JPH08319910A - Intake air stack duct - Google Patents

Abstract

PURPOSE: To restrict the vibration whose node is located at a reinforcing bead and to prevent the whole duct from resonating and thus to reduce sound muffled in the room of a vehicle by setting spacings between the centers of the reinforcing beads which are disposed in parallel at unequal intervals. CONSTITUTION: Spacings between the centers of reinforcing beads 9 which are disposed in parallel are set at unequal intervals of P1, P2, P3 and P4. The width of the beads 9 in their parallel direction is equally set at W and the length of them is equally set at L1. This structure reduces tendency to cause the vibration whose nodes are the reinforcing beads 9 and when a pulsation of a specified wavelength is caused by a specified number of revolutions of an engine, some parts of a duct body 6 may resonate but the other parts of them reduces tendency of a resonance, thereby reducing the sound muffled in the room of a vehicle.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an intake stack duct.

[0002]

2. Description of the Related Art Generally, a large vehicle such as a truck has a greater chance of traveling on an unpaved rough road than a passenger vehicle. Therefore, the intake air of the engine is not the air near the ground containing much dust, It is advisable to take in a sufficiently high level of clean air above the ground.

Therefore, in a large vehicle, as shown in FIG. 7, a duct body 6 fixed to a rear panel 5 of a cab 4 is connected to an intake duct 2 of an air cleaner 1 via a boot 3 having flexibility. Then, a hood 7 for preventing rainwater, fallen leaves, etc. from entering the inside of the duct main body 6 is attached to the upper end opening of the duct main body 6 to form an intake stack duct 8 that rises upward. Air is sucked in from the upper part of 8.

By the way, the intake stack duct 8 is
Since it is fixed to the rear panel 5 of the cab 4, the intake pulsation of the engine and the vibration of the engine itself transmitted from the engine through the intake hose (not shown) and the air cleaner 1 are transferred from the intake stack duct 8 to the cab 4. It is transmitted and leads to the generation of muffled sound inside the vehicle.

Therefore, as the intake stack duct 8,
It is necessary to prevent a large resonance point from existing in the frequency band of engine intake pulsation and vibration.
Conventionally, as shown in FIGS. 8 and 9, on the surface of the duct body 6 (the surface of the cab 4 facing the rear panel 5 or other surface), a plurality of reinforcing beads 9 are provided in the longitudinal direction of the duct body 6. Are arranged in parallel, and the reinforcing beads 9 are used to increase the surface rigidity.

[0006]

However, in the intake stack duct 8 as described above, the intervals between the centers of the reinforcing beads 9 for increasing the surface rigidity are set to be P evenly, and Since the width dimensions of the reinforcing beads 9 in the juxtaposed direction are all set to W, vibrations tending to occur at the reinforcing bead 9 are likely to occur, and the frequency of this vibration is the intake air of the engine. When the frequency of the pulsation or vibration matches, the duct body 6 resonates over the entire surface, which has a drawback that the muffled noise in the vehicle interior increases.

In view of the above situation, the present invention is an intake stack duct capable of suppressing the vibration of the reinforcing bead as a node, avoiding resonance on the entire surface of the duct body, and reducing the muffled noise in the vehicle interior. Is to provide.

[0008]

According to a first aspect of the present invention, a plurality of reinforcing beads are juxtaposed on a surface of a duct main body connected to an intake duct of an air cleaner with a required space in the longitudinal direction.
In the intake stack duct in which the duct main body having the reinforcing bead is fixed to a cab, the intervals between the centers of the reinforcing beads arranged in parallel are set to be non-uniform. It is a thing.

A second aspect of the present invention is a duct in which a plurality of reinforcing beads are arranged in parallel on a surface of a duct main body connected to an intake duct of an air cleaner with a required space in the longitudinal direction, and the reinforcing beads are formed. In the intake stack duct in which the main body is fixed to the cab, the width dimension of the reinforcing beads in the juxtaposed direction is set to be non-uniform.

