JP2022018899A - Cabin acoustic device - Google Patents

Abstract

To provide a cabin acoustic device comprising a speaker on a headrest of a seat back surface part of a seat, and suppressing affection of sound output from a speaker to an occupant who is seated on other seat.SOLUTION: A speaker 32 is stored in a headrest 31 positioned on a seat back surface part 4 of a seat, in the headrest 31, tube member groups 40a, 40b are provided on a front side of the speaker 32. One ends of plural tube members 41 forming the tube member groups 40a, 40b are closed, and opening end parts of the other ends are open to a position to which a sound pressure is applied from the speaker 32. Since the sound pressure generated by the speaker 32 is attenuated by the tube members 41, the sound pressure is suppressed from reaching to an occupant who is seated on other seat.SELECTED DRAWING: Figure 2

Description

The present invention relates to an in-vehicle acoustic device in which a speaker is installed in a headrest of a seat in the vehicle interior.

Patent Document 1 describes an invention relating to an vehicle interior acoustic device in which a speaker is installed in a headrest of a seat in the vehicle interior.
In this vehicle interior acoustic device, a pair of speakers are arranged inside a headrest located on the back surface of the seat in the vehicle interior. The pair of speakers are arranged at a distance in the left-right direction. A core material forming an internal space is housed inside the headrest, and this internal space functions as an enclosure for a pair of speakers. The core material and the two speakers are surrounded by a sound insulation pad. A pair of fiber pads sandwiched between sound insulation pads is provided at the front of the headrest, and each fiber pad faces the front surface of the speaker. The sound insulation pad and the fiber pad have a speaker grill structure, and the fiber pads are provided so as to be inclined outward from each other toward the front.

In the vehicle interior acoustic device described in Patent Document 1, a speaker grill structure is formed by a fiber pad for passing sound and a sound insulating pad for suppressing sound. Sound emitted from a pair of speakers placed at separate positions on the headrest passes through the fiber pads, but since the pair of fiber pads have a structure that spreads outward from each other as they move forward, the sound from the left and right speakers Pressure is directed to the ears on both sides of the occupant seated in the seat.

Japanese Unexamined Patent Publication No. 2016-43828

In recent vehicle interior sound devices, it is preferred that speakers are installed in a plurality of seats in the vehicle interior so that each of a plurality of passengers can individually listen to the sound related to different contents. However, in the vehicle interior acoustic device described in Patent Document 1, a pair of speakers are arranged at positions separated from each other on the left and right of the headrest of the seat, and the fiber pad of the duct structure spreads outward toward the front. It is formed. Therefore, the sound pressure tends to propagate not only to both sides of the occupant's head but also to the periphery in the left-right direction and further to the front. Especially in the midrange and low range, the sound pressure tends to be radiated to the surroundings by being caught not only in the front but also around the headrest due to the diffraction phenomenon, so that the sound pressure tends to propagate to both the left and right sides and the front. Therefore, the degree of sound separation between the seats is lowered, for example, the reproduced sounds from the speakers provided in the respective seats interfere with each other.

The present invention solves the above-mentioned conventional problems, can suppress the sound from the speaker provided in the headrest from radiating toward other seats, and separates the sounds by each passenger. The purpose is to provide an interior sound device that is easy to hear.

The present invention relates to an interior acoustic device in which a speaker for applying sound pressure to a passenger seated in the seat is installed in the headrest of a seat in the passenger compartment.
The headrest is characterized in that a tube member having a hollow inside is installed, and an open end portion of the tube member is provided at a position where sound pressure generated by the speaker is applied.

In the vehicle interior acoustic device of the present invention, it is preferable that a plurality of the pipe members having different pipe lengths are installed in the headrest.

In the vehicle interior acoustic device of the present invention, the open end of the tube member is located in front of the diaphragm provided in the speaker in the sounding direction.

Further, in the vehicle interior acoustic device of the present invention, the open end of the tube member is provided in the speaker and is located behind the diaphragm on the side opposite to the sounding direction. May be good.

