JPH04226499A - Local air conditioner - Google Patents

Abstract

PURPOSE:To provide the local air conditioner with a noise mechanism which can suppress the noise propagating in a local space with as simple construction. CONSTITUTION:An electronic silencing system is installed to the local air conditioner which cools and heats the local space 10. Namely, a sensor microphone 20 which detects the noise from noise generating equipment 18 and converts the noise to an electric signal is installed in the vicinity of the above-mentioned noise generating equipment 18. Speakers 28 for generating the additive sounds for negating the noise from the noise generating equipment 18 are installed in the vicinity of an air diffusion port 16 for conditioning air. Error microphones 30 which detect the additive sound from the speakers 28 and the propagated noise from the noise generating equipment 18 and convert these sounds to the electric signals are respectively installed in the local space 10. The sensor microphone 20, the speakers 28 and the error microphones 30 are connected to a controller 24.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a local air conditioner, and more particularly to a local air conditioner that cools and heats a local space where workers work on a production line for automobiles and the like.

0002

[Prior Art] Conventionally, this type of local air conditioning system has been used to provide a comfortable environment in local spaces where workers work in various work processes, including automobile manufacturing lines, in order to improve work efficiency. It is. The local air conditioner is arranged such that an outlet of a duct connected to the air conditioner is directed toward the local space. Conditioned cooling and heating air is blown out from this outlet to maintain a comfortable temperature and humidity in the local space.

0003

[Problem to be solved by the invention] However, although the temperature and humidity of the local space can be improved with a conventional local air conditioner, it is difficult to improve the temperature and humidity of the local space by using a conventional local air conditioner. However, in places where equipment is used, noise from noise-generating equipment degrades the environment and reduces work efficiency.

[0004] As a method to eliminate such problems,
There are ways to implement noise countermeasures throughout the entire automobile manufacturing line factory. However, this method has the disadvantage that the noise countermeasure costs are enormous. Another method is to partition a local space with a soundproof wall. However, this method has the disadvantage that it cannot be put to practical use because it may not be possible to install a soundproof wall due to the nature of the work.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a local air conditioner equipped with a silencing mechanism capable of silencing noise propagating in a local space with a simple structure.

[0006]

[Means for Solving the Problems] In order to achieve the above object, the present invention detects propagated noise from a noise source installed outside the local space and generates electricity in a local air conditioner that cools and heats a local space. a sensor microphone that converts into a signal; a speaker that is installed near the conditioned air outlet of the local air conditioner and that emits sound waves for canceling noise from the noise source; an error microphone that detects sound waves from the noise source and propagated noise from the noise source and converts them into electrical signals; and an output signal from the sensor microphone based on the output signal from the sensor microphone and the output signal from the error microphone. and a control device that creates a drive signal to be output to the speaker so that .

[0007]

[Operation] According to the present invention, an electronic silencing system is installed in a local air conditioner that cools and heats a local space. That is, a sensor microphone is installed near a noise source installed outside the local space, a speaker is installed near a cooling/heating air outlet, and an error microphone is installed inside the local space. Further, the sensor microphone, speaker, and error microphone are connected to the control device.

[0008] This makes it possible to muffle noise from a noise source propagating in a local space with a simple structure. Also,
Information transmission between the sensor microphone and the control device, information transmission between the error microphone and the control device, and information transmission between the control device and the speaker are wirelessly transmitted. This allows the sensor microphone, control device, and error microphone to be installed at appropriate locations even in locations where cables cannot be wired.

Furthermore, a speaker is installed inside the duct in which the conditioned air outlet is formed, and a sound wave having a low output and high sound pressure level is emitted from the conditioned air outlet due to the resonance effect inside the duct. This allows the use of a smaller speaker than a speaker installed outside the conditioned air outlet and generating the same output.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the local air conditioner according to the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 shows a first embodiment of a local air conditioner according to the present invention, and shows an embodiment in which this local air conditioner is applied to an automobile manufacturing line.

