JP2007253799A - Active vibration/noise control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an active vibration/noise control device capable of reliably reducing the noise at the position of ears of an occupant in a vehicle. <P>SOLUTION: The active vibration/noise control device 10 is mounted on a vehicle, and a circuit board 25 with noise signal input means 32, 36, a power supply 38, an ANC 40, output adjustment means 42, 44 and an amplifier 24 mounted thereon, and a speaker 20 are stored in a speaker box 12. The ANC 40 generates a first control signal Sc1 and a second control signal Sc2 based on the frequency fe detected by a vehicular state detection means 28, and error signals from the noise signal input means 32, 36. The speaker 20 outputs the first control sound based on the first control signal Sc1 in the vehicle as the canceling noise of the noise attributable to the vibration/noise of an engine at microphones 30, 34 in the vehicle (around positions of an occupant's ears). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an active vibration / noise control device that generates a control signal based on vibrations / noise generated in a vehicle, and more particularly, to vibrations / noise generated from noise / vibration sources such as a vehicle engine. The present invention relates to an active vibration / noise control device that generates a control signal based on the control signal.

  Conventionally, the noise in the vehicle caused by vibration / noise generated from vibration / noise sources such as the engine of the vehicle is detected by a microphone disposed in the vicinity of an occupant's ear position in the vehicle, and the detected noise An active vibration / noise control device that generates a control signal based on the above is disclosed (see Patent Document 1). In this case, the active vibration / noise control device outputs the control signal to a speaker provided in the vehicle, and the speaker outputs the input control signal as a control sound in the vehicle. Noise at the ear position is reduced by the control sound.

  Further, in the active vibration / noise control device according to another conventional example, it is noted that the vibration / noise is generated in synchronization with the rotation of the output shaft of the engine, and the rotation frequency of the engine and the microphone are used. A control signal based on the detected noise is output to the speaker.

  Since the speaker described above is a speaker that outputs an audio signal from the entertainment system provided in the vehicle as a musical sound into the vehicle, the active vibration / noise control device shares the speaker with the entertainment system. . The speaker and the entertainment system are standard equipment of the vehicle, but the active vibration / noise control device is not standard equipment of the vehicle, and is therefore provided separately in the vehicle.

Japanese Patent Laid-Open No. 61-112896

  By the way, the above-mentioned speakers are door speakers arranged at the doors on both sides of the front seat of the vehicle, and rear speakers arranged behind the rear seat, and these speakers are arranged at predetermined positions of the vehicle. In this case, the characteristics of the sound field between each speaker that outputs control sound and a microphone that detects noise (in the vicinity of the occupant's ear position) are the location of the door speaker, the rear speaker, and the microphone, It varies depending on the input / output characteristics, and also varies from vehicle to vehicle or vehicle type.

  Moreover, since the output level of the control sound at a low frequency of about 40 [Hz] or less is small in each speaker, it is difficult to reduce the low frequency noise. Alternatively, for the purpose of reducing the noise at the low frequency, the active vibration / noise control device improves the output characteristic of the control signal at the low frequency, and the control sound corresponding to the control signal with the improved output characteristic is When output from each speaker, the chatter sound from the door and the distortion of the control sound occur, and the low frequency noise cannot be reduced.

  Therefore, simply by providing the active vibration / noise control device in the vehicle and outputting the control sound from the speakers into the vehicle, noise at the ear position of the occupant can be reliably reduced. There is a problem that can not be.

  The present invention has been made in consideration of such a problem, and provides an active vibration / noise control device capable of reliably reducing noise at the position of an occupant's ear in a vehicle. Objective.

  Another object of the present invention is to provide an active vibration / noise control device capable of reducing the cost.

  The active vibration / noise control device according to the present invention has the following features (1) to (4).

  (1) A circuit board on which a control signal generating electronic circuit for generating a first control signal based on vibrations and noises generated in the vehicle is mounted, and the first control signal is output to the vehicle as a first control sound. The circuit board and the first speaker are housed in the same casing.

