JP3508152B2 - Vehicle vibration control device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle vibration control device for reducing vehicle vibration, that is, noise, by an interference action utilizing a reducing vibration.

[0002]

2. Description of the Related Art In a vehicle, particularly in an automobile in which noise vibration due to an engine, that is, a first vibration is a problem, a reducing vibration, that is, a second vibration is generated from a speaker in a passenger compartment.
It has been proposed to reduce the vibration in the vehicle compartment by the interference between the first vibration and the second vibration.

In this type of vibration reducing device, as shown in Japanese Patent Publication No. 1-501344, a reference signal generator for extracting a signal corresponding to the vibration from the vibration source, that is, the first vibration as a reference signal, , For generating a microphone that picks up vibration in the vehicle compartment where noise due to the first vibration is a problem, a speaker that generates second vibration toward the vehicle compartment, and a second vibration that is output from the speaker And the algorithm operation device for sequentially optimizing the filter coefficient of the filter. That is, while the adaptive digital filter adjusts the gain and phase of the reference signal according to the reference signal to generate the second vibration, the filter coefficient of the adaptive digital filter is reduced so that the vibration detected by the microphone becomes small. Are sequentially optimized by the algorithm calculation device. The least square method is generally used as the optimization algorithm.

[0004]

In the case of performing the vibration reduction utilizing the above-mentioned interference, it is considered that the speaker for the vibration output for reduction and the speaker for the audio sound output are both used. At this time, simultaneously with the output of the reducing vibration to the passenger compartment, the audio from the audio source such as the cassette deck is output.
It is possible that the Dio sound is output to the passenger compartment. In this case, there is a possibility that the vibration for reduction is not a little and adversely affects the audio sound. That is, the speaker has an upper limit output range in which sound can be output without distortion, but when an audio sound and a vibration for reduction are both output from one speaker, If the upper limit output range is exceeded, not only the audio sound cannot be reproduced well, but also the effect of vibration reduction is reduced. Such a situation is likely to occur when the vehicle is traveling at a high speed and the output level of the audio sound required by the occupant is high and the noise level to be reduced is high.

Therefore, it is an object of the present invention to prevent the output from the speaker from being distorted when the speaker is used both for the vibration output for reduction and for the audio sound output. An object of the present invention is to provide a vehicle vibration control device as described above.

[0006]

In order to achieve the above object, the present invention adopts the following configuration.

The present invention is a vehicle vibration reducing apparatus for reducing vibration in a vehicle compartment by outputting a reducing vibration into the vehicle compartment, wherein the speaker for reducing vibration output is also used as an audio speaker. It is based on the case.

On the above premise, the present invention has the following configuration. That is, as described in claim 1 in the claims,

In a vehicle vibration reducing apparatus for reducing vibrations in a vehicle compartment by outputting the reducing vibrations into the vehicle compartment, the reduction vibration output speaker is set to also serve as an audio speaker. When the output of the vibration for reduction and the audio output are being performed together, when the output level of the speaker exceeds a predetermined value set so as not to exceed the upper limit output that can output sound without distortion, the audio The output reducing means for lowering the output level of 1 is provided by a predetermined amount.

On the premise of the above configuration, the following configurations can be adopted together. That is, as described in claim 2 in the claims,

When the audio output is lowered by the operation of the audio output lowering means, and when the output level of the speaker exceeds the predetermined value, the reducing vibration output stopping means is stopped. Be prepared, you can.

[0012]

【The invention's effect】

According to the invention described in claim 1, while giving priority to the vibration reduction control, it is possible to enjoy audio sound, if not sufficient.

According to the second aspect of the invention, the audio sound can be finally enjoyed.

[0015]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1. Overall Overview In FIG. 1, an automobile 1 is a four-passenger passenger vehicle having a driver's seat 3, a passenger seat 4, and left and right rear seats 5 and 6 inside a passenger compartment 2. An in-line four-cylinder gasoline engine 8 is mounted on an engine room 7 formed in the front part of the vehicle body, and an ignition coil of the gasoline engine 8 is designated by reference numeral 9.

