Thermostatic valve having a sleeve

A valve includes a housing which defines openings for the inlet and outlet of a fluid. The valve also includes a sleeve for controlling the circulation of the fluid through the housing. The movement of the sleeve along its axis is controlled by a thermostatic element. In order to improve the maximum flow of fluid that the valve can take in, the valve further includes a seat part, which is fixedly mounted in the housing and which includes a fluid-tight wall. One of the two opposite surfaces of the wall extends transversally to the axis of the sleeve and defines a seat bearing the sleeve. The other one of these two opposite surfaces defines, between it and a wall of the housing according to the direction of the axis of the sleeve, a free volume wherein exists one of the openings and via which the fluid flows, being distributed over the entire periphery of the sleeve when this sleeve is in its open position.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the U.S. National Phase of International Application No. PCT/FR2011/050472, filed Mar. 8, 2011, designating the U.S. and published as WO 2011/110783 on Sep. 15, 2011 which claims the benefit of French Patent Application No. 10 51743 filed Mar. 11, 2010.

FIELD OF THE INVENTION

This invention relates to a thermostatic valve for a fluid circulation circuit, in particular coolant for a heat engine.

BACKGROUND OF THE INVENTION

Valves provided with a sleeve for controlling of which the movement is controlled by a thermostatic element typically equip cooling circuits associated with high-capacity heat engines, in particular those used in lorries and certain motor vehicles, for which the flows of coolant required for their operation are higher than those encountered for heat engines with a lower capacity, for which the thermostatic valves used have flaps.

Indeed, using a sleeve in general makes it possible to have a stopper referred to as balanced, i.e. a stopper for which the difference in the pressures on either side of the wall of the sleeve is substantially zero according to the direction of movement of the sleeve by the thermostatic element, with this direction corresponding in practice to the axial direction of the sleeve. Inversely, in a thermostatic flap valve, the latter generally extends in a plane perpendicular to the direction of movement of the flap by the thermostatic element, in such a way that the pressure difference on either side of the flap according to this direction reaches high values, in particular when the circulation of fluid is interrupted by the flap. The energy required to separate such a flap from its seat is therefore often substantial, and this all the more so when the flow of the liquid to be controlled is substantial and flows in the direction of closing of the flap.

That said, current sleeve valves have however limits with regards to their maximum allowable flow. One of the reasons is linked to a poor peripheral supply of the sleeve: although in theory, the entire periphery of the sleeve could be made use of in order to allow the flow of the fluid through this sleeve when the latter is open, it is observed in practice that the flow of fluid supplying the interior of the sleeve is “channeled” through the opening of the inlet opening for this fluid into the housing of the valve. Indeed, when the sleeve is opened, i.e. when the sleeve is separated from its bearing seat defined by a wall of the valve housing, arranged axially across from the sleeve, the fluid tends to transit through the sleeve by entirely and exclusively flowing in the extension of the aforementioned opening. As such, EP-A-1 106 883, on which is based the preamble of claim1, provides an example of a three-way valve, wherein the sleeve presses, via one of its axial ends, against a wall of the valve housing, separating two circulation ducts of the fluid, between which the fluid tends to transit “in a straight line” when the sleeve is separated from the aforementioned housing wall. The same applies for the valves disclosed in DE-A-44 10 249, U.S. Pat. No. 3,734,405, U.S. Pat. No. 4,022,377, FR-A-2 919 704 and US-A-2002/096571.

SUMMARY OF INVENTION

The purpose of this invention is to propose a thermostatic sleeve valve, authorizing a substantial maximum flow.

To this effect, the invention has for purpose a thermostatic valve for a fluid circulation circuit, such as defined in claim1.

The idea at the basis of the invention is to not press the sleeve directly against a wall of the housing, but to create, according to the flow path of the fluid between the inlet and outlet openings, a free space between the bearing seat of this sleeve and one of these openings. This free space in fact allows the fluid to be distributed, inside the housing, according to the periphery of the sleeve in such a way that, when the latter is open, the fluid flows between this free space and the interior of the sleeve, over the entire periphery of the latter. In particular, when the aforementioned opening is an inlet opening for the fluid in the housing, this amounts to saying that the free space is a supply space upstream of the seat, making it possible to supply the sleeve well over its entire periphery. According to the invention, this free space is defined using a part qualified as a seat part since it defines the bearing seat of the sleeve, which is fixedly mounted inside the housing, with axial interposition of the free space. The setting up of this seat part in the housing is quick and easy, by being for example carried out at the same time as the setting up of at least one other component of the valve, which does not extend the assembly duration assembly time of the valve. Thanks to this seat part, more precisely to the free space that is defines axially in alignment with the sleeve, the valve takes in a high maximum flow of fluid.