  Accordingly, it is possible to reduce noise at the ear position of the occupant in the vehicle only by appropriately arranging the casing in the vehicle. Therefore, in the present invention, compared with the prior art, the noise is reduced regardless of the difference in the vehicle and the vehicle type, the arrangement of the microphone and the speaker provided in the vehicle, and the input / output characteristics of the microphone and the speaker. It can be surely reduced. Therefore, the active vibration / noise control device can be easily arranged even in a vehicle that does not include the active vibration / noise control device.

  (2) Furthermore, an entertainment system for generating an audio signal based on a sound source and a second speaker for outputting the audio signal as a musical sound into the vehicle are provided in the vehicle, and the control signal generating electronic circuit is provided. Generates a second control signal based on the vibration / noise and outputs the second control signal to the second speaker via the entertainment system. The second speaker outputs the second control signal based on the musical sound and / or the second control signal. Two control sounds are output into the vehicle.

  Accordingly, the first control sound is output from the first speaker into the vehicle, and the second control sound is output from the second speaker to the vehicle, so that the noise can be reliably reduced. In addition, the occupant can hear the musical sound with the noise reduced.

  The first control signal and the second control signal are basically substantially the same frequency signal, and a control sound corresponding to each control signal is generated at the noise detection point (the position of the microphone). It is desirable to adjust the phase appropriately so as not to cause a problem that the noise reduction effect cannot be obtained due to interference with each other.

  (3) The first speaker is a woofer.

  Since the woofer is omnidirectional with respect to the output of low-frequency sound of about 80 [Hz] or less, the casing can be appropriately disposed at any location in the vehicle, and low-frequency noise in the vehicle can be reliably ensured. Can be reduced.

  In the present specification, the terms low frequency and high frequency are used to indicate whether the frequency is relatively low or high.

  (4) The casing is also used as a speaker box.

  Thereby, cost can be reduced.

  According to the present invention, it is possible to reliably reduce noise at the position of an occupant's ear in the vehicle. In addition, the cost can be reduced by using the casing that houses the circuit board on which the control signal generating electronic circuit is mounted and the first speaker as the speaker box.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic block diagram showing a configuration of an active vibration / noise control device 10 according to an embodiment of the present invention. FIG. 2 shows an example in which the active vibration / noise control device 10 is arranged on a vehicle 16. FIG. In FIG. 2, the door on the front seat 18 side and the door on the rear seat 19 side are omitted for the understanding of the explanation inside the vehicle 16.

  The active vibration / noise control device 10 is mounted on a vehicle 16 and basically includes noise signal input means 32 and 36, a power source 38, and control signal generation electronics in a speaker box 12 that also serves as a casing. A control signal generating means (hereinafter also referred to as ANC) 40 as a circuit, output adjusting means 42 and 44, an amplifier 24, and a speaker (first speaker) 20 are accommodated. In this case, the noise signal input means 32 and 36, the power supply 38, the ANC 40, the output adjustment means 42 and 44, and the amplifier 24 are mounted on the circuit board 25.

  The active vibration / noise control device 10 is incorporated as an optional equipment of the vehicle 16. In the example of FIG. 2, the active vibration / noise control device 10 is disposed on the floor surface below the front seat 18 in the vehicle 16. It can be arranged appropriately at the place. Further, in the vehicle 16, speakers (second speakers) 58 and 60 capable of outputting a higher frequency sound than the audio head unit (entertainment system) 14 and the speaker 20 are provided as standard equipment.

  The noise signal input means 32 outputs an error signal based on sound including noise detected by the microphone 30 disposed in the vicinity of the headrest of the front seat 18 in the vehicle 16 (in the vicinity of the occupant's ear position) to the ANC 40. Further, the noise signal input means 36 outputs an error signal to the ANC 40 based on sound including noise detected by the microphone 34 disposed in the vicinity of the headrest of the rear seat 19 (in the vicinity of the occupant's ear position).

  The power supply 38 adjusts a direct current voltage from a battery (not shown) to a predetermined voltage and supplies it to the amplifier 24, the noise signal input means 32 and 36, the ANC 40, and the output adjustment means 42 and 44 in the active vibration / noise control apparatus 10. .

