JP5012964B2 - Vehicle presence notification device - Google Patents

Description

  The present invention relates to a vehicle presence notification device that generates a notification sound outside a vehicle and notifies the presence of the vehicle to the surroundings, and in particular, an electric vehicle that generates rotational power by energization, such as an electric vehicle, a fuel cell vehicle, and a hybrid vehicle. The present invention relates to a technique suitable for use in a vehicle capable of traveling by a motor.

Vehicles with low vehicle running noise, such as vehicles that run on electric motors, have the problem that pedestrians are less likely to notice the vehicle.
Therefore, a proposal has been made to generate a “notification sound (pseudo engine sound, etc.)” from a dynamic speaker (speaker that directly radiates audible sound) attached to the vehicle to notify the existence of the vehicle around the vehicle. (For example, refer to Patent Document 1).

In a range in which the vehicle approaches the pedestrian (a range in which the distance between the vehicle and the pedestrian is short), it is desirable to generate a notification sound with a large sound pressure to the pedestrian in order to more reliably notify the pedestrian of the presence of the vehicle. .
Even if the distance between the vehicle and the pedestrian is long, it is desirable to notify the pedestrian far from the vehicle of the presence of the vehicle.
That is, in the vehicle presence notification device,
(I) In a range where the distance between the vehicle and the pedestrian is short (short range), a notification sound having a relatively large sound pressure is generated for the pedestrian,
(Ii) Even in a range where the distance between the vehicle and the pedestrian is long (long range), it is required to notify the pedestrian of the presence of the vehicle by sending a notification sound.

In order to satisfy the above (ii), it is necessary to increase the sound pressure generated by the dynamic speaker in order to send the notification sound to a pedestrian far away from the vehicle. Then, the sound pressure level that can be heard by a vehicle occupant (driver or the like) increases, and exceeds the limit of sensitivity of the vehicle occupant.
Conversely, if the output level of the dynamic speaker is lowered in order to lower the sound pressure level of the notification sound that can be heard by the vehicle occupant, the reach of the notification sound will be shortened, and the presence of the vehicle will be notified to pedestrians far away from the vehicle. It becomes impossible.

A specific example of the above problem will be described with reference to FIG.
First, the target reach distance for delivering the notification sound is set.
Given that the maximum speed of the vehicle on a snowy road is 20 km / h and the braking distance on the snowy road is about 10 m, it is necessary to make a pedestrian sound 10 minutes away from the vehicle. In this way, the target reach distance is set (10 m).

Next, the sound pressure level of the sound at the target reach distance is set. As a specific example, the lower limit at which the pedestrian can hear the pseudo engine sound is set to 50 dB.
In this way, the sound pressure level of the dynamic speaker is determined so as to generate a notification sound of 50 dB or more to a pedestrian 10 m ahead by the dynamic speaker.
If this is embodied, as indicated by a broken line J in FIG. 1, the sound pressure level generated by the dynamic speaker is about 72 dB in the vehicle (distance 0 m).

Here, since the notification sound is radiated from a dynamic speaker mounted on the vehicle, a vehicle occupant riding in the vehicle continues to listen to the notification sound radiated from the dynamic speaker for a long time.
For this reason, it is necessary to lower the sound pressure level that can be heard by the vehicle occupant from a limit value (for example, 65 dB) of the sensitivity of the vehicle occupant.

However, the sound pressure of the notification sound reaching the vehicle occupant in the passenger compartment exceeds the limit of sensitivity of the vehicle occupant.
Therefore, if the output level of the dynamic speaker is lowered in order to lower the sound pressure level of the notification sound that can be heard by the vehicle occupant from the limit of the sensitivity of the vehicle occupant, the arrival distance of the notification sound becomes shorter, and the notification sound is reduced to the target arrival distance. Can no longer be delivered to.

JP 2005-289175 A

The present invention has been made in view of the above problems, and its purpose is as follows.
-A nearby pedestrian generates a loud sound pressure sound,
・ Sound notification sound to pedestrians far away,
The provision of a vehicle presence notification device that can reduce the sound pressure of a notification sound that can be heard by a vehicle occupant (driver or the like).

[Means of Claim 1]
The vehicle presence notification apparatus employing the means of claim 1 generates a notification sound from the dynamic speaker toward the outside of the vehicle, and also generates a notification sound from the parametric speaker toward the outside of the vehicle.
A dynamic speaker is good at generating sound in the vicinity (see the dashed line A in FIG. 1).
The parametric speaker can skip sound far (see the two-dot chain line B in FIG. 1).