In the vehicle interior acoustic device of the present invention, the speaker is arranged at the center of the headrest in the left-right direction.

For example, in the vehicle interior acoustic device of the present invention, the speaker faces the back of the neck or the back of the head of the passenger.

In the vehicle interior sound device of the present invention, the sound pressure from the speaker propagates inside the tube member provided in the headrest, so that the sound energy is consumed, so that the sound pressure from the speaker is less likely to wrap around the headrest. , Sound propagation to both left and right sides and forward is suppressed. Therefore, the reproduced sound from the speaker provided in each seat can be heard by the passenger seated in that seat, but the sound pressure between different seats is less likely to affect each other, so that the passenger sits in each seat. It will be easier for passengers to separate the reproduced sound from the speakers and listen to it.

Further, if the headrest is provided with a plurality of tube members having different tube lengths, the energy of sound pressure having a wide range of frequencies can be consumed. When using a tube member whose end opposite to the open end is closed, set the tube length to 1/4 of the wavelength of the sound pressure at which you want to consume energy, and use a tube with both ends open. When using a member, the length of the tube is set to 1/2 of the wavelength of the sound pressure at which energy is desired to be consumed, thereby suppressing the sound pressure that tends to be diffracted around the headrest, such as in the midrange and low range. It is possible to do.

A plan view showing the passenger compartment of an automobile provided with the passenger compartment acoustic device according to the first embodiment of the present invention. A plan view including a partial cross section showing the rear seat interior acoustic device shown in FIG. 1. A side view including a partial cross section showing the rear seat interior acoustic device shown in FIG. 1. Partially enlarged cross-sectional view, which is an enlarged view of the IV arrow-viewing portion of FIG. (A) and (B) are enlarged cross-sectional views showing a cross section of FIG. 4 cut along a VV line according to an embodiment. Partially enlarged cross-sectional view corresponding to FIG. 4 showing the vehicle interior acoustic device according to the second embodiment of the present invention. A plan view including a partial cross section corresponding to FIG. 2, showing the vehicle interior acoustic device according to the third embodiment of the present invention.

FIG. 1 is a plan view showing a part of the passenger compartment of an automobile, and shows a front seat (driver's seat) 1, a rear seat 2, and a steering wheel 3 in front of the front seat 1. In each figure, the X1 direction is the front, the X2 direction is the rear, the Y1 direction is the left direction, and the Y2 direction is the right direction. Further, the Z1 direction is the upward direction, and the Z2 direction is the downward direction.

The front seat passenger 10 is seated in the front seat 1, and the rear seat passenger 20 is seated in the rear seat 2. FIG. 2 shows the shoulder portion 21 and the head portion 22 of the rear seat occupant 20 seated in the rear seat 2 and the ear portions 23 on the left side (Y1 side) and the right side (Y2 side). FIG. 3 shows the head 24 of the rear seat occupant 20.

As shown in FIG. 1, the vehicle interior acoustic device 30 of the first embodiment of the present invention is placed on the seat back portion (seat back) 4 of the front seat 1 and on the seat back portion 4 of the rear seat 2. Is provided. The vehicle interior acoustic device 30 has a headrest 31 installed on the back surface portion 4 of the seat and a speaker 32 housed inside the headrest 31. The front surface facing the front (X1 direction) of the headrest 31 is a central front surface 31a that is almost flat in the left-right direction (Y1-Y2 direction) and an inclined front surface 31b located on the left side (Y1 side) with the central front surface 31a in between. And an inclined front surface 31c located on the right side. The inclined front surface 31b and the inclined front surface 31c are inclined in a direction away from each other toward the front (X1 direction).

2 and 3 show a cross-sectional structure of the vehicle interior acoustic device 30 installed on the seat back surface portion 4 of the rear seat 2. FIG. 2 shows a center line O extending in the front-rear direction (X1-X2 direction). The center line O is a center line that divides the seat back surface 4 and the headrest 31 in the left-right direction (Y1-Y2 direction), and divides the rear seat occupant 20 and its head 22 and the neck 24 in the left-right direction (Y1-Y2). It is the center line that divides by (direction). The central front surface 31a is substantially perpendicular to the center line O, and the inclined front surface 31b and the inclined front surface 31c are obliquely facing the center line O.

