JPS6335462B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to an improved undercover for a motor vehicle engine.

Conventionally, an undercover has been installed on the underside of the engine compartment of a car to prevent water from getting into the engine while the car is running, and to prevent stones thrown by the tires from hitting the engine. Also, recently, noise emitted from the engine cooling air vent and engine vibration noise have become a problem, so it has been proposed to install sound-absorbing material on the top surface of the undercover to prevent the sound from escaping the vehicle as much as possible. There is.

However, conventional undercovers are generally made of iron plates or synthetic resin, and the sound absorbing material is thick pine such as glass wool, coarse wool felt, recycled felt, etc., and when installed on the undercover, a space is created between the cover and the sound absorbing material. It was a molded felt that was press-molded. Therefore, if a flying pebble or the like hits the lower surface of the undercover, it will make a loud impact sound if it is made of iron, and it may cause damage if it is made of synthetic resin. Furthermore, if the sound absorbing material is made of iron, if water comes into contact with it, the sound absorbing material absorbs water and retains the water, causing corrosion of the iron plate of the undercover, corrosion of the sound absorbing material itself, and a decrease in the sound absorbing effect. I end up. In addition, since molded felt is press-formed, it is expensive, and it also suffers from vibrations and
Due to water absorption, the mat loses its shape and its sound absorbing effect is reduced, and mats such as glass wool, coarse wool felt, and recycled felt must be thick, which increases costs. Therefore, in the present invention, the main body of the undercover is molded from a synthetic resin material, a large number of sound absorption chambers are provided on the upper surface of the undercover, and the openings of the sound absorption chambers of the main body are closed by a sound absorbing body having a sound absorbing material made of relatively thin mat. By doing so, the above-mentioned conventional problems have been solved, and the present invention will be explained below with reference to the illustrated embodiments.

In Figs. 1 to 4, reference numeral 1 denotes the main body of an undercover made of, for example, plastic, which is a synthetic resin material. The inside of each depression 4 has a field wall 5 that stands up integrally from the bottom of the depression and whose upper end substantially coincides with the open top surface of the depression.
It is partitioned into a large number of independent sound absorption chambers 6.

The plastic used to mold the main body is preferably high-density polyethylene, which does not break even at temperatures around -40°C or even when hit by flying pebbles, or cold-resistant, impact-resistant polypropylene. Further, the depth of the sound absorption chamber is approximately 20 mm, and the size of each sound absorption chamber is approximately 100 cm ² in planar area.

All the openings of this sound-absorbing chamber 6 are closed from above with a sound-absorbing body 7. The sound absorbing body is made of a sound absorbing material 8 made of a relatively thin mat of about 10 mm thick such as glass wool, coarse felt, or recycled felt, and a waterproof thin film 9 covering at least one side of the sound absorbing material 8, such as a polyethylene film. Configure.

In this embodiment, the waterproof thin film 9 is formed into a bag approximately the same size as the sound absorbing material 8, and the sound absorbing material is contained in the bag and sealed, so that the waterproof thin film is on both sides of the sound absorbing material. At the same time, the peripheral edge of the sound absorber 7 is the peripheral edge 9' of the bag.
(See Figure 4). This sound absorbing material may be large enough to cover all the openings of the sound absorbing chamber with one piece, or it may be made of multiple pieces with their edges slightly overlapped to close all the openings of the sound absorbing chamber. It may be hot. The sound absorber is fixed to the upper surface of the main body by adhering or fastening rivets to the outer part 4a of the recess 4, the adjacent part 4b between the adjacent recesses 4, 4, or in some cases to the upper end of the partition wall 5 that partitions the inside of the recess 4. This may be done by any means such as , stapling, etc.

The undercover of the present invention constructed in this manner is attached to the chassis or vehicle body 2 at both sides 3 with bolts or fastener rivets so as to be located under the engine, similar to the conventional one. In addition, in the case of this embodiment, the sound absorbing material 8 of the sound absorbing body 7 is covered with a waterproof thin film 9, but since the peripheral edge of the sound absorbing body 7 is formed of a waterproof thin film, even if water gets into the sound absorbing material, the sound absorbing material 8 is covered with a waterproof thin film 9. No reduction in sound absorption effect due to corrosion or water absorption.

Further, an integral field wall 5 and a wall 4' forming a recess are provided.
helps improve the rigidity of the body.

In addition, the sound generated in the engine room consumes energy when vibrating the waterproof thin film of the sound absorber and when passing through the sound absorbing material. Therefore, as shown in Figure 4, the sound waves (arrows) pass through the sound absorber from the engine room while consuming energy, enter each of the small sound absorption chambers, and pass through the air layer inside the sound absorption chamber. The sound then reflects off the interior walls and is considerably attenuated as it passes through the sound absorber again, making it possible to attenuate the noise inside the vehicle and outside the vehicle body.