(A) In the “short range (see 0 to 5 m in FIG. 1)” close to the vehicle, the notification sound from the dynamic speaker and the notification sound from the parametric speaker are combined. For this reason, the notification sound of a big sound pressure can be given with respect to the nearby pedestrian.
(B) In the “long range (see 5 m to 10 m in FIG. 1)” in which the distance from the vehicle is away from the short range, the notification sound emitted by the parametric speaker can be delivered. For this reason, a notification sound can be delivered to a pedestrian far away.

(C) Since the parametric speaker is a device in which ultrasonic waves are self-modulated in air away from the vehicle and converted into an audible sound, the notification sound generated by the parametric speaker is difficult for a vehicle occupant (driver or the like) to hear. .
For this reason, in the “short range”, the notification sound from the dynamic speaker and the notification sound from the parametric speaker are combined to generate a notification sound with a large sound pressure, but the vehicle occupant can hear the notification sound from the parametric speaker. Since it is difficult, the sound pressure of the notification sound heard by the vehicle occupant can be suppressed.

Thus, the vehicle presence notification device of the present invention is
-A nearby pedestrian generates a loud sound pressure sound,
・ Sound notification sound to pedestrians far away,
-The sound pressure of the notification sound that can be heard by vehicle occupants (drivers, etc.) can be reduced.

[Means of claim 2]
The dynamic speaker in the vehicle presence notification device according to claim 2 is an electromagnetic vehicle horn having an existing structure.
As described above, by using the “existing vehicle horn” as the dynamic speaker, it is possible to reduce the cost and to secure the vehicle mountability.
“Vehicle horn” is a “general term for an alarm device (horn) mounted on a vehicle and generates an alarm sound”, and is used for vehicles that do not have a horn member (a trumpet member that uses a square flute). "Alarm" is included.

[Means of claim 3]
The vehicle horn in the vehicle presence notification device according to the third aspect of the present invention is such that a self-excited voltage is applied and a warning sound is generated when a horn switch operated by a vehicle occupant is turned on.
As described above, by sharing the “vehicle horn that generates the alarm sound” and the “vehicle horn that generates the alarm sound”, it is possible to reduce the cost of the vehicle presence notification device and generate the notification sound. The space for mounting the vehicle horn can be easily secured.
In other words, it is not necessary to separately install a “dedicated dynamic speaker for generating a notification sound”, and the cost can be reduced and the mounting space can be easily secured.

[Means of claim 4]
The notification sound emitted from the dynamic speaker and the parametric speaker in the vehicle presence notification device of the means of claim 4 is a pseudo engine sound.
For this reason, the vehicle presence notification device can generate a pseudo engine sound that is hardly heard by a vehicle occupant (driver or the like) and easily noticed by a pedestrian.

It is explanatory drawing which shows the relationship between a sound pressure, the distance from a vehicle to a pedestrian, and a sound pressure. It is a schematic block diagram of a vehicle presence alerting | reporting apparatus. It is sectional drawing which shows a specific example of the horn for vehicles. It is a graph which shows the frequency characteristic at the time of operating the horn for vehicles by self-excitation, and when operating by separate excitation. It is the front view and top view of an ultrasonic speaker. It is explanatory drawing which shows the arrival distribution of alerting | reporting sound. It is explanatory drawing of a pseudo | simulation engine sound. It is a principle explanatory view of a parametric speaker.

An embodiment for implementing a vehicle presence notification device will be described with reference to the drawings.
The vehicle presence notification device notifies the presence of the vehicle S by a notification sound (pseudo engine sound or the like),
A dynamic speaker 1 for generating a notification sound is provided.
The dynamic speaker 1 uses an electromagnetic vehicle horn having an existing structure, and the electric horn 1 has an “electrical signal that generates a notification sound by a separate excitation voltage lower than the self-excitation voltage (for example, less than 8 V). ", A notification sound is generated from the vehicle horn 1.
In addition, the vehicle presence notification device includes a parametric speaker 2 that emits an ultrasonic wave obtained by ultrasonically modulating a notification sound toward the outside of the vehicle, and generates a notification sound from the dynamic speaker 1 toward the outside of the vehicle. A notification sound is generated toward the outside of the vehicle.

And the vehicle presence notification device
(I) In a short distance range close to the vehicle S, the notification sound by the dynamic speaker 1 and the notification sound by the parametric speaker 2 are synthesized to generate a notification sound with a large sound pressure;
(Ii) An alarm sound is generated by the parametric speaker 2 in a far distance range that is farther from the vehicle S than in the near distance range.