As shown in FIGS. 2 and 3, the headrest 31 is formed with a front region 33 from the central front surface 31a toward the rear (X2 direction). The front region 33 is a spatial region. Alternatively, a low-density fiber layer or cushioning material through which sound pressure can pass may be interposed. A concave storage space 34 is formed behind the front region 33. The speaker 32 is provided inside the storage space 34. In the central front surface 31a of the headrest 31, the front of the front region 33 is closed by the cover member 35. Sound pressure can pass through the cover member 35, and the cover member 35 is made of a porous soft sheet, a porous resin plate, or the like. A partition plate 36 is provided at the boundary between the front area 33 and the storage space 34, and the speaker 32 is installed in the opening formed in the partition plate 36.

The speaker 32 is fixed to the partition plate 36 inside the storage space 34. The speaker 32 includes a frame 32a fixed to the partition plate 36, a cone-shaped diaphragm 32b supported in front of the inside of the frame 32a, and a magnetic drive circuit 32c for vibrating the diaphragm 32b fixed to the frame 32a. Have. The diaphragm 32b faces the inside of the opening of the partition plate 36, and the speaker 32 has the sounding direction directed forward (X1 direction).

As shown in FIG. 2, the center line of the speaker 32, that is, the line passing through the center of the cone-shaped diaphragm 32b and the center of the magnetic drive circuit 32c coincides with the center line O in the plan view. As shown in FIG. 3, the speaker 32 faces the neck back portion 25 of the rear seat occupant 20 at a distance rearward (in the X2 direction). Further, the speaker 32 may face the back of the head 26 of the rear seat occupant 20 from behind, or may face the intermediate portion between the back of the neck 25 and the back of the head 26.

As shown in FIG. 2, inside the headrest 31, the pipe member group 40a is provided on the left side (Y1 side) of the front region 33, and the pipe member group 40b is provided on the right side (Y2 side) of the front region 33. ing. As shown in FIG. 3, inside the headrest 31, a tube member group 40c is provided on the upper side (Z1 side) of the front region 33.

FIG. 4 shows the IV arrow viewing portion of FIG. FIG. 4 shows an enlarged view of the pipe member group 40b on the right side (Y2 side). The pipe member group 40b has a plurality of pipe members 41. In the tube member group 40b shown in the cross-sectional view of FIG. 4, nine tube members 41 are arranged side by side in the front-rear direction (X1-X2 direction). The nine pipe members 41 extend linearly in the left-right direction (Y1-Y2 direction). However, the pipe member 41 may be provided so as to have a predetermined angle with respect to the left-right direction (Y1-Y2 direction).

A cross-sectional structure obtained by cutting a part of the pipe member group 40b shown in FIG. 4 along a VV line is shown in FIGS. 5A and 5B for each embodiment. The plurality of pipe members 41 are arranged side by side in the front-rear direction (X1-X2 direction), and are also arranged in a plurality of stages in the vertical direction (Z1-Z2 direction). In the embodiment shown in FIG. 5A, the cross section of each pipe member 41 is circular. Alternatively, it may be oval. In the embodiment shown in FIG. 5B, the cross section of each pipe member 41 is rectangular. Alternatively, it may be a square. The number of arrangements of the tube member 41 in the front-rear direction (X1-X2 direction) and the up-down direction (Z1-Z2 direction) may be larger or smaller than those in the embodiments shown in FIGS. 4 and 5.

As shown in FIG. 4, the right end (Y2 side) end of each pipe member 41 is a closed closed end 42, and the left end (Y1 side) end is an open open end 43. be. The open end 43 of some of the tube members 41 is open inside the front region 33, and the open end 43 of the other tube member 41 is open to the inclined front surface 31c of the headrest 31. In the embodiment shown in FIG. 4, the open end 43 of all the tube members 41 is located in front of the sounding direction of the speaker 32, and more accurately, in front of the diaphragm 32b of the speaker 32 (X1 direction). positioned.