The engine 8 is used as a noise generating source, ie, a first vibration source, which generates periodic vibrations according to the engine speed. The vehicle interior 2 is a predetermined space where the vibration of the engine 8 should be reduced. For this reason, five speaker 11 and eight microphones 12 are installed in the vehicle compartment 2 as a predetermined space. The speaker 11 serves as a second vibration source that generates a second vibration for reducing engine noise to the vehicle interior, and the microphone 12 serves as a vibration detection unit that detects actual vibration of the vehicle interior. As is well known, the instrument panel has an audio source including a combination of a tuner, a cassette deck, and a CD deck.
The space 31 is provided.

A control unit U constructed by using a microcomputer is mounted on the automobile 1. The input / output relationship to the control unit U is shown in FIG.
The control unit U has a control unit 20 including a CPU. A signal from the primary coil of the ignition coil 9, that is, an ignition pulse signal corresponding to the engine speed is input to the control unit 20 via the waveform shaping circuit 21 and the cycle calculation circuit 22, and the signals from the respective microphones 12 are input. , Amplifier 23, low-pass filter 24, and A / D converter 25. The output signal from the control unit 20 is D
It is output to the speaker 11 via the / A converter 26, the low-pass filter 27, and the amplifier 28.

The control unit 20 optimizes the second vibration as the reduction vibration to be output from the speaker 11 so that the vibration detected by the microphone 12 is reduced. Hereinafter, the generation of the second vibration by the control unit 20 will be described, but first,
The basic part of the generation of the second vibration will be described, and then the relationship with the audio will be described.

In the embodiment, the second vibration is intended to reduce periodic rotational vibration of the engine 8, for example, a rotational secondary component, and is generated collectively for one cycle of the periodic vibration of the engine 8. Therefore, the amount of calculation for optimizing the second vibration is reduced, and the load on the control system is reduced as much as possible. Of course, the second vibration can be generated by a known appropriate optimization method, and the present invention is not limited to a specific optimization method.

Generation of Second Vibration (Basic) FIG. 3 is a block diagram showing the control unit 20.
For simplification of the description, the case where the number of the speaker 11 and the number of the microphone 12 are each one is shown.

The control unit 20 adjusts the cycle of the vector y of the speaker input signal y output to the speaker 11 according to the result input from the cycle measuring circuit 22 (step 1,
With the built-in processor, the matrix h of the impulse response h, which is the transfer characteristic between the microphone 12 and the speaker 2, is time-sequentially h-converted (S).
2).

Next, the control unit 20 is a processor that sequentially optimizes the vector y by the time series h of the impulse response h and the microphone output signal e input from the microphone 12 (S
3) After that, this vector y is converted into a time series y to be a speaker input signal y (S4) and output to the speaker 11.

The speaker 11 receives the speaker input signal y.
Is reproduced as anti-noise Z. On the other hand, the microphone 12
Noise in which vibration energy is reduced by canceling noise d and anti-noise Z is detected, and the result is output to the processor incorporated in the control unit 20 as a digital microphone output signal e. Thereafter, the processor again executes the above step 3
And step 4 are repeated until the speaker input signal y
The vector y of the speaker input signal y is set so that the value of the microphone output signal e finally becomes 0.

Next, the calculation of the algorithm of the above steps performed by the control unit 20 will be described below.

First, the sampling period of the microphone output signal e of the microphone 12 by the control unit 20 is Δt. Assume that the impulse response h, which is the transfer characteristic between the microphone 12 and the speaker 11, converges to 0 within a finite time JΔt, and the value of the impulse response h after jΔt time has elapsed since the impulse input was applied. Let h _j be the noise d which is the first vibration generated from the engine 8, the anti-noise Z which is the second vibration generated from the speaker 11 when the speaker input signal y is given, and The relationship of the kth sample value e (k) of the microphone output signal e at the time k can be expressed by the following equation (1).

E (k) = d (k) + Z (k) = d (k) + matrix h ^T , matrix y (k) ... (1) where matrix h = [h ₀ h ₁ h ₂ ... h _J-1 ] ^T matrix y (k) = [y (k) y (k-1) y (k-2) ... y (k-J + 1)] ^T d ( k): component z (k) of noise d contained in e (k): component y (k) of anti-noise Z contained in e (k): kth sample of the speaker input signal y Therefore, Z (k) in the equation (1) is represented by the following equation (2).

[0027]

[Equation 1]

Since the noise d is a periodic noise having a certain period NΔt, the anti-noise Z for reducing the vibration energy of the noise d, the speaker input signal y, and the same period as the noise d. It must be a periodic vibration and a periodic signal with NΔt.