Next, a specific example of the vehicle presence notification device will be described with reference to FIGS. In the first embodiment, the same reference numerals as those in the “Mode for Carrying Out the Invention” denote the same functional objects.
[Configuration of Example 1]
The vehicle presence notification device according to the first embodiment notifies the surroundings of the vehicle S by a pseudo engine sound (an example of a notification sound). As shown in FIG. A vehicle horn 1, an ultrasonic speaker 3 that can emit ultrasonic waves, and a main body device 4 that controls the operation of the vehicle horn 1 and the ultrasonic speaker 3 are provided.

(Description of vehicle horn 1)
The vehicle horn 1 is an electromagnetic alarm sound generator having a known structure that generates an alarm sound toward the outside of the vehicle, and is mounted on, for example, the front portion of the vehicle S so as to emit the alarm sound toward the outside of the vehicle. Is.
A specific example of the vehicle horn 1 will be described with reference to FIG.

The vehicle horn 1 is attached to the vehicle S via a stay 11,
A coil 12 that generates a magnetic force when energized;
A fixed iron core (magnetic attraction core) 13 that generates a magnetic attraction force by the magnetic force generated by the coil 12, and
A movable core (movable core) 15 supported at the center of the diaphragm (diaphragm) 14 and supported so as to be movable toward the fixed core 13;
In conjunction with the movement of the movable iron core 15, the movable iron core 15 moves toward the fixed iron core 13 to move away from the fixed contact 16 and cut off the energization of the coil 12,
Is provided.

And, by applying a self-excited voltage (voltage of 8 V or more) equal to or higher than a threshold value to the direct current terminal (terminal connected to both ends of the coil 12) of the vehicle horn 1,
(I) A suction operation in which the movable iron core 15 is magnetically attracted to the fixed iron core 13 by energization of the coil 12;
(Ii) a restoration operation in which the movable contact 17 is separated from the fixed contact 16 by this suction operation, the energization of the coil 12 is stopped, and the movable iron core 15 and the movable contact 17 are restored;
Repeat continuously.

As described above, when the energization of the coil 12 is interrupted (interruption of generation of the magnetic attractive force of the fixed iron core 13), the vibration plate 14 vibrates together with the movable iron core 15, so that the vehicle horn 1 generates an alarm sound. .
The vehicle horn 1 is often set so that the fundamental frequency of the alarm sound is set to a low frequency around 400 Hz, and can generate a low frequency even if it is small.
A solid line A in FIG. 4 shows a frequency characteristic of an alarm sound generated by the vehicle horn 1 (an operating sound when a self-excited voltage is applied). As is clear from the solid line A in FIG. 4, the alarm sound generated by the vehicle horn 1 (the operation sound when a self-excited voltage is applied) is set at the fundamental frequency (the ON-OFF interval of the movable contact 17). Frequency) and its harmonic frequency.

Note that the vehicle horn 1 of FIG. 3 (a) enhances an alarm sound due to vibration of the diaphragm 14 by a horn member (a spiral trumpet member in the drawing) 18 and emits it outside the vehicle. The vehicle horn 1 of FIG. 3B resonates the resonance plate 19 with an alarm sound due to vibration of the diaphragm 14, and emits an alarm sound enhanced by the resonance sound to the outside of the vehicle.
Hereinafter, as a specific example, the embodiment will be described using the vehicle horn 1 including the horn member 18 (trumpet member), but the embodiment is not limited thereto.

(Description of ultrasonic speaker 3)
Like the vehicle horn 1 described above, the ultrasonic speaker 3 is attached to, for example, the front portion of the vehicle S so as to emit generated ultrasonic waves toward the front of the vehicle S, and preferably is a vehicle. It is attached at a position adjacent to (approaching) the horn 1 for use.

A specific structural example of the ultrasonic speaker 3 is shown in FIG. In addition, the structure of the ultrasonic speaker 3 shown in FIG. 5 is an example, and is not limited.
The ultrasonic speaker 3 is an ultrasonic generator that generates air vibrations having a frequency (20 kHz or higher) higher than a human audible band.
The ultrasonic speaker 3 of this embodiment is a speaker array in which a plurality of piezoelectric speakers (ceramic speakers, piezoelectric speakers, etc.) 21 suitable for ultrasonic reproduction are arranged. In addition, the piezoelectric speaker 21 used in this embodiment includes a piezo element that expands and contracts according to an applied voltage (charge / discharge) and a diaphragm 14 that vibrates air by the expansion and contraction of the piezo element. Of structure.

