FIELD OF INVENTION

The present invention relates to an intake duct structure for a vehicle.

BACKGROUND OF THE INVENTION

It is known that an intake duct structure for a vehicle includes a duct body with an opening into which an outside air flows in a bottom plate and an intake cover which constitutes a flow path from the front of the vehicle to the opening along with the bottom plate, as is disclosed in Japanese Laid-open Publication No. JP2020-131889A1 hereinafter called PTL1.

In order to prevent the water droplets from the front and the water from below flowing into the intake unit, the duct body includes a front end surface formed at the front side of the opening and a front end portion of the bottom plate that extends from the front end surface to the opening as well as the intake cover includes a flange which is inclined downward and overlaps with the front end portion when viewed from above.

In PTL1, since the opening is exposed in the flow path through which water passes, there is a possibility that the water which comes from above via the gap between vehicle parts (such as hood) flows into the opening when the vehicle is been washing or is running through the rain.

Moreover, in order to prevent the water that comes with the air from the front from flowing into an inlet port, it is known that an intake guide structure for a vehicle includes the longitudinal wall member which is formed inside the intake guide structure and projected rearward so as to cover the inlet port from the front, as is disclosed in International Publication No. WO2016/135972A1 hereinafter called PTL2.

In PTL2, in order to separate the water from the air, a labyrinth passage is formed inside the intake guide structure by longitudinal wall member and so on. The labyrinth passage causes an increase of a friction resistance which affects the performance of an airflow of the intake unit. In particular, the better performance of the intake unit will be necessary upon the spec of engine capacity.

Therefore, the development of the intake duct structure which prevents the water from upper, front and bottom directions of the intake unit, as well as decreases the friction resistance which is caused by the labyrinth passage, is required. CITATION LIST Patent Literature

PTL 1: Japanese Laid-open Publication No. JP2020-131889A1 PTL 2: International Publication No. WO2016/135972A1

SUMMARY OF THE INVENTION

It is an objective of the present invention to provide an intake duct structure for a vehicle which prevents the water from upper, front and lower directions of the intake duct structure and suppresses the increase of a friction resistance of the outside air which is sucked by the air intake unit.

In order to achieve the above objective, an embodiment of the present invention provides an intake duct structure for a vehicle comprising: a duct member that is positioned within an engine room, mounted to the vehicle and, connected to an intake unit; and a bottom cover that is positioned below the duct member and mounted to the vehicle, so that an air flowing in from a front side of the engine room goes to the intake unit through the duct member and the bottom cover, wherein the duct member includes a first wall and a second wall which are arranged to be straight downward and parallel from each other, and the first wall is arranged at the frontward of the second wall with respect to the vehicle front-rear direction wherein the bottom cover includes a downward surface that is arranged to be inclined downward to the front direction of the vehicle and to be faced to the first wall and the second wall, wherein a first space portion is formed between an outer end of the first wall and the downward surface, and a second space portion is formed between an outer end of the second wall and the downward surface, and wherein a lower end of the first wall is positioned lower than a lower end of the second wall.

According to the embodiment of the present invention, firstly, the first wall is arranged to be straight downward and at the frontward of the second wall with respect to the vehicle front- rear direction. If the water comes from the upper direction of the intake duct structure, the first wall can lead the water to flow to the downward surface of the bottom cover.

Since the downward surface faces to the first wall and is arranged to be inclined downward to the front direction of the vehicle, the water flows down on the downward surface. As such, the water is drained from the intake duct structure.

Secondly, the second wall is arranged at the rearward of the first wall with respect to the vehicle front-rear direction to be straight downward and parallel with the first wall as well as faces to the downward surface of the bottom cover. If the outside air with the water comes from the front direction of the intake duct structure, the outside air from the front direction of the intake duct structure passes through the first space portion, and then flows to the downward surface. After that, the water flowing in the intake duct structure with the outside air collides with the downward surface, and then the flow of the water changes in the oblique upper direction and collides with the second wall.

