JPH0497697A - Ceiling speaker for vehicle - Google Patents

Abstract

PURPOSE:To simplify a manufacture process and to reduce a manufacture cost by adhering a vibration unit formed through a thin and light weight piezoelectric acoustic driver inserted between foam plates to an upper face of a ceiling plate shaped as a prescribed shape as a ceiling material of a vehicle. CONSTITUTION:A vibration unit 9 formed by inserting a piezoelectric acoustic driver 3 between foam plates 1a, 1b is fitted to a roof of a vehicle of a ceiling plate 20 made of a foam shaped as a prescribed shape as a ceiling member of a vehicle and an interior 7 is arranged to a face in a cabin of the vehicle. Thus, the vibration unit 9 is assembled separately from the ceiling plate 20 and the speaker is manufactured by only fitting the unit 9 to the unit to the ceiling plate 20. Thus, the manufacture process is simplified and the manufacture cost is reduced.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a ceiling speaker for a vehicle that is installed on the ceiling of various vehicles such as automobiles, buses, trucks, and trains, ships, aircraft, and other vehicles. This invention relates to a vehicle ceiling speaker using a piezoelectric acoustic driver.

[Prior Art] In conventional audio systems for vehicles such as automobiles and trucks, dynamic speakers are usually used as speakers. As sound systems become more sophisticated, the number of speakers used increases, and systems using 8 to 10 speakers have been developed. In such sound systems, speakers are usually embedded in a door panel, a front panel, a rear shelf, or the like.

[Problems to be Solved by the Invention] However, dynamic speakers normally used in vehicle sound systems have a large thickness due to their structure, which limits miniaturization. It may not be possible to store it in the door panel, front panel, rear shelf, etc. Furthermore, since the speaker is heavy, there are restrictions on where it can be installed even if it is installed in a location other than the above, and there is a problem in that it is not possible to install the required number of speakers and a sufficient acoustic effect cannot be obtained. Furthermore, if the speaker is forcibly installed, there is a problem in that the speaker narrows the interior of the vehicle and reduces the comfort of the vehicle.

The present invention solves the above-mentioned problems, and aims to provide a lightweight and thin vehicle ceiling speaker that can be attached to the ceiling of a vehicle.

[Means for Solving the Problems] In order to solve the above-mentioned problems, a ceiling speaker for a vehicle according to the present invention includes a ceiling panel made of a foam formed into a predetermined shape as a ceiling material for a vehicle, and a ceiling panel facing each other. A piezoelectric acoustic driver is housed and supported in the space formed by the mutually opposing recesses by joining two foam plates each having recesses at opposing positions on the ceiling plate. The vehicle is characterized by comprising: a vibration unit joined to a surface on the vehicle roof side of the ceiling plate; and an interior lining disposed on a surface of the ceiling plate on the vehicle interior side.

[Function] The ceiling speaker for a vehicle of the present invention uses a vibration unit formed by sandwiching a piezoelectric acoustic driver between foam plates as a vehicle roof material, which is a ceiling plate made of a foam formed into a predetermined shape. It is attached to the side surface and is formed by arranging interior material on the inside surface of the vehicle. Therefore, it is possible to manufacture the vibration unit by simply assembling it separately from the ceiling plate and attaching it to the ceiling plate, which simplifies the manufacturing process and reduces manufacturing costs. In addition, the vibration unit is thin and lightweight, and the vehicle ceiling speaker constructed by bonding it to the ceiling board is also thin and lightweight, and is installed inside the vehicle and forms the ceiling of the vehicle. The acoustic driver vibrates the foam board and ceiling board of the vibration unit, causing the entire ceiling to function as a speaker. In other words, the speaker of the present invention effectively utilizes the upper surface (ceiling surface) that occupies a large area in the vehicle interior as the installation surface, and the inside of the vehicle interior has a shape that is no different from a normal ceiling in appearance, so it is suitable for use in vehicles. To achieve excellent acoustic effects by making the entire ceiling function as an acoustic speaker without reducing the livability of a vehicle interior by making the interior narrow or spoiling the aesthetics of the interior.

