Structure for reducing wind noise

Details Structure for reducing wind noise Structure for reducing wind noise

2000-06-02

2001-08-21

Dayoan, D. Glenn (Department: 3612)

Land vehicles: bodies and tops

Bodies

With distinct wind deflector

C224S316000

Reexamination Certificate

active

06276747

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a structure for reducing wind noise. The structure for reducing wind noise is provided above a roof of a vehicle along the width of the vehicle.
BACKGROUND OF THE INVENTION
One example of a structure for reducing wind noise mounted on a vehicle is shown in Japanese Laid-Open Patent Application No. 9-2339.
As shown in
FIG. 5
, a vehicle is equipped with a roof spoiler
100
on a roof of the vehicle at a predetermined height along the width of the vehicle. The roof spoiler
100
has a structure for reducing wind noise. The roof spoiler
100
comprises two surfaces, which are an upper surface
100
A and a lower surface
100
B. A flow regulating means
102
is shaped at least on one of two surfaces (It is the lower surface in the case shown in FIG.
5
.). The flow regulating means
102
regulates a direction of the air flow flowing along the surfaces of the roof spoiler
100
to a predetermined direction, so that two pressures or two velocities generated along the upper and lower surfaces
100
A,
100
B of the roof spoiler
100
are unbalanced at the place near the rear end portion
100
C. By the advantage of this structure, the distance between the very front and the very rear of the roof spoiler
100
is not unnecessarily long. That is, the size of the roof spoiler
100
is restrained, and a Karman vortex of the air flow is reduced. Accordingly, a wind noise of the roof spoiler
100
is reduced.
In the structure for reducing wind noise shown in
FIG. 5
, however, the difference between two pressures or velocities of the upper and lower air flows along the roof spoiler
100
might not be sufficiently high, because the flow regulating means
102
is shaped at least on one of the upper and lower surfaces
100
A and
100
B. It might result in not sufficiently eliminating the Karman vortex, which is the cause of the wind noise. It means that the wind noise might not be reduced efficiently by the above-mentioned structure for reducing wind noise.
SUMMARY OF THE INVENTION
It is thus one object of the present invention to solve the aforementioned problems. That is, the object of the invention is to provide a structure for reducing wind noise efficiently.
A structure for reducing wind noise provided above a roof along the width of a vehicle comprises an upper surface and a lower surface of the structure. The upper surface introduces an attached flow of air from the front of the vehicle to the rear of the vehicle. The lower surface of the structure comprises a flow compression face, a flow leading face, and a flow separation portion. The flow compression face in the front of the lower surface introduces and compresses the air flow from the front of the vehicle. The flow leading face in the center of the lower surface leads the air flow compressed from the front of the structure to the rear of the structure. The flow separation portion in the rear of the lower surface separates the air flow from the front of the structure.
The lower flow of the air from the front of the vehicle and above the roof of the vehicle, is first introduced to the roof side and compressed by the flow compression face in the front of the lower surface. Accordingly, the pressure of the air flow increases. Next, the air flow is lead to the rear of the structure by the flow leading face in the center of the lower surface, and the air flow is separated from the structure by the flow separation portion in the rear of the lower surface. Then, in the rear of the structure the separated air flow unites together with the air flow along the upper surface of the structure. Consequently, the difference of the pressures, the velocities, or etc. between the two air flow separated to the lower and upper sides of the structure is greater. Then, a Karman vortex which causes a wind noise of the structure can be avoided, though a front-rear length of the structure is not unnecessary long. In these ways the wind noise of the structure can efficiently be reduced.
The above-mentioned flow compression face is hollowed toward the center point of the cross-section of the structure, the flow leading face is a smooth convex arc of a circle as the cross-section, and the flow separation portion is notch shaped like a step.
Furthermore, the upper surface of the structure is smoothly curved and convex toward the upper direction.
The above-mentioned upper surface of the structure can restrain the separation of the air flow along the upper surface of the structure. Consequently, a Karman vortex which causes a wind noise can be sufficiently avoided, and the wind noise of the structure can be reduced efficiently.
Furthermore, in the center part of the width of the structure along the width of the vehicle, the vertical center line connecting the middle point on the upper surface from the view point of the front-rear direction with the center point of the cross-section of the structure coincides or substantially coincides with the normal line of the roof of the vehicle.
This means that the horizontal center line of the structure is parallel or substantially parallel to the flowing line of the air along the roof of the vehicle, and the horizontal center line is parallel or substantially parallel to a line which is tangent to the roof line as the cross-section. Accordingly, the air flow is compressed efficiently between the flow compression face and the surface of the roof. Then, the wind noise of the structure is further efficiently reduced.


REFERENCES:
patent: 4195874 (1980-04-01), Janssen et al.
patent: 4501385 (1985-02-01), Bott
patent: 4743057 (1988-05-01), Loren
patent: 5240536 (1993-08-01), Kurobe
patent: 5282560 (1994-02-01), Ozog
patent: 5474218 (1995-12-01), Arenault, Jr. et al.
patent: 9-2339 (1997-01-01), None
patent: 10-45046 (1998-02-01), None
patent: 10-278855 (1998-10-01), None

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