JP4683136B2 - Vehicle presence notification device - Google Patents

Description

  The present invention relates to a vehicle presence notification device that notifies the approach of a vehicle.

  In recent years, vehicles driven by motors such as electric vehicles and hybrid cars are increasing. And since driving driving by a motor is quieter than driving driving by an engine, a pedestrian or the like may not feel the approach of the vehicle. Therefore, a vehicle presence notification device that mounts a speaker on a vehicle to generate a pseudo engine sound and informs a pedestrian or the like of the approach of the vehicle is known (for example, see Patent Documents 1 and 2).

  However, since conventional notification sounds such as pseudo engine sounds have the same sound pressure level and the same frequency, even if pedestrians can grasp the approach of the vehicle itself, they can feel the distance to the vehicle. There is a possibility that it cannot be grasped.

  That is, the sound pressure level of the background noise around the vehicle changes variously depending on the daytime or nighttime, the city or the countryside, and the way the notification sound is heard depends on the sound pressure level of the background noise. As a result, for example, when the sound pressure level of the background noise is high, the notification sound is heard to be small and the distance to the vehicle is large, or conversely, if the sound pressure level of the background noise is low, the notification sound May sound loud and may feel that the distance to the vehicle is small.

  Patent Document 3 discloses a vehicle presence notification device that transmits a notification radio wave together with the emission of a notification sound and receives the radio wave so that the approach of the vehicle can be grasped tactilely or visually. ing. However, in order to grasp the approach of the vehicle by this vehicle presence notification device, it is necessary to equip the vehicle with a radio wave transmission device, and for a pedestrian or the like, the radio wave reception device or radio wave reception is activated. It is necessary to carry a sensory device or the like, which is inconvenient to handle.

Japanese Patent Laid-Open No. 10-201001 JP 2006-199110 A JP 2007-182195 A

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a vehicle presence notification device that enables a pedestrian or the like to grasp a sense of distance from a vehicle regardless of the sound pressure level of background noise. It is to provide.

[Means of Claim 1]
The vehicle presence notification device according to claim 1 notifies the approach of the vehicle by a notification sound that vibrates at a frequency in the audible region.
In addition, the vehicle presence notification device includes a speaker that radiates the notification sound on the carrier wave that vibrates at a frequency in the ultrasonic region and radiates it in the air, and carrier frequency switching means that switches the frequency of the carrier wave. The carrier frequency switching means stores a carrier frequency switching pattern for switching the carrier frequency between a plurality of numerical values, and switches the carrier frequency according to the carrier frequency switching pattern.

  As a result, while the ultrasonic wave radiated from the speaker propagates through the air, it is a non-linear characteristic of the air ("air takes longer time to recover from compression than when compressed") ) To self-demodulate and become a notification sound.

  Here, the position where the ultrasonic wave radiated from the speaker is self-demodulated and can be heard as a notification sound depends on the frequency of the carrier wave. Depends on the carrier frequency (the lower the carrier frequency, the farther the self-demodulating position is from the speaker. The lower the carrier frequency, the farther the position where the notification sound generated by self-demodulation can be heard is farther from the speaker. Become).

  For this reason, by switching the frequency of the carrier according to the carrier frequency switching pattern, it is possible to vary the way the notification sound is heard according to the distance from the speaker. For example, when the frequency of a carrier wave is periodically switched between two values of a low value and a high value, at a position close to the speaker, the notification sound carried on the carrier wave of both the low and high values is heard and the speaker is heard. At a distant position, it is possible to listen only to a portion on a low-frequency carrier wave.

  As described above, a pedestrian or the like can grasp a sense of distance from the vehicle regardless of the sound pressure level of background noise.