Additional advantageous characteristics of the valve in accordance with the invention, taken separately or according to all of the combinations that are technically possible, are specified in the dependent claims2to10.

DETAILED DESCRIPTION OF THE EMBODIMENTS

FIGS. 1 and 2show a valve1adapted to control the circulation of a fluid, entering into a housing10of the valve via an opening11and exiting from this housing by an opening12, after having passed through a regulating chamber13wherein the openings11and12exit. In this chamber13are arranged a mobile sleeve20, a fixed seat part30and a thermostatic element40for controlling the movement of the sleeve with regards to the seat part. The valve1is for example used in a cooling circuit of a heat engine of a vehicle.

The sleeve20has a generally tubular shape, centred on a longitudinal axis X-X through which pass the section planes ofFIGS. 1 and 2. This sleeve is arranged in the chamber13in such a way that the opening11exits into this chamber in a way that is substantially perpendicular to the axis X-X, while, in the example embodiment being considered here, the opening12is globally centred on this axis.

The sleeve20comprises a cylindrical main body21, centred on the axis X-X and with a circular base, of which the wall is solid over its entire periphery. At the axial end20A of the sleeve, turned to the side of the opening11, the body21is provided with an internal peripheral edge22from which arms23extend rigidly in the direction of the axis X-X. At their free end, these arms23are connected fixedly to a heat-conducting cup41of the thermostatic element40, containing a thermoexpandable material, such as a wax. This cup41, which extends in length in a centred manner over the axis X-X, receives interiorly a rod42, which itself also extends in length in a centred manner over the axis X-X and which is also able to be deployed and to be retracted, via translation according to this axis, with regards to the interior of the cup41, under the effect of a variation in the volume of the thermoexpandable material. In the portion of its end arranged to the exterior of the cup41, the rod42is fixedly connected to the housing10by known arrangements, such as by overmolding, press fitting and/or gluing, which will not be described any further herein.

Advantageously, in the example embodiment considered here, an electric heating resistance R, shown in dotted lines onFIG. 2, is arranged inside the rod42, carried out in this case in the form of a metal tube, in such a way that this resistance can, when it is supplied with electricity, heat the thermoexpandable material contained in the cup41. The housing10is then exteriorly provided with a base14(FIG. 2) for connecting an external electrical power source, from which electrical conductors C extend to the terminals of the aforementioned heating resistance, being for example embedded in a insulating resin15added exteriorly to the housing10.

It is understood that, when the thermoexpandable material contained in the cup41is heated up, its expansion causes the translation of the cup41along the axis X-X, in the direction opposite to the rod42, i.e. downwards inFIGS. 1 and 2. Doing this, the cup41drives according to a corresponding translation movement the sleeve20, as indicated by arrow F inFIG. 2.

According to the axial position of the sleeve20, controlled by the thermostatic element40, the axial end20A of this sleeve is more or less separated from an associated wall31belonging to the seat part30. More precisely, this wall31has the general shape of a solid disc, centred on the axis X-X and with a circular base that is substantially identical to that of the body21of the sleeve20. On its surface directed towards the sleeve20, this wall31defines a peripheral edge constituting a sealed bearing seat32for the edge22of the sleeve20: in the axial position of the sleeve20shown inFIGS. 1 and 2, the edge22is as such pressed against the seat32of the wall31, this edge and this seat thus cooperating via the complementarity of the shapes along their entire periphery, in such a way as to cut a flow of fluid between the exterior and the interior of the sleeve20.

As can be easily seen inFIGS. 3 and 4, the wall31has a through bore33centred on the X axis-X and adapted to receive in a sealed manner the rod42, as shown inFIG. 1. As such, as shown inFIGS. 1 and 2, in the housing10, the wall31is arranged in such a way that its central region is located axially pressing against an internal over-thickened portion16of the housing10, to which the rod42is fixedly connected and through which the electric heating resistance R internal to this rod is supplied with electricity.