Incidentally, since the sound is reduced by both the sound-absorbing chamber group containing the air tank and the sound-absorbing body, there is no need to use thick mat as the sound-absorbing material used for the sound-absorbing body, which is advantageous in terms of cost.

Next, FIG. 5 shows another embodiment, in which the main body 1 has high upright walls on both sides 3, and these upright walls are reinforced with a plurality of upward ribs 10 on the inner wall. , is attached to the chassis or vehicle body 2 at the upper end. Both sides of the sound absorbing body 7 have extension parts 7' extending outward from the outer shell 4a of the recess 4, and the extension parts 7' extend upward along the ribs 10 and are attached to the upper end of the upstanding wall protruding outward. The tip is fixed to the portion 11.

In other words, the ribs 10 on the inner surface of the upright wall provide reinforcement and at the same time form a sound absorption chamber on the inner surface of the main body 1, and the extension 7' of the sound absorber closes this from the inner surface to further improve the sound absorption effect.

The waterproof thin film 9 that forms the sound absorbing body together with the sound absorbing material is not limited to a bag, and may be attached to the front and back sides of the sound absorbing material 8 as shown in FIG.
However, if this is fixed to the upper surface of the main body as it is, the sound absorbing material 8 will be exposed at the edges, and when water gets wet, the sound absorbing material will absorb water from the edges. Therefore, in this case, the upper surface of the main body 1 is cut a little larger than the surface to be covered, and the edge 9' is preferably folded downward as shown in the figure, thereby covering the peripheral edge of the sound absorber with the waterproof thin film 9 on either the front or back side. All you have to do is form it and fix it. Furthermore, the edge 9' may be folded and glued in advance before being fixed, or may be fixed while being folded back during fixing.

Furthermore, the waterproof thin film is not limited to being on both the front and back sides of the sound absorbing material 8, but may be simply on the surface that becomes the top surface of the sound absorbing material 8 when it is fixed to the top surface of the main body, as shown in the embodiment of FIG. In this case, the edge 9' is necessarily folded downward, and the thin film 9 forms the peripheral edge of the sound absorber, similar to the embodiment shown in FIG.

As is clear from the above, the present invention is inexpensive, and has high sound absorption performance because it attenuates sound with at least a triple structure of a sound absorption chamber, a sound absorption material, and a waterproof thin film. It is possible to provide an engine undercover that does not cause deterioration, and is particularly effective for use in automobiles equipped with diesel engines that generate high engine noise. In use, it is more effective to attach sound absorbing material to the inner surface of the hood or bonnet that forms the upper surface of the engine compartment, and to the surface facing the engine compartment of the wall that separates the engine compartment from the vehicle compartment (see Figure 1).

[Brief explanation of the drawing]

Fig. 1 is a partially sectional side view of one embodiment of the present invention in use, Fig. 2 is a plan view of a portion of the same, Fig. 3 is an enlarged sectional view of the same, and Fig. 4 is a sound absorption 5 is a sectional view similar to FIG. 3 of another embodiment, FIG. 6 is an enlarged sectional view of a main part of another embodiment, and FIG. 7 is also a sectional view of another embodiment. This is an enlarged cross-sectional view of the main parts of the example. In the figure, 1 is the main body of the undercover, 5 is the partition wall, 6 is the sound-absorbing chamber, 7 is the sound-absorbing body, 8 is the sound-absorbing material, and 9 is the same waterproof thin film.

Claims (1)

[Claims] 1. An engine undercover for an automobile that is located under the engine of the automobile and attached to the lower surface of the engine compartment, which is molded from a synthetic resin material and has a plurality of upper walls formed of an integral partition wall on the upper surface. It consists of a main body having an open sound-absorbing chamber, and a sound-absorbing body having at least one side of the sound-absorbing material covered with a waterproof thin film. An engine undercover for an automobile, characterized in that the opening of the engine is closed with a sound absorbing material to form at least a triple structure of a sound absorbing chamber, a sound absorbing material, and a waterproof thin film. 2. An automobile engine undercover according to claim 1, wherein the sound-absorbing material is enclosed in a bag made of a waterproof thin film, and the peripheral edge of the waterproof thin-film bag forms the peripheral edge of the sound-absorbing bag. engine under cover. 3. In the engine undercover for an automobile according to claim 1, the sound absorbing body is made of a sound absorbing material and a waterproof thin film attached to at least one side of the sound absorbing material, and the sound absorbing body is folded short at the edge to cover the peripheral edge of the sound absorbing body. An automobile engine undercover characterized by being formed of a waterproof thin film adhered to a sound absorbing material.