Valves and valve actuation – Fluid actuated or retarded – Plural operations
Reexamination Certificate
1998-04-29
2001-03-06
Joyce, Harold (Department: 3749)
Valves and valve actuation
Fluid actuated or retarded
Plural operations
C137S875000, C251S129110, C251S158000, C251S249500
Reexamination Certificate
active
06196520
ABSTRACT:
FIELD OF THE INVENTION
The invention related to an air distribution device having a shutter of the drum type suitable for use in a motor vehicle heating and/or air conditioning installation.
The invention concerns more particularly a device comprising a casing provided with a generally cylindrical wall having at least one air passage opening, a shutter mounted so as to pivot with respect to an axis of rotation and having a generally cylindrical obturation wall and rotational control means for bringing the shutter into chosen positions in which the obturation wall selectively controls the air passage opening or openings of the casing.
BACKGROUND OF THE INVENTION
Shutters of this type are already known, which are also referred to as “drum shutters”, in which the obturation wall of the shutter is normally a length of a cylindrical wall which pivots inside a length of a cylindrical wall forming part of a distribution casing, the two cylindrical walls being coaxial.
Generally the cylindrical wall of the casing has several passage openings which are spaced apart angularly and which can be closed off or opened selectively by the obturation wall of the shutter according to the angular position taken by the latter. These devices have the advantage of enabling all the air distribution to be controlled with a single shutter placed in a single casing, which simplifies the design and also affords greater compactness.
One of the problems posed by this type of shutter is that of airtightness. It is in fact necessary for the shutter to guarantee perfect airtightness of the different air passage openings, also referred to as “vents”, when the shutter is in a closure position.
In the past, this airtightness is provided by a joint, for example by a foam joint covered with a polyamide cloth, bonded externally to the periphery of the obturation wall of the shutter.
Such a joint theoretically guarantees good airtightness, but at the cost of a high maneuvering force, because of the friction generated by the joint.
In addition, this joint has a tendency to lose its sealing capability because of wear, and is sensitive to ambient humidity.
It must also be stated that producing such a joint is tricky and that the resulting cost is relatively high.
SUMMARY OF THE INVENTION
An object of the invention is notably to overcome the aforementioned drawbacks.
The present invention proposes an improved air distribution device, in which the obturation wall is mounted so as to be movable with respect to a body of the shutter, consisting of two plates, in a direction substantially radial with respect to the axis of rotation of the shutter body, and in which the device comprises movement control means, coordinated with the rotation control means in order to move the obturation wall of the shutter away from the wall of the casing when the shutter is in an open position and to bring the obturation wall of the shutter closer to the wall of the casing when the shutter is in a closed position.
Thus, whereas in the past the obturation wall was always situated at a constant distance with respect to the axis of rotation of the shutter, the invention makes provision for varying this distance according to the angular position of the shutter. When the shutter is in an open position, the obturation wall is away from the wall of the casing, so that there is no friction between these two walls. When the shutter is thereafter moved in the direction of a closed position, the obturation wall of the shutter is moved away from the axis in order to move closer to the wall of the casing and come into contact with it, when the obturation wall is opposite a passage opening in the casing. The movement of the shutter body and the movement of the obturation wall of the shutter are coordinated and can be effected either simultaneously or in succession.
It is thus no longer necessary to provide sealing joints operating on rotation like the ones used in the past.
When the device comprises a sealing joint, this is compressed only in the radial direction and at the moment when the obturation wall of the shutter arrives in the closed position.
Thus the rotational movement of the shutter takes place without friction and therefore without maneuvering force. In addition, wear on the joint is minimal since the latter undergoes only compression in a substantially radial direction, at the moment of closure.
The movement of the obturation wall with respect to the body of the shutter in a substantially radial direction can take place in two ways.
In a first embodiment, the obturation wall is movable in translation with respect to the body of the shutter and the movement control means comprise translation control means.
In a second embodiment, the obturation wall is movable in rotation with respect to the body of the shutter and the movement control means comprise rotation control means.
In a first general embodiment of the invention, the movement control means comprise a lever fixed to a drive spindle coaxial with the axis of rotation of the shutter body, this lever being articulated on the obturation wall of the shutter, either directly, or indirectly by means of at least one connecting rod, transmission means having a chosen transmission ratio being connected to the rotation control means and to the movement control means.
Thus the movement of the shutter is effected in a particularly simple fashion by means of a lever, the rotation of which is coordinated with that of the shutter body, and if applicable at least one connecting rod.
In one embodiment of the invention, the device comprises a drive shaft on which there is fixed a driving pinion driving a toothed sector fixed to the body of the shutter and driving a pinion fixed to the spindle of the lever with the interposition of an intermediate pinion.
The device of the invention applies in particular to the case where the shutter can be moved between two closed positions with a given angular movement. In such a case, the transmission ratio is chosen so that the lever turns through an angle of 360° minus the value of the angular movement, when the shutter pivots from one of its two positions to the other.
Thus, in each of the closed positions, the obturation wall of the shutter is always at the same distance from the axis of rotation of the shutter.
Advantageously, in each of the closed positions of the shutter, the connecting rod is situated in line with the lever so that the obturation surface of the shutter is always furthest away from the axis of rotation of the shutter body.
In another embodiment, the device comprises a drive shaft on which there are fixed a drive pinion driving a toothed sector fixed to the body of the shutter and a toothed sector driving a pinion fixed onto the rotation spindle of the shutter.
This solution is particularly suitable in cases where the shutter can be moved between at least three closure positions with a given angular movement between two successive closed positions, the transmission ratio being chosen so that the lever turns through an angle of 360° plus the aforementioned angular movement, when the shutter passes from one of two consecutive closure positions to the other.
In another embodiment of the invention, the device comprises a drive shaft coupled to the body of the shutter and also comprises a transmission pinion mounted loose around a spindle fixed to the body of the shutter and meshing on the one hand with a pinion fixed onto the lever spindle and on the other hand with teeth in the shape of an arc of a circle carried by the casing and centered on the axis of rotation of the shutter body and of the lever.
In this embodiment, the transmission pinion, the pinion fixed onto the lever spindle and the teeth in the shape of an arc of a circle can all be situated outside the shutter, or else inside the shutter.
As a variant, the transmission pinion is a pinion in the form of an annulus rotating about a hub fixed to the shutter body, the transmission pinion, the pinion fixed onto the lever spindle and the teeth in the shape of an arc of a circle being situated ou
Barbier Thierry
Vincent Philippe
Joyce Harold
Morgan & Finnegan , LLP
Valeo Climatisation
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