit are mounted in a flow passage or to the air inlet and outlet. CONSTITUTION:A motor 2, a moving vane 3 driven with the aid of the motor 2, a guide vane 4, and a heater 5 are disposed in a casing 1. A microphone 8, a speaker 11, an amplifier 10 for driving the speaker, and a control circuit 9 to control the phase and amplitude of an output signal from the microphone 8 are mounted in a flow passage or to an air inlet and outlet. Sound waves emitted from the speaker 11 erase sound waves generated from the motor 2 and the moving vane 3, resulting in the possibility to sharply reduce an amount of noise emitted through a suction port 6.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a low-noise system that suppresses the propagation of noise generated inside the casing, such as fan wind noise, motor rotation noise, and casing internal resonance noise, to the outside. This relates to a blower.

[Conventional technology]

In recent years, with the progress and miniaturization of office automation equipment and home appliances, there has been a need for small-sized and large-volume electronic equipment cooling fans, blowers, and the like for dryers.

Generally, as shown in FIG. 2, a dryer includes a motor 2 as a driving source, moving blades 3 rotatably driven by the motor 2, guide blades 4, a heater 5 as a heat source, etc. in a hollow casing 1. The air introduced into the casing 1 by the rotation of the rotor blades 3 from the suction port 6 provided at one location of the casing 1 is heated by the heater 5, and then hot air is released from the blowout lower provided at another location of the casing 1. It is supposed to be blown out as follows.

The basic performance of a dryer is to be small, lightweight, and secure a specified air volume.In order to meet these requirements, it has been considered to increase the rotational speed of the rotor blades 3 to increase the air volume. It will be done. However, a problem arises in that the noise increases as the rotational speed of the rotor blades 3 increases.

In order to avoid such problems, efforts are being made to ensure a specified air volume at low rotational speeds by improving the characteristics of the motor 2 and the shape of the rotor blades 3, but it is difficult to obtain satisfactory results. Not yet reached.

In the above explanation, a dryer is used as an example of a blower, but the blower is not limited to this, and noise can be a problem even if the blower is used in other devices such as pumps and air conditioners. There is.

[Problem to be solved by the invention]

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to provide a blower with a large air volume and low noise.

[Means to solve the problem]

The gist of the present invention is to provide a motor, a rotor blade driven by the motor, a motor that encases the motor and the rotor blade,
and a blower consisting of a casing that fixes these, a microphone, a speaker, an amplifier that drives the speaker, and a control circuit that controls the phase and amplitude of the output signal of the microphone are provided in the flow path or at the entrance and exit of the air, It is characterized by emitting sound waves that are generated from the fan and motor and have a phase opposite to the sound waves that are emitted to the outside from the air inlet and outlet. That is, a microphone detects the sound waves generated by the fan and motor, propagates through the flow path, and is emitted to the outside from the air outlet and exit, and emits a sound wave with an opposite phase that cancels out the sound waves. In this way, the resistance of the flow path can be increased (noise can be reduced).

〔Example〕

FIG. 1 shows a sectional view of an embodiment of the present invention.

The explanation will be given below based on FIG.

Since the structure is the same as that of the conventional example described above except for the parts explained below, the explanation thereof will be omitted.

The amplifier 10, the control circuit 9, the microphone 8, and the speaker 11 are arranged in the housing 1 between the suction port 6 and the rotor blade 3, corresponding to the center of the rotor blade 3 corresponding to the dead center of the flow. The reason why it is placed at a portion corresponding to the dead center of the flow is to prevent flow resistance from increasing due to the placement of the amplifier 10 and the like.

If the amplifier 10 and control circuit 9 are integrated into ICs and the ultra-small microphone 8 and speaker II are used, the increase in flow path resistance due to their installation can be almost ignored.

The microphone 8 serves to detect sound waves generated from the motor 2 and the rotor blades 3 and exiting from the suction port 6 to the outside. The control circuit 9 calculates a signal with the opposite phase of this signal and sends the calculated signal to the amplifier IO. amplifier 10
amplifies the signal received from the control circuit 9 and sends it to the speaker 11.
to drive.

The sound waves emitted from the speaker 11 cancel out the sound waves generated from the motor 2 and the rotor blades 3, thereby greatly reducing the noise emitted from the suction port 6.

Control circuit 9, amplifier 10. The speaker 11 can be made smaller by using an IC, etc., and can be placed in the center where there is less flow resistance, so noise can be reduced without reducing the air volume.

〔Effect of the invention〕

As described above, according to the blower according to the present invention, it is possible to reduce the noise generated from the air inlet/outlet of the blower.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing one embodiment of the present invention, and FIG. 2 is a sectional view showing a conventional example. l... Housing, 2... Motor, 3... Moving blade,
4... Stationary blade, 5... Heater, 6... Suction port,
7... Air outlet, 8... Microphone, 9...
-Control circuit, 10...amplifier, 11...speaker.

Claims (1)

[Claims] (1) a motor, a rotor blade driven by the motor,
In a blower consisting of a casing that encloses and fixes the motor and rotor blades, there is a microphone, a speaker, an amplifier that drives the speaker, and the phase and amplitude of the output signal of the microphone in the flow path or at the air entrance/exit. A blower is provided with a control circuit for controlling the fan and the motor, and emits sound waves that are generated from a fan and a motor and have a phase opposite to the sound waves that are radiated to the outside from an air inlet/outlet.