On the other hand, the peripheral region of the wall31is not pressing against the housing over-thickened portion16, but, on the contrary, is separate, according to the direction of the axis X-X, from the wall of the housing10from which this over-thickened portion16extends protruding towards the interior of the chamber13. In this way, the peripheral region of the wall31and the aforementioned wall of the housing10define between them, according to the direction of the axis X-X, a free space V, which belongs to the chamber13, which surrounds the housing over-thickened portion16and which, in the example embodiment considered here, has a global annular shape, centred on the axis X-X.

As can be easily seen inFIG. 1, the opening11opens freely into the free space V: moreover, in the embodiment considered here, the free space V is located, according to a direction perpendicular to the axis X-X, in the straight extension on the one hand substantial, approximately half, of the opening of opening11into the chamber13. Advantageously, the surface of the wall31, which defines the free space V, is provided with reinforcement ribs34, easily seen inFIG. 4.

In service, when the opening11is supplied with fluid to be controlled by the valve1, this fluid penetrates into the chamber13, filling at least partially the free space V: the fluid is as such distributed over the entire periphery of the sleeve20in such a way that, when this sleeve is moved from its closed position, shown inFIGS. 1 and 2, to an open position in which its end20A is axially distant from the seat32, the fluid flows inside the sleeve20, passing between the arms23, and this over the entire periphery of the sleeve. It is understood that the valve1is capable of taking in a substantial flow of fluid passing through it, with the entire periphery of the sleeve being made use of to authorize the flow of fluid through this valve when the sleeve is in open position. The interest of the ribs34is thus to avoid a significant deformation of the wall31, under the action of a high flow of fluid.

Moreover, the seat part30advantageously includes a crown35which, as can be easily seen inFIGS. 3 and 4, is co-axial to the wall31, while being located at a different axial level from the latter. Elbow arms36, distributed in a substantially regular manner according to the periphery of the seat part30, rigidly connect the wall31and the crown35. In the valve1, as shown inFIGS. 1 and 2, the crown35is arranged is such a way, on the one hand, as to be located axially between the openings11and12and, on the other hand, to be radially interposed between the body21of the sleeve20and the housing10. According to its external periphery, the crown35forms with the housing10a fixed contact, sealed by a seal37which, in the example embodiment shown, is retained in a peripheral groove38of the crown. On its inner periphery, the crown35forms with the body21of the sleeve20an axially sliding contact, sealed by a lip seal39. This lip seal39is received in a complementary peripheral indentation310of the crown35.

As such, the crown35insulates in a sealed manner the openings11and12one in relation to the other, around the sleeve20. In other words, to the exterior of this sleeve, the crown35compartmentalizes the chamber13into two separate portions in a sealed manner, with one of them in free communication with the opening11while the other in communication with the opening12.

In service, when the opening11is supplied with fluid to be controlled by the valve1, the crown35reinforces the effect of the wall31described hereinabove, allowing for the supplying of the sleeve20over its entire periphery: indeed, with regards to the radial dimension of the crown35, the free space V of peripheral supply of the sleeve20is, somewhat, extended axially all around this sleeve, as such increasing the maximum allowable flow of the valve1. When the sleeve20is in its open position, the fluid penetrates inside this sleeve, passing between the arms36, without the latter inducing any significant resistance to the flow, in light of their low thickness.

In practice, the seat part30also has the interest of being able to be mounted quickly and easily inside the housing10, provided beforehand with the joint37and the lip seal39. In addition, as in the example embodiment considered in the figures, this seat part30is manufactured beforehand in a single part, in particular via moulding a plastic material. In terms of an alternative not shown, the seal37and/or lip seal39are directly overmolded on the seat part30.

As an advantageous option, the crown35incorporates a degassing function. More precisely, as shown inFIG. 2, the crown35, according to the direction of the axis X-X, has a through bore311of which the outlet, on the side of the opening11, can be sealed with a ball312. This ball can be moved in relation to the crown35, being retained by a cage313, integral with the crown, here integrally formed with the latter. In this way, when the opening11is supplied with a fluid to be controlled by the valve1, this fluid presses the ball312against the outlet of the hole311, thus blocking the latter in a sealed manner. On the other hand, when the air is trapped inside the housing10, on the side of the opening12, in particular during the filling under pressure of the circuit wherein the valve1is incorporated, for its initial putting into service or following maintenance intervention, while the sleeve20is in its closed position, the ball312allows this trapped air to escape into the portion of the chamber13in communication with the opening11.

