Abstract:
A thermostatic element, a main seal, that can be moved axially relative to a fixed seat to open and close a main valve and linked to the movable part of the thermostatic element to open the main valve, the main seal and the thermostatic element assembled together and forming a first module. A spring biasing the movable part towards the fixed part of the thermostatic element, controlling the closing of the main valve. A bracket supporting the spring and interposed axially between the spring and a fixed casing. A support cradle supporting the first module, removably inserting the first module therein, by axially interposing the cradle between the first module and the spring, including a by-pass seal, that is axially movable relative to a fixed seat of the bracket so as to open/close a by-pass valve when the main valve is opened/closed, and linked to the bracket in an axially movable manner, with the spring interposed axially and held fixedly to the bracket to keep the spring in the compressed state between them.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This is a U.S. national phase application under 35 U.S.C. §371 of International Patent Application No. PCT/EP2015/072034, filed Sep. 24, 2015, and claims benefit of priority to French Patent Application No. 1459080, Sep. 25, 2014. The entire contents of these applications are hereby incorporated by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention relates to a thermostatic device, as well as a thermostatic valve comprising such a device. 
         [0003]    The invention in particular relates to the thermostatic devices and valves that are used in cooling circuits of heat engines, in particular those of motor vehicles, heavy trucks, two-wheeled vehicles and stationary engines. That being said, this scope of application does not limit the invention, inasmuch as the device and the valve according to the invention can be used in various other fluid circuits, for example gearbox cooling circuits, water circuits, oil circuits, etc. 
       BACKGROUND 
       [0004]    In many applications in the fluid field, in particular for cooling vehicle heat engines, thermostatic valves are used to regulate the flow of a fluid, i.e., to distribute this incoming fluid in different flow pathways, based on the temperature of that fluid. These valves are said to be thermostatic inasmuch as the movement of their inner shutter(s) is controlled by a thermostatic element, i.e., an element that comprises a body, containing a thermodilatable material, and a piston, submerged in this thermodilatable material, the body and the piston being movable relative to one another in translation along the longitudinal axis of the piston. A thermodilatable material being one that can expand with an increase in temperature. 
         [0005]    The invention more specifically examines three-way valves, which distribute a fluid inlet between two fluid outlets or which supply a fluid outlet from two fluid inlets. These three-way valves are typically used to regulate the flow of a cooling fluid with respect to both an engine to be cooled by this fluid and a heat exchanger, in particular a radiator, cooling this fluid: when the fluid has an excessively high temperature at the valve, the latter sends it to the exchanger to be cooled therein before being sent to the engine to be cooled, then returned to the valve, whereas when the temperature of the fluid is low enough at the valve, the latter sends the fluid directly to the engine, from which it is returned to the valve, via a bypass channel not passing through the exchanger. To that end, the valve includes a main valve, which commands the flow of the fluid with respect to the heat exchanger, and a bypass valve, which commands the flow of the fluid in the aforementioned bypass. EP-A-1,936,141 and US-A-2005/001044 provide examples of this. 
         [0006]    The invention examines valves whereof the same thermostatic element actuates, inversely, the main valve and the bypass valve. In this case, it is known that the moving part of the thermostatic element is securely connected to a same piece of equipment including the shutter of the main valve and the shutter of the bypass valve, subject to the interposition of a return spring between this piece of equipment and a bracket, which, during use, is securely connected to a casing or a similar part, fastened to the valve casing to which the stationary part of the thermostatic element is fixedly connected. By further providing that the piece of equipment and the bracket, which, when the valve is in use, are movable relative to one another to open and close the bypass valve, are permanently retained to one another so as to keep the return spring compressed between them, the unit formed by the assembly of the thermostatic element, the piece of equipment, the bracket and the return spring constitutes an integrated device with a pre-stressed spring: such a spring has the advantage of being able to be mounted in a single piece on the aforementioned casings, in particular without using tooling dedicated to compressing the return spring. DE-U-20 2010 017 837 provides one example of this. 
