JP2021011132A - Vehicular soundproof device - Google Patents

Abstract

To provide a vehicular soundproof device configured so that complicated calculation is not required and a soundproof effect is improved.SOLUTION: A soundproof device 6, which is provided in an automobile 1, comprises piezoelectric element parts 40 and 50 constituted of piezoelectric elements and a control part 10 with a variable resistor which at least controls the piezoelectric element parts 40 and 50 by allowing variable resistor to vary resistance values. The piezoelectric element parts 40 and 50 comprise a detecting piezoelectric element part 40 for detecting sound, mounted on the automobile 1 and an output piezoelectric element part 50 for outputting sound, mounted on the detecting piezoelectric element part 40. The control part 10 reverses sound detected by the detecting piezoelectric element part 40 into an opposite phase, and amplifies the sound at a predetermined amplification factor and then makes the output piezoelectric element part 50 output the sound, which when at least one of input change of an accelerator, input change of a brake and speed change occurs in the automobile 1, makes the variable resistor vary the resistance values to vary the predetermined amplification factor.SELECTED DRAWING: Figure 1

Description

The present invention relates to a soundproofing device for vehicles.

Conventionally, as a soundproofing device for a vehicle, the one described in Patent Document 1 is known. In the vehicle soundproofing device (noise control device) described in Patent Document 1, the control device main body generates control space noise caused by the vibration of the floor panel according to the vibration amount of the floor panel of the vehicle detected by the acceleration sensor. It is disclosed that the piezo actuator is controlled so as to give a noise reducing vibration for reducing noise and a vibration damping vibration for suppressing sensor vibration to the floor panel. Further, it is disclosed that the control device main body includes a control command value calculation unit composed of a microcomputer for calculating a control command value for controlling the drive of the piezo actuator.

JP-A-2010-78852

However, in the configuration disclosed in Patent Document 1, a complicated calculation is required in the microcomputer, and the response speed of the control device main body is slow. On the other hand, if the sound (noise) detected by the sensor can be inverted and amplified by a control unit provided with an analog circuit and output from the actuator, the soundproofing function can be exhibited by a relatively simple calculation. Further, in order to improve the soundproofing effect, the control device main body is required to accurately invert and amplify the sound detected by the sensor and output it from the actuator.

The present invention has been completed based on the above circumstances, and one object of the present invention is to provide a soundproofing device for vehicles that does not require complicated calculations. Another further object is to provide a soundproofing device for vehicles with improved soundproofing effect.

The present invention is a soundproofing device for a vehicle provided on a vehicle, which has a piezoelectric element portion made of a piezoelectric element and a variable resistor, and at least the variable resistor controls the piezoelectric element portion by changing the resistance value. A control unit is provided, and the piezoelectric element unit includes a detection piezoelectric element unit that is attached to the vehicle to detect sound, and an output piezoelectric element unit that is attached to the detection piezoelectric element unit and outputs sound. The control unit inverts the sound detected by the detection piezoelectric element unit in the opposite phase, amplifies the sound at a predetermined amplification factor, and outputs the sound from the output piezoelectric element unit. In the vehicle, the accelerator It is characterized in that when at least one of an input change, a brake input change, and a speed change occurs, the resistance value is changed by the variable resistor to change the predetermined amplification factor.

According to such a soundproofing device for vehicles, for example, when the vehicle is accelerated by the input of the accelerator, friction noise and collision noise generated between the tire and the road surface, driving noise of the engine, motor, etc., wind noise, etc. Noise (road noise) rises. At this time, the sound detected by the detection piezoelectric element unit can be inverted in the opposite phase, and the amplification factor can be increased by changing the resistance value to output the sound from the output piezoelectric element unit. In addition, when the vehicle decelerates due to the input of the brake, the road noise is reduced. At this time, the sound detected by the detection piezoelectric element unit can be inverted in the opposite phase, and the amplification factor can be lowered by changing the resistance value to output the sound from the output piezoelectric element unit. In this way, road noise can be effectively canceled and soundproofed by changing the resistance value without performing complicated arithmetic processing.

In the above configuration, the control unit lowers the predetermined amplification factor when the voltage exceeds a predetermined voltage when the input voltage increases with the increase of the sound detected from the detection piezoelectric element unit. If the voltage does not exceed a predetermined voltage, the predetermined amplification factor can be increased.