Furthermore, a third aspect of the invention is to form a plurality of reinforcing beads in parallel on the surface of the duct main body connected to the air intake duct of the air cleaner with a required interval in the longitudinal direction. In an intake stack duct in which the duct body is fixed to the cab, the spacing between the centers of the reinforcing beads that are arranged in parallel is set unevenly, and the width dimension of the reinforcing beads in the direction of parallel installation is also set unevenly. The present invention relates to an intake stack duct characterized by the above.

[0011]

In the first aspect of the present invention, if the intervals between the centers of the reinforcing beads arranged side by side are set to be uneven, it becomes difficult for the vibration of the reinforcing beads to occur as a node. When pulsation of a certain wavelength occurs, resonance occurs at some parts of the duct body, but resonance does not easily occur at other parts, and the muffled sound inside the vehicle is reduced.

Further, in the second aspect of the invention, if the width dimensions of the reinforcing beads in the juxtaposed direction are set to be uneven, even if the intervals between the centers of the reinforcing beads are uniform, the resonance on the surface of the duct main body is caused. Since the frequency changes for each part of the reinforcing bead, it is difficult for vibration to occur at the part of the reinforcing bead, and even if a pulsation of a certain wavelength occurs due to a certain engine speed, resonance occurs on the entire surface of the duct body. Will not occur and the muffled noise inside the vehicle will be reduced.

Furthermore, in the third aspect of the invention, when the intervals between the centers of the reinforcing beads to be arranged in parallel are set to be nonuniform, and the width dimensions of the reinforcing beads in the parallel installation direction are also set to be nonuniform, In addition to the uneven spacing between the centers of the reinforcing beads, the resonance frequency on the surface of the duct body changes for each reinforcing bead part, so vibrations with the reinforcing bead parts as nodes are less likely to occur. When pulsation of a certain wavelength occurs due to a certain engine speed, resonance occurs at some parts of the duct main body, but resonance does not occur at other parts, and the muffled sound inside the vehicle is reduced.

[0014]

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

1 and 2 show a first embodiment of the present invention. In the drawings, the parts denoted by the same reference numerals as those in FIGS. 8 and 9 represent the same things, and the basic structure is as shown in FIG. 8 and 9 is the same as the conventional one, but the feature of this embodiment is that, as shown in FIGS. 1 and 2, the spacing between the centers of the reinforcing beads 9 arranged in parallel is P _The points are set to be ₁ , P ₂ , P ₃ , and P ₄ unevenly. The width dimensions of the reinforcing beads 9 in the juxtaposed direction are set uniformly to W. Further, the length dimension is set to L ₁ in all cases.

As described above, when the intervals P ₁ , P ₂ , P ₃ , P ₄ between the centers of the reinforcing beads 9 arranged side by side are set unevenly, the vibration of the reinforcing beads 9 as a node is generated. It is less likely to occur, and the wavelength will be 2P ₁
When the pulsation occurs, the resonance occurs in the portion of the duct body 6 where the distance between the centers of the reinforcing beads 9 is P ₁ , but the resonance does not occur easily in other portions, and the muffled noise in the vehicle is reduced. .

In this way, it is possible to suppress the vibration of the reinforcing bead 9 as a node, avoid the resonance on the entire surface of the duct body 6, and reduce the muffled noise in the vehicle.

FIGS. 3 and 4 show a second embodiment of the present invention. In the drawings, the parts designated by the same reference numerals as those in FIGS. 1 and 2 represent the same parts, and the reinforcing beads 9 are arranged in parallel. The width dimension in the installation direction is set to be W ₁ , W ₂ , W ₃ , W ₄ unevenly. In addition, the intervals between the centers of the reinforcing beads 9 are uniformly set to P. Further, the length dimension is set to L ₂ in all cases.

As shown in FIGS. 3 and 4, the reinforcing bead 9 is used.
If the width dimensions W ₁ , W ₂ , W ₃ , W ₄ in the parallel installation direction are set to be non-uniform, even if the spacing D between the centers of the reinforcing beads 9 is uniform, the resonance frequency on the surface of the duct body 6 is increased. Changes for each part of each reinforcing bead 9, it is less likely to generate vibration with the part of the reinforcing bead 9 as a node, and even if a pulsation with a wavelength of, for example, 2P occurs due to a certain engine speed, the duct body 6 Resonance does not occur on the entire surface, and the muffled sound inside the vehicle is reduced.