  The ANC 40 is configured by a microcomputer and includes a frequency counter that detects a frequency of the engine pulse (engine rotation frequency) fe obtained from a Hall element or the like as the traveling state of the vehicle 16 every time the output shaft of the engine 26 rotates. Detection means 28 is provided. In this case, a signal (cylinder deactivation signal) indicating that the cylinder deactivation is being controlled is input to the vehicle state detection means 28 from an ECU (not shown) that controls deactivation of the cylinders of the engine 26 according to the traveling state of the vehicle 16. Is done.

  For example, in the case of a six-cylinder engine 26, the cylinder deactivation signal indicates that three of the six cylinders are deactivated under the control of the ECU while the vehicle 16 is decelerating / cruising. A signal for notifying the state detection means 28.

  The ANC 40, based on the error signal from the noise signal input means 32 and 36 and the frequency fe detected by the vehicle state detection means 28, generates vibration / noise (for example, engine sound and the output) generated from the engine 26. A first control signal Sc1 and a second control signal Sc2 are generated for canceling noise at the microphones 30 and 34 (the position of the occupant's ear) in the vehicle 16 due to the excitation force generated by the rotation of the shaft. That is, the ANC 40 generates a reference signal having a predetermined harmonic with the frequency fe as the frequency of the basic order, and generates the first control signal Sc1 and the second control signal Sc2 based on the reference signal.

  In this case, the first control signal Sc1 is a control signal for outputting a first control sound that cancels the noise from the speaker 20. The second control signal Sc2 is used to output the second control sound from the speaker 58, which is a door speaker arranged in the vicinity of the front seat 18, and from the speaker 60, which is a rear speaker arranged behind the rear seat 19. It is a control signal. In other words, the first control sound output from the speaker 20 is a canceling sound for low-frequency noise based on the first control signal Sc1, and the second control sound output from the speakers 58 and 60 is the first control sound. 2 is a canceling sound for high frequency noise based on the control signal Sc2. The first control signal Sc1 and the second control signal Sc2 are basically substantially the same frequency signals, and the control signals Sc1, Sc2 are detected at the noise detection points (the positions of the microphones 30, 34). It is desirable to adjust the phase appropriately so that the control sounds based on the above will interfere with each other and the noise reduction effect cannot be obtained.

  Further, when there is an input of the cylinder deactivation signal to the vehicle state detection means 28, the ANC 40 determines that the vehicle 16 is decelerating / cruising and the engine 26 is in the cylinder deactivation state, and the first control is performed. It is also possible to output only the signal Sc1 to the output adjusting means 42. That is, the noise in the vehicle 16 in the cylinder deactivation state is mainly noise having a frequency lower than that of the second control sound, and therefore can be canceled only by the first control sound.

  The output adjustment means 42 is a low-pass filter that outputs a signal component of a predetermined frequency or less in the first control signal Sc1 from the ANC 40 to the amplifier 24, and the output adjustment means 44 is a predetermined value in the second control signal Sc2 from the ANC 40. This is a low-pass filter that outputs a signal component of a frequency or lower to the audio head unit 14. The amplifier 24 amplifies the first control signal Sc1 from the output adjustment means 42 and outputs the amplified signal to the speaker 20 as the output signal Sd1.

  The speaker 20 is a woofer that outputs the frequency range of 33 [Hz] to 80 [Hz] in the output signal Sd1 as the first control sound into the vehicle 16.

  The audio head unit 14 is disposed on the dashboard 21 in front of the front seat 18 and includes a power source 46, a sound source 48, mixers 50 and 52, and amplifiers 54 and 56.

  The power supply 46 adjusts the DC voltage from the battery to a predetermined voltage and supplies it to the mixers 50 and 52 and the amplifiers 54 and 56.

  The mixers 50 and 52 synthesize the second control signal Sc2 from the output adjusting unit 44 and the audio signal Sa from the sound source 48 such as a CD, a cassette tape, and a tuner radio, and the synthesized signals Sm1 and Sm2 are amplified by the amplifier 54 and the like. To 56.

  The amplifiers 54 and 56 amplify the combined signals Sm1 and Sm2 from the mixers 50 and 52, and output the amplified signals to the speakers 58 and 60 as output signals Sd21 and Sd22.