Since the second wall is straight downward, the second wall makes the water collide with and drop on the downward surface of the bottom cover. As such, the water is drained from the intake duct structure.

Thirdly, the bottom cover is a member that is positioned below the duct member. If the water comes from the lower direction of the intake duct structure, it is possible that the bottom cover prevents the water from the lower direction from flowing to the intake duct structure.

Fourthly, since the lower end of the first wall is positioned lower than the lower end of the second wall, the lower end of the first wall makes the water from the upper direction drop in opposite direction to the intake unit. Even if a small amount of water goes to the intake unit direction, it is possible to be blocked by the second wall which provides the same effect as the first wall.

Moreover, since the lower end of the first wall is positioned lower than the lower end of the second wall, it is possible to arrange the first and second space portions to be followed the direction of the downward surface of the bottom cover. The outside air from the front direction of the intake duct structure can smoothly flow between the lower end of the first wall and the downward surface and between the lower end of the second wall and the downward surface, into the intake unit. As such, since there is no need to form a labyrinth passage in the intake duct structure, it is possible to suppress the increase of a friction resistance of the outside air which is sucked by the air intake unit.

Therefore, the intake duct structure for the vehicle of the embodiment of the present invention, can prevent the water from upper, front and lower directions of the intake duct structure and suppress the increase of a friction resistance of the outside air which is sucked by the air intake unit.

In the intake duct structure for the vehicle of the embodiment of the present invention, the bottom cover includes at least one drain hole and at least one cover portion, and the cover portion is formed to cover the space above the drain hole from the top, side, and rear directions, for the vehicle front-rear direction. Though the duct member prevents the water comes from the lower direction of the intake duct structure from flowing to the intake duct structure, there is a possibility that water flows into the bottom cover via the drain hole.

According to the intake duct structure of the embodiment of the present invention, since the cover portion is formed to cover the space above the drain hole from the top, side, and rear directions for the vehicle front- rear direction, it is possible to prevent the water from the lower direction of the intake duct structure from passing through the drain hole because the cover portion acts as a barrier member. Therefore, the intake duct structure for the vehicle of the embodiment of the present invention, can prevent the water from the lower directions of the intake duct structure from flowing to the intake duct structure.

Moreover, though there is a possibility that the drain hole reduces the strength of the structure due to the material shortage, the cover portion can improve the strength of the structure.

In the intake duct structure for the vehicle of the embodiment of the present invention, the bottom cover includes a plain surface that is arranged so as to extend horizontally toward the rear of the vehicle, and an upward surface that is arranged so as to incline upward from the plain surface to the downward surface and connect to the rear end of the downward surface.

According to the intake duct structure of the embodiment of the present invention, since the upward surface is formed to incline upward from the plain surface to the downward surface and connect to the rear end of the downward surface, it is possible to arrange a top portion of the bottom cover located between the downward surface and the upward surface so that it is difficult for the water to flow against the gravity from lower to higher positions, thereby the water is difficult to flow into the intake unit.

Therefore, the intake duct structure of the embodiment of the present invention can prevent the water from flowing into the intake unit. In the intake duct structure for the vehicle of the embodiment of the present invention, the duct member includes an upper duct panel and a lower duct panel which are attached each other from upper and lower directions, and the lower duct panel is arranged to be parallel with the downward surface.

Once the outside air from the front direction of the intake duct structure flows to the downward surface, collides with the downward surface, and then the air flow changes in the oblique upper direction.

According to the intake duct structure of the embodiment of the present invention, since the lower duct panel is arranged to be parallel with the downward surface, the air can more smoothly flow into the intake unit because there is no need to form a labyrinth passage in the intake duct structure.

Therefore, the intake duct structure for the vehicle of the embodiment of the present invention, can suppress the increase of a friction resistance of the outside air which is sucked by the intake unit and improve the performance of the intake unit.

In the intake duct structure for the vehicle of the embodiment of the present invention, the first wall is positioned to cover a front side and lateral sides of the second wall for the vehicle front-rear direction.