According to such a soundproofing device for vehicles, when the accelerator input and speed increase, and the sound detected from the detection piezoelectric element increases due to the increase in road noise, a predetermined voltage (voltage that can be supplied from the power supply). It is possible to prevent a decrease in the soundproofing effect by increasing a predetermined amplification factor until it exceeds.

In the above configuration, the control unit changes the predetermined amplification factor when an accelerator input change or a brake input change occurs in the vehicle, and when a change in speed occurs, the changed state. The amplification factor can be further changed.

According to such a soundproofing device for vehicles, when a change in speed occurs after an accelerator input or a brake input occurs, it is detected from the detection piezoelectric element unit by changing and adjusting the amplification factor again. The sound can be suitably inverted and amplified by the control unit and output from the output piezoelectric element unit.

In the above configuration, the control unit can adjust the impedance by changing the resistance value with a variable resistor different from the variable resistor when the predetermined amplification factor is changed.

According to such a soundproofing device for vehicles, the phase shift between the detection piezoelectric element unit and the output piezoelectric element unit can be suitably adjusted, and the voltage can be efficiently amplified by the control unit.

In the above configuration, the control unit can amplify and invert the sound detected by the detection piezoelectric element unit by the amplifier circuit unit having the variable resistor and at least two operational amplifiers. ..

According to such a soundproofing device for vehicles, the piezoelectric element unit can be controlled by a relatively simple analog circuit. Further, the sound detected by the detection piezoelectric element unit can be amplified stepwise by the two operational amplifiers. For example, the first operational amplifier can be used as an inverting amplifier circuit and the second operational amplifier can be used as a non-inverting amplifier circuit for stepwise amplification.

According to the present invention, it is possible to provide a soundproofing device for vehicles that does not require complicated calculations. Further, it becomes possible to provide a soundproofing device for vehicles with improved soundproofing effect.

Explanatory drawing of the automobile according to the embodiment as viewed from the left Block diagram showing the electrical configuration of a vehicle soundproofing device Circuit diagram showing the amplifier circuit section A flowchart showing a procedure for changing the voltage amplification factor when an accelerator input change or a brake input change occurs. A flowchart showing a procedure for changing the voltage amplification factor when the vehicle speed changes.

<Embodiment>
Embodiments of the present invention will be described with reference to FIGS. 1 to 5. In the present embodiment, the soundproofing device (soundproofing device for vehicles) 6 mounted on the automobile (vehicle) 1 as a vehicle will be described. In FIG. 1, the arrow direction Fr is forward, the arrow direction Rr is rearward, the arrow direction T is upward, the arrow direction B is downward, the direction on the front side of the paper is left, and the direction on the back side of the paper is right. explain.

The automobile 1 includes wheels 2 and 2 that rotate to allow the automobile 1 to travel, and seats 3 and 3 that are interior materials provided on the vehicle interior side and allow occupants to sit. Further, the automobile 1 is provided in front of the vehicle and comprises an engine room 5 for accommodating an engine or the like, a floor of the vehicle, a sheet metal floor panel 4 to which seats 3 and 3 are attached, and a floor panel 4 and the like. It is provided with a soundproofing device 6 that insulates road noise (noise) transmitted to the interior side to make the interior space of the vehicle soundproof.

The soundproofing device 6 includes piezoelectric element units 40 and 50 which are made of piezoelectric elements and have piezoelectricity, and control units 10 which are housed in the engine room 5 and control the piezoelectric element units 40 and 50. The piezoelectric element units 40 and 50 are attached to the vehicle interior side of the floor panel 4 to detect sound, and the detection piezoelectric element unit 40 and the output piezoelectric element unit 40 attached to the vehicle interior side of the detection piezoelectric element unit 40 to output sound. It has a two-layer structure including a portion 50. The piezoelectric characteristics of the piezoelectric element constituting the detection piezoelectric element unit 40 are the same as those of the piezoelectric element constituting the output piezoelectric element unit 50.