Therefore, the following equation (3) is established for the speaker input signal y. y (k) = y (K-qN) = y (k) y (k-1) = y (k-qN-1) = y (k + N-1) y (k-2) = y (k -qN-2) ＝ y (k + N-2) ・ ・ ・ ・ (3) ・ ・ ・ ・ ・ ・ ・ ・ ・ y (k-N + 1) ＝ y (k- (q + 1) N + 1) = y (k + 1) However, q = 0,1,2, ... Therefore, the equation (1) is e (k) = d (k) + vector h ^T and time series y (k ) ・ ・ ・ ・ (4) However, time series y (k) = [y (K) y (K + N-1) y (K + N-2) ・ ・ ・ ・ y (K + 1)] ^T

[0030]

[Equation 2]

Note that Q is the minimum value of the integer q that satisfies J ≦ (q + 1) N.

Next, the K + i sample value e of the microphone output signal e at the time k + i when the time i further elapses from the time k
(K + i) (where i = 1, 2, ...) is expressed by the following equation (5).
Can be expressed as

E (k + i) = d (k + i) + vector h T / time series y (k + i) = d (k + i) + time series h (i) T / time series y (k ) (5) However, time series y (k + i) = [y (k + i) ' y (k + i ' -1) y (k + N-1) y (k + N -2) ····· y (k + i '+1)] T time series h (i) = [Ba -h i' Ba -h i + 1 '····· bar -h N + 1 Ba -h 0 Ba -h 1 · · · · bar -h i '-1] T Note that, i' is an integer remainder of the division of the i in N.

By the way, in the equation (5), k only represents an arbitrary initial time point of the microphone input signal e. Therefore, when k = 0 is set and i is replaced by k again, the following expression (6) is obtained.

[0035] e (k) = d (k ) + time series h (k) ^T · time series y (0) = d (k ) + time series h (k) ^T · vector y However, the vector y = [y (0) y (N-1) y (N-2) ... y (1)] ^T = [y ₀ y _N-1 y _N-2 ... y ₁ ] ^T where: Introduce a function. F = E [e (k) ² ] = E [d (k) + time series h (k) ^T · vector y] = E [d (k) ² ] +2 vector y ^T · E [d (k) when the series h (k)] + vector y ^T · E [time series h (k) · time series h (k) ^T] vector y ······ (7) However, E [] is the expected value Let (E be the expectation operator). From equation (7), the vector y of this evaluation function
The gradient with respect to is given by the following equation (8). ∂F / ∂ vector y = 2E [d (k) / time series h (k)] + 2E [time series h (k) / time series h (k) ^T ] vector y = 2E [time series h (k) { d (k) + time series h (k) ^T vector y}] = 2E [time series h (k) .e (k)] (8) where E [time series h (k) If the time series h (k) · e (K) is used as the instantaneous estimated value of [e (K)], then a spin having a cycle NΔt (that is, the number of elements N) giving the minimum value of F The value of the vector y, which is the output signal vector, can be optimized by iteratively calculating the following recurrence formula (9) based on the steepest descent method.

[0036]   Vector y (K + 1) = Vector y (k) -μ ・ e (k) ・ Time series h (k) (9) However, μ / 2 is a convergence coefficient.

The recurrence formula (9) thus obtained corrects the setting of the anti-noise vibration energy by which the processor, which is the data processing device incorporated in the control unit 20, reduces the noise vibration energy. In that case, it is replaced with a simpler algorithm as shown below.

First, a pair of speaker 11 and microphone 1
When using 2, the recurrence formula (9) is replaced with the following formula (10). y _{(k-j + QN)} ^' (k + 1) = y _{(k-j + QN)} ^'・ (k) −μ ・ e (k) ・ h _j (10) At this time, the processor In k, for example, the following four operation procedures are performed.

Operation 1: Operation of outputting the speaker input signal y _k ^' (k) to the speaker 11 2: Operation of inputting the microphone output signal e (K) from the microphone 12 3: Period measurement circuit 22 Engine 22 input from
Regarding the operation 4: j = 0, 1, 2, ..., J-1 in which the integer value closest to the value obtained by multiplying the rotation cycle of Ord / Δt or 1 / (Ord · Δt) is N Calculation of recurrence formula (10) is performed, where k ′ and (k−j + QN) ′ are k (k−)
j + QN) is the integer remainder when divided by N, and Ord is an arbitrary constant integer for setting the lowest order of the engine speed of the noise to be reduced.