The opening ends 43 of all the pipe members 41 are opened at positions where sound pressure directed forward (in the X1 direction) is applied by the vibration of the diaphragm 32b. Since the sound pressure of the speaker 32 strongly acts on the front region 33, the sound pressure is likely to propagate to the internal space of the tube member 41 in which the opening end portion 43 is located in the front region 33. Further, the opening end 43 of the front pipe member 41 is open to the inclined front surface 31c, but since the inclined front surface 31c diagonally faces the center line O, it spreads in the left-right direction along the opening end 43. The sound pressure to be tried also easily propagates inside the pipe member 41.

The pipe member group 40a located on the left side (Y1 side) of the center line O in FIG. 2 has a plane-symmetrical structure with the pipe member group 40b shown in FIG. 4 sandwiching the center line O. The tube member group 40c shown in FIG. 3 is located above the front region 33, and a plurality of tube members 41 are arranged in the front-rear direction and the left-right direction. The upper end of the pipe member 41 is the closed end portion 42, and the lower end is the open end portion 43. The opening end portion 43 of each pipe member 41 is released inside the front region 33, and is opened at a position where the sound pressure emitted forward from the speaker 32 is applied.

In the pipe member groups 40a, 40b, 40c provided on the headrest 31, pipe members 41 having different pipe lengths are combined. The pipe length here means the length dimension from the open end portion 43 to the closed end portion 42 in the internal space of each pipe member 41. In the pipe member group 40b shown in FIG. 4, pipe members 41 having pipe lengths L1, L2, L3, L4, and L5 are combined and arranged. In the pipe member groups 40a, 40b, 40c, the pipe lengths of the pipe members 41 may be different one by one. One pipe member group may include those having the same pipe length, and may be a combination of different pipe lengths as a whole.

FIG. 1 shows the shoulder portion 11, the head portion 12, and the ear portion 13 of the front seat occupant 10 seated in the front seat 1. The vehicle interior sound device 30 is also provided on the seat back portion 4 of the front seat 1. The structure of the headrest 31 and the speaker 32 of the vehicle interior acoustic device 30 provided in the front seat 1 is the same as that provided in the rear seat 2 shown in FIGS. 2, 3 and 4.

The reproduced sound of the speaker 32 provided in the vehicle interior acoustic device 30 provided in the front seat 1 and the speaker 32 provided in the rear seat 2 is monaural.

In the vehicle interior sound device 30 of the first embodiment shown in FIGS. 1 and 2, the front seat 1 and the rear seat 2 can individually generate sounds based on different contents from the speaker 32. .. For example, from the speaker 32 of the front seat 1, the road guidance sound of the navigation system, other vehicle traveling information, and the operation information of the air conditioner are given to the front seat occupant 10 who is the driver as voice. Further, the music reproduction sound may be given from the speaker 32 of the front seat 1. The speaker 32 of the rear seat 2 gives the passenger 20 of the rear seat a sound based on a game operation, a sound of a television receiver, or a playback sound of music that he / she wants to listen to personally.

As shown in the plan views of FIGS. 1 and 2, the center of the speaker 32 is located on the center line O, and as shown in FIG. 3, the speaker 32 faces the back of the neck 25 (or the back of the head 26) from the rear. is doing. Since a space is formed between the speaker 32 and the back of the neck 25 (or the back of the head 26), the sound pressure easily reaches the ears 23 of the rear seat occupant 20, and the rear seat occupant 20 is located nearby. The reproduced sound of the speaker 32 can be heard at a sufficient volume.