[Example] Hereinafter, an example of the present invention will be described based on the drawings. In this embodiment, a ceiling speaker for a vehicle will be described as a ceiling speaker for a vehicle, but the ceiling speaker of the present invention can be applied not only to vehicles but also to ceiling speakers for ships, aircraft, and various other vehicles. .

FIG. 1 is an exploded perspective view showing the structure and manufacturing process of a vibration unit according to an embodiment of the present invention.

As shown in the figure, in the vibration unit of this example,
Two foam plates 1a made of modified polystyrene foam
and ifl of mutually opposing surfaces of 1b
A plurality of recesses 2 are formed in y, and small protrusions 2a are formed in the recesses 2.

These four parts 2 facing each other form four spaces 8 (FIG. 5) in which the piezoelectric acoustic drivers 3 are housed when the foam plates 1a and 1b are bonded together.

The piezoelectric acoustic driver 3 has one on both sides of the piezoelectric ceramic plate, as shown in the plan view and front view in FIGS. 2 and 3.
It is formed by bonding a piezoelectric element 4 provided with an S-pole film (not shown) to both sides of a thin circular metal plate 5 to form a bimorph structure, and a lead wire is connected to the piezoelectric element 4 and the metal plate 5. 6 is connected (Fig. 3), by horizontally inserting this piezoelectric acoustic driver 3 into the recess 2 of the foam board 1a, and gluing the center part of the piezoelectric element 4 to the upper surface of the small protrusion 2a. Next, as shown in FIGS. 4 and 5, two foam plates 1a are mounted to support the piezoelectric acoustic driver 3 in the recess 2.
and 1b are bonded together, and the small protrusion 2 of the upper foam board 1b is attached.
a is brought into contact with the center of the upper surface of the piezoelectric element 4 of the piezoelectric acoustic driver 3 and bonded.

In the vibration unit 9 configured in this way, the piezoelectric acoustic driver 3 is supported (center supported) at the center portions of its upper and lower surfaces by the small protrusions 2a, 2a of the recesses 2 of the foam plates 1a, 1b. It is housed in a space 8 formed by opposing recesses 2.2 in a manner suitable for vibration. Further, the lead wires 6 connected to each piezoelectric type acoustic driver 3 are combined into two wires and pulled out as lead wires 6a from the ends of the foam plates 1a and 1b (FIG. 4).

The ceiling plate 20 is made of modified polystyrene foam, and is formed into a predetermined shape corresponding to the shape of the roof of the vehicle as a ceiling material for a vehicle (vehicle), as shown in FIG. Further, a sheet-like interior material 7 made of polyvinyl chloride is attached to the surface of the ceiling plate 20 that faces the interior of the vehicle (FIG. 7).

The above-mentioned vibration unit 9 is bonded to the upper surface of the ceiling plate 20, that is, the flat part of the surface on the roof side of the vehicle using an adhesive.

The ceiling speaker 10 for a vehicle (vehicle) thus formed is attached to the vehicle 11 from the indoor side as a ceiling material, as shown in FIG.

In addition, when installing the ceiling speaker 10 to the vehicle 11, a spacer or the like is used to connect the vibration unit 9 and the inner surface of the vehicle 11 so that the vibration unit 9 does not come into contact with the upper surface of the interior of the vehicle 11 and its vibration is hindered. The ceiling speaker 10 is attached to the ceiling side of the vehicle interior by a method such as screwing or gluing while maintaining a predetermined gap therebetween.

In the vehicle (vehicle) ceiling speaker 10 configured as described above and attached to a vehicle, the lead wire 6a drawn out from the ceiling speaker 10 is connected to an output terminal of a vehicle audio device (not shown) such as a car stereo. By applying a predetermined electric signal, the plurality of piezoelectric acoustic drivers 3 mechanically vibrate, vibrating the foam plates 1a and 1b of the vibration unit 9 via the upper and lower small protrusions 2a, and causing the vibration unit to vibrate. The vibration of 9 is transmitted to the ceiling board 20, vibrates the entire surface of the ceiling board 20, and generates sound.

