JP3687164B2 - Low noise vehicle sound generator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sound generator for a low-noise vehicle for alerting the surroundings in an electric propulsion vehicle (electric vehicle) or other low-noise vehicle, or creating a sense of reality when the vehicle is driven, and can generate sound with a simple structure and low energy. It is what I did.
[0002]
[Prior art]
In a low noise vehicle such as an electric vehicle, a noise level is lower than that of a vehicle powered by an internal combustion engine, so that a person in the vicinity or another vehicle is not aware of the approach of the vehicle and may cause a collision accident. In addition, since the noise level in the vehicle during driving is low, there is a tendency that the speed is increased and the mood is lowered. Therefore, in order to solve such problems, a sound source device is installed in the vehicle, and the vehicle is driven while emitting sound toward the outside, so that the surrounding people or other vehicles are aware of the approach of the vehicle and driving. It is considered to give the driver a sense of realism during driving to prevent excessive speed. Conventionally, as this type of sound source device, it has been considered to prepare sound data electrically and pronounce the sound data from a speaker toward the outside of the vehicle while the vehicle is running.
[0003]
[Problems to be solved by the invention]
In the case of generating sound from the speaker, since the electroacoustic conversion efficiency of the speaker is generally low, a large electric energy is necessary to obtain a sufficient sound volume. For example, it is usually necessary to obtain a sound volume of 120 dB continuously. In consideration of the fact that several hundred watts of electric energy is required in this audio system, this type of loudspeaker method has a problem of significantly reducing the one-charge travel distance in the case of an electric vehicle.
[0004]
In addition, a large speaker and a large power amplifier are required, and there are problems such as an installation space, an increase in vehicle weight, and an increase in cost. In addition, it is necessary to perform control for generating sound or stopping generation of sound according to running and stopping of the vehicle, and control for changing volume and frequency according to the speed of the vehicle.
[0005]
The present invention solves the problems in the prior art and can generate a sound with a simple configuration and with a small amount of energy that can be used to notice the approach of the vehicle or to create a sense of realism when driving the vehicle. A sound source device for a vehicle is to be provided.
[0006]
[Means for Solving the Problems]
According to the present invention, a rotating shaft of a siren rotor is connected to a driving rotating shaft of a vehicle directly or via a transmission mechanism, and the stator of the siren is fixed to a fixed portion of the vehicle. A sound is generated from the siren by rotating the siren rotor by rotating the shaft.
[0007]
According to this, since the siren (hydrodynamic sound source) is more energy efficient than the speaker, it can be pronounced with less energy (only a little energy is needed at the start of rotation (at the start of running), it is constant) If it becomes faster, there is almost no energy consumption.) In the case of an electric vehicle, the mileage can be extended by one charge. In addition, the siren can produce a large volume even when it is small, and since it does not require an electric device such as an amplifier, it can be configured compactly, which reduces the installation space and reduces the increase in vehicle weight. , Can reduce the cost. Also, when the vehicle stops, the sound generation stops automatically, and the sound frequency and volume automatically change according to the speed of the vehicle, so that no special control is required.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below. FIG. 1 schematically shows a sound generation mechanism according to the present invention. In the case of an electric vehicle, the drive source 10 corresponds to a motor and a transmission, and is driven using the power of a battery mounted on the vehicle. The power of the drive source 10 is transmitted to the vehicle tires (wheels) 16 and 18 via the drive rotary shaft 12 and the drive rotary shaft 14 (axle).
[0009]
The siren 20 is disposed in the hood of the vehicle or at the bottom of the vehicle outer side, and the rotating shaft 32 of the rotor is connected to the driving rotating shaft 12 or 14 of the vehicle directly or via a transmission mechanism such as a transmission for driving rotation. It is driven to rotate according to the rotation of the shaft 12 or 14. The stator of the siren 20 is fixedly disposed on a fixed part (body, frame, etc.) of the vehicle. The siren 20 is driven to rotate in accordance with the rotation of the drive rotary shaft 12 or 14 of the vehicle, whereby the pressure or particle velocity energy accumulated in the internal space of the siren 20 is periodically released to the atmosphere. To generate sound waves.
[0010]
Compressed air is forcibly sent into the siren 20 from an external compressor 22. In this case, the compressor 22 can be driven using the driving force of the drive rotary shafts 12 and 14 of the vehicle, or can be driven by preparing a separate motor. Instead of the compressor 22, the siren 20 itself can be provided with an outside air suction configuration such as a rotary blade as in other specific examples described later. In addition, the output of the siren 20 controls the sound pressure waveform generated from the port by providing a filter element such as an acoustic tube or a horn or a resonator 24 at the port that releases pressure or particle velocity energy to the atmosphere. Any sound pressure waveform can be obtained.
[0011]
A specific example of the siren 20 is shown in a longitudinal sectional view in FIG. The siren 20 includes a stator 26 and a rotor 28. The rotor 28 is formed of a disk-shaped member, and a plurality of holes (movable side ports) 30 penetrating the front and back surfaces and arranged at equal intervals in the circumferential direction are formed near the outer peripheral portion thereof. A rotating shaft 32 is fixedly connected to the rotor 28 on the central axis thereof. The rotary shaft 32 is directly connected to the drive rotary shaft 12 or 14 of the vehicle or connected via a transmission mechanism such as a transmission.