The ultrasonic speaker 3 can control the amount of energy of the generated ultrasonic waves and the directivity range of the ultrasonic waves emitted from the piezoelectric speakers 21 depending on the number and arrangement of the piezoelectric speakers 21 to be used. Moreover, the directivity range of an ultrasonic wave can be controlled also by using the directivity control member (horn member) 22 shown in FIG.
In this embodiment, an example in which the piezoelectric speaker 21 is used as an example of a speaker that generates ultrasonic waves is shown. However, this is only an example and is not limited. The ultrasonic wave generation means may be used.

Here, in FIG. 6 (a), the reach range α of the pseudo engine sound by the parametric speaker 2 is shown, and in FIG. 6 (b), the reach range β of the pseudo engine sound by the vehicle horn 1 is shown. FIG. 6 shows a range where the sound pressure of the pseudo engine sound is 50 dB.
As described above, the ultrasonic speaker 3 according to the first embodiment is provided so as to radiate ultrasonic waves toward the front of the vehicle S.
Further, the vehicle horn 1 is provided so that the pseudo engine sound reaches the periphery of the vehicle horn 1 evenly when the vehicle S is viewed from above. As a specific example, the opening of the horn member 18 in the vehicle horn 1 is attached so as to be directed downward (in the direction toward the road surface) of the vehicle S. The direction of the opening of the horn member 18 is not limited.

(Description of the main device 4)
Next, the main body device 4 that generates a pseudo engine sound from the vehicle horn 1 and the ultrasonic speaker 3 will be described. In addition, the structure of the main body apparatus 4 demonstrated below is an example, and is not limited.
The main unit 4 is
(A) a pseudo engine sound creating unit 23 that creates a frequency signal that forms a pseudo engine sound;
(B) a horn drive amplifier 24 (power amplifier) that drives the vehicle horn 1 by a frequency signal of a pseudo engine sound (an electrical signal that forms a pseudo engine sound);
(C) an ultrasonic amplitude modulation unit 25 that modulates a frequency signal of the pseudo engine sound (an electric signal that forms the pseudo engine sound) into an ultrasonic frequency;
(D) An ultrasonic speaker amplifier 26 that drives the ultrasonic speaker 3 with the modulated ultrasonic frequency is provided.
The main unit 4 operates when an operation signal (pseudo engine sound generation instruction signal) is given from an ECU (abbreviation of engine control unit), for example.

Hereinafter, the means (a) to (d) mounted on the main unit 4 will be described.
(Description of the pseudo engine sound creation unit 23)
The pseudo engine sound creating unit 23 is configured by a computer having a well-known structure including a CPU that performs arithmetic processing, storage means (memory) that stores a program, an input circuit, an output circuit, and the like. The storage means stores an engine sound generation program (acoustic software) for creating “an electric signal that makes a pseudo engine sound” by digital technology.

An example of the engine sound generation program will be described. The engine sound generation program described below is a specific example and is not limited.
The engine sound generation program of this embodiment creates a frequency signal (waveform signal) that forms a pseudo engine sound based on a clock signal generated by a reference clock (crystal oscillator) mounted on a computer,
(I) A predetermined frequency (for example, a selected frequency selected from 1 Hz to 10 Hz) is “AHz”,
(Ii) A pseudo engine sound is generated by simultaneously generating a number of continuous frequency signals at intervals of “AHz”.

As a specific example, this embodiment shows an example in which a fixed frequency of “4 Hz” is used as “AHz”. Note that “4 Hz” is a specific example, and for example, “8 Hz” that is twice as much may be used. Alternatively, a fixed frequency including a decimal point (for example, a frequency selected from “3.5 Hz to 4.5 Hz” or “7.5 Hz to 8.5 Hz”) may be used.
Further, in this embodiment, the frequency signal forming the pseudo engine sound is composed of a large number of frequency signals continuous at intervals of “AHz (4 Hz)” as described above. A part of the frequency signal may be partially thinned out. That is, the frequency signal at intervals of 4 Hz may be partially absent.