As shown in FIG. 2, the control unit 10 supplies electricity to the ECU (Electronic Control Unit) 11 that controls the engine drive and the like based on the accelerator input changes and the like detected from the detection units 13, 14 and 15. The amplifier circuit unit 12 is provided so as to invert the sound detected by the detection piezoelectric element unit 40 in the opposite phase, amplify the sound at a predetermined amplification factor, and output the sound from the output piezoelectric element unit 50. Each of the detection units 13, 14 and 15 includes an accelerator detection unit 13 that detects an accelerator input change, a brake detection unit 14 that detects a brake input change, and a vehicle speed detection unit 15 that detects a change in vehicle speed. .. The detection piezoelectric element unit 40 is electrically connected to the output piezoelectric element unit 50 via the control unit 10.

As shown in FIG. 3, the amplifier circuit unit 12 is connected to the detection piezoelectric element unit 40, and the inverting amplifier circuit 20 which inverts and amplifies the electric signal obtained from the sound detected by the detection piezoelectric element unit 40 in the opposite phase. The non-inverting amplifier circuit 30 which is connected to the inverting amplifier circuit 20 and the output piezoelectric element section 50, further amplifies the electric signal inverted and amplified by the inverting amplifier circuit 20 and transmits it to the output piezoelectric element section 50. Become. An AC power supply 29 is connected to the inverting amplifier circuit 20 via the detection piezoelectric element unit 40.

The inverting amplifier circuit 20 includes an operational amplifier 21 and a plurality of resistors 23, 24, 25. A detection piezoelectric element 40 is connected to the non-inverting input terminal of the operational amplifier 21, and positive feedback is applied via the capacitor 22 and the resistor 23. A resistor 24 is connected to the inverting input terminal of the operational amplifier 21, and negative feedback is applied via the resistor 25. The resistor 23 and the resistor 25 are variable resistors whose resistance values can be changed based on the operation of the ECU 11 (see FIG. 2).

In the inverting amplifier circuit 20, the resistance value of the resistor 24 is R24, the resistance value of the resistor 25 is R25, the voltage value of the signal input to the non-inverting input terminal of the operational amplifier 21 is V0, and the output terminal of the operational amplifier 21 outputs the voltage value. When the voltage value of the signal to be output is V1, the relationship of V1 = V0 * (1 + R25 / R24) is established. Therefore, by changing the ratio of the resistance values of the resistor 24 and the resistor 25 (that is, the resistance value of the variable resistor 25), the amplification factor for amplifying the voltage value V0 to the voltage value V1 can be changed (inversion). The amplification factor of the voltage in the amplifier circuit 20 can be changed).

Further, in the inverting amplifier circuit 20, the impedance is adjusted by changing the resistance value of the resistor 23, and the sound frequency (peak frequency) at which the soundproofing effect of the piezoelectric element units 40 and 50 is maximized is set. Can be done.

The non-inverting amplifier circuit 30 includes an operational amplifier 31 and a plurality of resistors 32 and 33. The output terminal of the operational amplifier 21 is connected to the non-inverting input terminal of the operational amplifier 31. A resistor 32 is connected to the inverting input terminal of the operational amplifier 31, and negative feedback is applied via the resistor 33. The resistor 33 is a variable resistor whose resistance value can be changed based on the operation of the ECU 11 (see FIG. 2).

In the non-inverting amplifier circuit 30, the resistance value of the resistor 32 is R32, the resistance value of the resistor 33 is R33, and the signal input to the non-inverting input terminal of the operational amplifier 31 (the signal output from the output terminal of the operational amplifier 21). When the voltage value of is V1 and the voltage value of the signal output from the output terminal of the operational amplifier 31 is V2, the relationship of V2 = V1 * (1 + R33 / R32) is established. Therefore, by changing the ratio of the resistance values of the resistor 32 and the resistor 33 (that is, the resistance value of the variable resistor 33), the amplification factor that amplifies the voltage value V1 to the voltage value V2 can be changed (non-). The amplification factor of the voltage in the inverting amplifier circuit 30 can be changed).