Thus, also in the case of the embodiment shown in FIGS. 3 and 4, it is possible to suppress the vibration of the reinforcing bead 9 as a node and avoid the resonance on the entire surface of the duct main body 6, thereby making a muffled noise in the interior of the vehicle. Can be reduced.

FIGS. 5 and 6 show a third embodiment of the present invention. In the drawings, the parts denoted by the same reference numerals as those in FIGS. 1 and 2 represent the same parts, and are arranged in parallel for reinforcement. The intervals between the centers of the beads 9 are set to be P ₁ , P ₂ , P ₃ , and P ₄ unevenly, and the width dimensions of the reinforcing beads 9 in the juxtaposed direction are set to W ₁ , W ₂ , W. They are set to be ₃ , W ₄ , and W _{5 in} an uneven manner. Further, the length dimension is set to L ₃ in all cases.

As shown in FIGS. 5 and 6, the intervals P ₁ , P ₂ , P ₃ , P ₄ between the centers of the reinforcing beads 9 arranged side by side are set unevenly, and the reinforcing beads 9 are arranged in parallel. If the width dimensions W ₁ , W ₂ , W ₃ , W ₄ , W ₅ in the installation direction are set unevenly, the resonance frequency on the surface of the duct body 6 changes greatly for each part of each reinforcing bead 9, so that When the vibration of the bead 9 for reinforcement becomes less likely to occur and a pulsation with a wavelength of, for example, 2P ₁ occurs due to a certain engine speed, resonance occurs at the portion where the interval between the centers of the reinforcing bead 9 is P _1. However, resonance does not occur in other portions, and the muffled noise in the vehicle interior is reduced.

Thus, in the case of the embodiment shown in FIGS. 5 and 6, it is possible to more reliably suppress the vibration of the reinforcing bead 9 as a node and avoid the resonance on the entire surface of the duct main body 6, and thus the interior of the vehicle. The muffled sound can be reduced.

The intake stack duct of the present invention is not limited to the above-mentioned embodiment, and it goes without saying that various modifications can be made without departing from the scope of the present invention.

[0025]

As described above, the first aspect of the present invention is as described above.
According to the intake stack ducts described in 3 to 3, it is possible to suppress the vibration of the reinforcing bead portion as a node, avoid the resonance on the entire surface of the duct main body, and reduce the indoor muffled noise of the vehicle. Can play.

[Brief description of drawings]

FIG. 1 is an external view of a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is an external view of the second embodiment of the present invention.

4 is a sectional view taken along the line IV-IV in FIG.

FIG. 5 is an external view of the third embodiment of the present invention.

6 is a sectional view taken along line VI-VI in FIG.

FIG. 7 is a schematic perspective view of a vehicle including an intake stack duct.

FIG. 8 is an external view of a conventional example.

9 is a sectional view taken along line IX-IX in FIG.

[Explanation of symbols]

 1 Air Cleaner 2 Intake Duct 4 Cab 6 Duct Body 8 Intake Stack Duct 9 Reinforcing Beads

Claims (3)

[Claims] 1. A plurality of reinforcing beads are juxtaposed on a surface of a duct main body connected to an air intake duct of an air cleaner at required intervals in a longitudinal direction, and the duct main body having the reinforcing beads is fixed to a cab. In the air intake stack duct, the air intake stack duct is characterized in that the intervals between the centers of the reinforcing beads arranged in parallel are set unevenly. 2. A plurality of reinforcing beads are juxtaposed on the surface of the duct main body connected to the intake duct of the air cleaner at required intervals in the longitudinal direction, and the duct main body having the reinforcing beads is fixed to the cab. In the intake stack duct as described above, the width dimension of the reinforcing beads in the juxtaposed direction is set to be uneven. 3. A plurality of reinforcing beads are juxtaposed on a surface of a duct main body connected to an intake duct of an air cleaner at required intervals in a longitudinal direction, and the duct main body having the reinforcing beads is fixed to a cab. In the intake stack duct, the air intake is characterized in that the intervals between the centers of the reinforcing beads that are arranged in parallel are set to be uneven, and the width dimensions of the reinforcing beads in the direction of installation are also set to be uneven. Stack duct.