According to the intake duct structure of the embodiment of the present invention, the first wall can prevent the water which comes from the upper direction of the intake duct structure from flowing into the intake duct structure from the front and both sides of the duct member.

Therefore, the intake duct structure of the embodiment of the present invention can more surely prevent the water from flowing into the intake unit.

In the intake duct structure for the vehicle of the embodiment of the present invention, the drain hole is positioned between the upward surface and the plain surface.

As the upward surface inclines upward from the plain surface to the downward surface, the water flows down to the plain surface if the water reaches at the higher position than the top portion of the upward surface.

According to the intake duct structure of the embodiment of the present invention, since the drain hole is positioned between the upward surface and the plain surface formed to extend horizontally toward the rear of the vehicle, the water can be easily drained from the drain hole to the outside of the bottom cover.

Therefore, the intake duct structure of the embodiment of the present invention can furthermore surely prevent the water from flowing into the intake unit.

BRIEF DESCRIPTION OF DRAWINGS

The principle of the present invention and its advantages will become apparent in the following description taking in consideration with the accompanying drawings in which:

FIG.1 is a perspective view of a vehicle front portion when viewed from diagonally forward and above, including an intake duct structure 10 according to an embodiment of the present invention;

FIG.2 is a cross sectional view taken along line II-II of FIG.1 ;

FIG.3 is a cross sectional view taken along line III-III of FIG.2; FIG.4 is a perspective view of the intake duct structure 10;

FIG.5 is a cross sectional view taken along line V-V of FIG.4;

FIG.6A is a perspective view of a bottom cover 50 when viewed from above;

FIG.6B is an enlarged view of a portion X surrounded by the dashed rectangle of FIG.6A.

DETAILED DESCTIPTION OF EMBODIMENTS OF THE INVENTION

Hereinafter, an embodiment of the present invention will be described in detail with reference to FIG.l to FIG.6B.

In the following detailed description, relative positional terms such as “front”, “rear”, “right” and “left” of a vehicle front structure correspond to those directions considered from the vantage point of a driver, seated in the driver's seat and facing forwardly.

As shown in FIG.l, a vehicle front portion includes a vehicle body 2 and a grille 3. Inside the front part of the vehicle body 2, the engine room 4 is provided to accommodate an engine 8, an intake unit 5, an intake duct structure 10, etc. The grille 3 is arranged at the front part of the vehicle 1 and is a member for taking in the outside air from the outside into a radiator (not shown) and an engine room 4 and for cooling them. The grille 3 is also used as an air inlet for an air conditioner.

The intake duct structure 10 is positioned within the engine room 4, mounted to the vehicle 1 and, connected the intake unit 5 so as to guide the outside air taken in through the grille 3 to the intake unit 5.

As shown in FIG.2, the intake duct structure 10 guides the outside air taken into the intake unit 5 through a grille opening section 3 a of the grille 3 from the front direction of the intake duct structure 10, but the water accompanies the outside air. The intake duct structure 10 according to the embodiment has a function of preventing the water from flowing into the intake unit 5, as described later.

With respect to the water separated and removed by the intake duct structure 10, as the water flows in through gaps located above the intake duct structure 10, for example, the gap between the vehicle body 2 and the hood 6, the water comes not only from front and lower directions of the intake duct structure 10 but also an upper direction of the intake duct structure 10.

The intake duct structure 10 includes a duct member 20 that is mounted to the vehicle 1 and connected the intake unit 5, and a bottom cover 50 that is positioned below the duct member 20 and mounted to the vehicle 1, so that the outside air flowing in from a front side of the engine room 4 through the grille 3 goes to the intake unit 5 through the duct member 20 and the bottom cover 50;

The duct member 20 includes an upper duct panel 30 and a lower duct panel 40 which are attached each other from upper and lower directions. A passage is formed between the upper duct panel 30 and the lower duct panel 40. By passing the air through the inside of the passage, the air is guided from the front direction of the intake duct structure 10 to the intake unit 5.