On the other hand, in the engine sound generation program, “frequency range specifying means (program) for generating“ a large number of continuous frequency signals (frequency signals forming a pseudo engine sound) ”at intervals of 4 Hz“ only within a predetermined frequency range ”. Is provided.
Here, an example of selecting the “predetermined frequency range” will be described.
When the frequency characteristic of the actual engine sound shows the characteristic of the solid line E in FIG. 7A, the frequency range of the engine sound that is heard by the human ear is from “maximum sound pressure to −10 dB lower than the sound pressure”. A sound that is “main frequency L (frequency range within Δ10 dB)” and deviates from “main frequency L” (sound with low sound pressure) is masked by sound of “main frequency L” and is hardly recognized.

  Therefore, the engine sound generation program uses the fact that only “main frequency L” of the engine sound can be heard by the human ear, and as shown in FIG. The “frequency signal (frequency signal forming the pseudo engine sound)” is generated with “only the main frequency L”.

This will be specifically described.
When the simulated engine sound is made to resemble the “real engine sound of a specific vehicle type”, the “real engine sound of a specific vehicle type” is measured.
The “frequency range from the maximum sound pressure to the sound pressure reduced by −10 dB” in the engine sound is measured. This measurement range is the “main frequency L” described above. The main frequency L substantially matches the frequency range (about 250 Hz to 4 kHz) with high human sound sensitivity. For this reason, as shown in FIG. 7B, the engine sound generation program is provided so as to generate the “frequency signal forming the pseudo engine sound” only at “250 Hz to 4 kHz (main frequency L)”. .

  Further, the engine sound generation program is provided with a frequency characteristic processing means (program) for processing (characterizing) the frequency characteristics of “a large number of frequency signals continuous at intervals of 4 Hz (frequency signals forming a pseudo engine sound)”. It has been.

When the simulated engine sound is made to resemble the “actual engine sound of a specific vehicle type”, it is assumed that the frequency characteristic of the engine sound of the specific vehicle type shows the characteristic indicated by the solid line E in FIG.
In that case, the frequency characteristics of the “frequency signal forming the pseudo engine sound” (the sound pressure levels of a large number of frequency signals are set to match the frequency characteristics of the specific vehicle model {characteristics of the solid line E in FIG. 7A)}. The characteristic to be drawn is processed into a frequency characteristic indicated by a broken line E in FIG.

(Description of Horn Drive Amplifier 24)
The horn drive amplifier 24 is a power amplifier (power amplification circuit) for operating the vehicle horn 1 as a dynamic speaker, and the waveform signal output from the simulated engine sound creation unit 23 (electrical signal forming the simulated engine sound) “ The voltage increase / decrease change is amplified and applied to the energization terminals of the vehicle horn 1 (terminals connected to both ends of the coil 12).
The maximum output of the horn drive amplifier 24 (maximum output for generating the pseudo engine sound) is limited to less than 8V (another excitation voltage), and the vehicle horn is generated by the voltage output for generating the pseudo engine sound. 1 is provided so as not to generate an alarm sound.

(Description of Ultrasonic Amplitude Modulator 25)
The ultrasonic amplitude modulation unit 25 includes an ultrasonic oscillator capable of oscillating at an ultrasonic frequency (that is, a frequency exceeding 20 kHz: 25 kHz as an example), and a waveform signal (pseudo) output from the pseudo engine sound creation unit 23. The “voltage increase / decrease change” of the electrical signal (engine signal) is modulated to the “frequency change of the oscillation voltage” of the ultrasonic frequency.
In this embodiment, an example in which the ultrasonic amplitude modulation unit 25 is provided independently is provided to assist understanding. However, the function of the ultrasonic amplitude modulation unit 25 may be included in the computer program described above.

The ultrasonic modulation by the ultrasonic amplitude modulation section 25 (modulation of “frequency signal forming the pseudo engine sound” to “amplitude change of oscillation voltage”) will be described with reference to FIG.
For example, it is assumed that the “frequency signal forming the pseudo engine sound” input to the ultrasonic amplitude modulation unit 25 is a voltage change shown in FIG. 8A (in the figure, a single frequency is used for assisting understanding). This is actually a signal waveform with a synthetic frequency of 4 Hz intervals).
On the other hand, it is assumed that the ultrasonic oscillator mounted on the ultrasonic amplitude modulator 25 oscillates at the ultrasonic frequency shown in FIG.