[Means of claim 2]
According to the vehicle presence notification apparatus of the second aspect, the carrier wave frequency switching pattern has an interval in which the generation of the carrier wave is temporarily stopped when the carrier wave frequency is switched from one numerical value to another numerical value.
As a result, in the sound wave of the notification sound, the notification sound is interrupted and cannot be heard during the interval at a position where a part (hereinafter referred to as a target part) on the carrier wave of one numerical value and another numerical frequency can be heard. For this reason, the variation for making a pedestrian etc. grasp | ascertain a distance feeling with a vehicle can be increased.

[Means of claim 3]
According to the vehicle presence notification device of the third aspect, the carrier wave frequency switching pattern continues without interruption when the carrier wave frequency is switched from one numerical value to another numerical value.
Thereby, the notification sound of the target part can be heard without interruption at a position where the target part can be heard in the sound wave of the notification sound. For this reason, the variation for making a pedestrian etc. grasp | ascertain a distance feeling with a vehicle can be increased.

[Means of claim 4]
The vehicle presence notification device according to a fourth aspect includes notification sound frequency switching means for switching the frequency of the notification sound, and the notification sound frequency switching means switches the frequency of the notification sound in accordance with the switching of the frequency of the carrier wave.
Thereby, the change of the timbre of the notification sound can be heard at the position where the target portion can be heard in the sound wave of the notification sound. For this reason, the variation for making a pedestrian etc. grasp | ascertain a distance feeling with a vehicle can be increased.

(A) is a waveform diagram showing a notification sound, (b) is a waveform diagram showing a carrier wave, (c) is a waveform diagram showing an ultrasonic wave obtained by amplitude-modulating the carrier wave based on the notification sound, (D) is a waveform diagram showing an ultrasonic wave being distorted, and (e) is a waveform diagram showing a notification sound after self-demodulation (Example 1). 1 is a configuration diagram of a vehicle presence notification device (Example 1). FIG. (A) is explanatory drawing which shows a carrier wave frequency switching pattern, (b) is explanatory drawing which shows self-demodulation of the notification sound in position P1 ', (c) shows self-demodulation of the notification sound in position P2'. (D) is explanatory drawing which shows the self-demodulation of the alerting | reporting sound in the position P3 '(Example 1). (A) is explanatory drawing which shows the notification sound in position P1, (b) is explanatory drawing which shows the notification sound in position P2, (c) is explanatory drawing which shows the notification sound in position P3 (Example) 1). (A) is explanatory drawing which shows a carrier wave frequency switching pattern, (b) is explanatory drawing which shows self-demodulation of the notification sound in position P1 ', (c) shows self-demodulation of the notification sound in position P2'. It is explanatory drawing, (d) is explanatory drawing which shows the self-demodulation of the alerting | reporting sound in the position P3 '(Example 2). (A) is explanatory drawing which shows the notification sound in position P1, (b) is explanatory drawing which shows the notification sound in position P2, (c) is explanatory drawing which shows the notification sound in position P3 (Example) 2). (Example 3) which is a block diagram of a vehicle presence alerting | reporting apparatus. (A) is explanatory drawing which shows the notification sound in position P1, (b) is explanatory drawing which shows the notification sound in position P2, (c) is explanatory drawing which shows the notification sound in position P3 (Example) 3). (A) is explanatory drawing which shows a carrier wave frequency switching pattern, (b) is explanatory drawing which shows the notification sound in the position P4, (c) is explanatory drawing which shows the notification sound in the position P5 (modification). .

The vehicle presence notification device according to the first embodiment notifies the approach of the vehicle by a notification sound that vibrates at a frequency in the audible region.
In addition, the vehicle presence notification device includes a speaker that radiates the notification sound on the carrier wave that vibrates at a frequency in the ultrasonic region and radiates it in the air, and carrier frequency switching means that switches the frequency of the carrier wave. The carrier frequency switching means stores a carrier frequency switching pattern for switching the carrier frequency between a plurality of numerical values, and switches the carrier frequency according to the carrier frequency switching pattern.

