Land vehicles: bodies and tops – Tops – Roof structure
Reexamination Certificate
1999-12-15
2001-04-10
Pedder, Dennis H. (Department: 3612)
Land vehicles: bodies and tops
Tops
Roof structure
Reexamination Certificate
active
06213543
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the invention
The present invention relates to a deflector of an automobile sunroof which protrudes upward from front the edge portion of a sunroof opening provided in an automobile roof and changes the airflow direction.
2. Description of the Related Art
When an automobile is running at a high speed in a state where the opening of the roof is opened by removing a sunroof panel or a sunroof glass of the sunroof, unpleasant noise referred to as wind throb is generated by hitting of the airflow against the edge portion of the roof located at the back of the opening. The deflector is used to avoid such situation.
Referring to the sectional view in
FIG. 21
, a conventional deflector
20
is formed such that it protrudes upward from an opening
21
when a sunroof panel or a sunroof glass is removed from the opening
21
. The deflector
20
has a guide face
22
which deflects the airflow
24
upward. The airflow
24
which has flown from the front along the roof
23
is prevented from hitting against the edge portion of the roof located at the back of the opening
21
by enlarging the angle of inclination a formed by the guide face
22
and a roof
23
or enlarging the protrusion amount h of the guide face
22
from the roof
23
(refer to Japanese Patent Application Laid-Open HEI 7-285343).
When the airflow is deflected upward by the deflector, the direction of flow is changed by the deflector. It is known that the speed of the slip stream separated by the deflector, or the vortex flow is increased as the curvature for changing the flow direction is made larger. On the other hand, the wind noise generated by the deflector becomes larger in proportion to the sextuplicate of flow velocity. Accordingly, referring to
FIG. 22
showing the characteristics of sound pressure level against deflector protrusion amount, the wind throb A at vehicle speed of 55 km/h is decreased as the deflector protrusion amount increases, while the wind noise B at vehicle speed of 100 km/h is increased as the deflector protrusion amount increases. As apparent from
FIG. 22
, wind throb A and wind noise B are contradictory items.
Conventionally, the airflow from the front is changed upward by the deflector to prevent the airflow from hitting against the edge portion of the roof located at the back of the opening. However, after repeating the experiment while varying the position and shape of the deflector, an equivalent effect was proved to be achieved by restricting the airflow behind the deflector from going downward.
SUMMARY OF THE INVENTION
The present invention provides a deflector of an automobile sunroof which is capable of restricting the generation of wind throb and reducing the wind noise.
The present invention is a deflector which protrudes upward from the edge portion of the roof located before the sunroof opening provided in an automobile roof.
According to a first aspect of the present invention, the deflector is altogether smoothly curved upward in a convex shape, and is provided with a guide face having a maximum height at almost a center thereof in the vehicle fore-aft direction.
According to a second aspect of the present invention, the deflector is provided with a portion which is distanced from the edge portion of the roof located before the roof opening in order to create airflow toward the opening via under the deflector while the vehicle is running forward.
According to a third aspect of the present invention, the deflector as a whole is altogether smoothly curved upward in a convex shape, and is provided with a guide face having a maximum height at almost a center thereof in the vehicle fore-aft direction. Further, the deflector is provided with a portion which is distanced from the roof edge located before the roof opening in order to create airflow from toward the opening via under the deflector while the vehicle is running forward.
The automobile may be provided with a sunroof panel or a sunroof glass for opening and closing the opening. The deflector may be made such that it protrudes from the opening when the opening is opened.
The deflector may be made installable to the edge portion located before the opening or to the roof portion located before this edge.
By removing the sunroof panel or the sunroof glass when the automobile is moving forward, the airflow along the roof hits the deflector, and thus the direction of flow is changed.
With the invention wherein the deflector is provided with a guide face curved upward in a convex shape, the airflow is directed upward and thus the airflow is prevented from reaching the edge portion of the roof located at the back of the opening. Because the guide face of the deflector as a whole is smoothly curved upward in a convex shape, the curvature for changing the direction of flow is small, and therefore generation of a slip stream can be restricted.
Because the airflow, the flow direction of which has been changed by the deflector, is prevented from reaching the edge portion of the roof located at the back of the opening, the generation of wind throb can be restricted. Further, because the curvature for changing the direction of the flow by the deflector is small, little slip stream is generated when the airflow hits the deflector, and the degree of a speed increase in the generated slip stream is small. Accordingly, the generation of wind noise can be restricted, and when the wind noise is generated, it can be restricted to a low level.
With the invention wherein the airflow is led under the deflector, air not only flows backwards via the portion above the deflector but also flows backward via the portion under the deflector. The airflow which has reached the opening via the portion under the deflector can maintain a pressure relationship between the backward airflow via the portion above the deflector such that the former supports the latter from underneath. Accordingly, it becomes difficult for the air flowing backward via the portion above the deflector to flow downward, thus airflow is prevented from reaching the rear edge portion of the opening.
In the invention where the deflector is provided with a guide face curved upward in a convex shape and wherein the airflow is led under the deflector, the airflow directed upwards along the guide face toward the back is supported by the airflow which has reached the opening via the portion under the deflector. This reduces the amount of protrusion of the guide face, thereby further reducing the wind noise.
REFERENCES:
patent: 5836643 (1998-11-01), Preiss
patent: 90433 (1988-04-01), None
patent: 7-285343 (1995-10-01), None
patent: 6603193 (1967-09-01), None
patent: 7510515 (1975-09-01), None
Pedder Dennis H.
Pillsbury & Winthrop LLP
Toyota Jidosha & Kabushiki Kaisha
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