The duct member 20 includes a first wall 34 and a second wall 36 which are arranged to be straight downward and parallel from each other, in the front portion of the duct member 20. The first wall 34 is arranged at the frontward of the second wall 36 with respect to the vehicle front-rear direction.

The duct member 20 is provided with mounting portions 44,44 so that the duct member 20 can be fixed to a cross frame 7 of the engine room 4, and the duct member 20 can be attached to the vehicle 1 by each fastening member 46 such as a bolt inserted through the mounting portions 44.

In order to fix the upper duct panel 30 and the lower duct panel 40, the upper duct panel 30 is provided with catch members 32 which are protrusions having a substantially rectangular cross section, and the lower duct panel 40 is provided with a clip member 42 like a plate spring, which includes a clip member opening 42a. The clip member opening 42a is formed so as to be engageable with the catch member 32 according to the position and shape of the catch member 32.

The bottom cover 50 is a substantially rectangular member when viewed from above (See FIG.6A) and has a function that the outside air taken in from the grille 3 is flown to the duct member 20.

As a bottom surface 52 of the bottom cover 50, the bottom cover 50 includes a downward surface 54 that is arranged to be inclined downward to the front direction of the vehicle 1 , a plain surface 60 that is arranged so as to extend horizontally toward the rear of the vehicle 1, and an upward surface 62 that is arranged so as to incline upward from the plain surface 60 to the downward surface 54 and connect to the rear end of the downward surface 54. The downward surface 54 is arranged so as to be faced to the first wall 34 and the second wall 36.

As shown in FIG.2 and FIG.5, for the purpose of preventing the water from flowing into the intake unit 5, a top portion 64 of the bottom cover 50 located between the downward surface 54 and the upward surface 62 is arranged so that it is difficult for the water on the bottom cover 50 to flow against the gravity from lower to higher positions, thereby the water is difficult to flow into the intake unit 5.

As shown in FIG.6A and FIG.6B, the bottom surface 52 of the bottom cover 50 includes drain holes 56 and cover portions 58. The cover portion 58 is formed to cover the space above the drain hole 56 from the top, side, and rear directions, for the vehicle front- rear direction. As such, though there is a possibility that the drain hole 56 reduces the strength of the structure due to the material shortage, the cover portion 58 can improve the strength of the structure.

The drain hole 56 is positioned between the upward surface 62 and the plain surface 60 formed to extend horizontally toward the rear of the vehicle 1. As such, the water can be easily drained from the drain hole 56 to the outside of the bottom cover 50.

Moreover, the bottom cover 50 includes a pair of side walls 52a, 52a and a rear wall 52b provided so as to surround the periphery of the bottom surface 52 and stand up from the bottom surface 52. The rear wall 52b of bottom cover 50 is provided with mounting portions 66,66 so that the bottom cover 50 can be fixed to a cross frame 7 of the engine room 4, and the bottom cover 50 can be attached to the vehicle 1 by each fastening member 68 such as a bolt inserted through the mounting portion 66.

As shown in FIG.3, when the duct member 20 is attached to the bottom cover 50, an opening portion is formed between the downward surface 54 of the bottom cover 50 and the duct member 20 to allow outside air to be taken in when viewed form the front of the vehicle 1.

Next, Moreover, referring to FIG. 1 to FIG. 5, the position relation between the duct member 20 and the bottom cover 50 will be provided.

As mentioned above, the first wall 34 and the second wall 36 of the duct member 20 are arranged to be straight downward and parallel from each other as well as the first wall 34 is arranged at the frontward of the second wall 36. As such, as shown in FIG.5, a first space portion 70 is formed between an outer end of the first wall 34 and the downward surface 54, and a second space portion 72 is formed between an outer end of the second wall 36 and the downward surface 54. In this embodiment, the shape of the first space portion 70 is formed to correspond to the shape of the second space portion 72.