Next, when a plurality of speakers 11 ... And a microphone 12 ... Are used, for example, based on the steepest descent method,

[0041]

[Equation 3]

As an instantaneous estimated value of

[0043]

[Equation 4]

Using, the evaluation function

[0045]

[Equation 5]

The optimum value of the vector y ₁ that is the first speaker output signal vector that minimizes is the following recurrence formula (11).
It is obtained by iteratively calculating.

[0047]

[Equation 6]

Where y _lk ^' : the first speaker input signal _{em at the} time k, _m : the mth microphone output signal h _lmj : _jΔt time after the impulse response between the first speaker and the mth microphone. Value L: Number of speakers M: Number of microphones J: Integer value indicating that the impulse response between all the speakers and microphones converges to 0 within a finite time Δt. Also, vector y _l = [y _{l 0 y l N-1 y} l N-2 ··· y l 1] T time series h _lm (k) = [server -h _{lm k 'bus} -h _{lm k' +} 1 ··· server -h _{lm N + 1} bar h _{lm 0} bar h _{lm 1} ... bar h _{lm k'-1} ] ^T Furthermore, bar h _{lm 0} = h _{lm 0} + h _{lm N} + ... h _{lm QN} bar h _{lm 1} = h _{lm 1} + h _{lm N + 1} + ・ ・ ・ h _{lm QN + 1}・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Bar-h _{lm j-QN-1} = h _{lm j- QN-1 + h lm j- (} Q-1) N-1 + ··· + h lm j-1 server _{-h lm j-QN = h lm} j-QN + h lm j- (Q-1) N + ··・ ＋0 ・ ・ ・ ・... ..... ..... server _{-h lm N-1 = h lm} N-1 + h lm 2N-1 + ··· +0 l = 1,2, ····, L m = 1, 2, ..., M Therefore, the recurrence formula (9) is replaced by the following formula (12).

[0049]

[Equation 7]

At this time, the processor performs the following four operation procedures at time k, for example.

Operation 11: Speaker input signal y _1k ^' (k),
Operation for outputting y _2k ^' (k), ..., Y _lk ^' (k) to the first speaker, the second speaker ,. Output signal e ₁ (k), e ₂ (k), ..., e _M (k)
, Which is input from the first microphone, the second microphone, ..., And the Mth microphone 13: Engine 2 input from the cycle measuring circuit 22
Let N be the integer value closest to the value obtained by multiplying the rotation cycle of 2 by Ord / Δt or 1 / (Ord · Δt). Operation 14: 1 = 1, 2, ... L and j = 0,
1, 2, ..., Calculation of recurrence formula (12) is performed for J-1. Further, the plurality of speakers 11 ...
..When using and

[0052]

[Equation 8]

As an instantaneous estimated value of α, time series h _1k ^' (k)
・ By using e _k ^' (k), the evaluation function is based on the steepest descent method.

[0054]

[Equation 9]

The optimum value of the vector y ₁ which is the first speaker output signal vector that minimizes is the following recurrence formula (13).
It is obtained by iteratively calculating. Vector y ₁ (k + 1) = vector y ₁ (k) −μ · α · time series h _1k ^“ (k) · e _k ^” (k) ··· (13) where k ”is k This is a value obtained by adding 1 to the integer remainder when it is divided by, and α is an arbitrary constant.This recurrence formula (13) can be calculated in a shorter time than the recurrence formula (11).

Therefore, the recurrence formula (9) is replaced by the following formula (14). y _{1 (k-J + QN)} ^' (k + 1) = y _{1 (K-j + QN)} ^' (k) -μ ・ α ・ e _k (k) ・ h _1k ^" _j・ ・ ・ ・ ・ ( 14) At this time, the processor is performing the following four operation procedures at the time, for example.

Operation 21: Speaker input signal y _1k ^' (k), y
_2k ^' (k), ..., y _Lk ^' (k) are respectively set to the first speed.
Output to the second speaker, the second speaker ,. Operation 22: Microphone output signal e _k ^" (k) is input from the k" th microphone Operation 23: Engine 2 input from the cycle measuring circuit 22
Let N be the integer value closest to the value obtained by multiplying the rotation period of 2 by Ord / Δt or 1 / (Ord · Δt). Operation 24: 1 = 1, 2, ..., L and j = 0,
The recurrence formula (14) is calculated for 1, 2, ..., J-1. Therefore, the operation of the above algorithm is performed by the recurrence formulas (9), (11) and (13), or the recurrence formulas (10), (12) and (1
Since it is only necessary to repeatedly calculate 4), it is possible to reduce the calculation time of the speaker input control.