Then, as shown in FIG. 8C, the ultrasonic amplitude modulation unit 25
(I) Increasing the amplitude of the voltage due to ultrasonic vibration as the signal voltage of the frequency forming the pseudo engine sound increases,
(Ii) The amplitude of the voltage due to ultrasonic vibration is reduced as the signal voltage of the frequency forming the pseudo engine sound is reduced.
In this way, the ultrasonic amplitude modulation unit 25 modulates the “frequency signal forming the pseudo engine sound” input from the pseudo engine sound creation unit 23 to “amplitude change in oscillation voltage” of the ultrasonic frequency. is there.

  In this embodiment, as an example of the ultrasonic amplitude modulation section 25, the change in the signal voltage of the frequency forming the pseudo engine sound is changed to “the width of the voltage magnitude” as shown in FIG. 8C. An example is shown. On the other hand, unlike FIG. 8 (c), the change in the signal voltage of the frequency forming the pseudo engine sound may be changed to the “voltage generation time width” using the PWM modulation technique. good.

(Description of the ultrasonic speaker amplifier 26)
The ultrasonic speaker amplifier 26 drives each piezoelectric speaker 21 based on “an ultrasonic signal obtained by amplitude-modulating a frequency signal forming a pseudo engine sound (an output signal of the ultrasonic amplitude modulation unit 25)”. By controlling the applied voltage (charging / discharging state) of the speaker 21, “an ultrasonic wave obtained by amplitude-modulating a frequency signal that forms a pseudo engine sound” is generated from each piezoelectric speaker 21.
As a specific example, the ultrasonic speaker amplifier 26 is a charge switching circuit (or a charge / discharge circuit of a piezoelectric element) that can be applied to each piezoelectric speaker 21 by switching a positive voltage or a negative voltage. When the waveform signal shown in FIG. 8C is given from the amplitude modulation unit 25 to the ultrasonic speaker amplifier 26, the ultrasonic speaker amplifier 26 gives the waveform voltage shown in FIG. An ultrasonic wave having an output waveform shown in FIG. 8C is generated from the piezoelectric speaker 21.

(Description of sound pressure setting of vehicle horn 1 and parametric speaker 2)
The vehicle presence notification device in this embodiment is
(I) By synthesizing “pseudo engine sound by the vehicle horn 1” and “pseudo engine sound by the parametric speaker 2” in a preset short distance range (for example, 0 m to 5 m forward from the front end of the vehicle S), While generating a pseudo engine sound with a large sound pressure in the short range,
(Ii) In order to generate a “pseudo engine sound by the parametric speaker 2” in a preset long distance range (for example, 5 m to 10 m forward from the front end of the vehicle S),
The above-described “number of piezoelectric speakers 21 to be used” and “amplification gain (amplifier gain) of the horn drive amplifier 24 and the ultrasonic speaker amplifier 26” are set.

A specific example will be described.
First, in order to set the long distance range, the target reach distance for delivering the notification sound is set. In this embodiment, the target reach distance is 10 m.
Also, the sound pressure level of the sound at the target reach distance is set. In this embodiment, the sound pressure level at the target reach distance is 50 dB.
In that case, the number and arrangement of the piezoelectric speakers 21 to be used are set, and the amplification gain of the ultrasonic speaker amplifier 26 is set so that the sound pressure level of 50 dB can be achieved by the parametric speaker 2 at a target reach distance of 10 m (see FIG. (See two-dot chain line B in FIG. 1).

Next, the short distance range is set. In this embodiment, a range in which a pseudo engine sound having a high sound pressure is generated (a range in which a pedestrian is more surely informed of the presence of a vehicle) is set within 5 m.
In that case, the sound pressure of the horn drive amplifier 24 is increased within 5 m so that the sound pressure is increased by the synthesis of the “pseudo engine sound by the vehicle horn 1” and the “pseudo engine sound by the parametric speaker 2” (solid line C in FIG. 1). Amplification gain is set (see the one-dot chain line A in FIG. 1).

  In this way, in the vehicle presence notification device, as shown by the solid line C in FIG. 1, the sound pressure characteristic of the pseudo engine sound (notification sound) with respect to the distance exhibits a V-characteristic.

[Operation of Example 1]
The operation of the vehicle presence notification device of the first embodiment will be described.
As described above, this vehicle presence notification device operates by being given an operation signal from, for example, an ECU.
(I) one that operates constantly during traveling of the vehicle S (for example, during forward traveling);
(Ii) one that operates only when the traveling speed of the vehicle S is within a predetermined speed range;
(Iii) It operates only when the vehicle S is traveling and the presence of a person in the traveling direction of the vehicle S is confirmed by a “person recognition system (not shown)”.