Subsequently, the procedure in which the control unit 10 controls the piezoelectric element units 40 and 50 will be described with reference to FIGS. 1 to 5. It is assumed that the coupler (circled number 1) shown in the lower right of FIG. 4 is connected to the coupler (circled number 1) shown in the upper left of FIG. First, as shown in FIG. 4, in S1, the control parameter is set to the reference value. Specifically, the resistance values (control) of the variable resistors 23, 25, 33 so as to match the initial values (reference values) obtained in order to insulate the noise measured in advance in the driving test of the automobile 1. Parameter) is set (the amplification factor of the voltage amplified by the amplifier circuit unit 12 at this time is called a "predetermined amplification factor").

Next, in S2, noise is detected by the detection piezoelectric element unit 40. Here, in S3, if there is no accelerator input (the accelerator input is not detected by the accelerator detection unit 13 and the accelerator input does not change), the process proceeds to S4. If there is no brake input in S4 (the brake input is not detected by the brake detection unit 14 and the brake input change does not occur), the process proceeds to S5 shown in FIG. In S5, when the vehicle speed does not change (the speed change of the vehicle 1 is not detected by the vehicle speed detection unit 15), the resistance values of the variable resistors 23, 25, 33 and the like are not changed from the initial values. , Impedance and voltage amplification factor are maintained.

As shown in FIG. 4, if there is an accelerator input in S3 (the accelerator input is detected by the accelerator detection unit 13 and an accelerator input change occurs), the process proceeds to S6. In S6, the voltage value V0 (input voltage) of the electric signal obtained from the noise detected by the detection piezoelectric element unit 40 increases due to the increase in the road noise. Here, in S7, if the limit of the control voltage is not reached (the voltage amplified by the amplifier circuit unit 12 does not exceed the upper limit of the voltage that can be supplied from the AC power supply 29), the process proceeds to S8. In S8, the resistance value of the variable resistor 23 is changed to adjust the impedance, and in S9, the resistance values of the variable resistors 25 and 33 are increased to increase the amplification factor of the voltage amplified by the amplifier circuit unit 12 (predetermined). Increase the amplification factor of).

On the other hand, in S7, when the limit of the control voltage is reached (the voltage amplified by the amplifier circuit unit 12 exceeds the upper limit of the voltage that can be supplied from the AC power supply 29), the process proceeds to S10. In S10, the resistance value of the variable resistor 23 is changed to adjust the impedance, and in S11, the resistance values of the variable resistors 25 and 33 are lowered to lower the amplification factor of the voltage amplified by the amplifier circuit unit 12 (predetermined). Decrease the amplification factor of).

When there is a brake input in S4 (the brake input is detected by the brake detection unit 14 and a change in the brake input occurs), it is detected by the detection piezoelectric element unit 40 in S12 due to a decrease in road noise. The voltage value V0 (input voltage) of the electric signal obtained from the noise is reduced. Then, in S13, the resistance value of the variable resistor 23 is changed to adjust the impedance, and in S14, the resistance values of the variable resistors 25 and 33 are lowered to lower the amplification factor of the voltage amplified by the amplifier circuit unit 12. ..

As shown in FIG. 5, when the vehicle speed changes in S5 (the change in the speed of the automobile 1 is detected by the vehicle speed detection unit 15), the process proceeds to S15. If the vehicle speed does not increase in S15, that is, if the vehicle speed decreases in S16, the process proceeds to S17, and the input voltage decreases due to the decrease in road noise. Then, in S18, the impedance is adjusted by changing the resistance value of the variable resistor 23. In S19, since the limit of the control voltage has not been reached, the resistance values of the variable resistors 25 and 33 are increased to increase the amplification factor of the voltage amplified by the amplifier circuit unit 12. As a result, the soundproof state in the vehicle interior is maintained.

In S15, when the vehicle speed increases, the process proceeds to S20, and the input voltage increases due to the increase in road noise. Here, in S21, if the limit of the control voltage is not reached, the process proceeds to S22. In S22, the resistance value of the variable resistor 23 is changed to adjust the impedance, and in S23, the resistance values of the variable resistors 25 and 33 are increased to increase the voltage amplification factor. On the other hand, when the limit of the control voltage is reached in S21, the process proceeds to S24. In S24, the resistance value of the variable resistor 23 is changed to adjust the impedance, and in S25, the resistance values of the variable resistors 25 and 33 are lowered to lower the voltage amplification factor.

