JPS643437B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vehicle acoustic device that utilizes various panel members for the interior and exterior of a vehicle as an acoustic diaphragm.

Examples of conventional vehicle audio equipment include those shown in Figure 1~
There is something like the one shown in Figure 3.
No. 135114). First of all, Fig. 1 shows a driver D which is an acoustic exciter.A vibration plate 2 and a cover plate 3 are fixed to the front and rear (top and bottom in Fig. 1) end surfaces of a cylindrical frame 1, respectively, and a case body is formed. A yoke 5 having an annular magnet 4 is disposed in the center of the case body. The yoke 5 consists of a pole piece 5a and a yoke plate 5b, which together with the magnet 4 form a magnetic circuit having a gap, and are elastically supported by the frame 1 via a damper 6 at the yoke plate 5b. There is. Further, a coil 7 wound around a bobbin is arranged in the gap, and the bobbin is fixed to the vibration plate 2. As shown in FIGS. 2 and 3, the driver D configured in this manner is attached to a panel member 8 forming a rear parcel of an automobile or the like by screwing or the like at the frame 1. In this manner, in the vehicle acoustic device, the driver D is directly attached to the panel member 8 for the interior and exterior of the automobile, and the entire panel member 8 is used as it is as an acoustic diaphragm. This acoustic diaphragm is used not only for the interior and exterior parts of automobiles as shown in the figure, but also for the wall panels of living rooms.Such panel members 8, etc. are generally made of materials such as compressed cardboard or plywood. It is rigidly fixed to the vehicle body etc. at its outer edge.

When the audio signal is energized to the coil 7, it is connected to the magnet 4 side and the frame 1 via the damper 6.
side, that is, the vibrating plate 2 side, vibrates relative to each other, and the panel member 8 is vibrated by the vibration of the vibrating plate 2, etc., thereby reproducing a low frequency range.

However, in such conventional vehicle acoustic devices, the entire panel member 8 is used as an acoustic diaphragm as it is, so the diaphragm is formed with the fixed part as a node and has multiple natural resonance points. However, due to this natural resonance, peaks and dips appear in the reproduced output as shown in the reproduction frequency characteristic of FIG. 4, resulting in a problem that the appropriate reproduction bandwidth is narrow and it is difficult to achieve a wide band. Further, there is a problem that split vibration occurs in which each part of the panel member 8 vibrates at a different phase, resulting in low efficiency in band portions other than the resonance point (peak point).

This invention was made by focusing on such conventional problems, and the interior and exterior panel members are separated into a fixed vehicle panel, a main diaphragm, and a sub-diaphragm to which an acoustic exciter is attached. The object of the present invention is to obtain a vehicle acoustic device that solves the above-mentioned problems by molding and connecting each member via a flexible sheet.

The present invention will be explained below based on the drawings. Fifth
7 to 7 are diagrams showing an embodiment of the present invention. In the drawings, parts that are the same as those in the prior art are designated by the same reference numerals and redundant explanations will be omitted.

First, the configuration will be described. In this embodiment, a panel member (vehicle panel) 9 is made of a rigid body, and a mounting hole 9a having a circular required area is opened in the rigid panel member 9, for example. A diaphragm 11 is supported by a flexible sheet 12 in this mounting hole 9a. Furthermore, the diaphragm 11 is concentrically divided into two parts, a sub-diaphragm 11a on the center side and a main diaphragm 11b on the outer circumference, and the sub-diaphragm 11a is divided into a main diaphragm 11b on the outer peripheral side.
is supported via a flexible sheet 13.
Both the main and sub-diaphragms 11a and 11b are made of a material that is not permeable to air, such as foamed acrylic. The driver D, which is an acoustic vibrator, is attached to the sub-diaphragm 11a on the center side, and has the same structure as the conventional one.

To describe the operation, in this embodiment, the main diaphragm 11 is excited by the driver D and is expressed by the following formula.
It operates as a mechanical two-way speaker with the high-frequency limit frequency _b of b as the crossover frequency.
That is _, as shown by the solid line in the _playback frequency characteristics of FIG.
Both sub diaphragms 1a vibrate, and in the frequency band above the high limit frequency _b , only the sub-diaphragm 11a vibrates, expanding the reproduction band to the frequency range above the high limit frequency _b . Therefore, a flat frequency characteristic is obtained from a low frequency range to a high frequency range, and no peaks or dips occur.

