JP2015175297A - Air-intake duct - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air-intake duct capable of suppressing the immersion of water into an induction system while making the suppression of size enlargement and the attenuation effect of a sound radiation compatible.SOLUTION: An air-intake duct 10 comprises: a cylindrical body member 11 having an opening 13 in a wall surface; and a cylindrical porous member accommodated in the inside of the body member 11. The body member 11 is equipped with a cover 50 for covering the opening 13 from an upper portion. The cover 50 is equipped with a wound radiation attenuation hole 60.

Description

  The present invention relates to an intake duct constituting an intake system of an in-vehicle internal combustion engine.

2. Description of the Related Art An intake duct that attenuates radiated sound generated in an intake system of an in-vehicle internal combustion engine by configuring a part of a wall surface with a porous member has been conventionally known.
For example, in the intake duct disclosed in Patent Document 1, a cylindrical porous member is accommodated inside a cylindrical main body member that forms the outline of the intake duct. Since an opening is formed in the wall surface of the main body member, the porous member is exposed at a portion where the opening is provided, and the inside and outside of the intake duct are separated from each other via the porous member. In the intake duct disclosed in Patent Document 1, the sound emitted from the intake system is attenuated by ensuring the air permeability by the porous member.

  Further, in the intake duct disclosed in Patent Document 2, an opening is not formed on the wall surface of the main body member, but a space is provided between the main body member and the porous member. In the intake duct disclosed in Patent Document 2, the sound generated in the intake system is attenuated by the air layer formed by this space.

JP 2012-193691 A JP 2003-343373 A

  By the way, in the intake duct disclosed in Patent Document 1, when water is applied to the intake duct, the porous member may be directly exposed to water through the opening, and the water that has permeated the porous member may enter the intake system. is there. On the other hand, in the intake duct disclosed in Patent Document 2, since no opening is formed on the wall surface of the main body member, it is possible to suppress water from splashing on the porous member, and to prevent water from entering the intake system. it can. However, in the air intake duct disclosed in Patent Document 2, it is necessary to provide a sufficiently large space between the main body member and the porous member in order to attenuate the radiated sound. Absent.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to achieve intake air that can suppress water intrusion into the intake system while achieving both suppression of increase in size and securing of an attenuation effect of radiated sound. To provide a duct.

  An air intake duct for solving the above-mentioned problems is one in which a cylindrical porous member is accommodated inside a cylindrical main body member having an opening on a wall surface. In the intake duct, a cover that covers the opening from above is provided on the main body member, and a radiation sound attenuation hole is provided in the cover.

  According to the above configuration, when the water is applied to the intake duct, it is possible to suppress the water from being directly applied to the porous member by the cover. Moreover, since the radiation sound attenuation hole is provided in the cover, the radiation sound is attenuated when passing through the radiation sound attenuation hole. For this reason, even if the space between the cover provided on the main body member and the porous member is not large, a sufficient radiated sound attenuation effect can be obtained. Accordingly, it is possible to suppress the intrusion of water into the intake system while achieving both the suppression of the increase in size of the intake duct and the securing of the radiation sound attenuation effect.

The perspective view which shows the air intake duct as one Embodiment. The disassembled perspective view of the main body member and porous member which comprise an air intake duct. The top view of an intake duct. The perspective view which shows the cross section along line 4-4 of FIG. The perspective view which expands and shows the cross section of the site | part similar to FIG. 4 of the main body member in another example. The perspective view which expands and shows the cross section of the site | part similar to FIG. 4 of the main body member in another example.

Hereinafter, an embodiment of an intake duct will be described with reference to FIGS.
As shown in FIG. 1, the intake duct 10 includes a cylindrical main body member 11 that forms an outer shell, and a cylindrical porous member 31 that is accommodated inside the main body member 11. Both the main body member 11 and the porous member 31 are made of resin such as polyethylene. The intake duct 10 is connected upstream of the air cleaner of the in-vehicle internal combustion engine.

  As shown in FIG. 2, the main body member 11 is formed by combining a half-cylindrical first main body member 12 and a second main body member 22. The first main body member 12 and the second main body member 22 are formed with main body ribs 14 and 24 extending in the axial direction, respectively. The first main body member 12 constitutes an upper outline of the intake duct 10, and the second main body member 22 constitutes a lower outline of the intake duct 10. A plurality of openings 13 and 23 are formed on the wall surfaces of the first main body member 12 and the second main body member 22, respectively.