In the vehicle (vehicle) ceiling speaker of the above embodiment, since the vibration unit 9 is connected to the flat part of the upper surface of the ceiling plate 20, the vibration unit 9 is connected to the ceiling plate 20.
Since it can be manufactured by simply assembling it separately from 0 and joining it to the ceiling plate 20, the manufacturing process is simplified and the manufacturing cost is reduced. Further, the piezoelectric acoustic driver 3 has a thickness of about 0.21 In and a diameter of about 6 In, for example.
0 to 8011, weight = approximately 8 g, and is thin and lightweight.The vibration unit 9 formed by sandwiching this between foam plates is also lightweight and thin, and is joined to the surface of the ceiling plate 20 on the opposite side from the inside of the vehicle. Therefore, the interior side of the vehicle (vehicle) of the ceiling speaker 10 has the same shape as a normal ceiling material, which impairs the aesthetic appearance of the interior, compresses the interior space, and reduces the comfort of the interior. Furthermore, as shown in Figure 9, the piezoelectric acoustic driver 3 has excellent frequency characteristics in the mid-to-high range, so it can be combined with a normal dynamic speaker that has excellent frequency characteristics in the bass range. This makes it possible to achieve excellent acoustic effects across the entire frequency domain. Furthermore, some piezoelectric acoustic drivers have excellent frequency characteristics in the low frequency range, and when these are used, sufficient acoustic effects can be obtained with only the piezoelectric acoustic driver. In addition, the ceiling plate 20 (vibration unit 9
Since the entire surface of the vehicle (including the vehicle) vibrates and generates sound, the acoustic effect inside the vehicle (vehicle) is further improved.

In the above embodiment, a case was explained in which modified polystyrene foam was used for the foam plates 1a and 1b and the ceiling plate 20, but these materials are not limited to this, and any material containing air bubbles may be used. , has a predetermined heat resistance (at least heat resistance in the range where the temperature inside the vehicle (vehicle) increases) and has an apparent density of 0.01 to 0.2.
Materials within the range of g/ctx3, such as modified styrene-polypropylene copolymer foam, polypropylene foam, polyethylene foam, polyurethane foam, and other materials can be used. Furthermore, the foam plates 1a, 1b and the ceiling plate 2o may be made of the same material, or may be made of different materials.

Further, in the above embodiment, a case was explained in which a polyvinyl chloride sheet was used as the interior material 7, but the material is not particularly limited, and may be a fiber fabric (woven fabric, non-woven fabric, knitted fabric) or a polyvinyl chloride sheet. In addition to those to which slab urethane foam is attached, various interior materials for vehicles (vehicles) can be arbitrarily selected and used.

In the above embodiment, the piezoelectric acoustic driver (with piezoelectric elements 4 bonded to both sides of the metal plate 5 as 3) was used. ) It is not limited to the one with the Kuimorph structure, but it is also possible to use one with other structures, and as shown in FIG. may also be used.

Furthermore, in the vibration unit 9 of the above embodiment, an example was explained in which the piezoelectric acoustic driver 3 was centrally supported by the small protrusions 2a, 2a from both upper and lower surfaces (FIG. 5).
As shown in FIG. 1, the piezoelectric acoustic driver may be supported by small protrusions 2a from only one surface (the lower surface in FIG. 11).Furthermore, center support is preferable as the method of supporting the piezoelectric acoustic driver, but this is not always the case. The support is not limited to the center, and in some cases, it is possible to obtain the necessary vibration by supporting other parts than the center.

There are no particular restrictions on the shape of the vibration unit 9, and it may be configured in a circular or other shape.

Further, although it is desirable to have a flat plate shape, it is also possible to configure it in a curved shape or other bent shape.

