BACKGROUND ART A number of control valve embodiments are known in which a discoidal valve body is displaceable in translation and closes an aperture or passage, the throughput being controllable by distancing to a greater or lesser extent the valve body from its seat so as to modify the dimensions of the slot which forms the passage section when the valve body detaches from the aperture and is distanced from the latter.

Figs. 1 to 3 show a known embodiment of a valve device of this type, more particularly in the case of a thermostat valve for a cooling circuit comprising a valve body 2 which is mounted on a shaft and is displaceable in translation with respect to a hollow body 3, of which it can close an aperture by coming into contact with the peripheral edge of the latter.

Fig. 1 shows a section of the valve device in the closed state and Fig. 2 shows, also in section, said device in an open position, Fig. 3 being a perspective view from below of said device in its configuration in Fig. 2.

With a construction of this type of the valve device, the development of the throughput as a function of the position in translation of the valve body will always be proportional, in particular in the open positions with low amplitude, and determined by the product of the distance separating the aperture edge of the valve body by the circumference of said aperture.

However, in certain applications, it may be desirable to have finer control of the throughput, in other words a smaller variation of the throughput as a function of

the translation of the valve body, in certain opening ranges of the valve device and in particular at the start of opening.

DISCLOSURE OF INVENTION The object of the present invention is therefore to provide a simple solution allowing a response to the above-mentioned desire and, preferably, allowing a great variety of evolutionary profiles (throughput/position of the valve body) in a certain opening range of a valve body of this type.

For this purpose, the present invention relates to a control device with a valve, in particular for a circuit for circulation of liquid, in particular coolant, comprising mainly a valve body, which is movable in translation and a hollow body comprising an aperture, a peripheral edge zone of which constitutes a seat adjusted for the valve body, allowing complete closure of said aperture when said body rests intimately against said seat, characterised in that at least one protruding structure is provided on the hollow body around the aperture and/or on the valve body in the region of its face turned toward the aperture of the hollow body, said at least one structure being disposed and extending in a manner such that it obstructs, at least partially, the circumferential slot forming the passage section substantially defined between the edge of the aperture and the valve body, when said valve body is situated at a distance from its seat.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described in more detail with the aid of the description hereinafter which relates to preferred embodiments given by way of non-limiting examples and explained with reference to the attached schematic drawings, in which : Figs. 4A and 4B are sectional views of a valve device according to a first embodiment of the invention, respectively in the closed position and an open position; Fig. 5 is a perspective view from below of the valve device shown in Fig. 4B;

Figs. 6A and 6B are sectional views of a valve device according to a second embodiment of the invention, respectively in the closure position and an opening position and, Fig. 7 is a perspective view from below of the valve device shown in Fig. 6B.

BEST MODE FOR CARRYING OUT THE INVENTION As Figs. 4 to 7 of the attached drawings show, the control device 1 with a valve, in particular for a circuit for circulation of liquid, in particular coolant, comprises mainly a valve body 2, for example substantially discoidal in shape, which is movable in translation following a direction D and a hollow body 3 comprising an aperture 4, a peripheral edge zone 5 of which constitutes a seat adjusted for the valve body 2, allowing complete closure of said aperture 4 when said body 2 rests intimately against said seat According to the invention at least one protruding structure 6 is provided on the hollow body 3 around the aperture 4 and/or on the valve body 2 in the region of its face 2'turned toward the aperture 4 of the hollow body 3, said at least one structure 6 being disposed and extending in a manner such that it obstructs, at least partially, the circumferential slot forming the passage section 7 substantially defined between the edge of the aperture 4 and the valve body 2, when said valve body 2 is situated at a distance from its seat 5.

Thus the principle on which the invention is based consists in limiting the passage section between the aperture 4 and the valve body 2 when the latter is detached from its seat, by creating at least one obstructing obstacle for the fluid flow and therefore reducing the fluid throughput flowing in the aperture 4.

According to a first embodiment of the invention shown in Figs. 4 and 5 of the attached drawings, said at least one protruding structure 6 is in the form of at least one wall portion, is disposed or formed on the hollow body 3 in immediate proximity around the edge zone 5 of the aperture 4 forming the seat and follows the exterior contour thereof.

According to a second embodiment of the invention shown in Figs. 6 and 7 of the attached drawings said at least one protruding structure 6 is in the form of at least one wall portion, is disposed or formed on the face 2'of the valve body 2 turned toward the hollow body 3, in immediate proximity of the interior circumference of the peripheral edge zone 8 of said valve body intended to rest on the seat 3, and follows the contour of said internal circumference.

It may also be provided, as a function of possible production constraints or particular section/distance evolution profiles, that the hollow body 3 and the valve body 2 are both provided with at least one obstructing wall portion 6.

The protruding structures 6, for example in the form of wall portions, may extend over the entire circumference of the aperture 4 or the valve body 2 or only one part of the latter and possibly have a profiled exterior shape facilitating the flow of the fluid after the passage section 7.

Moreover said protruding structures 6 may be formed in one piece with the hollow body 3 or the valve body 2, or be connected on these or one of these latter.

According to a preferred embodiment of the invention and as shown in Figs. 4 to 7 of the attached drawings said at least one wall portion 6 consists of an annular collar or skirt provided with cut-outs 9, notches, indentations or similar and of which the generating line is parallel to the direction of translation D of the valve body 2.

To arrange a passage section determined not zero from the detachment of the body of the valve 2 from its seat 5, at least some of the cut-outs or notches 9 may extend from the free edge 6'of the collar 6 to its base, thus dividing it into a plurality of adjacent distinct elementary wall portions 10, disposed to follow the external contour of the aperture edge 4.

The collar 6 and the wall portions 10 are disposed and extend in such a way that it or they run in a practically adjusted manner in the aperture 4 when it/they is/are mounted or formed on the body of the valve 2 or that said valve body 2 runs along it/them in a practically adjusted manner when it/they is/are fitted or formed around the aperture 4 on the hollow body 3.

Although the cut-outs or notches 9 may optionally have different shapes and sizes, the collar 6 will advantageously comprise a plurality of cut-outs 9 which are triangular in shape, one of the cut out sides of the triangles being merged with the free edge 6'of said collar 6, these cut-outs 9 preferably being in the form of an isosceles triangle and distributed uniformly on the circumference of said collar 6.

According to another embodiment, not shown in the attached drawings, the collar 6 may have a substantially continuous structure and a variable height along the circumference, for example so as to form a succession of elevations and hollows.

To ensure a good seal in the closed state and guiding with centring of the valve body 2 in its displacement immediately prior to closure, the edge zone 5 of the aperture 4 forming the seat and the peripheral edge zone 8 of the valve body 2 cooperating with one another to produce closure consists of bevelled areas (see Fig. 4 to 7). Moreover, the edge 8 of the body 2 can be provided with at least one closure joint.

Although the invention can apply to control devices with a valve 1 with different shape and structures, it will preferably be applied when the aperture 4 of the hollow body 3 and the valve body 2 have circular shapes.

The invention is obviously not limited to the production methods described and shown in the attached drawings. Modifications remain possible, in particular from the point of view of the constitution of the various elements or by substituting equivalent techniques, without thus deviating from the scope of protection.