The sound pressure directed forward (X1 direction) from the speaker 32 hits the back of the neck 25 (or the back of the head 26), and the sound pressure is suppressed from going straight ahead of the neck 24 and the head 22. Further, the sound pressure from the speaker 32 in the left-right direction and the up-down direction is diffracted near the left end (Y1 side) end portion and the right side (Y2 side) end portion of the headrest 31, so that the sound pressure is diffracted in the left-right direction and up-down direction. It spreads in the direction. Since the high-pitched sound component of the sound pressure emitted from the speaker 32 has high forward directivity, it is easily blocked by the back of the neck 25 (or the back of the head 26). However, since the sound pressure in the low range and the mid range has a lower forward directivity than the high range, it tends to wrap around in the left-right direction and the up-down direction and diffuse to the surroundings.

In the vehicle interior acoustic device 30, the pipe member group 40a and the pipe member group 40b are provided on both the left and right sides in front of the speaker 32 in the sounding direction, and the pipe member group 40c is provided on the upper side. In the tube member groups 40a, 40b, 40c, the opening end portion 43 of the tube member 41 opens in the front region 33 and also opens in the inclined front surface 31b, 31c, and is generated by the vibration of the diaphragm 32b of the speaker 32. Sound pressure is applied to the open end 43 of all the pipe members 41.

The sound pressure is consumed by propagating from the opening end 43 of each pipe member 41 through the internal space of the pipe member 41, and the sound energy emitted from the speaker 32 is consumed around the front of the headrest 31. As shown in FIG. 4, when one end of the pipe member 41 is a closed end portion 42 and only one end portion is an open end portion 43, air vibration having a wavelength four times the length of the pipe resonates in the pipe. Energy is greatly attenuated. The pipe member 41 may have a structure in which both ends are open ends and sound pressure is applied to one of the open ends. In this case, air vibration having a wavelength twice the length of the tube resonates in the tube and the energy is significantly attenuated.

In the pipe member groups 40a, 40b, 40c, as shown in FIG. 4, pipe members 41 having different pipe lengths L1, L2, L3, L4, and L5 are used in combination. Therefore, at a plurality of frequencies, the air vibration resonates in the tube, and the sound energy can be attenuated in the front region of the headrest 31 in a wide frequency band.

In the vehicle interior acoustic device 30, as shown in FIGS. 2 and 3, the center of the speaker 32 is located on the center line O in a plan view, and the speaker 32 is located on the back of the neck 25 or the back of the head 26 of the rear seat occupant 20. Facing each other. Therefore, since the sound pressure in the high frequency range emitted from the speaker 32 has a high forward directivity, it is easy to block the forward propagation by hitting the back of the neck 25 or the back of the head 26. Therefore, it is effective to attenuate the energy of the sound pressure in the low range and the mid range, which have relatively low directivity, by the resonance of the plurality of tube members 41.

Generally, the frequency in the low frequency range is about 100 to 150 Hz, and the frequency in the midrange is 150 Hz to 4 KHz. Assuming that the speed of sound is 340 m / s, the wavelength of sound pressure vibration in the low frequency range is 3.4 m to 2.3 m, and the wavelength of air vibration in the midrange is 2.3 m to 8.5 cm. In order to attenuate the air vibration in the bass range and the midrange by the resonance of the tube, in the case of the tube member 41 having a closed end 42 at one end, the tube lengths L1, L2, L3, L4 and L5 are 85 cm to 2.1 cm. It is preferable to select from the numerical values in the range and use it. When a pipe member having open ends at both ends is used, it is preferable to select and use a pipe length in the range of 1.7 m to 4.3 cm. That is, it is preferable that among the plurality of pipe members 41 constituting the pipe member group 40a, 40b, 40c, those having a pipe length of any one within the above numerical range are included.

The acoustic effect of the vehicle interior acoustic device 30 provided in the front seat 1 is the same as that of the vehicle interior acoustic device 30 provided in the rear seat 2. In the vehicle interior sound device 30, the sound pressure emitted from the speaker 32 hits the occupant's neck back 25 and the back of the head 26 to attenuate the sound energy, and the air vibration due to the sound pressure is caused by the pipe members 40a, 40b, 40c. It is attenuated by propagating inside each tube member 41. Therefore, the sound reaches the ears of the passengers seated in each seat at a sufficient volume, but the propagation of sound pressure to other seats can be suppressed. Therefore, the passengers seated in each seat can individually listen to the reproduced sound without being affected by the sound from the speakers of the other seats.