When the vehicle presence notification device operates, an electric signal based on a separately excited voltage for generating a pseudo engine sound in the vehicle horn 1 is given.
In the electromagnetic vehicle horn 1, the movable contact 17 is in contact with the fixed contact 16 and the coil 12 is energized below the separately excited voltage. For this reason, when an “electric signal that makes a pseudo engine sound” is applied to the coil 12 of the vehicle horn 1, a magnetic force change occurs according to the “electric signal that makes a pseudo engine sound”, and the diaphragm 14 and the movable iron core 15 Vibrates in response to “electrical signals that make pseudo engine sound”.
Thus, the electromagnetic vehicle horn 1 can be used as a dynamic speaker, and a pseudo engine sound can be generated from the vehicle horn 1.

A frequency characteristic of the vehicle horn 1 when the vehicle horn 1 is used as a dynamic speaker is shown by a broken line B in FIG. This broken line B is a frequency characteristic when a 1 V sine wave sweep signal (a variable signal from a low frequency to a high frequency) is applied to the vehicle horn 1.
As is apparent from the broken line B in FIG. 4, the vehicle horn 1 can be used as a dynamic speaker.

When the vehicle presence notification device operates, the ultrasonic speaker 3 emits an ultrasonic wave (inaudible sound wave) obtained by amplitude-modulating the signal waveform of the pseudo engine sound, as shown in FIG.
Then, as shown in FIG. 8D, as the ultrasonic wave propagates through the air, the ultrasonic wave having a short wavelength is distorted and blunted by the viscosity of the air.
As a result, as shown in FIG. 8 (e), the amplitude component contained in the ultrasonic wave is self-demodulated in the air being propagated, and as a result, the ultrasonic wave generation source (the vehicle on which the ultrasonic speaker 3 is mounted). A pseudo engine sound is generated at a location away from S).

[Effect 1 of Example 1]
The vehicle presence notification device of the first embodiment can obtain the following effects by adopting the above configuration.
(A) In the “short distance range (0 m to 5 m)” in front of the vehicle, the pseudo engine sound from the dynamic speaker 1 (one-dot chain line A in FIG. 1) and the pseudo engine sound from the parametric speaker 2 (two-dot chain line B in FIG. 1). ) And a pseudo engine sound (solid line C in FIG. 1) having a large sound pressure can be generated.
For this reason, when the distance between the vehicle S and the pedestrian is “short range (0 m to 5 m)”, a pseudo engine sound having a large sound pressure can be given to the pedestrian, and the vehicle is more reliably supplied to the pedestrian. The existence of S can be notified.

(B) In the “long range (5 m to 10 m)” in front of the vehicle, as shown by the two-dot chain line B in FIG. 1, the notification sound emitted by the parametric speaker 2 can be delivered.
For this reason, even if the distance between the vehicle S and the pedestrian is far, the pseudo engine sound can be delivered to the pedestrian, and the existence of the vehicle S can be notified to the pedestrian far away.

(C) Since the parametric speaker 2 is one in which the ultrasonic wave is self-modulated in the air away from the vehicle S and converted into an audible sound, the pseudo engine sound generated by the parametric speaker 2 is a vehicle occupant (driver or the like). ) Is hard to hear.
Specifically, as shown in FIG. 1, when it is assumed that “the sound pressure level at a distance of 2 m is audible to the vehicle occupant in the vehicle interior”, the sound pressure audible to the vehicle occupant in the vehicle interior is represented by the sensitivity of the vehicle occupant. It can be suppressed to 63 dB lower than the limit (65 dB).
As described above, in the “short range”, the pseudo engine sound from the dynamic speaker 1 and the pseudo engine sound from the parametric speaker 2 are synthesized to generate a pseudo engine sound having a large sound pressure. Since it is difficult for the occupant to hear the pseudo engine sound from the parametric speaker 2, the sound pressure of the pseudo engine sound audible to the vehicle occupant can be suppressed.

As indicated above, the vehicle presence notification device
-A nearby pedestrian generates a pseudo engine sound with a large sound pressure,
-Deliver pseudo engine sound to pedestrians far away,
-The sound pressure of the pseudo engine sound that can be heard by vehicle occupants (drivers, etc.) can be reduced.
That is, the vehicle presence notification device can generate a pseudo engine sound that is not easily heard by a vehicle occupant (driver or the like) and is easily noticed by a pedestrian.

