JPH0245480Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a device that prevents noise caused by standing waves generated in a recessed space formed around an engine.

<Prior art> Various auxiliary machines or parts are attached around the engine, and recessed spaces are formed between these auxiliary machines or parts or between these and the engine body, and as the engine operates, concave spaces are formed. Standing waves may be generated in the recessed space of the lever and become one of the sources of noise emitted from the engine to the surroundings.

For this purpose, in the past, as seen in, for example, Japanese Utility Model Publication No. 57-7779 or Japanese Utility Model Application Publication No. 55-14018, the recessed space formed around the engine has been filled with a sound absorbing material. When the recessed space is filled with a sound absorbing material in this way, the recessed space itself no longer exists, thereby preventing the generation of standing waves and reducing noise.

However, with these devices filled with sound absorbing material to prevent standing waves, there is a possibility that the filled sound absorbing material may fall off, or if the shape of the recessed space is complex, it may be difficult to manufacture the sound absorbing material. becomes difficult. Furthermore, as the recess space becomes larger, it is necessary to increase the size of the sound-absorbing material, which also poses a problem in that the economic burden increases.

In order to eliminate such problems, as shown in FIGS. 1 and 2, a plate-shaped body is installed in the recessed space 4 formed between the cylinder block 1, oil pan 2, and flywheel housing 3 of the engine. It is also effective to separate the recessed space 4 into a plurality of spaces by the plate-like body 5.

When the recessed space 4 is divided into a plurality of spaces by the plate-shaped body 5 in this way, the frequency of the standing wave generated in each space can be shifted to the high frequency side, so-called It is effective in reducing noise in harsh areas. However, even in this case, since the noise energy itself is not reduced, there is a problem in that it is not possible to prevent side effects caused by standing waves that have shifted to the high frequency side. In FIGS. 1 and 2, numeral 7 denotes a bolt that tightens and fixes the plate-shaped body 5 to the cylinder block 1 together with the oil pan 2, and 7 denotes a gasket.

<Problem to be solved by the invention> The present invention was made in view of the above-mentioned circumstances, and is a noise prevention method that can effectively prevent standing waves themselves and reduce engine noise without using sound-absorbing materials. The challenge is to provide equipment.

<Means for Solving the Problems> The present invention provides a device for preventing noise caused by standing waves generated in a recess space formed around an engine, in which a plate-like body is provided to partition the recess space. ing. The present invention is characterized in that the plate-like body is provided with a small hole that allows adjacent recess spaces to communicate with each other across the plate-like body.

<Operation> In other words, since the recessed spaces formed around the engine are separated by plate-shaped bodies, it is possible to shift the standing waves generated in the individual recessed spaces to the higher frequency side where they are less harmful. can. In addition, since the adjacent recessed spaces across the plate-like body are kept in communication through the small holes provided in the plate-like member, the standing waves generated in the adjacent recessed spaces can interact with each other via the small holes. The energy of the standing waves is attenuated by friction. Furthermore, if the size of the small holes provided in the plate-shaped body is appropriately selected, the small holes also have a sound absorbing effect, so that noise caused by standing waves can be reduced more effectively.

<Example> Hereinafter, an example of the present invention will be described in detail based on FIG. 3. Note that parts having the same functions as those of the conventional example shown in FIGS. 1 and 2 are designated by the same reference numerals, and detailed explanation thereof will be omitted.

In Figure 3, the engine cylinder block 1, oil pan 2, and flywheel housing 3 are shown.
By attaching the plate-like body 5 to the concave space 4 formed by the plate-like body 5, the concave space 4 is
It is divided into two spaces. Numeral 6 is a bolt for tightening and fixing the plate-like body 5 to the cylinder block 1 together with the oil pan 2, and 7 is a gasket inserted between the joint surface of the cylinder block 1 and the oil pan 2.

By attaching an auxiliary plate 8 having a substantially T-shaped cross section to the lower part of the plate-like body 5, the downward opening area of the recessed space 4 partitioned by the plate-like body 5 is reduced. There is. Further, the plate-shaped body 5
and the auxiliary plate 8 are both made of plate-like rubber, and by providing a large number of small holes 9 in each of the plate-like body 5 and the auxiliary plate 8, the concave spaces adjacent to each other with the plate-like body 5 in between can be connected to the small holes. In addition to maintaining communication via the plate 5 and the auxiliary plate 8, the plate member 5 and the auxiliary plate 8 have a sound absorbing effect.

Therefore, the recessed space 4 formed by the cylinder block 1, oil pan 2, and flywheel housing 3 is divided by the plate-shaped body 5, and the natural frequency of the standing wave in each space becomes high, resulting in a harsh area. noise is reduced.

In addition, since the concave spaces adjacent to each other with the plate-like body 5 in between (spaces partitioned by the plate-like body 5) are maintained in communication via the small holes 9 provided in the plate-like body 5, both spaces The standing waves interfere with each other and are attenuated by friction. For this reason, the noise energy itself due to the standing waves generated in each space is reduced, and the secondary effects due to the standing waves that have shifted to the high frequency side are also avoided.
Furthermore, since the plate-shaped body 5 has a sound absorbing effect by providing the small holes 9, standing waves are more effectively suppressed, and the effect of preventing engine noise is enhanced.

In addition, when the auxiliary plate 8 is attached to the lower part of the plate-like body 5 to reduce the downward opening area of each space as in the embodiment, the confinement effect by the auxiliary plate 8 also acts, causing noise. The prevention effect can be further enhanced. Furthermore, when the plate-like body 5 is made of rubber as in the embodiment, the plate-like body 5
This is advantageous because no secondary noise is generated due to the vibration of the spacer, and since the volume of the isolated recessed space is not specified, the effect of preventing standing waves can be further enhanced.

<Effects of the invention> As is clear from the above explanation, according to the invention, by providing small holes in the plate-shaped body that partitions the recessed space formed around the engine, it is possible to Since adjacent recessed spaces are maintained in communication through the small holes, engine noise due to standing waves can be effectively prevented without using expensive sound absorbing materials.

[Brief explanation of drawings]

FIG. 1 is a schematic side view of an engine showing a conventional example;
FIG. 2 is an enlarged side view of the main parts of the conventional example, and FIG. 3 is an enlarged side view of the main parts showing an embodiment of the present invention. 1...Cylinder block, 2...Oil pan,
3... flywheel housing, 4... recessed space, 5... plate-like body, 6... bolt, 7... gasket, 8... auxiliary plate, 9... small hole.

Claims (1)

[Scope of utility model registration request] In a device that prevents noise caused by standing waves generated in a recessed space formed around an engine, a plate-like body is provided to partition the recessed space, and an adjacent recessed space is provided with the plate-like body interposed therebetween. A noise prevention device for an engine, characterized in that a small hole is provided in the plate-like body to communicate with each other.