  As shown in FIG. 2, the cylindrical porous member 31 is formed by combining a half cylindrical first porous member 32 and a second porous member 42. Porous ribs 34 and 44 extending in the axial direction are formed on the first porous member 32 and the second porous member 42, respectively. In addition, the 1st porous member 32 and the 2nd porous member 42 are formed by pressing a resin-made nonwoven fabric sheet. The first porous member 32 constitutes the upper wall surface of the porous member 31, and the second porous member 42 constitutes the lower wall surface of the porous member 31.

  The end portion 32a located on the left side in FIG. 2 of the first porous member 32 and the end portion 42a located on the left side in FIG. 2 of the second porous member 42 each have a semicircular shape. Moreover, the end part 32b located on the right side in FIG. 2 of the first porous member 32 and the end part 42b located on the right side in FIG. 2 of the second porous member 42 are also semicircular. Therefore, when the first porous member 32 and the second porous member 42 are combined, the end portion 32 a and the end portion 42 a are combined to form a circular opening at the end portion 31 a of the porous member 31. Similarly, the end portion 32 b and the end portion 42 b are combined to form a circular opening at the end portion 31 b of the porous member 31.

  The first porous member 32 and the second porous member 42 are accommodated between the first main body member 12 and the second main body member 22 in a state where the porous rib 34 and the porous rib 44 are abutted. Here, the porous ribs 34 and the porous ribs 44 are sandwiched between the main body ribs 14 and 24 in a state where they are abutted. The main body ribs 14, 24 are fitted together with the porous ribs 34, 44 held between the main body ribs 14, 24, and the main body ribs 14, 24 are engaged with each other, whereby the first main body member 12 and the second main body member 22 are engaged. Are integrated to form the main body member 11, and the porous member 31 is accommodated in the main body member 11.

  As shown in FIG. 3, the first main body member 12 of the main body member 11 is provided with a cover 50 that covers the opening 13 from above. The cover 50 of the present embodiment has a curved shape along the outer peripheral surface of the first main body member 12. Further, the cover 50 of the present embodiment is provided so as to cover two openings 13 closest to the upstream end 10a of the intake duct 10 from above among the openings 13 in the first main body member 12. Yes. The portion provided with the cover 50 is a portion that is particularly located above the intake duct 10 when the intake duct 10 is attached to the vehicle-mounted internal combustion engine and mounted on the vehicle. It is an easy-to-hang part.

  As shown in FIGS. 3 and 4, the cover 50 is provided with a circular radiated sound attenuation hole 60. Thereby, the inside and the outside of the main body member 11 communicate with each other through the radiated sound attenuation hole 60. Four radiated sound attenuation holes 60 of the present embodiment are provided side by side along the axial direction of the main body member 11. The radiated sound attenuation hole 60 has a diameter of about 3 to 5 millimeters and has a smaller opening area than the opening 13 in the first body member 12 and the opening 23 in the second body member 22.

  As shown in FIG. 4, the cover 50 has a rib 51 extending toward the first porous member 32. The tips of the ribs 51 are in contact with the outer peripheral surface of the first porous member 32 covered with the first main body member 12. The rib 51 is provided at an intermediate portion in the circumferential direction of the cover 50. Therefore, the cover 50 having the ribs 51 has a T-shaped cross section in the direction orthogonal to the axial direction of the main body member 11 as shown in FIG.

Next, the operation of the intake duct 10 will be described.
In the present embodiment, as described above, the cover 50 is provided in a portion where water is easily applied. Therefore, it is possible to suppress water from being directly applied to the porous member 31 through the opening 13 of the first main body member 12, and to prevent water from penetrating the porous member 31 and entering the intake system.

  Further, since the radiated sound attenuation hole 60 is provided in the cover 50, the radiated sound is attenuated when passing through the radiated sound attenuation hole 60. For this reason, even if the space between the main body member 11 including the cover 50 and the porous member 31 is not large, a sufficient radiated sound attenuation effect can be obtained.

According to the intake duct 10 described above, the following effects can be achieved.
(1) When water is applied to the intake duct 10, it is possible to prevent the cover 50 from directly applying water to the porous member 31. Further, since the radiated sound attenuation hole 60 is provided in the cover 50, the radiated sound is attenuated when passing through the radiated sound attenuation hole 60. For this reason, even if the space between the cover 50 provided on the main body member 11 and the porous member 31 is not large, a sufficient radiated sound attenuation effect can be obtained. Accordingly, it is possible to suppress the intrusion of water into the intake system while achieving both the suppression of the increase in size of the intake duct 10 and the securing of the radiation sound attenuation effect.