  The carrier frequency switching pattern has an interval in which generation of a carrier wave is temporarily stopped when the frequency of the carrier wave is switched from one numerical value to another numerical value.

  According to the vehicle presence notification device of the second aspect, the carrier wave frequency switching pattern continues without interruption when the carrier wave frequency is switched from one numerical value to another numerical value.

  The vehicle presence notification apparatus according to the third aspect includes notification sound frequency switching means for switching the frequency of the notification sound, and the notification sound frequency switching means switches the frequency of the notification sound in accordance with the switching of the frequency of the carrier wave.

[Configuration of Example 1]
A configuration of the vehicle presence notification device 1 according to the first embodiment will be described with reference to the drawings.
The vehicle presence notification device 1 is mounted on a vehicle in which a pedestrian or the like may not feel an approach due to silence due to motor driving, such as an electric vehicle or a hybrid car, for example, a pedestrian in front of the vehicle, or the like. To inform the approach of the vehicle.

  In addition, the vehicle presence notification device 1 puts a notification sound (see FIG. 1 (a)) that vibrates at a frequency in the audible region on a carrier wave (see FIG. 1 (b)) that vibrates at a frequency in the ultrasonic region. It radiates into the air and uses the principle of a so-called “parametric speaker”. That is, the sound wave radiated from the vehicle presence notification device 1 is an ultrasonic wave, and this ultrasonic wave is an amplitude-modulated carrier wave based on the notification sound (see FIG. 1C). By using ultrasonic waves, great directivity can be exhibited.

  And while the ultrasonic wave radiated | emitted from the vehicle presence alerting | reporting apparatus 1 propagates in the air, it takes a longer time to restore from the non-linear characteristic of air ("the air is restored from the compression than when it is compressed. ”) (See FIG. 1D), and self-demodulates at a position corresponding to the frequency of the carrier wave to become a notification sound (see FIG. 1E).

  For example, as shown in FIG. 2, the vehicle presence notification device 1 includes an oscillation unit 2 that generates an electrical signal that vibrates at a frequency in the ultrasonic region, and an electrical signal that is generated by the oscillation unit 2 based on the waveform of the notification sound. Amplitude modulation means 3 for amplitude modulating the electrical signal output from the amplitude modulation means 3 into a mechanical vibration, and an ultrasonic wave with a notification sound on the carrier (that is, the carrier wave is amplitude-modulated based on the notification sound) The speaker 4 which radiates | emits the ultrasonic wave (refer FIG.1 (c)) obtained by this in the air, and the carrier frequency switching means 5 which switches the frequency of a carrier wave are provided.

Here, the oscillating means 2, the amplitude modulating means 3, and the carrier frequency switching means 5 are functions incorporated in an electronic control unit (ECU) 6 mounted on the vehicle, for example.
The ECU 6 is configured to include a CPU having a control function and an arithmetic function, various storage devices such as a ROM and a RAM, an input device, and a known microcomputer having an output device.

  The oscillating means 2 is, for example, a voltage-controlled oscillator that can vary the oscillation frequency in accordance with the applied voltage, and generates an electrical signal that oscillates at the frequency of the ultrasonic region, that is, an electrical signal that oscillates at the frequency of the carrier wave. The electric signal output from the voltage control transmitter is subjected to processing such as waveform shaping and is input to the amplitude modulation means 3.

The amplitude modulation unit 3 is an amplitude modulator that modulates the amplitude of the electrical signal output from the oscillation unit 2 based on the sound wave waveform of the notification sound, for example.
Due to the functions of the oscillating means 2 and the amplitude modulating means 3, the ECU 6 outputs an electric signal having a frequency in the ultrasonic region and amplitude-modulated based on the sound wave waveform of the notification sound.

  The speaker 4 converts an electrical signal input to itself into mechanical vibrations and generates ultrasonic waves by the mechanical vibrations. The electric signal input to the speaker 4 is obtained by amplifying the electric signal output from the ECU 6 by the amplifier 7. That is, the electric signal output from the ECU 6 is amplified by the amplifier 7 to such an extent that the speaker 4 can be driven.