According to FIG. 1, an air outlet 16 of an air-conditioning duct 14 is arranged above the local space 10 and faces the local space 10, and the conditioned cooling air or heating air is supplied from the air outlet 16 to the local space 10. It is blown out into space 10. Thereby, the temperature and humidity of the local space 10 are maintained by the conditioned air. Further, a noise generating device 18 is installed outside the local space 10.

[0012] By the way, an electronic silencing system, which will be described below, is installed in the workshop of the automobile manufacturing line constructed as described above. That is, a sensor microphone 20 is attached near the noise generating device 18 and connected to a controller 24 via a cable 22. Further, the controller 24 is connected to a pair of speakers 2 via cables 26, 26.
8 and 28 are connected. The pair of speakers 28, 28
are fixed to both sides of the air outlet 16 described above, with their sound wave generating surfaces facing the local space 10. Additionally, a pair of error microphones 30, 30 are installed within the local space 10 and are connected to the controller 24 via cables 32, 32, respectively.

Next, a control system for electronic silencing using the controller 24 will be explained with reference to FIG. The controller 24 mainly includes an A/D converter 36,
38, 38, D/A conversion sections 40, 40, an adaptive digital filter 42, and a control section 44, and a drive for controlling the speakers 28, 28 based on output signals from the sensor microphone 20 and error microphones 30, 30. Create a signal.

That is, the noise generating device 18 shown in FIG.
When the propagating sound waves generated from the sensor microphone 20 and the error microphones 30, 30 detect the propagating sound waves, the output signal from the sensor microphone 20 is first inputted to the adaptive digital filter 42 and the control filter 44 via the A/D converter 36, respectively. be done. Furthermore, output signals from the error microphones 30, 30 are input to the control section 44 via A/D conversion sections 38, 38, respectively. Then, the control section 44
First, we will calculate these characteristics by considering the propagation characteristics of the sound waves from the speaker 28 to the sensor microphone or the error microphone, changes in the propagation characteristics due to disturbances within the local space 10, and changes in the characteristics of each electroacoustic transducer itself. Find the transfer function shown. Next, based on the determined transfer function, an error microphone 30 detects an interference state between the propagating sound wave from the noise generating device 18 and the additional sound emitted from the speakers 28, 28;
The transfer function to be applied to the adaptive digital filter 42 is determined so that the output signal from the adaptive digital filter 30 is minimized. Next, control parameters for specifying this transfer function are set in the adaptive digital filter 42. Note that the control section 44 can modify the control parameters at any time in accordance with changes in the propagation characteristics of the noise generating device 18 and changes in the characteristics of the control system.

As a result, the noise generating device 18 detected by the sensor microphone 20 and the error microphones 30, 30
The propagating sound waves from the A/D converter 3 are converted into electrical signals.
6 to the adaptive digital filter 42. This input signal is converted into a digital signal having predetermined amplitude characteristics and phase characteristics based on the transfer function given from the control section 44. The digital signal is D
D/A conversion is performed by the /A converter 40, and the speaker 28
, 28 is applied to the drive coils of the speakers 28, 28. As a result, additional sound for canceling the propagating sound waves from the noise generating device 18 is emitted from the speakers 28, 28, so that at the installation positions of the error microphones 30, 30, that is, within the local space 10, due to the interference of sound waves. The propagating sound waves from the noise generating device 18 are eliminated, and the local space 10
The noise propagating inside can be muffled.

Therefore, according to this embodiment, the local space 10
It has a simple structure and can create a comfortable working environment without noise. In this embodiment, an air conditioning duct type central air conditioning system is applied, but the present invention is not limited to this, and the present invention can also be applied to an individual air conditioning system such as a packaged air conditioner.