Regarding the total number of piezoelectric acoustic drivers 3 to be provided in the ceiling speaker 10, the ceiling plate 20 (including the vibration unit 9)
From the standpoint of making the whole vibrate sufficiently, it is desirable that the number be 2 or more, and there is no particular upper limit to the number, but in consideration of acoustic effects, economic efficiency, etc., it is desirable that the number be in the range of 2 to 16. .

Therefore, the number of piezoelectric acoustic drivers 3 to be installed per vibration unit 9 is determined based on the number of vibration units 9 to be connected to the ceiling plate 20 and the total number of piezoelectric acoustic drivers 3 to be provided on the entire ceiling plate. An appropriate number (for example, 1 to 8) is selected in consideration of the relationship and the influence on the manufacturing process.

Although not particularly shown, a recess with a shape corresponding to the shape of the vibration unit 9 is formed on the surface of the ceiling plate 20 to which the vibration unit 9 is to be bonded, and the vibration unit 9 is inserted into the recess. By fitting it in, the vibration unit 9 can be attached to any location! It is possible to make the decision easier and further simplify the assembly work.

[Effects of the Invention] As described above, the vehicle ceiling speaker of the present invention has a vibration unit formed by sandwiching a thin and lightweight piezoelectric acoustic driver between foam plates, and is molded into a predetermined shape as a vehicle ceiling material. Since it is configured to be connected to the top surface of the ceiling board, the vibration unit is assembled separately from the ceiling board.
This can be manufactured by simply bonding it to the top surface of the ceiling board, simplifying the manufacturing process and reducing manufacturing costs.3 Additionally, this ceiling speaker for vehicles can be installed as a ceiling material in the vehicle cabin, so The ceiling, which occupies a large area within the vehicle interior, is effectively used, and the inside of the vehicle interior has a shape that is no different from a normal ceiling, so it does not spoil the aesthetics or reduce the comfort of the vehicle interior. The entire ceiling can be used as a high-quality acoustic speaker.

Furthermore, even better acoustic effects may be obtained by combining the vehicle ceiling speaker of the present invention with a conventional dynamic speaker with excellent low frequency characteristics.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view showing the structure and manufacturing process of a vibration unit for a vehicle ceiling speaker according to an embodiment of the present invention, and FIGS. 2 and 3 show a vibration unit used in the vehicle ceiling speaker of the present invention. FIG. 4 is a plan view and front view showing a piezoelectric acoustic driver, FIG. 4 is a perspective view showing a vibration unit according to an embodiment of the present invention, and FIG. 5 is a state in which the piezoelectric acoustic driver is housed and supported between foam plates. 6 is a perspective view showing the process of joining the vibration unit to the upper surface of the ceiling plate, FIG. 7 is a perspective view showing a ceiling speaker for a vehicle according to an embodiment of the present invention, and FIG. 8 is a perspective view showing a ceiling speaker for a vehicle according to an embodiment of the present invention. FIG. 9 is a diagram showing the frequency characteristics of the vehicle ceiling speaker; FIG. 10 is a diagram showing a piezoelectric acoustic driver according to another embodiment; FIG. FIG. 7 is a sectional view showing a supported state of a piezoelectric acoustic driver according to another embodiment. 1 a, b... Foam plate 2... Concavity 3... Piezoelectric acoustic driver 4... Piezoelectric element 5... Metal plate 7...Interior material 9...Vibration unit 0...Vehicle ceiling speaker patent applicant Murata Manufacturing Co., Ltd. Patent consultant Suminoe Textile Co., Ltd.

Claims (1)

[Claims] (1) By joining a ceiling board made of foam molded into a predetermined shape as a ceiling material for a vehicle, and two foam boards with recesses provided at mutually opposing positions on opposing surfaces, the above-mentioned A piezoelectric acoustic driver is housed and supported in a space formed by mutually opposing recesses, and includes a vibration unit connected to a surface of the ceiling plate on the vehicle roof side, and a vibration unit arranged on the surface of the ceiling plate on the vehicle interior side. A ceiling speaker for a vehicle, characterized in that it is equipped with an interior material.