  The carrier frequency switching unit 5 switches the frequency of the carrier by switching the oscillation frequency of the oscillation unit 2, for example. The carrier frequency switching means 5 stores a carrier frequency switching pattern for switching the oscillation frequency of the oscillation means 2, that is, the frequency of the carrier wave, between a plurality of numerical values. Then, the carrier wave frequency switching unit 5 instructs the oscillation unit 2 to switch the oscillation frequency according to the carrier wave frequency switching pattern. For example, the carrier frequency switching means 5 outputs a control signal so as to vary the voltage applied to the voltage controlled oscillator according to the carrier frequency switching pattern.

  The carrier frequency switching pattern (hereinafter referred to as pattern 1) of the first embodiment is set so that the carrier frequency is switched between three different numerical values fa, fb, and fc, for example, as shown in FIG. ing. The magnitude relationship between the numerical values fa to fc is fa <fb <fc. The pattern 1 is set so that the frequency repeats fa → fc → fb → fc, and further has an interval at which the generation of the carrier wave is temporarily stopped when the frequency is switched from one numerical value to another numerical value. Is set to

  Here, the position where the ultrasonic wave radiated from the speaker 4 is self-demodulated and can be heard as a notification sound depends on the frequency of the carrier wave. The lower the frequency of the carrier wave, the farther the position for self-demodulation is from the speaker 4.

For this reason, when ultrasonic waves are radiated from the speaker 4 according to the pattern 1, the notification sound increases in the distance from the speaker 4 and can be heard by self-demodulating sequentially from the portion on the carrier wave having a high frequency. .
For example, as shown in FIGS. 3B to 3D, the notification sound partially self-demodulates sequentially at positions P1 ′, P2 ′, and P3 ′ where the distance from the speaker 4 is sequentially increased, and finally, Therefore, all the notification sounds can be heard.

  That is, in the notification sound radiated on the carrier wave, the portion of the notification sound placed on the carrier wave having the frequency fc is first self-demodulated and heard at the position P1 ′ closest to the speaker 4 among the positions P1 ′ to P3 ′. (See FIG. 3B). Subsequently, the portion on the carrier wave having the frequency fb can be heard by self-demodulating at a position P2 ′ which is an intermediate position between the positions P1 ′ to P3 ′ (see FIG. 3C). Finally, the portion of the carrier wave having the frequency fa can be heard by self-demodulating at the position P3 ′ farthest from the speaker 4 among the positions P1 ′ to P3 ′ (see FIG. 3D).

  Further, when the frequency of the carrier wave is switched between a plurality of numerical values, the position where the ultrasonic wave radiated from the speaker 4 is self-demodulated and can be heard as the notification sound differs depending on the frequency of the carrier wave. The position at which it cannot be heard also depends on the frequency of the carrier wave. That is, the position where the sound pressure level of the notification sound is lower than the human audible level also depends on the frequency of the carrier wave. Since the position of self-demodulation is farther from the speaker 4 as the frequency of the carrier wave is lower, the position where the notification sound generated by the self-demodulation is not heard is further away from the speaker 4 as the frequency of the carrier wave is lower.

For this reason, after all the ultrasonic waves radiated from the speaker 4 according to the pattern 1 are self-demodulated to become a notification sound, the notification sound is a portion on the carrier wave having a high frequency as the distance from the speaker 4 increases. The sound decays sequentially and disappears.
For example, as shown in FIG. 4, at the positions P1, P2, and P3 where the distance from the speaker 4 is sequentially increased, the notification sound is partially attenuated and cannot be heard, and finally all the notification sounds can be heard. Disappear. It should be noted that the position P1 is larger than the position P3 ′ with respect to the speaker 4, and the sound pressure level of all self-demodulated notification sounds exceeds the audible level at the position P1, and all notification sounds are heard. (See FIG. 4 (a)).