  The speaker 58 is disposed on a door (not shown) on the side of the front seat 18, and the vehicle 16 uses a frequency range of 40 [Hz] to several tens [kHz] in the output signal Sd21 as an output sound including the second control sound. It is a full range type door speaker that outputs to the inside. The speaker 60 is disposed behind the rear seat 19 and outputs a frequency range of 40 [Hz] to several tens [kHz] in the output signal Sd22 into the vehicle 16 as an output sound including the second control sound. This is a full-range rear speaker.

  As described above, the mixers 50 and 52 combine the second control signal Sc2 and the audio signal Sa to generate the combined signals Sm1 and Sm2, and the output signals Sd21 and Sd22 based on the combined signals Sm1 and Sm2 are output from the speaker 58. , 60, the output sound from each speaker 58, 60 is a synthesized sound of the second control sound corresponding to the second control signal Sc 2 and the musical sound based on the audio signal Sa from the sound source 48.

  When the audio signal Sa is input to the mixers 50 and 52 and the second control signal Sc2 is not input, only the musical sound based on the audio signal Sa is output from the speakers 58 and 60 into the vehicle 16 as an output sound. The On the other hand, when the audio signal Sa is not input to the mixers 50 and 52 and the second control signal Sc2 is input, only the second control sound based on the second control signal Sc2 is output from the speakers 58 and 60 as the vehicle. 16 is output.

  Here, when the vehicle state detection unit 28 detects the frequency fe, the ANC 40 outputs a first control signal Sc1 based on the detected frequency fe to the output adjustment unit 42 and also outputs a second control signal Sc2 based on the frequency fe. It outputs to the output adjustment means 44.

  The output adjusting means 42 outputs a signal component having a predetermined frequency or less in the first control signal Sc1 from the ANC 40 to the amplifier 24. The amplifier 24 amplifies the first control signal Sc1 and uses the amplified signal as an output signal Sd1. Output to the speaker 20.

  The speaker 20 outputs a frequency range of 33 [Hz] to 80 [Hz] in the output signal Sd1 as the first control sound into the vehicle 16, and as a result, the positions of the microphones 30 and 34 (near the occupant's ear position). ), Low-frequency noise (for example, noise of 80 [Hz] or less) due to vibration and noise of the engine 26 is reduced or canceled by the first control sound.

  On the other hand, the output adjustment unit 44 outputs a signal component having a frequency equal to or lower than a predetermined frequency in the second control signal Sc2 from the ANC 40 to the mixers 50 and 52. The mixers 50 and 52 receive the second control signal Sc2 and the sound source 48 from the sound source 48, respectively. The audio signal Sa is synthesized and the synthesized signals Sm1 and Sm2 are output to the amplifiers 54 and 56. The amplifiers 54 and 56 amplify the combined signals Sm1 and Sm2, and output the amplified signals to the speakers 58 and 60 as output signals Sd21 to Sd22.

  The speaker 58 outputs a frequency range of 40 [Hz] to several tens [kHz] in the output signal Sd21 as an output sound including the second control sound and / or the musical sound, and the speaker 60 A frequency range of 40 [Hz] to several tens [kHz] in the output signal Sd22 is output into the vehicle 16 as an output sound including the second control sound and / or the musical sound. Accordingly, high-frequency noise (for example, noise of about 80 [Hz] or more) due to vibration / noise of the engine 26 at the positions of the microphones 30 and 34 (near the occupant's ear position) is caused by the second control sound. Reduced or counteracted.

  The noise reduced by the first control sound and the second control sound is detected as residual noise by the microphones 30 and 34, and the noise signal input means 32 and 36 output an error signal based on the detected residual noise to the ANC 40. To do.

  When there is a cylinder deactivation signal input to the vehicle state detection means 28, the ANC 40 outputs only the first control signal Sc1 to the output adjustment means 42, and the speaker 20 outputs the first control sound into the vehicle 16. . As a result, at the positions of the microphones 30 and 34, low-frequency noise caused by vibration and noise of the engine 26 is reduced or canceled by the first control sound.

  Thus, the active vibration / noise control device 10 has the following features and effects (1) to (4).

  (1) The first control signal Sc1 and the second control signal Sc2 based on the frequency fe according to the vibration / noise generated from the engine 26 as the vibration / noise source in the vehicle 16 and the noise detected by the microphones 30, 34. The circuit board 25 having the ANC 40 and the like for generating the sound signal and the speaker 20 for outputting the first control signal Sc1 as the first control sound into the vehicle 16 are provided. The circuit board 25 and the speaker 20 serve as the same casing. The speaker box 12 is accommodated.

