Air passage switching system for air conditioner

Details Air passage switching system for air conditioner Air passage switching system for air conditioner

1999-08-24

2001-02-27

Gravini, Stephen (Department: 3749)

Ventilation

Vehicle

C049S483100, C049S504000

Reexamination Certificate

active

06193600

ABSTRACT:

CROSS-REFERENCE TO RELATED APPLICATION
This application relates to and claims priority from Japanese Patent Applications No. Hei. 10-239029 filed on Aug. 25, 1998, and No. Hei. 11-209587 filed on Jul. 23, 1999, the contents of which are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an air passage switching system having a door for opening and closing an air passage through which air flows. The air passage switching system is suitable for an air outlet mode switching unit for a vehicle air conditioner.
2. Related Art
A conventional air passage switching system for an air conditioner of a vehicle has an air conditioning case for forming an air passage, and a butterfly door for switching the air passage. A rotation shaft for rotating the butterfly door is disposed at side end centers of the door. The butterfly door is rotatably held in the air conditioning case to be rotated by the rotation shaft. The butterfly door includes a door body portion made of resin having a high rigidity, and a lip-seal like seal member made of an elastomer. The seal member is formed into a thin-plate like (i.e., flat sheet) integrally with the door body portion on the outer peripheral portion of the door body portion. However, because the seal member is formed into the thin-plate like to have a low rigidity, the seal member is readily deformed due to inner shrinking force, and is readily bent upwardly on a corner portion. To prevent this problem, when a seal member
202
is formed into a lip like having a T-shaped or Y-shaped end section around a door body portion
200
as shown in
FIGS. 15A
,
15
B, the rigidity of the seal member
202
is increased, and the seal member
202
is not readily deformed. However, it is compared with the seal member formed into a thin-plate like, the T-shaped or Y-shaped end section is difficult to be molded, and the producing cost of the seal member
202
is increased. Further, the thickness of the top end of the seal member
202
becomes larger due to the T-shaped or Y-shaped end section, an area of an air passage is reduced and pressure loss of the air passage is increased when the door is opened.
SUMMARY OF THE INVENTION
In view of the foregoing problems, it is an object of the present invention to provide an air passage switching system which opens and closes an air passage by using a door where a thin and flat plate-like seal member made of an elastic material is attached to an outer peripheral portion of a door body. In the air passage switching system, the door is produced in low cost while preventing air leak due to deformation of the seal member.
According to the present invention of the present invention, an air passage switching system includes a door for opening and closing an opening of a case. The door includes a door body made of a material having a rigidity higher than a predetermined value, and a seal member made of an elastic material having a heat contraction and being attached to an outer peripheral portion of the door body. The seal member continually extends from the outer peripheral portion of the door body toward an outer side to have a thin plate-like shape. In the air passage switching system, the case has a case seal surface around the opening, the seal member of the door is press-fitted to the case seal surface to have a predetermined deformation amount when the opening is closed, the seal member has inner stress (i.e., inner contracting force) generated during molding, and the seal member and the case seal surface are provided in such a manner that the predetermined deformation amount of the seal member when the seal member is press-fitted to the case seal surface is made larger than a deformation amount of the seal member due to the inner stress. Thus, even when the door is used in a long time and the seal member is deformed due to the inner shrinking force, a clearance is not caused between the case seal surface of the case and the door so that air leak can be accurately prevented, because the deformation amount of the seal member when the seal member is press-fitted to the case seal surface is larger than the deformation amount due to the inner shrinking force. Further, because the seal member is formed into the thin plate like, the air passage switching system is produced in low cost while accurately preventing the air leak.
Preferably, on a corner portion of the seal member, the seal member and the case seal surface are provided in such a manner that the deformation amount of the seal member when being press-fitted to the case seal surface is made larger than the deformation amount of the seal member due to the inner stress. Therefore, on the corner portion of the seal member, the air leak due to deformation of the seal member can be effectively prevented.
More preferably, the seal member has an outer peripheral curvature radius (R
D
) on a corner portion, the seal member is press-fitted to the case seal surface along a seal line when the opening is closed, the case seal surface has an inner peripheral curvature radius (R
C
2
) on a corner portion of the seal line, corresponding to the corner portion of the seal member, and the inner peripheral curvature radius (R
C
2
) is set to be larger than the outer peripheral curvature radius (R
D
). Therefore, when the opening is closed, an inner peripheral portion of the case seal surface tightly contacts the seal member on the corner portion. That is, the corner portion of the seal member can be beforehand elastically deformed from an initial using time by an elastic deformation amount larger than the deformation amount due to the inner shrinking force. Thus, the air leak due to the inner shrinking force can be further prevented.
Still more preferably, the inner peripheral curvature radius (R
C
2
) is set to be in a range of 1.5 R
D
-4 R
D
, relative to the outer peripheral curvature radius (R
D
). Therefore, the clearance between the case seal surface of the case and the door can be further prevented, and an interference between the case seal surface and the door body can be prevented.
Further, a corner portion of the door body corresponding to the corner portion of the seal member has a protrusion protruding toward the corner portion of the seal member. Therefore, the protrusion dimension of the seal member on the corner portion can be reduced by the protrusion amount of the protrusion of the door body. Accordingly, an upwardly bent amount of the seal member on the corner portion can be reduced, and deformation of the seal member on the corner portion due to dynamical pressure of blown-air can be reduced. As a result, the air leak on the corner portion can be effectively prevented. Further, because the door body portion including the protrusion is made of a material having a high rigidity, the rigidity of the seal member on the corner portion can be improved by the protrusion, and the deformation of the seal member due to the inner shrinking force on the corner portion can be effectively prevented.
Preferably, the protrusion protruding toward the corner portion of the seal member has a smoothly curved outer surface. Therefore, stress with the door opening-closing operation is not collected in the corner portion of the seal member, and the bonding performance between the seal member and the door body can be maintained in a long time.


REFERENCES:
patent: 3308745 (1967-03-01), Davies
patent: 4402586 (1983-09-01), Jacquet
patent: 4492361 (1985-01-01), Jacquet et al.
patent: 5669350 (1997-09-01), Altmann et al.

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