Conditions for Execution of Vibration Reduction Control Next, with reference to FIG. 4 and the following, a description will be given of whether or not to execute the vibration reduction control utilizing the above-mentioned vibration for reduction (hereinafter referred to as ANC). 4 to 12 are reference examples, and FIG. 13 corresponds to the present invention.

First, referring to FIG. 4, audio source 3
After passing through the amplifier 32, the audio signal from 1 is added to the signal of the reducing vibration formed as described above by the adder 30 and output from the common speaker 11. 4, a noise detection circuit 41 for detecting the noise level in the vehicle interior and a determination circuit 42 for determining whether or not to execute the ANC control according to the noise level detected by the circuit 41 are provided. . In the embodiment, when the noise level detected by the noise detection circuit 41 is equal to or higher than the predetermined value, the output level from the speaker 11 is determined to be equal to or higher than the predetermined value, and the ANC control is prohibited (OFF). .

The noise level detection circuit 41 receives the input I
The noise level is detected based on the G pulse r, the microphone signal e, and the reduction vibration y. The noise detection circuit 41 is configured, for example, as shown in FIG. That is, the circuit 51
The residual noise in the vehicle compartment is detected based on the microphone signal e. In addition, the circuit 52 outputs the signal y indicating the reduction vibration.
The noise reduced by the ANC control is estimated based on The sum of the noises detected by both circuits 51 and 52 can be regarded as the noise actually generated in the vehicle interior. For this reason, both circuits 5 are added by the adder 53.
After the outputs of 1 and 52 are added, they are rectified and smoothed by the circuit 54 to obtain the noise level lave.

The circuit 51 has a tracking filter 55 that passes only frequencies near the predetermined frequency fc, and the circuit 56 adjusts the predetermined frequency fc to a frequency according to the engine speed. FIG. 6 shows the predetermined frequency fc set by the circuit 56, and in the embodiment, it is assumed to correspond to the rotational secondary component of the engine.

The circuit 52 has a transfer characteristic model 57 between the microphone 12 and the speaker 11, and the output signal vector y to the speaker 11 is a vibration vector y estimated to be reduced. ', And the circuit 58 performs code conversion. That is, the vector y currently output to the speaker 11 is represented by y = {y _(n) , y _(n-1) , y _(n-2) , ... Y _(nk) }. , The transfer characteristic h is represented by h = {h ₀ , h ₁ , h ₂ , ... H _k }, and the reduced vibration vector y ′ estimated at this time is given by the following equation (15). Shown.

[0063]

[Equation 10]

Judgment circuit 42 makes a judgment as shown in FIG. That is, if the noise level lave is less than or equal to the predetermined threshold value L1, it is judged that the ANC control is to be executed (Q2). Make a decision to stop. Of course, the control unit U (the control unit 20 thereof)
According to the determination result of the determination circuit 42,
Control is executed and stopped. The threshold value L1 is as shown in FIG.
As shown in FIG. 5, the margin is secured between L1 and L2 by setting the value slightly lower than the limit output level L2 at which the output sound from the speaker 11 begins to be distorted.

9 and 10, the starting point of ANC control is also set. That is, as shown in FIG. 10, a start threshold value LO is set according to the audio sound level, and the noise level lave is in the range between the start threshold value LO and the threshold value L1. Only when (LO <L1), the ANC control is executed. The start threshold value LO is set to be larger as the audio sound level is higher, but the higher audio sound level means that the noise in the vehicle interior is relatively loud, while the noise is louder. Sometimes the ANC control does not have any adverse effect on the audio sound.
When the Dio sound is low, the noise is relatively low and ANC
It is thought to require no control).

FIG. 11 shows a circuit of the speaker 11 by the circuit 61.
The input level of the signal is calculated (the signal level after being added by the adder 30 of FIG. 4 is calculated), and the ANC control is executed by the judgment circuit 62 based on the speaker input level calculated by the circuit 61. Whether or not to perform is determined. At the time of this determination, the ANC control is stopped when the speaker input level is equal to or higher than a predetermined threshold value.