  Thereby, the noise at the occupant's ear position in the vehicle 16 can be reduced by appropriately arranging the speaker box 12 in the vehicle 16. Therefore, in this embodiment, compared with the prior art, regardless of the difference in the vehicle and the vehicle type, the arrangement of the microphones 30 and 34 and the speakers 58 and 60, and the input / output characteristics of the microphones 30 and 34 and the speakers 58 and 60. The noise can be reliably reduced. Therefore, the active vibration / noise control device 10 can be easily arranged even in a vehicle that does not include the active vibration / noise control device 10.

  (2) The audio head unit 14 that generates the audio signal Sa and the speakers 58 and 60 that output the audio signal Sa to the vehicle 16 as musical sound are provided in the vehicle 16, and the ANC 40 transmits the second control signal Sc2 to the audio. The sound is output to the speakers 58 and 60 via the head unit 14, and the speakers 58 and 60 output the musical sound and / or the second control signal Sc2 into the vehicle 16 as the second control sound as an output sound.

  As a result, the first control sound is output from the speaker 20 into the vehicle 16 and the second control sound is output from the speakers 58, 60 into the vehicle 16, so that the noise can be reliably reduced. The passenger can hear the output sound in a state where the noise is reduced.

  (3) If the speaker 20 is a omni-directional woofer with respect to the output of low frequency sound of about 80 [Hz] or less, the speaker box 12 can be appropriately disposed at an arbitrary location in the vehicle 16. Low frequency noise can be reliably reduced.

  For example, with respect to the basic order (third order) (fe = 74 [Hz]) in the combustion / expansion stroke of a six-cylinder engine, the noise in the vehicle 16 in the cylinder deactivation state (decelerated traveling / cruise traveling) is 1. In the case of the fifth harmonic noise (37 [Hz]), it is difficult for the full-range speakers 58 and 60 to output the first control sound of 37 [Hz] from the speaker 20 into the vehicle 16. , Low frequency noise of 80 [Hz] or less can be easily reduced or silenced.

  Further, when there is an input of a cylinder deactivation signal to the vehicle state detection means 28, noise in the vehicle 16 can be reduced only by the first control sound output from the speaker 20, so that the low frequency of 80 [Hz] or less. Noise can be efficiently reduced.

  (4) By using the casing as the speaker box 12, the cost can be reduced.

  Of course, the present invention is not limited to the above-described embodiment, and may employ various configurations.

It is a block diagram which shows the structure of the active type vibration and noise control apparatus which concerns on this embodiment. It is a side view which shows the state which has arrange | positioned the active vibration and noise control apparatus of FIG. 1 in the vehicle.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Active type vibration and noise control device 12 ... Speaker box 14 ... Audio head unit 16 ... Vehicle 20, 58, 60 ... Speaker 25 ... Circuit board 26 ... Engine 28 ... Vehicle state detection means 30, 34 ... Microphone 32, 36 ... Noise signal input means 40 ... ANC 48 ... sound source 50, 52 ... mixer

Claims (4)

A circuit board on which an electronic circuit for generating a control signal for generating a first control signal based on vibration and noise generated in the vehicle is mounted, and a first that outputs the first control signal as a first control sound in the vehicle. A speaker,
The active vibration / noise control device, wherein the circuit board and the first speaker are accommodated in the same casing. The active vibration / noise control device according to claim 1,
Furthermore, an entertainment system for generating an audio signal based on a sound source and a second speaker for outputting the audio signal as a musical sound into the vehicle are provided in the vehicle,
The control signal generation electronic circuit generates a second control signal based on the vibration and noise, and outputs the second control signal to the second speaker via the entertainment system,
The active vibration / noise control device, wherein the second speaker outputs the musical sound and / or a second control sound based on the second control signal into the vehicle. The active vibration / noise control device according to claim 1 or 2,
The active vibration / noise control device according to claim 1, wherein the first speaker is a woofer. In the active type vibration and noise control device according to any one of claims 1 to 3,
The casing is also used as a speaker box. An active type vibration / noise control device.

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