Further, the speakers 28, 28 and the error microphones 30, 30 do not necessarily need to be installed in the air conditioning duct, but the speakers 28, 28 may be installed near the air outlet 16, and the error microphones 30, 30 may be installed in the local space 10. For example, it may be placed at an arbitrary position. Furthermore, error microphone 30,3
By placing a temperature/humidity sensor in the vicinity of 0, the thermal environment of the local space 10 can be easily controlled.

FIG. 3 shows a second embodiment of the local air conditioner according to the present invention, and the same or similar members as those of the local air conditioner shown in FIGS. 1 and 2 will be described with the same reference numerals. . According to the second embodiment, a wireless transmission device 46 is connected to the sensor microphone 20. This wireless transmission device 46 transmits the signal detected by the sensor microphone 20 to the controller 24A using a microwave 48 using a microwave digital communication method.

As shown in FIG. 4, the wireless transmission device 46 includes a quantization circuit 50, a modulation circuit 52, and a transmitter 5.
Consists of 4. That is, the output signal from the sensor microphone 20 is digitized by the quantization circuit 50, this digital signal is subjected to pulse code modulation by the modulation circuit 52, and then transmitted to the controller 24A by the transmitter 54 as the aforementioned microwave 48. The microwave 48 electrically transmitted to the controller 24A is then transmitted to the controller 24A shown in FIG.
After being received by the 4A receiver 56 and processed by the demodulation circuit 58, it is processed by the controller 24A as a detection signal from the sensor microphone 20.

In this way, in the second embodiment, the detection signal from the sensor microphone is transmitted wirelessly to the controller 24A, so that the wiring of the cable 22 shown in FIG. 1 is no longer necessary. Therefore, even in a place where the cable 22 cannot be wired, the sensor microphone 20 can be installed at an appropriate place. In the second embodiment, the sensor microphone 20 is targeted, but the invention is not limited to this. Information transmission between the error microphone 30 and the controller 24A, and information transmission between the controller 24A and the speakers 28, 28 can be performed by wireless transmission. You may also do this.

Furthermore, although the second embodiment employs a microwave digital communication system, the present invention is not limited to this, and amplitude modulation or frequency modulation may also be used. FIG. 6 shows a third embodiment of the local air conditioner according to the present invention, and FIG.
Components that are the same as or similar to those of the local air conditioner shown in FIG. 2 will be described with the same reference numerals.

According to the third embodiment, the speakers 28, 28
is installed inside the air conditioning duct 14, specifically inside the conditioned air outlet chamber. As a result, the additional sound emitted from the speakers 28 and 28 is radiated into the air outlet chamber, is amplified by resonance within the air outlet chamber, and is radiated from the air outlet 16 toward the local space 10. . Note that a closed cabinet is used for the speakers 28, 28.

Next, a comparison of the acoustic characteristics of a local air conditioner configured as described above and a local air conditioner in which the speaker 28 is installed outside the outlet chamber will be explained with reference to FIGS. 7 and 8. In FIG. 7, the speaker 28 is connected to the air conditioning duct 14.
It is a diagram that experimentally confirmed the group delay characteristics when installed inside and outside the device, with the vertical axis showing the delay time and the horizontal axis showing the frequency. Further, in FIG. 8, the speaker 28 is connected to the air conditioning duct 14.
It is a diagram that experimentally confirmed the frequency characteristics when installed inside and outside of the device.The vertical axis shows the sound pressure level, and the horizontal axis shows the frequency.

As shown in FIG. 7, in terms of group delay characteristics, in the low frequency range, installing the speaker 28 outside the air conditioning duct 14 results in a lower delay than installing the speaker 28 inside the air conditioning duct 14. This is suitable because it takes a short time. However, as shown in FIG. 8, when the speaker 28 is installed inside the air conditioning duct 14, the output sound pressure level in the low frequency range is
Since resonance occurs inside the air conditioning duct 14, a higher output sound pressure can be obtained compared to a speaker 28 of the same capacity installed outside the air conditioning duct 14.