Subsequently, the effect of this embodiment will be described. In the present embodiment, the soundproofing device 6 provided in the automobile 1 has piezoelectric element portions 40 and 50 made of piezoelectric elements and variable resistors 25 and 33, and at least the variable resistors 25 and 33 determine the resistance value. A control unit 10 for controlling the piezoelectric element units 40 and 50 is provided. The piezoelectric element units 40 and 50 are attached to the automobile 1 and are attached to the detection piezoelectric element unit 40 for detecting sound and the detection piezoelectric element unit 40. The control unit 10 includes an output piezoelectric element unit 50 that is attached and outputs sound, and the control unit 10 inverts the sound detected by the detection piezoelectric element unit 40 in the opposite phase and amplifies it at a predetermined amplification factor to output piezoelectric. It is output from the element unit 50, and when at least one of the accelerator input change S3, the brake input change S4, and the speed change S5 occurs in the automobile 1, S9, S11, S14, S19, In S23 and S25, it was shown that the variable resistors 25 and 33 change the resistance value to change the predetermined amplification factor.

According to such a soundproofing device 6, for example, when the automobile 1 is accelerated by the input of the accelerator, a friction sound or a collision sound generated between the tire and the road surface, a driving sound of an engine or a motor, a wind noise, or the like ( Road noise) rises. At this time, the sound detected by the detection piezoelectric element unit 40 can be inverted in the opposite phase, and the amplification factor can be increased by changing the resistance value to output the sound from the output piezoelectric element unit 50. Further, when the vehicle 1 decelerates due to the input of the brake, the road noise is reduced. At this time, the sound detected by the detection piezoelectric element unit 40 can be inverted in the opposite phase, and the amplification factor can be lowered by the change of the resistance value to output from the output piezoelectric element unit 50. In this way, road noise can be effectively canceled and soundproofed by changing the resistance value without performing complicated arithmetic processing.

Further, the control unit 10 exceeds the voltage that can be supplied from the AC power supply 29 when the input voltage increases with the increase in the sound detected from the detection piezoelectric element unit 40 in S7 and S21 (limit voltage). When the limit is reached), the predetermined amplification factor is lowered in S11 and S25, and when the predetermined voltage is not exceeded (the limit of the limit voltage is not reached), the predetermined amplification factor is increased in S9 and S23.

According to such a soundproofing device 6, when the input of the accelerator and the speed are increased and the sound detected from the detection piezoelectric element unit 40 is increased due to the increase of the road noise, the voltage (limit voltage) that can be supplied from the power supply is increased. Until it exceeds, the predetermined amplification factor can be increased to prevent the soundproofing effect from being lowered.

Further, the control unit 10 changes a predetermined amplification factor in S9, S11, and S14 when an accelerator input change or a brake input change occurs in S3 and S4, and when a speed change occurs in S5. , S19, S23, S25, the amplification factor after the change is further changed.

According to such a soundproofing device 6, when a change in speed occurs after an accelerator input or a brake input occurs, it is detected by the detection piezoelectric element unit 40 by changing and adjusting the amplification factor again. The sound can be suitably inverted and amplified by the control unit 10 and output from the output piezoelectric element unit 50.

Further, when changing the predetermined amplification factor, the control unit 10 changes the resistance value in S8, S10, S13, S18, S22, S24 by a variable resistor 23 different from the variable resistors 25 and 33. , Perform impedance adjustment.

According to such a soundproofing device 6, the phase shift between the detection piezoelectric element unit 40 and the output piezoelectric element unit 50 can be suitably adjusted, and the voltage can be efficiently amplified by the amplifier circuit unit 12.

Further, the control unit 10 amplifies and inverts the sound detected by the detection piezoelectric element unit 40 by the amplifier circuit unit 12 having the variable resistors 25 and 33 and the two operational amplifiers 21 and 31.

According to such a soundproofing device 6, the piezoelectric element units 40 and 50 can be controlled by a relatively simple analog circuit. Further, the sound detected by the detection piezoelectric element unit 40 can be amplified stepwise by the two operational amplifiers 21 and 31. As shown in the present embodiment, the first operational amplifier 21 can be used in the inverting amplifier circuit 20 and the second operational amplifier 31 can be used in the non-inverting amplifier circuit 30 for stepwise amplification.