  Then, in the self-demodulated notification sound, first, the portion on the carrier wave having the frequency fc is not heard at the position P2 which is an intermediate position between the positions P1 to P3 (see FIG. 4B). Subsequently, the portion of the carrier wave having the frequency fb cannot be heard at the position P3 farthest from the speaker 4 among the positions P1 to P3 (see FIG. 4C). Finally, the portion on the carrier wave having the frequency fa cannot be heard at a position farther from the speaker 4 than the position P3.

As described above, for example, the tone color corresponding to one pulse of the notification sound above the audible level shown in FIG. 4 is represented by “pi”, and the portion corresponding to one pulse of the notification sound below the audible level is not sounded. When indicated by “·”, a notification sound can be heard continuously at the position P1. Further, at the position P2, a notification sound is heard so as to take a breath between “pi pi pi pi pi”. Further, at the position P3, a notification sound is heard so as to take between three breaths with "pi ... pi ... pi ...".
In FIG. 4, the frequency of the carrier wave is displayed on the upper side of the notification sound pulse, and the timbre is displayed on the lower side.

  For this reason, when the vehicle approaches a pedestrian or the like, the relative position of the pedestrian or the like with respect to the vehicle changes as position P3 → position P2 → position P1. If it continues to radiate, the notification sound that can be heard by pedestrians and the like changes in the following manner: “pi ... pi ... pi ...” → “pi / pi / pi / pi” → “pipipipipipi”.

[Effect of Example 1]
The vehicle presence notification apparatus 1 according to the first embodiment places a notification sound on a carrier wave that vibrates at a frequency in the ultrasonic region and radiates the notification sound as an ultrasonic wave into the air. The ECU 6 switches the frequency of the carrier wave according to the pattern 1. The pattern 1 repeats fa → fc → fb → fc between three different numerical values fa, fb, fc (fa <fb <fc), and the frequency is switched from one numerical value to another numerical value. It is sometimes set to have an interval at which the generation of the carrier wave is temporarily stopped.

  As a result, the notification sound generated by the self-demodulation of the ultrasonic wave is not heard because the distance from the speaker 4 is increased, and the sound is partially attenuated sequentially. For this reason, when the vehicle approaches a pedestrian or the like while radiating ultrasonic waves from the vehicle presence notification device 1, the notification sound heard by the pedestrian or the like is gradually shortened (for example, FIG. 4). ("Pi ... pi ... pi ..." → "Pi-pi-pi-pi-"-> "Pipi-pipipi").

  As described above, a pedestrian or the like can hear the notification sound so that the closer the vehicle is, the shorter the interval between sound generations. For this reason, a pedestrian or the like can grasp a sense of distance from the vehicle regardless of the sound pressure level of background noise.

[Example 2]
According to the vehicle presence notification device 1 of the second embodiment, the carrier wave frequency switching pattern continues without interruption when the carrier wave frequency is switched from one numerical value to another numerical value (hereinafter referred to as the second embodiment). The carrier wave frequency switching pattern is referred to as pattern 2 (see FIG. 5A).

  For example, the pattern 2 is set to repeat fa → fc → fb → fc between three different numerical values fa, fb, and fc similarly to the pattern 1. And unlike the pattern 1, the pattern 2 is set so that the generation of the carrier wave is continuous without interruption when the frequency is switched from one numerical value to another numerical value.

  For this reason, when ultrasonic waves are radiated from the speaker 4 according to the pattern 2, for example, as shown in FIGS. 5B to 5D, positions P1 ′, P2 ′, where the distance from the speaker 4 sequentially increases. At P3 ′, the notification sound partially self-demodulates sequentially and finally, all notification sounds can be heard.