  (2) When a water droplet falls on the porous member 31, water pressure is applied to the porous member 31 due to a drop that has dropped the water droplet. In the present embodiment, since a large space is not required between the porous member 31 and the cover 50, even if water drops fall through the radiation sound attenuation hole 60 of the cover 50 and water is splashed on the porous member 31, At that time, the water pressure acting on the first porous member 32 due to the drop from the cover 50 to the first porous member 32 becomes small. Therefore, in the intake duct 10 of the present embodiment, even if a water droplet falls on the porous member 31 through the radiated sound attenuation hole 60, it is difficult for water to penetrate into the porous member 31.

  (3) Since the cover 50 is in contact with the outer peripheral surface of the porous member 31 via the rib 51, the cover 50 is reinforced by the rib 51, while most of the outer peripheral surface of the porous member 31 can be opened. . For this reason, the air permeability of the porous member 31 can be ensured while ensuring the rigidity of the cover 50, and a sufficient attenuation effect of the radiated sound generated in the intake system can be obtained.

It should be noted that the above-described embodiment can be implemented with the following modifications.
The frequency of the radiated sound that can be effectively attenuated varies depending on the size and shape of the radiated sound attenuating hole 60 and the interval between adjacent radiated sound attenuating holes 60. Therefore, the size, shape, interval, and the like of the radiated sound attenuation hole 60 can be appropriately changed according to the frequency of the radiated sound to be attenuated. For example, as shown in FIG. 5, the length of the body member 11 in the axial direction is 3 millimeters, and the length of the body member 11 in the circumferential direction is 10 millimeters. The radiated sound attenuation holes 160 may be provided in the cover 150 at intervals of 10 millimeters. In such a case, a high attenuation effect is exhibited with respect to a radiated sound having a relatively high frequency of 1000 Hz to 3000 Hz. Moreover, as shown in FIG. 6, the length of the main body member 11 in the axial direction is 20 millimeters, and the length of the main body member 11 in the circumferential direction is 5 millimeters. When the radiated sound attenuation hole 260 is provided in the cover 250, a high attenuation effect is exhibited with respect to a radiated sound having a relatively low frequency of 100 Hz to 400 Hz.

  As shown in FIGS. 5 and 6, the cover 50 may be provided with two ribs 51, or the cover 50 may be provided with three or more ribs 51. However, as the number of ribs 51 is increased, the outer peripheral surface of the first porous member 32 is covered by the ribs 51, and thus it is difficult to ensure air permeability. Therefore, the number of ribs 51 is preferably changed within a range in which the air permeability of the first porous member 32 can be secured.

  -The arrangement | positioning position of the cover 50 in the 1st main body member 12 can be set freely. Moreover, the range which covers the opening part 13 by the cover 50 among the 1st main body members 12 can also be set freely.

The number of radiated sound attenuation holes 60, 160, 260 in the covers 50, 150, 250 can be freely changed within a range in which the radiated sound attenuation effect can be obtained.
-The shape of the 1st main body member 12 and the 2nd main body member 22 is not restricted to a half cylinder shape, A shape may mutually differ. In short, if the cylindrical main body member 11 can be formed by combining the first main body member 12 and the second main body member 22, the shapes of the first main body member 12 and the second main body member 22 can be freely set. It can be set.

  In addition, the main body member 11 may be composed of a single part having a cylindrical shape as a whole, or the number of parts constituting the main body member 11 may be three or more. In short, the same effect as that of the above embodiment can be obtained by covering the opening of the upper part of the body member 11 with the cover 50 from above.

-If the main body member 11 is a cylinder shape, such as a rectangular cylinder shape, the cross-sectional shape will not be limited.
-The shape of the 1st porous member 32 and the 2nd porous member 42 is not restricted to a half cylinder shape, The shape may mutually differ. In short, if the cylindrical porous member 31 can be formed by combining the first porous member 32 and the second porous member 42, the shapes of the first porous member 32 and the second porous member 42 can be freely set. It can be set.

-Moreover, the porous member 31 may consist of one part which makes the whole cylindrical shape, and the part which comprises the porous member 31 may be three or more.
The shape of the porous member 31 is not limited to a cylindrical shape, and is not limited as long as the porous member 31 has a cylindrical shape such as a rectangular cylindrical shape.

  DESCRIPTION OF SYMBOLS 10 ... Air intake duct, 11 ... Main body member, 12 ... 1st main body member, 13, 23 ... Opening part, 22 ... 2nd main body member, 31 ... Porous member, 32 ... 1st porous member, 42 ... 2nd porous member, 50, 150, 250 ... cover, 51 ... rib, 60, 160, 260 ... radiated sound attenuation hole.

Claims (1)

In an intake duct that houses a cylindrical porous member inside a cylindrical main body member having an opening on the wall surface,
A cover is provided on the main body member to cover the opening from above,
An intake duct, wherein the cover is provided with a radiation sound attenuation hole.