In FIG. 12, the audio sound level is calculated by the circuit 63, and the calculated audio sound level and the noise level detected by the noise detection circuit 41 are added by the adder 64, Based on this added level LG, determination circuit 65 determines whether or not to execute ANC control. In this determination, the ANC control is stopped when the addition level LG is equal to or higher than the predetermined threshold value L10.

FIG. 13 shows that when the addition level LG in FIG. 12 is equal to or higher than the predetermined threshold value L10, the audio output is temporarily reduced by a predetermined ratio, for example 5%, without immediately stopping the ANC control (Q23. ), When the addition level LG does not become smaller than the threshold value L10 even if the audio output is reduced a predetermined number of times, for example, six times (Q2
4, Q25), the ANC control is stopped for the first time (Q26). In this case, in Q26, A
Instead of stopping the NC control, the audio output can be stopped.

In FIG. 13, instead of decreasing the audio output in Q23 by a predetermined ratio, the output of the ANC control may be decreased by a predetermined ratio (the vibration level of the vibration for reduction is decreased by a predetermined ratio).

In Q23 of FIG. 13, both the audio output and the vibration output for reduction may be reduced by a predetermined ratio. In addition, a switch manually operated by the driver may be provided to allow Q23 to select either the audio output or the vibration output for reduction.

Although the embodiment has been described above, the vibration to be reduced is not limited to the engine vibration, but may be an appropriate noise that causes a problem in the passenger compartment. Further, as a method for optimizing the vibration for reduction, a known appropriate method can be adopted.

[Brief description of drawings]

FIG. 1 is a view of a vehicle to which the present invention is applied, viewed from above.

FIG. 2 is an overall control system diagram for generating vibration for reduction.

FIG. 3 is a block diagram showing the configuration of an optimization part of the reduction vibration in FIG.

FIG. 4 is a diagram showing a relationship among an audio source, a noise level detection circuit, and a vibration reduction control system.

FIG. 5 is a diagram showing a specific example of a noise level detection circuit.

FIG. 6 is a diagram showing an example of frequencies adjusted by a circuit 56 shown in FIG.

FIG. 7 is a flowchart for determining whether or not to execute vibration reduction control according to a noise level.

FIG. 8 is a diagram showing an example of setting a threshold value used for determining whether or not to perform vibration reduction control.

FIG. 9 is a flowchart showing another example for determining whether or not to execute vibration reduction control.

FIG. 10 is a diagram for setting a starting threshold value LO used in FIG.

FIG. 11 is a diagram showing an example of a circuit for determining whether to execute vibration reduction control according to a speaker input level.

FIG. 12 is a diagram showing an example of a circuit for determining whether or not to execute vibration reduction control according to an added value of an audio sound level and a noise level.

FIG. 13 is a flowchart showing another control example for determining whether or not to perform vibration reduction.

[Explanation of symbols]

1: Car 2: Vehicle compartment 8: Engine (vibration source) 11: Speaker 12: Mike 31: Audio source 41: Noise level detection circuit 42: Judgment circuit 62: Judgment circuit 65: Judgment circuit

─────────────────────────────────────────────────── --- Continuation of the front page (72) Inventor Kunio Segawa 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Mazda Co., Ltd. (56) Reference JP-A-4-373399 (JP, A) JP-A-62 -188596 (JP, A) JP 3-30506 (JP, A) JP 5-11779 (JP, A) JP 5-11773 (JP, A) JP 5-61482 (JP, A) ) Japanese Patent Laid-Open No. 4-34599 (JP, A) Actually developed 63-12454 (JP, U) Actually developed 52-146950 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) G10K 11/178 B60R 11/02 F16F 15/02 G10K 11/16 H04R 3/02

Claims (2)

(57) [Claims] 1. A vehicle vibration reduction device for reducing vibration in a vehicle compartment by outputting vibration for reduction from the speaker to the vehicle compartment, wherein the speaker for vibration output for reduction is set also as an audio speaker. The output level of the speaker distorts the sound when both the output of the reduction vibration and the audio output are performed.
A vehicle, characterized by comprising an output lowering means for lowering the audio output level by a predetermined amount when the output exceeds a predetermined value which is set so as not to exceed an upper limit output that can be output . Vibration control device. 2. The reduction according to claim 1, wherein when the audio output is lowered by the operation of the audio output lowering means and the output level of the speaker is equal to or higher than the predetermined value, the output of the vibration for reduction is stopped. And a vehicle vibration output canceling means.