JPH07293373A - Air intake hose - Google Patents

Abstract

PURPOSE:To reduce an air intake sound or a pulsation sound with an intake hose proper, while preventing an increase in intake resistance. CONSTITUTION:The air drawn into a hose body 1 formed out of the body 1 itself having a bent section 10, and a sponge layer 2 laid on the internal surface of the section 10 at least faced to an intake air flow, collides with the layer 2 and the vibrations of the intake air are absorbed by the sponge layer 2. The occurrence of a noise can, therefore, be effectively prevented, due to sound attenuation resulting from the vibration absorption.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake hose such as an air cleaner hose arranged between an air cleaner of an automobile and an engine, and more particularly to an intake hose having a sound deadening function.

[0002]

2. Description of the Related Art As a material for an intake hose used for an intake system of an automobile engine, it is desirable that the intake hose is resistant to and absorbs vibrations from the engine and the vehicle body. The elastic body of is used. On the other hand, the vibration of air generated in the intake stroke of the engine resonates in the intake hose, so that noise called intake sound or pulsating sound is emitted from the intake port of the intake hose. However, although the intake hose formed of an elastic body such as rubber or thermoplastic elastomer has a vibration damping effect, it is difficult to absorb noise due to resonance, and the noise cannot be reduced.

Therefore, when quietness is required,
An intake resonator is arranged in an intake system of a vehicle, and noise at a specific frequency is reduced by applying the Helmholtz resonance principle.

[0004]

However, when the intake resonator is arranged, the space in the engine room is extremely narrowed, and the number of assembling steps and the number of parts are large, which causes a problem in terms of cost. On the other hand, a sound absorbing material such as glass wool, which is porous and highly breathable, is generally used to absorb sound (vibration of air) and prevent diffusion, thereby lowering the sound pressure level. However, when such a sound absorbing material is arranged in the intake hose, noise is reduced but intake resistance increases.

The present invention has been made in view of the above circumstances, and an object thereof is to reduce intake noise and pulsation noise by the intake hose itself while preventing an increase in intake resistance as much as possible.

[0006]

An intake hose of the present invention for solving the above-mentioned problems has a hose body made of rubber or thermoplastic elastomer having a bent portion and formed on at least an inner peripheral surface of the bent portion facing the intake flow. And a sponge layer that is formed. As the sponge layer, it is desirable to use a sponge having a high sound absorption coefficient and a wide frequency band and good sound absorption characteristics. As a sponge like this,
For example, there is a porous material having open cells and a high density.

The thickness of the sponge layer is 5 to 20 mm
Can be If the thickness is too thin, the sound absorption characteristics deteriorate, and if it becomes too thick, not only the sound absorption characteristics deteriorate but also the possibility of intake resistance increases, which is not preferable. It is desirable that the hose body is provided with an enlarged diameter portion and the bent portion is formed in the enlarged diameter portion. By doing so, the inner diameter of the sponge layer can be made equal to the inner diameter of the general portion of the hose body other than the expanded diameter portion, and an increase in intake resistance can be avoided.

[0008]

In the intake hose of the present invention, the sponge layer is provided on the inner peripheral surface of the bent portion of the hose body at a position facing the intake flow. Therefore, since the intake flow sucked into the hose body surely collides with the sponge layer, the vibration of the intake flow is transmitted to the sponge layer and is absorbed by the sponge layer. As a result, the sound is attenuated and the generation of noise can be prevented.

If the bent portion is provided in the expanded diameter portion, the sponge layer can be accommodated in the expanded diameter portion, and the sponge layer can be prevented from becoming an intake resistance.

[0010]

EXAMPLES The present invention will be specifically described below with reference to examples. (Embodiment 1) FIG. 1 is an overall view showing a half section of an intake hose of an embodiment of the present invention, and FIG. 2 is a sectional view taken along line AA of FIG.

The intake hose is an air cleaner hose that connects an automobile engine and an air cleaner, and has one end connected to the air cleaner and the other end connected to an electronically controlled fuel injection device. The hose body 1 is made of resin, and the bellows portion 1 for deforming the bent portion 10 is provided.
1 is formed. The inner diameter of the bellows portion 10 is 15 mm larger than the inner diameter of the general portion.

A cylindrical sponge layer 2 is adhered to the inner peripheral surface of the bent portion 10. The sponge layer 2 is made of an open-cell porous material and has a thickness of 10 mm. In the intake hose of this embodiment, the intake flow sucked into the hose body 1 from the direction of the arrow in FIG. Therefore, the vibration of the intake air is surely transmitted to the sponge layer 2 and absorbed by the sponge layer 2. As a result, the intake sound and the pulsating sound are attenuated and the generation of noise is prevented. (Embodiment 2) In Embodiment 1, the sponge layer 2 is provided only on the bent portion 10, but the sponge layer 2 may be extended and provided on the bellows portion 11 as shown in FIG. By doing so, the chances of contact between the intake air and the sponge layer 2'increases, and noise can be further prevented.

Moreover, in the present embodiment, the bellows portion 11 is in a state of being expanded in diameter. Therefore, the sponge layer 2'is accommodated in the expanded diameter portion, and the increase in intake resistance is suppressed to the minimum. Of course, it is needless to say that if the bent portion 10 is also formed in the enlarged diameter portion, the increase in intake resistance can be further suppressed. (Comparative Example) Example 1 except that the sponge layer 2 was not provided.
An intake hose having the same structure as the above was manufactured. (Test Example) The intake hoses of Example 1 and the comparative example configured as described above were mounted on an engine dynamo and swept up to 1000 to 6000 rpm under a full load condition, and the sound pressure level of noise generated at the intake port was changed to The number of rotations was measured respectively. The results are shown in Fig. 4.

From FIG. 4, it is clear that the intake hose of Example 1 is more noise-proof than the comparative example, and it is clear that this is due to the presence of the sponge layer 2.

[0015]

That is, according to the intake hose of the present invention,
Noise can be reduced only by providing a sponge layer on at least the bent portion. Therefore, it is advantageous in terms of space as compared with the case where a conventional intake resonator is provided, the increase in intake resistance is small, and the intake hose itself can reduce noise such as intake noise and pulsation noise.

[Brief description of drawings]

FIG. 1 is a front view showing a half section of an intake hose according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a front view showing a half section of an intake hose according to a second embodiment of the present invention.

FIG. 4 is a graph showing the relationship between the number of revolutions of the engine dynamo and the sound pressure level and showing the noise measurement results of the intake hoses of the example and the comparative example.

[Explanation of symbols]

1: Hose body 2: Sponge layer 1
0: bent part

Claims (2)

[Claims] 1. An intake hose comprising a hose body having a bent portion and made of rubber or thermoplastic elastomer, and a sponge layer formed on at least an inner peripheral surface of the bent portion facing the intake flow. . 2. The intake hose according to claim 1, wherein the hose body has an enlarged diameter portion, and the bent portion is formed in the enlarged diameter portion.