         [0007]    The integration of these devices nevertheless has the drawback of causing them not to be very configurable, inasmuch as the design and sizing of such a device are specific to the assembly environment of this device. In particular, due to its design, the aforementioned piece of equipment freezes both the diameter of the shutter of the main valve and the diameter of the shutter of the bypass valve, which therefore limits the possibilities for using pre-existing thermostatic elements, with various shapes and sizes, and which requires the shape of the bracket to be adapted in a specifically dedicated manner. The cost of manufacturing and restocking these devices is affected as a result. 
       SUMMARY 
       [0008]    The aim of the present invention is to propose a thermostatic device of the aforementioned type, which, while being easy to mount within a corresponding thermostatic valve, is more configurable. 
         [0009]    To that end, the invention relates to a thermostatic device for regulating the flow of a fluid, comprising:
       a thermostatic element, which includes a stationary part, intended to be securely connected to a first casing that channels the fluid, and a moving part, movable along an axis relative to the stationary part, moving away from the stationary part resulting from expansion of a thermodilatable material of the thermostatic element;   a main shutter, which is axially movable relative to a stationary seat of the first casing so as to open and close a main valve and which is connected to the moving part of the thermostatic element such that, during expansion of the thermodilatable material, the moving part of the thermostatic element drives the main shutter so as to open the main valve, the main shutter and the thermostatic element being assembled to one another while forming a first module of the thermostatic device;   a spring, which is compressed in the axis and which returns the moving part toward the stationary part of the thermostatic element during contraction of the thermodilatable material so as to command the closing of the main valve;   a bracket for bearing the spring, the bracket being intended to be securely connected to a second casing that channels the fluid and that is provided to be fastened to the first casing, while being axially interposed between the spring and the second casing; and   a cradle for supporting the first module, the cradle:
           being suitable for attaching the first module therein removably, by axially interposing the cradle between the first module and the spring,   including a bypass shutter, axially movable relative to a fixed seat of the bracket so as both to open a bypass valve when the main valve closes, and to close the bypass valve when the main valve opens, and   being connected to the bracket axially movably, with axial interposition of the spring, while being permanently retained at the bracket so as to keep the spring compressed between them,   
               
 
         [0018]    the spring, the bracket and the cradle being assembled to one another independently of the first module, while forming a second module of the thermostatic device, separate from the first module. 
         [0019]    One of the ideas at the base of the invention is to avoid having a “completely” integrated device, i.e., each of the components of which would specifically be designed relative to the other components in order to be assembled to one another in a dependent manner. Conversely, the invention seeks to be able to use, within the device according to the invention, various pre-existing thermostatic elements, in particular having various shapes and sizes, and pre-existing main valve shutters, associated with these thermostatic element and able to be broken down into various shapes and sizes, in particular various diameters. To that end, the invention provides that the device is made up of two separate modules, i.e., a first module corresponding to the assembly of the thermostatic element and the shutter of the main valve, the production of this assembly being able to be particularly cost-effective because it can be based on the use of pre-existing parts available at a low cost, and a second module corresponding to the assembly of the bracket, the spring and a removable support cradle of the first module. One clever aspect of the invention lies in the fact that this cradle is designed to accommodate various shapes and sizes of the first module, i.e., various shapes and sizes of the shutter of the main valve and/or the thermostatic element: the first module is attached removably to this cradle, in particular while being essentially, or even solely, placed on the cradle, before the first and second modules are associated within a thermostatic valve, while being jointly mounted on the casings to which the stationary part of thermostatic element of the first module and the bracket of the second module are then respectively securely connected. By providing that the cradle and the bracket are assembled with the spring so as to keep the spring compressed between them, this spring is pre-stressed within the second module, the latter being somewhat comparable to a spring box: the assembly of the device according to the invention on the aforementioned casings is made easier as a result because tooling dedicated to compressing the spring is not necessary. Thus, the device according to the invention separates the assembly of the parts of the first module and the assembly of the parts of the second module from one another, in order to facilitate the design of each of these modules and more easily integrate pre-existing parts into each of them, which reduces the manufacturing and restocking cost of the device according to the invention, while having a device that is practical to mount on valve casings. 