[0012]
The stator 26 is constituted by a cylindrical case having a size for accommodating the rotor 28, and is fixed to a fixed portion of the vehicle. The rotor 28 is disposed in the inner space (pressure chamber) 34 of the stator 26 at a position close to the one surface 26 a of the stator 26. On one surface 26a of the stator 26, a plurality of holes arranged at equal intervals in the circumferential direction at the same pitch as the single or movable side port 30 penetrating the front and back surfaces at a position facing the movable side port 30 of the rotor 28. (Fixed side port) 36 is formed. Moreover, the other surface 26b of the stator 26 is formed with a single or a plurality of holes 38 penetrating the front and back surfaces. Compressed air is fed into the hole 38 at a constant pressure from the compressor 32 (FIG. 1).
[0013]
According to the above configuration, when the drive source 10 (FIG. 1) is driven, the drive rotating shafts 12 and 14 are rotationally driven, the vehicle tires 16 and 18 are rotated, and the vehicle travels. At this time, the rotating shaft 32 of the siren 20 is rotated by the driving force of the driving rotating shaft 12 or 14, and the rotor 28 is rotated. When the rotor 28 rotates, the compressed air supplied from the hole 38 is accumulated in the pressure chamber 34 at a rotation angle at which the movable side port 30 and the fixed side port 36 do not coincide. At the rotation angle at which the movable side port 30 and the fixed side port 36 coincide, the compressed air accumulated in the pressure chamber 34 is discharged from the fixed side port 36 to the external space. In this manner, the energy of the pressure or particle velocity accumulated in the pressure chamber 34 is periodically released to the atmosphere by the periodic overlap (change in cross-sectional area) of the movable side port 30 and the fixed side port 36. To release sound waves to the outside. When the speed of the vehicle changes, the period and volume of the sound waves change automatically.
[0014]
It should be noted that the instantaneous change rate of the cross-sectional area of the port can be changed by adjusting the shapes of the openings of both the movable side and fixed side ports 30 or 36, or an acoustic tube, a horn, etc. An arbitrary sound pressure waveform (tone color) can be obtained by controlling the sound pressure waveform by providing a resonator or the like. Further, the frequency of the sound wave can be arbitrarily adjusted by changing the number of ports and the transmission ratio of the transmission arranged between the drive rotary shaft 12 or 14 and the rotary shaft 32. Also, the sound pressure level can be adjusted by adjusting the port diameter.
[0015]
Another specific example of the siren 20 is shown in a longitudinal sectional view in FIG. The siren 20 includes a stator 40 and a rotor 42. The rotor 42 is configured by arranging a plurality of blades 46 at a constant pitch. The rotating shaft 32 is fixedly connected to the rotor 42 on the central axis thereof. The rotary shaft 32 is directly connected to the drive rotary shaft 12 or 14 of the vehicle or connected via a transmission mechanism such as a transmission.
[0016]
The stator 40 is configured by a cylindrical case having a size for accommodating the rotor 42 and is fixed to a fixed portion of the vehicle. On the outer peripheral surface 40a of the stator 40, holes (fixed side ports) 48 of the same number as the blades 46 are formed at the same pitch at positions facing the tip portions of the blades 46 of the rotor 42. An opening 50 is formed at the center of the one surface 40b of the stator 40. The opening 50 is opened to the atmosphere, or compressed air is fed at a constant pressure from the compressor 22 (FIG. 1) as necessary.
[0017]
According to the above configuration, when the drive source 10 (FIG. 1) is driven, the drive rotating shafts 12 and 14 are rotationally driven, the vehicle tires 16 and 18 are rotated, and the vehicle travels. At this time, the rotating shaft 32 of the siren 20 is rotated by the driving force of the driving rotating shaft 12 or 14, and the rotor 42 rotates. When the rotor 42 rotates, outside air is taken in from the opening 50 and discharged from the fixed port 48. At this time, the pressure or particle velocity energy is periodically released from the fixed side port 48 by the action of the blades 46 of the rotor 42, and sound waves are emitted to the outside. When the speed of the vehicle changes, the period and volume of the sound waves change automatically.
[0018]
It should be noted that the instantaneous change rate of the cross-sectional area of the port is adjusted by adjusting the shape of the opening of the fixed side port 48, or an acoustic tube, a horn, a resonator, etc. are provided outside the fixed side port 48 in communication with the port 48. Thus, an arbitrary sound pressure waveform (tone color) can be obtained by controlling the sound pressure waveform. Further, the frequency of the sound wave can be arbitrarily adjusted by adjusting the number of ports and the gear ratio of the transmission arranged between the drive rotary shaft 12 or 14 and the rotary shaft 32. Also, the sound pressure level can be adjusted by adjusting the port diameter.
[0019]
【The invention's effect】
As described above, according to the present invention, it is possible to generate a sound with a simple configuration and with a small amount of energy so as to alert the surroundings of the vehicle or to give a sense of realism when driving the vehicle.
[Brief description of the drawings]
FIG. 1 is a diagram showing an embodiment of the present invention, and schematically showing a sound generation mechanism according to the present invention.
FIG. 2 is a longitudinal sectional view showing a specific configuration of the siren 20 of FIG.
3 is a perspective view showing another specific configuration of the siren 20 of FIG. 1; FIG.
[Explanation of symbols]
12, 14 Drive rotary shaft 20 of vehicle Siren 26, 40 Stator 28, 42 Rotor 32 Rotor rotary shaft

Claims (1)

A rotating shaft of a siren rotor is connected to a driving rotating shaft of a vehicle directly or via a transmission mechanism, and the stator of the siren is fixed to a fixed portion of the vehicle. By rotating the driving rotating shaft of the vehicle, A low noise vehicle sound source device in which a rotor of the siren is rotated to generate sound from the siren.

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