  In addition, after all the ultrasonic waves radiated from the speaker 4 according to the pattern 2 are self-demodulated to become a notification sound, the notification sound is, for example, a position where the distance from the speaker 4 sequentially increases as shown in FIG. At P1, P2, and P3, the sound is partially attenuated and becomes inaudible, and finally all notification sounds are inaudible.

As described above, for example, the tone color corresponding to one pulse of the notification sound at or above the audible level shown in FIG. 6 is represented by “pea”, and the portion corresponding to one pulse of the notification sound below the audible level is not sounded. When indicated by “·”, a notification sound is heard at the position P1 so that “P” is stretched. Further, at the position P2, a notification sound is heard so as to take a breath between “Peep Peep Peep”. Furthermore, at the position P3, a notification sound is heard so as to take a time between three breaths.
In FIG. 6, the frequency of the carrier wave is displayed on the upper side of the notification sound pulse, and the timbre is displayed on the lower side.

For this reason, when a vehicle approaches a pedestrian or the like while radiating ultrasonic waves from the vehicle presence notification device 1, the notification sound heard by the pedestrian or the like is "P ... P ... P ..."・ It changes like “Pee-Pee-Pee-” → “Pee”.
As described above, a pedestrian or the like can hear the notification sound so that the closer the vehicle is, the shorter the interval between sound generations. For this reason, a pedestrian or the like can grasp a sense of distance from the vehicle regardless of the sound pressure level of background noise.

Example 3
According to the vehicle presence notification device 1 of the third embodiment, as shown in FIG. 7, the ECU 6 includes a function of notification sound frequency switching means 8 that switches the frequency of the notification sound, and the notification sound frequency switching means 8 The frequency of the notification sound is switched according to the frequency change. For example, the notification sound frequency switching means 8 instructs the amplitude modulation means 3 to switch the frequency of the notification sound in accordance with the carrier frequency switching means 5 instructing the oscillation means 2 to switch the frequency of the carrier wave.

  Here, for example, the carrier frequency switching pattern of the third embodiment is the same as the pattern 1 of the first embodiment, and the notification sound frequency switching means 8 has different notification sounds for each of the numerical values fa to fc of the carrier frequency. The numerical values fx, fy, and fz of the frequency are set. That is, the notification sound frequency switching means 8 places a notification sound with the frequency fx on the carrier wave with the frequency fa, puts a notification sound with the frequency fy on the carrier wave with the frequency fb, and puts the notification sound with the frequency fc on the carrier wave with the frequency fc. It functions to put a notification sound.

  As described above, regarding the timbre corresponding to one pulse of the notification sound having an audible level or higher shown in FIG. 8, the timbre when the frequency is fx is “pi”, the timbre when the frequency is fy is “pa”, and the frequency is When the tone color at fz is represented by “po” and the portion corresponding to one pulse of the notification sound below the audible level is represented by “·” indicating that there is no sound, at the position P1, “pipopapopipopapop” A notification sound can be heard continuously. Further, at position P2, a notification sound is heard so as to take a breath with “pi-pa-pi-pa-”. Further, at the position P3, a notification sound is heard so as to take between three breaths with "pi ... pi ... pi ...".

  In FIG. 8, the frequency of the carrier wave is displayed on the upper upper side of the notification sound pulse, and the frequency of the notification sound is displayed on the lower stage. In addition, a timbre is displayed below the notification sound pulse.

For this reason, when the vehicle approaches a pedestrian or the like while emitting ultrasonic waves from the vehicle presence notification device 1, the notification sound heard by the pedestrian or the like is “pi ... pi ... pi ...” → “pi”.・ Pa-Pi-Pa-> → “Pipopapopipopapop” changes.
As described above, a pedestrian or the like can hear the notification sound such that the closer the vehicle is, the shorter the interval between sound generations and the different sound generation patterns. For this reason, a pedestrian or the like can grasp a sense of distance from the vehicle regardless of the sound pressure level of background noise.