Moreover, the valve1further comprises a return spring50of the cup41towards the rod42, arranged co-axially around this cup. This spring50is retained in relation to the housing10by a part60which, advantageously, also provides for the retaining of the seat part30.

More precisely, as can easily be seen inFIG. 5, this retaining part60includes an annular crown61, which is centred on the axis X-X and against which is pressed the end of the spring50, opposite that bearing against the cup41. The retaining part60further comprises two arms62which extend from two diametrically opposite zones62A of the collar61. Opposite the crown61, each arm62includes an end portion62B forming a lug fixedly connected to the housing10, being received in a complementary cavity17defined interiorly by the housing, as shown inFIGS. 1 and 2. Advantageously, the peripheral dimension of this end portion62B is substantially equal to that of the cavity17for the purposes of the relative blocking in rotation around the axis X-X, by adjusting shapes.

Between its end portions62A and62B, each arm62has an elbowed running portion62C having globally the shape of a U turned towards the opening12: the bottom of this U shape is adapted to axially support the crown35of the seat part30, advantageously by retaining the lip seal39in its reception indentation310. To do this, the running portion of arm62C has, on its surface directed towards the opening11, a complementary surface63of the surfaces across from the crown35and of the lip seal39. Advantageously, the aforementioned surface of the crown35is arranged at the bottom of an indentation314of this crown, of which the peripheral dimension is substantially equal to that of the surface63of the arm62for the purposes of relative blocking in rotation around the axis X-X, by adjusting shapes.

Of course, U shape of the running portion62C of the arms62is provided in order to not interfere with the body21of the sleeve20during translational movements of the latter according to the axis X-X.

In order to facilitate the setting up of the retaining part60inside the housing10, this part60has a capacity of elastic deformation radially to the axis X-X: in practice, in the example embodiment considered here, this amounts to say that each lug62B is pulled back elastically against the running portion62C during the axial introduction of the part60inside the housing10, then, after the release of this lug, the latter is introduced into the receiving cavity17, via the elastic return effect.

Various arrangements and alternatives to the thermostatic valve1described until now can moreover be considered. By way of example:as a complement or as a replacement to the axial retaining action of the seat part30by the retaining part60, the part30can be fixed directly to the housing10by any suitable mechanical means; in order to show this alternative,FIG. 1shows that the over-thickened portion16of the housing10defines, in its surface against which the wall31is pressing, two holes18for receiving fastening screws not shown, noting that these holes18are drawn in axial alignment with two socket screws315defined in the surface of the wall31turned towards the sleeve20, these socket screws as such making it possible to locate and to facilitate the setting into place of the aforementioned screws;the geometry of the housing10can be modified in relation to that considered in the figures, in particular to adapt to the installation environment of the valve1and/or in order to facilitate the manufacture thereof; moreover, at least one other opening can be provided in addition to the opening11in order to supply the valve with fluid; likewise, at least one other opening than the opening12can be provided for the outlet of the fluid; in this later case, in a manner known per se, the cup41of the thermostatic element40can be extended by a bar provided with a mobile flap for the purposes of controlling the adjustment of the circulation of the fluid between the various outlet openings, in particular in order to provide a by-pass function in the cooling circuit of a heat engine;the valve1can be used in cooling circuits with a direction of circulation of the fluid that is inversed in relation to that described until now, i.e. with a fluid inlet at least via the opening12and a fluid outlet at least via the opening11;other embodiments than the ball312can be considered in order to constitute, on the crown35, a mobile valve for cutting off the degassing hole311; and/orthe shape and the number of arms62of the retaining part60are not limited to those shown in the figures; as such, by way of example, the shape of these arms62can be provided as substantially planar, rather than of a U shape; and/orthe thermostatic element40can be functionally linked to the rest of the valve1in a manner that is inverse to that considered in the example shown in the figures; in other words, in this case, it is the cup41which is fixedly connected to the housing10while the rod42pushes on the sleeve20in order to drive it in movement; such an arrangement can in particular be considered when it is renounced to control the valve1via a electric heating resistance, internal to the rod42.