JPH0143327Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a dart panel silencer that is used in a vehicle's dart panel to insulate the interior of the vehicle from noise from the engine room.

A darts panel silencer is attached to the interior side of the darts panel that separates the engine room and the interior of an automobile to isolate the interior of the vehicle from noise from the engine compartment.

This darth panel silencer generally has a structure in which a felt sound absorbing material and a skin, which is a sound insulating material, are attached to the inside of the darth panel.

However, in order to improve the sound insulation characteristics of a silencer that combines sound absorbing material and skin,
It is necessary to increase the thickness of the sound-absorbing material or the skin material, which leads to a reduction in indoor space, and it is difficult to improve the sound-absorbing and sound-insulating characteristics in a space with limited installation space. In addition, an increase in weight due to an increase in the thickness or surface density of the sound absorbing or sound insulating material increases the weight of the vehicle body and reduces the workability of assembling it to the vehicle body.

Furthermore, the dart silencer using felt sound-absorbing material has excellent sound insulation properties for medium and high frequency sounds, but it has poor sound insulation properties for low frequency sounds. There is no improvement.

The present invention takes the above facts into account, and aims to provide a darts panel silencer that can provide effective sound insulation in a limited installation space and does not increase the weight of the vehicle.

In the dash panel silencer according to the present invention, an asphalt-impregnated polyurethane layer is provided on the dash panel side of the sound absorbing material to achieve effective sound absorption and insulation without increasing the wall thickness.

Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, a dart panel silencer 10 according to the present embodiment is installed on a dart panel 1 that partitions an engine room 14 and a passenger compartment 16 of a vehicle body 12.
It is attached to the indoor side of 8.

As shown in detail in FIG. 2, this dash panel silencer 10 has a polyurethane layer 20, a sound absorbing material layer 22, and a skin 24 attached in this order to the interior side of the dash panel 18.

Because the polyurethane layer 20 is in close contact with the dash panel 18 due to its elasticity, the dash panel 1
Even if the indoor side surface of 8 has an uneven shape, no gap is created between it and the dash panel 18. Therefore, the polyurethane layer 20 not only improves the sound absorption and sound insulation performance of the silencer 10 but also has a vibration damping function for the dash panel 18.

Furthermore, this polyurethane layer 20 is impregnated with an appropriate amount of an adhesive substance such as asphalt. As a result, the polyurethane layer 20 has improved sound absorbing and sound insulating properties in the low to medium frequency range, and its adhesion to the dash panel 18 is improved due to the adhesiveness of the asphalt. The sound absorption, sound insulation, and vibration damping properties of the silencer 10 can be tuned by changing the amount of asphalt impregnated into the polyurethane layer 20.

The sound absorbing material layer 22 may be made of general sound absorbing materials such as felt or glass wool. However, it is preferable that the material has excellent sound absorption properties, especially in the medium and high frequency range.
The skin 24 serves as a sound insulating material and is a part that directly faces the occupants in the room, so it is made of rubber, synthetic resin vinyl chloride, or the like as in the past.

In the dash panel silencer of this embodiment configured as described above, the polyurethane layer 20 is sandwiched between the sound absorbing material layer 22 and the dash panel 18, so that the polyurethane layer 20 is in close contact with the dash panel 18 and is not installed in the engine compartment. Absorbs and insulates noise from 14, especially in the low frequency range,
The sound absorbing material layer 22 absorbs noise in the medium and high frequency range, and the polyurethane layer 20 also damps vibrations of the dash panel 18, thereby improving the quietness of the interior 16.

In the case where the polyurethane layer 20 is interposed as in this embodiment, the dash panel silencer 10
The overall wall thickness of the dash panel silencer 10 can be made equal to or less than the wall thickness of a conventional dartshi panel silencer, and the increase in weight due to asphalt is compensated for by the decrease in the density and thickness of the sound absorbing material layer 22. Overall weight increase can be kept to a minimum.

FIG. 3 shows the transmission loss when comparing the dash panel silencer of this embodiment with the conventional dash panel silencer. In addition, Figure 4 shows the acceleration mobility of the darts panel silencer of this example compared to the case without a silencer and the conventional silencer (the lower the acceleration mobility is, the less likely it is to vibrate), and the sound absorption and vibration damping properties are shown. It is found that the darth panel silencer of this example is superior in both properties.

Note that when impregnating the polyurethane layer 20 with asphalt, a tool such as a grommet that is fitted into a wire harness passage hole penetrating the dash panel 18 can also be used, and this also improves the sound insulation performance. be able to. Alternatively, instead of directly bringing the polyurethane layer 20 into close contact with the dash panel 18, an asphalt sheet may be attached to the dash panel 18, and the polyurethane layer may be brought into close contact with the asphalt sheet to improve the damping effect.

As explained above, the darth panel silencer according to the present invention has an asphalt-impregnated polyurethane layer attached to the sound-absorbing material on the darth panel side.
It has the effect of suppressing weight increase and providing effective sound absorption and insulation in a limited and minimal space.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the darth panel silencer according to the present invention, FIG. 2 is an enlarged view of a portion of FIG. 1, and FIG. 3 is an experimental result of this embodiment.
FIG. 4 is a diagram showing the relationship between transmission loss and 1/30ct center frequency to show the improvement in sound absorption. FIG. . 10... Datsushi panel silencer, 18...
...Dutch panel, 20...Polyurethane layer, 2
2...Sound absorbing material layer, 24...Skin.

Claims (1)

[Scope of utility model registration request] A dartshi panel silencer having a sound absorbing material and a skin on the interior side of a dartshi panel, characterized in that an asphalt-impregnated polyurethane layer is provided on the dartshi panel side of the sound absorbing material.