<Other embodiments>
The present invention is not limited to the embodiments described by the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention, and further, within the scope not deviating from the gist other than the following. It can be implemented with various changes.

(1) In the above embodiment, the piezoelectric element portion is provided on the vehicle interior side of the floor panel, but the present invention is not limited to this. For example, the piezoelectric element portion may be provided on the outside of the vehicle interior of the floor panel, the outside of the vehicle interior of the instrument panel, the fender liner of the wheel house, or the like.

(2) In addition to the above embodiment, the procedure for the control unit to control the piezoelectric element unit can be appropriately changed. In the above embodiment, the control unit determines whether or not to change the predetermined amplification factor in the order of the accelerator input change, the brake input change, and the speed change, but the present invention is not limited to this. For example, it may be determined whether or not to change the predetermined amplification factor in the order of the brake input change, the accelerator input change, and the speed change. Further, after determining all the changes in the accelerator input, the brake input, and the speed, it may be determined whether or not to change the predetermined amplification factor.

(3) In addition to the above embodiment, the circuit arrangement of the amplifier circuit unit can be changed as appropriate. The circuit arrangement of the amplifier circuit unit may be such that the sound detected by the detection piezoelectric element unit is inverted and amplified in the opposite phase and can be output from the output piezoelectric element unit.

(4) In addition to the above embodiment, the procedure for changing the resistance value of the variable resistor can be changed as appropriate. For example, when an accelerator input change or a brake input change occurs, the voltage amplification factor is changed by changing only the resistance value of the variable resistor of the inverting amplifier circuit, and when the vehicle speed changes, it is not. The voltage amplification factor may be changed by changing only the resistance value of the variable resistor of the inverting amplifier circuit.

(5) The vehicle soundproofing device exemplified in the above embodiment is not limited to the one provided for a vehicle, and may be provided in various vehicles. For example, the above-mentioned soundproofing device for vehicles can be applied to trains and amusement vehicles as ground vehicles, and airplanes and helicopters as flight vehicles.

1 ... Automobile (vehicle), 6 ... Soundproofing device (soundproofing device for vehicle), 10 ... Control unit, 12 ... Amplifier circuit unit, 21,31 ... Operational amplifier, 23, 25, 33 ... Variable resistor, 40 ... Detection piezoelectric element Part (piezoelectric element part), 50 ... Output piezoelectric element part (piezoelectric element part)

Claims (5)

A soundproofing device for vehicles installed on vehicles.
Piezoelectric element part made of piezoelectric element and
It has a variable resistor, and at least includes a control unit that controls the piezoelectric element unit by changing the resistance value with the variable resistor.
The piezoelectric element portion is
A detection piezoelectric element unit that is attached to the vehicle and detects sound,
An output piezoelectric element unit that is attached to the detection piezoelectric element unit and outputs sound is provided.
The control unit inverts the sound detected by the detection piezoelectric element unit in the opposite phase, amplifies the sound at a predetermined amplification factor, and outputs the sound from the output piezoelectric element unit. In the vehicle, the accelerator is input. A soundproofing device for vehicles, characterized in that, when at least one of a change, a change in brake input, and a change in speed occurs, the variable resistor changes the resistance value to change the predetermined amplification factor. .. The control unit receives when the input voltage increases as the sound detected from the detection piezoelectric element unit increases.
When the voltage exceeds a predetermined voltage, the predetermined amplification factor is lowered to reduce the predetermined voltage.
The soundproofing device for a vehicle according to claim 1, wherein when the predetermined voltage is not exceeded, the predetermined amplification factor is increased. In the vehicle, the control unit
When the input change of the accelerator or the input change of the brake occurs, the predetermined amplification factor is changed.
The soundproofing device for a vehicle according to claim 1 or 2, wherein when a change in speed occurs, the amplification factor after the change is further changed. Claims 1 to 3 are characterized in that, when the control unit changes the predetermined amplification factor, the impedance is adjusted by changing the resistance value with a variable resistor different from the variable resistor. The vehicle soundproofing device according to any one of the above. The first aspect of the present invention is characterized in that the control unit amplifies and inverts the sound detected by the detection piezoelectric element unit by an amplifier circuit unit having the variable resistor and at least two operational amplifiers. Item 4. The soundproofing device for a vehicle according to any one of items 4.

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