FIG. 6 shows a part of the vehicle interior acoustic device 130 according to the second embodiment of the present invention. FIG. 6 is a partially enlarged cross-sectional view corresponding to FIG. In the vehicle interior acoustic device 130 shown in FIG. 6, a pipe member group 40b having the same structure as that shown in FIG. 4 is provided on the right side (Y2 side) of the front region 33. One end of the pipe member 41 constituting the pipe member group 40b is a closed end portion 42, and the open end portion 43 is open in front of the diaphragm 32b of the speaker 32 (in the X1 direction). In the vehicle interior acoustic device 130, the back tube member group 40d is provided behind the diaphragm 32b of the speaker 32. The back tube member group 40d is also provided with a plurality of tube members 41 having different tube lengths. One end of the pipe member 41 is a closed end portion 42, and the open end portion 43 at the other end is inside the storage space 34 in which the speaker 32 is located and opens behind the diaphragm 32b of the speaker 32. ing.

In the vehicle interior sound device 130 shown in FIG. 6, the pipe member 41 constituting the pipe member groups 40a, 40b, 40c located in front of the speaker 32 is given to the front (X1 direction) by the vibration of the diaphragm 32b. The energy of the sound pressure is attenuated. In the storage space 34, which is a space behind the diaphragm 32b, the vibration of the diaphragm 32b generates a back sound pressure whose phase is reversed from the sound pressure given to the front. This back sound pressure propagates inside the pipe member 41 constituting the back pipe member group 40d, and the energy of the back sound pressure is attenuated. By attenuating the air vibration of the back sound pressure, even if the back sound pressure may pass through the partition plate 36 forward, the sound pressure given to the front from the vibrating plate 32b and the back sound pressure interfere with each other. It is possible to prevent this and improve the sound quality.

In the vehicle interior acoustic device 230 shown in FIG. 7, two speakers 32 are installed inside the storage space 34 of the headrest 31. The two speakers 32 are arranged at a distance in the left-right direction so as to be able to function as a stereo sound device. Also in this vehicle interior acoustic device 230, tube member groups 40a, 40b, 40c are provided in front of the two speakers 32. It is possible to attenuate the sound energy by the pipe member 41 provided in the pipe member group 40a, 40b, 40c.

1 Front seat 2 Rear seat 4 Seat back 10 Front passenger 20 Rear passenger 22 Head 23 Ear 25 Neck back 26 Rear head 30 Car interior acoustic device 31 Headrest 31a Central front 31b, 31c Tilt front 32 Speaker 33 Front area 34 Storage area 40a, 40b, 40c Pipe member group 40d Back pipe member group 41 Pipe member 42 Closed end 43 Open end 130, 230 Vehicle interior acoustic device L1, L2, L3, L4, L5 Pipe length

Claims (6)

In the vehicle interior sound system in which a speaker that gives sound pressure to the passengers seated in the seat is installed in the headrest of the seat in the vehicle interior.
A vehicle interior acoustic device characterized in that a tube member having a hollow inside is installed in the headrest, and an open end portion of the tube member is provided at a position where sound pressure generated by the speaker is applied. The vehicle interior acoustic device according to claim 1, wherein a plurality of the pipe members having different pipe lengths are installed in the headrest. The vehicle interior acoustic device according to claim 1 or 2, wherein the open end of the tube member is located in front of the diaphragm provided in the speaker in the sounding direction. The vehicle interior acoustic device according to any one of claims 1 to 3, wherein the open end portion of the tube member is provided in the speaker and is located behind the diaphragm on the side opposite to the sounding direction. .. The vehicle interior acoustic device according to any one of claims 1 to 4, wherein the speaker is arranged at the center of the headrest in the left-right direction. The vehicle interior acoustic device according to claim 5, wherein the speaker faces the back of the neck or the back of the head of the passenger.

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