As shown in FIG.4, the first wall 34 is positioned to cover a front side 36a and lateral sides 36b, 36b of the second wall 36 for the vehicle front- rear direction, so that the first wall 34 can prevent the water which comes from the upper direction of the intake duct structure 10 from flowing into the intake duct structure 10 from the front and both sides of the duct member 20. Moreover, the lower duct panel 40 of the duct member 20 is arranged to be parallel with the downward surface 54 of the bottom cover 50. Namely, A tangent plane PI of a lower duct panel upper surface 40a of the lower duct panel 40 is arranged to be parallel with a tangent plane P2 of a downward surface upper surface 54a of the downward surface 54, so that the outside air can smoothly flow into the intake unit 5.

Next, referring to FIG.5, the operation of the intake duct structure 10 will be provided. It is noted that an arrow with a solid line in FIG.5 represent the flow of the outside air A, and an arrow with a dashed line represent the flow of the water W 1 , and an arrow with a dashed- dotted line represent the flow of the water W2.

(1) Case where the water W1 comes from above the intake duct structure 10

As the water W1 flows in through gaps located above the intake duct structure 10, for example, the gap between the vehicle body 2 and the hood 6, the water W1 which comes from above via the gap flows into the intake duct structure 10 when the vehicle 1 is been washing or is running through the rain.

The first wall 34 is arranged to be straight downward and at the frontward of the second wall 36 with respect to the vehicle front- rear direction. If the water W1 comes from the upper direction of the intake duct structure 10, the first wall 34 can lead the water W1 to flow to the downward surface 54 of the bottom cover 50.

Since the downward surface 54 faces to the first wall 34 and is arranged to be inclined downward to the front direction of the vehicle 1, the water W1 flows down on the downward surface 54. As such, the water W1 is drained from the intake duct structure 10.

Furthermore, the lower end of the first wall 34 is positioned lower than the lower end of the second wall 36. The lower end of the first wall 34 makes the water from the upper direction drop in opposite direction to the intake unit 5. Even if a small amount of water goes to the intake unit direction, it is possible to be blocked by the second wall 36 which provides the same effect as the first wall 34.

As shown in FIG.4, since the first wall 34 is positioned to cover the front side 36a and lateral sides 36b, 36b of the second wall 36 for the vehicle front- rear direction, the first wall 34 can prevent the water W1 which comes from the upper direction of the intake duct structure 10 from flowing into the intake duct structure 10 from the front and both sides of the duct member 20.

( 2) Case where the outside air A with the water W2 comes from the front direction of the intake duct structure 10 When the vehicle 1 is running in the forward direction, the outside air A is flown from the outside into the intake duct structure 10 through the grille opening section 3 a of the grille 3.

The outside air A from the front direction of the intake duct structure 10 passes through the first space portion 70, and then flows to the downward surface 54. And then, the water W2 flowing in the intake duct structure 10 with the outside air A collides with the downward surface 54, and then the flow of the water W2 changes in the oblique upper direction and collides with the second wall 36.

As the second wall 36 is arranged at the rearward of the first wall 34 to be straight downward and parallel with the first wall 34 as well as the downward surface 54 faces to the second wall 36, the second wall 36 makes the water W2 dropped on the downward surface 54 of the bottom cover 50.

Since the downward surface 54 is arranged to be inclined downward to the front direction of the vehicle 1, the water W2 flows down on the downward surface 54 and is drained from the intake duct structure 10.

Even if the water W2 flows over the downward surface 54 into the upward surface 62 that is arranged so as to incline upward from the plain surface 60 to the downward surface 54, since the top portion 64 of the bottom cover 50 located between the downward surface 54 and the upward surface 62 is arranged so that it is difficult for the water W2 on the bottom cover 50 to flow into the intake unit 5, the intake duct structure 10 can prevent the water W2 from flowing into the intake unit 5.