Here, the formula for displaying the high-frequency limit frequency _b is as follows: m _b : equivalent mass of the main diaphragm 11b, m _a : equivalent mass of the sub diaphragm 11a, k ₃ : sub diaphragm edge 1
When the spring constant is 3, the high frequency limit frequency _b is expressed by the following formula from the general formula.

Next, in the configuration example in which the diaphragm is concentrically divided into two parts as described above, the auxiliary diaphragm 11a side has a diaphragm 14 that is permeable to air as shown in FIG.
It is also possible to do this. In FIG. 7, 14a is an example of a frame made of FRP (fiber reinforced plastic), and 14b is a cloth attached to the frame 14a.

When the sub-diaphragm 11a is transparent, air is hardly driven by the sub-diaphragm 11a above the high-range limit frequency _b , so that frequency signals above the high-range limit frequency _b are highly cut. .
Therefore, it is possible to provide a vehicle acoustic device with a mechanical filter.

Next, FIGS. 9 and 10 show modified examples of the connecting portion of the flexible sheet 12 in this invention. In this modification, a damper member 16 such as a thin stainless steel plate is attached to the flexible sheet 12 at the flexible sheet connection portion. 16a is a slit. With such a double structure, the connecting portion of the flexible sheet 12 can be mechanically reinforced, and the diaphragm 11 can be vibrated in an appropriate holding state at all times.

As described in detail above, according to the present invention, a mounting hole of a required area is formed in a panel member, and a sub-diaphragm with an excitation driver attached to the mounting hole is connected to the main diaphragm through a flexible sheet. Because it is supported, the piston motion vibration of the diaphragm can generate sound pressure and reproduce the desired low frequency range, making it possible to flatten the frequency response, further expanding the reproduction frequency band and improving efficiency. The effect is that it is possible to achieve the following.

In addition to the above-mentioned common effects, the embodiments also have the following effects.

That is, according to an embodiment in which the panel member is a rigid body and the diaphragm is composed of a sub-diaphragm to which a driver is attached and a main diaphragm that supports this sub-diaphragm with a flexible sheet, the sub-diaphragm is By making it non-transparent or transparent, it is possible to operate as a mechanical two-way spacer to further expand the reproduction band, or to function as a vehicle acoustic device with a mechanical filter.

[Brief explanation of drawings]

FIG. 1 is a partially sectional side view showing the driver portion of a conventional vehicle audio system, FIG. 2 is a plan view of the conventional vehicle audio system, and FIG. 3 is a side view of the same vehicle audio system. Fig. 4 is a characteristic curve diagram showing the reproduction frequency characteristics of the vehicle audio device as above, Fig. 5 is a plan view showing an embodiment of the present invention, Fig. 6 is an end view taken along the line - - of Fig. 5, and Fig. 7 is the same as above. A plan view showing an example of a diaphragm permeable to air applied to the embodiment, FIG. 8 is a characteristic curve diagram showing the reproduction frequency characteristics of the embodiment of FIG. 5, and FIG. FIG. 10 is a vertical cross-sectional view showing a modification of the flexible sheet connecting portion, and is a view taken from the - line in FIG. 9. 8: panel member, 8b: rigid panel member (vehicle panel), 9a: mounting hole, 11: diaphragm, 11
a: Sub-diaphragm, 11b: Main diaphragm, 12, 13:
Flexible sheet, 14: diaphragm permeable to air, 14b: cloth, D: driver.

Claims (1)

[Scope of Claims] 1. In a vehicle acoustic device in which an acoustic vibrator is attached to an interior/exterior panel member of a vehicle and the panel member is used as a diaphragm, the interior/exterior panel member is a vehicle panel fixed to the vehicle. , a main diaphragm that vibrates in the vicinity of the vehicle panel, and a sub-diaphragm that is disposed in the vicinity of the main diaphragm and to which an acoustic exciter is attached are molded separately, and the vehicle panel, the main diaphragm, A vehicle acoustic device characterized in that a sub-diaphragm and a sub-diaphragm are connected to each other via a flexible sheet. 2. The vehicle acoustic device according to claim 1, wherein the sub-diaphragm is non-permeable to air. 3. The vehicle acoustic device according to claim 1, wherein the sub-diaphragm is permeable to air.