Therefore, by installing the speaker 28 inside the air conditioning duct 14, it is possible to install the speaker 28 smaller than the speaker 28 installed outside the air conditioning duct 14. Furthermore, if the speaker 28 is installed outside the air conditioning duct 14, a large speaker 28 must be used in a local air conditioner that requires high output in a low frequency range, but the speaker 28 cannot be installed inside the air conditioning duct 14. Once installed, a small speaker 28 can be used.

In the third embodiment, the delay time of the group delay characteristic becomes longer as shown in FIG. 7, but if the noise emitted from the noise generating device 18 is periodic noise, the difference in the group delay characteristic becomes a problem. Therefore, it can be effectively applied to noise in the low frequency range. Also, information transmission between the sensor microphone 20 and the controller 24, information transmission between the error microphone 30 and the controller 24, and information transmission between the controller 24 and the speaker 2.
8 may be transmitted wirelessly as described in the second embodiment.

[0027]

Effects of the Invention As explained above, according to the local air conditioner according to the present invention, an electronic silencing system consisting of a sensor microphone, a speaker, an error microphone, and a control device is installed in the local air conditioner. It is possible to muffle the sound with a simple structure, improve the environment against noise in the local space, and improve work efficiency.

Furthermore, information transmission between the sensor microphone and the control device, information transmission between the error microphone and the control device, and information transmission between the control device and the speaker are transmitted wirelessly, so that the cable is not wired. The sensor microphone, control device, and error microphone can be installed at appropriate locations even in locations where this is not possible. Furthermore, the speaker is installed inside the duct in which the conditioned air outlet is formed, and low-output, high-output additional sound is radiated from the conditioned air outlet due to resonance inside the duct.
The speaker can be made smaller.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing a first embodiment of a local air conditioner according to the present invention.

FIG. 2 is a block diagram of an electronic silencing system installed in the first embodiment of the local air conditioner according to the present invention.

FIG. 3 is an explanatory diagram showing a second embodiment of the local air conditioner according to the present invention.

FIG. 4 is a configuration diagram of a wireless transmission device applied to a second embodiment of a local air conditioner according to the present invention.

FIG. 5 is a block diagram of an electronic silencing system installed in a second embodiment of the local air conditioner according to the present invention.

FIG. 6 is an explanatory diagram showing a third embodiment of the local air conditioner according to the present invention.

FIG. 7 is an explanatory diagram confirming the group delay characteristics of the third embodiment of the local air conditioner according to the present invention.

[Fig. 8] An explanatory diagram confirming the frequency characteristics of the third embodiment of the local air conditioner according to the present invention.

[Explanation of symbols]

10...Local space 14...Air conditioning duct 20...sensor microphone 24, 24A...controller 28...Speaker 30...Error microphone 46...Wireless transmission device

Claims (3)

[Claims] Claim 1: A local air conditioner that cools and heats a local space includes a sensor microphone that detects propagated noise from a noise source installed outside the local space and converts it into an electrical signal, and a sensor microphone that detects propagated noise from a noise source installed outside the local space and converts it into an electrical signal, and an air-conditioned air blower of the local air conditioner. A speaker installed near the exit and emitting sound waves for canceling the noise from the noise source; and a speaker installed in the local space for detecting the sound waves from the speaker and propagated noise from the noise source. Create a drive signal to be output to the speaker so that the output from the sensor microphone is minimized based on an error microphone that converts into an electrical signal, an output signal from the sensor microphone, and an output signal from the error microphone. A local air conditioner comprising: a control device; 2. Information transmission between the sensor microphone and the control device; information transmission between the error microphone and the control device;
The local air conditioner according to claim 1, characterized in that information transmission between the control device and the speaker is transmitted wirelessly. 3. The local air conditioner according to claim 1, wherein the speaker is installed inside a duct in which the conditioned air outlet is formed.