         [0020]    In practice, the device according to the invention is naturally integrated into a three-way valve, as mentioned above. That being said, this device can also equip a two-way valve: in this case, the main valve of the device controls the flow of the fluid between the two paths of the valve, while the bypass valve does not provide any regulation between these two paths, but without hindering the regulation done by the main valve. 
         [0021]    According to additional advantageous features of the device according to the invention:
       The cradle is suitable for attaching the first module removably therein, while connecting them to one another at least by axial bearing of the first module on the cradle.   The cradle is suitable for attaching the first module removably therein, while connecting them to one another at least by axial bearing of the main shutter of the first module on the cradle.   The cradle is suitable for attaching the first module removably therein, while connecting them to one another exclusively by axial bearing of the first module on the cradle.   The cradle is suitable for attaching the first module removably therein, while connecting them to one another exclusively by axial bearing of the main shutter of the first module on the cradle.   The cradle includes, axially opposite the bypass shutter, a crown which is substantially centered on the axis and which has a first face and a second face which are axially opposite, and a sealing gasket of the main shutter bears against the first face of the crown and an end turn of the spring bears against the second face of the crown when the first module is attached to the cradle.   The crown defines, on its second face, a housing for receiving and axially centering the end turn of the spring.   The cradle further includes a part connecting the crown to the bypass shutter, said part being provided with through flow openings for the fluid and said part being arranged radially around and separated from the moving part of the thermostatic element when the first module is attached to the cradle.   The cradle defines at least one surface for radially wedging the first module, which cooperates by shape matching with a frame of the main shutter when the first module is attached to the cradle.   The bypass shutter is a single piece, being integral with the rest of the cradle.   The bypass shutter is integral with the crown via the part connecting them.   The device according to claim  1 , wherein the bypass shutter includes both a fixed part which is stationary relative to the rest of the cradle and which cooperates with the fixed seat of the bracket in order to open and close the bypass valve, and a deballasting part which is movable relative to the stationary part of the bypass seal, while being moved against a return spring when an overpressure occurs at the bypass seal.   The fixed seat of the bracket comprises a cylindrical surface, which is substantially centered on the axis and inside which the bypass shutter is received in a complementary manner to close the bypass valve, and the bracket is provided with surfaces guiding the axial sliding of the cradle, said guide surfaces being connected to the fixed seat of the bracket and being distributed around the axis, while defining free flow passages between them for the fluid.   The fixed seat of the bracket consists of a cylindrical surface, which is substantially centered on the axis and inside which the bypass shutter is received in a complementary manner to close the bypass valve, and the bracket is provided with surfaces guiding the axial sliding of the cradle, said guide surfaces being connected to the fixed seat of the bracket and being distributed around the axis, while defining free flow passages between them for the fluid.       
 
         [0035]    The invention also relates to a thermostatic valve, including a first casing and a second casing which are fastened to one another, and further including a thermostatic device as mentioned above, the stationary part of the thermostatic element and the bracket of the thermostatic device being respectively securely connected to the first and second casings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0036]    As mentioned just above, this valve typically has three paths, but may also have two paths for circuits with no bypass path. 
           [0037]    The invention will be better understood upon reading the following description, provided solely as an example and done in reference to the drawings, in which: 
           [0038]      FIG. 1  is a longitudinal sectional view of a thermostatic valve according to the invention; 
           [0039]      FIG. 2  is a perspective view of a longitudinal half-section of the thermostatic device belonging to the valve of  FIG. 1 ; 
           [0040]      FIG. 3  is a view similar to  FIG. 2 , showing only part of the device of  FIG. 2 ; 
           [0041]      FIGS. 4 and 5  are views similar to  FIG. 1 , respectively showing operating configurations of the valve different from one another and different from the operating configuration shown in  FIG. 1 ; 
           [0042]      FIG. 6  is a view similar to  FIG. 3 , illustrating an alternative of the thermostatic device according to the invention; and 
           [0043]      FIG. 7  is a longitudinal sectional view of the alternative of  FIG. 6 , showing an operating configuration different from that shown in  FIG. 6 . 