[Modification]
According to the vehicle presence notification device 1 of the embodiment, the ECU 6 switches the frequency of the carrier wave between the three numerical values fa to fc. However, the ECU 6 may switch between the two numerical values fd and fe.

In this case, the carrier frequency switching pattern is such that the frequency repeats fd → fe → fd → fe → as in pattern 3 shown in FIG. 9 and the frequency is switched from one numerical value to another numerical value. For example, at position P4, a notification sound is heard continuously at "Pipipipipi", and at position P5 farther from the speaker 4 than at position P4, " You can hear the alarm sound as if you take a breath with "Pi Pi Pi Pi."
9B and 9C, the frequency of the carrier wave is displayed on the upper side of the notification sound pulse, and the timbre is displayed on the lower side.

  For this reason, when a vehicle approaches a pedestrian or the like while emitting ultrasonic waves from the vehicle presence notification device 1, the notification sound that can be heard by the pedestrian or the like is "Pi-Pi-Pi-Pi-P" " Since it changes, pedestrians and the like can grasp the sense of distance from the vehicle regardless of the sound pressure level of background noise.

  Further, the frequency of the carrier wave may be switched between four or more numerical values, and the frequency of the notification sound may be switched between two or four or more numerical values. In addition, switching with an interval and switching without an interval may be included in one carrier frequency switching pattern. Furthermore, instead of setting different frequency values of the notification sound for each numerical value of the carrier frequency, for example, when four numerical values of the carrier frequency are set, The frequency of the carrier wave and the frequency of the notification sound can be set in various ways, such as setting the numerical value of the frequency of one notification sound.

  Further, according to the vehicle presence notification device 1 of the embodiment, the ECU 6 was provided with the functions of the oscillation means 2, the amplitude modulation means 3, the carrier wave frequency switching means 5 and the notification sound frequency switching means 8, but the oscillation means 2, The apparatus apparatus etc. which have the function of the amplitude modulation means 3, the carrier wave frequency switching means 5, and the notification sound frequency switching means 8 are not limited to such an aspect.

  Furthermore, according to the vehicle presence notification device 1 of the embodiment, the carrier frequency switching means 5 instructs the oscillation means 2 to switch the frequency of the carrier wave, and the notification sound frequency switching means 8 instructs the amplitude modulation means 3. However, the mode of switching the frequency of the carrier wave and the mode of switching the frequency of the notification sound are not limited to such a mode.

DESCRIPTION OF SYMBOLS 1 Vehicle presence notification apparatus 4 Speaker 5 Carrier frequency switching means 8 Notification sound frequency switching means patterns 1, 2, 3 Carrier frequency switching patterns fa, fb, fc, fd, fe Numeric value of carrier frequency

Claims (4)

In the vehicle presence notification device that notifies the approach of the vehicle by a notification sound that vibrates at a frequency in the audible region,
A speaker that radiates the notification sound on the carrier wave that vibrates at a frequency in the ultrasonic region and radiates it in the air, and carrier wave frequency switching means for switching the frequency of the carrier wave,
The carrier frequency switching means stores a carrier frequency switching pattern for switching the carrier frequency between a plurality of numerical values, and changes the frequency of the carrier according to the carrier frequency switching pattern. apparatus. The vehicle presence notification device according to claim 1,
The vehicle presence notification device, wherein the carrier frequency switching pattern has an interval in which the generation of the carrier wave is temporarily stopped when the frequency of the carrier wave is switched from one numerical value to another numerical value. The vehicle presence notification device according to claim 1,
The vehicle presence notification device, wherein the carrier wave frequency switching pattern is continuous without interruption when the frequency of the carrier wave is switched from one numerical value to another numerical value. In the vehicle presence notification device according to any one of claims 1 to 3,
A notification sound frequency switching means for switching the frequency of the notification sound;
The notification sound frequency switching means switches the frequency of the notification sound in accordance with switching of the frequency of the carrier wave.

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