[Effect 2 of Example 1]
In the vehicle presence notification device of the first embodiment, as shown at the intersection of the one-dot chain line A and the two-dot chain line B in FIG. 1, the distance between the pedestrian and the vehicle S (ultrasonic speaker 3) is a predetermined distance (position of about 2 m). , The magnitude relationship between the “pseudo engine sound from the parametric speaker 2” and the “pseudo engine sound from the vehicle horn 1” is reversed.
That is, the ratio of “pseudo engine sound by the parametric speaker 2” increases when the distance is 2 m or more, and the ratio of “pseudo engine sound by the vehicle horn 1” increases within 2 m.

On the other hand, the parametric speaker 2 is deficient in bass, and therefore has a different tone color from the dynamic speaker.
For this reason, the timbre of the pseudo engine sound that the pedestrian can hear when the vehicle S approaches the pedestrian changes from “a timbre with insufficient bass by the parametric speaker 2” to “a timbre that does not cause a lack of bass with the vehicle horn 1”. To do.
As described above, since the “timbre” of the pseudo engine sound changes as the vehicle S approaches the pedestrian, the pedestrian can easily notice the pseudo engine sound, and the pedestrian can know the existence of the vehicle S with high probability. it can.

[Effect 3 of Example 1]
The vehicle horn 1 according to the first embodiment is provided such that a self-excited voltage is applied to generate an alarm sound when the horn switch is turned on by an occupant. In other words, the vehicle horn 1 according to the first embodiment shares the “vehicle horn 1 that generates an alarm sound” and the “vehicle horn 1 that generates a pseudo engine sound”.
Thereby, it is not necessary to separately mount a “dedicated dynamic speaker for generating pseudo engine sound”, the cost of the vehicle presence notification device can be reduced, and a mounting space can be easily secured.

  In the above-described embodiment, an example in which a notification sound (pseudo engine sound) is generated in front of the vehicle S when the vehicle S travels forward is described. (Pseudo engine sound) may be generated.

  The mounting position of the ultrasonic speaker 3 and the vehicle horn 1 that generates the notification sound (pseudo engine sound or the like) is not limited to the front portion of the vehicle S, and the ultrasonic speaker 3 is connected to the rear of the vehicle S or the vehicle, for example. It may be mounted toward the lower side of S, and may be provided so as to emit a notification sound (such as a pseudo engine sound) toward the rear periphery of the vehicle S when the vehicle is traveling backward (during back travel).

  The term “pedestrian” used in the above specification is a general term for a “person” to be protected when the vehicle is traveling, and is not necessarily limited to a “walking person” in a narrow sense. That is, it naturally includes a person who is running, a person who is stationary, a person who is sitting, a person who is in a wheelchair, etc. in the vicinity of the vehicle S or in the traveling direction of the vehicle S.

1 Vehicle horn (dynamic speaker)
2 Parametric speaker 3 Ultrasonic speaker 4 Main unit 12 Coil 23 Pseudo engine sound creation unit S Vehicle

Claims (4)

In the vehicle presence notification device that notifies the presence of the vehicle by a notification sound,
This vehicle presence notification device
While generating a notification sound from the dynamic speaker (1) that generates a sound wave in the audible band by a change in magnetic force accompanying a change in power applied to the coil toward the outside of the vehicle,
From the parametric speaker (2) that emits ultrasonically modulated ultrasonic waves toward the outside of the vehicle, a notification sound is generated toward the outside of the vehicle,
In a short distance range close to the vehicle, a notification sound of the dynamic speaker (1) and a notification sound of the parametric speaker (2) are combined to generate a notification sound with a large sound pressure,
A vehicle presence notification device that generates a notification sound by the parametric speaker (2) in a far distance range farther from the vehicle than the short distance range. The vehicle presence notification device according to claim 1,
The dynamic speaker is an electromagnetic vehicle horn (1) that generates a warning sound by applying a self-excited voltage equal to or higher than a threshold value with direct current,
The vehicle horn (1) generates a notification sound from the vehicle horn (1) by providing an electric signal that generates a notification sound with a separate excitation voltage lower than the self-excitation voltage. Notification device. The vehicle presence notification device according to claim 2,
The vehicle horn (1) is provided with a self-excited voltage when a horn switch operated by a vehicle occupant is turned on to generate a warning sound. In the vehicle presence notification device according to any one of claims 1 to 3,
The notification sound emitted from the dynamic speaker (1) and the parametric speaker (2) is a pseudo engine sound,
This pseudo engine sound is created by a digital technique in a pseudo engine sound creating unit (23) mounted on the vehicle presence notifying apparatus.

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