Furthermore, even if the water W2 flows down to the plain surface 60 and the water reaches at the higher position than the top portion 64 of the upward surface 62, since the drain hole 56 is positioned between the upward surface 62 and the plain surface 60 ( See FIG.2, FIG. 5 and FIG.6A) , the water W2 can be easily drained from the drain hole 56 to the outside of the bottom cover 50.

On the other hand, once the outside air A from the front direction of the intake duct structure 10 flows to the downward surface 54, collides with the downward surface 54, and then the air flow changes in the oblique upper direction.

Since the shape of the lower end of the first wall 34 is positioned lower than the lower end of the second wall 36 as shown by the line LI in FIG.5, it is possible to arrange the first space portion 70 and the second space portion 72 to be followed the direction of the downward surface 54 of the bottom cover 50. The outside air from the front direction of the intake duct structure 10 can smoothly flow between the lower end of the first wall 34 and the downward surface 54 and between the lower end of the second wall 36 and the downward surface 54, into the intake unit 5. As such, since there is no need to form a labyrinth passage in the intake duct structure 10, it is possible to suppress the increase of a friction resistance of the outside air which is sucked by the intake unit 5.

Furthermore, since the tangent plane P I of the lower duct panel upper surface 40a of the lower duct panel 40 is arranged to be parallel with the tangent plane P2 of a downward surface upper surface 54a of the downward surface 54 so that the outside air A can smoothly flow into the intake unit 5, there are no obstacles that increases a friction resistance of the flow of the outside air A. Therefore, the intake duct structure 10 can suppress the increase of a friction resistance of the outside air A and improve the performance of the intake unit 5.

(3) Case where the water comes from the lower direction of the intake duct structure 10

If the water comes from the lower direction of the intake duct structure 10, since the bottom cover 50 is a member that is positioned below the duct member 20, it is possible that the bottom cover 50 prevents the water from the lower direction from flowing to the intake duct structure 10.

Even though the duct member 20 prevents the water comes from the lower direction of the intake duct structure 10 from flowing to the intake duct structure 10, there is a possibility that water flows into the bottom cover 50 via the drain hole 56.

In this embodiment, since the cover portion 58 is formed to cover the space above the drain hole 56 from the top, side, and rear directions, it is possible to prevent the water from the lower direction of the intake duct structure 10 from passing through the drain hole 56 because the cover portion 58 acts as a barrier member. As such, the intake duct structure 10 can prevent the water from the lower directions of the intake duct structure 10 from flowing to the intake duct structure 10.

Therefore, the intake duct structure 10 of the embodiment can prevent the water from upper, front and lower directions of the intake duct structure 10 and suppress the increase of a friction resistance of the outside air which is sucked by the intake unit 5. As a result, the intake duct structure 10 of the embodiment can improve the performance of the intake unit 5

Although specific embodiments of the invention have been disclosed and described as well as illustrated in the companying drawings, it is simply for the purpose of better understanding of the principle of the present invention and it is not as a limitation of the scope and spirit of the teaching of the present invention. Adaption and modification to various structures such as design or material of the invention, mounting mechanism of various parts and elements or embodiments are possible and apparent to a skilled person without departing from the scope of the present invention which is to be determined by the claims.

List of reference:

1 vehicle

2 vehicle body

3 grille

3 a grille opening section

4 engine room

5 intake unit

6 hood

7 cross frame

8 engine

10 intake duct structure

20 duct member

30 upper duct panel

32 catch member

34 first wall

36 second wall

36a front side of second wall

36b lateral side of second wall

40 lower duct panel

40a lower duct panel upper surface

42 clip member

42a clip member opening

44 mounting portion

46 fastening member

50 bottom cover

52 bottom surface

52a side wall

52b rear wall

54 downward surface

54a downward surface upper surface 56 drain hole 58 cover portion 60 plain surface 62 upward surface 64 top portion

66 mounting portion 68 fastening member 70 first space portion 72 second space portion A outside air

LI line indicating that a lower end of the first wall is positioned lower than the lower end of the second wall

W1, W2 water PI, P2 tangent plane