       
    
    
     DETAILED DESCRIPTION 
       [0044]      FIGS. 1 to 5  show a valve  1  comprising a thermostatic device  2  for regulating the flow of a fluid. This fluid is in particular a cooling fluid, the valve  1  then for example belonging to a cooling circuit of a heat engine, in particular a motor vehicle engine. The device  2  is shown alone in  FIG. 2 , whereas in  FIGS. 1, 4 and 5 , this device is arranged in casings  4  and  6  of the valve  1 , having noted that these casings  4  and  6  are stationary relative to one another, in particular securely fastened to one another, when the valve  1  is in use as shown in  FIGS. 1, 4 and 5 . In practice, in the figures, the casings  4  and  6  are shown only partially and schematically, their embodiment not being limiting with respect to the invention. In all cases, when the valve  1  is in the usage configuration, the casings  4  and  6  channel the fluid by defining three flow paths  1 A,  1 B and  1 C for the fluid: these three paths constitute either one fluid inlet and two fluid outlets, or two fluid inlets and one fluid outlet for the valve  1 . As an example that will be mentioned again below, when the valve  1  belongs to a cooling circuit of an engine, the path  1 A constitutes a cooling fluid inlet, coming from the engine to be cooled, whereas on the one hand, the path  1 B constitutes a first outlet for this cooling fluid, sending the latter to a heat exchanger, in particular a radiator, designed to lower the temperature of the fluid traversing it, before this fluid is sent to the engine to be cooled, and on the other hand, the path  1 C constitutes a second outlet for the cooling fluid, which directly sends the latter to the engine to be cooled, without going through the aforementioned heat exchanger. It will be understood that the path  1 C feeds a bypass. Thus, the cooling fluid sent to the engine by the valve  1  comes from the outlets  1 B and  1 C of the latter and, after having cooled this engine, is sent back to the valve, more specifically to its path  1 A. 
         [0045]    The device  2  includes a thermostatic element  10  that is centered on a geometric axis X-X. This thermostatic element  10  includes a body  12 , centered on the axis X-X and containing a thermodilatable material such as a wax. The thermostatic element  10  also comprises a piston  14 , the longitudinal geometric axis of which is aligned on the axis X-X within the device  2  and a terminal axial part of which is submerged in the thermodilatable material contained in the body  12 . The body  12  and the piston  14  are translatable relative to one another along the axis X-X: under the effect of the expansion of the thermodilatable material, the piston  14  deploys outside the body  12 , while, during a contraction of the thermodilatable material, the piston is retractable inside the body  12 . 
         [0046]    Within the valve  1  when the latter is in use, the piston  14  of the thermostatic element  10  is securely fastened to the casing  4 . More specifically, in a manner known in itself, the terminal part of this piston  14 , opposite that submerged in the body  12 , is securely fastened to a part  4 A of the casing  4  arranged across the axis X-X. In practice, various embodiments can be considered regarding the secure fastening of the aforementioned terminal part of the piston  14  to the part  4 A of the casing  4 : this secure fastening can be done either solely by axial bearing, or by removable fastening, of the clipping or sliding fitting type, or by permanent securing of the forced fitting type, overmolding, or addition of a mechanical maintaining system. In all cases, it will be understood that, when the thermodilatable material of the body  12  of the thermostatic element  10  expands or contracts, the piston  14  is kept immobile relative to the casing  4 , due to the secure fastening of its aforementioned terminal part to this casing. 
         [0047]    The device  2  also comprises a main shutter  20  that is movable along the axis X-X relative to a stationary seat  4 B of the casing  4 , so as to open and close a corresponding main valve: within the valve  1  during use, when the shutter  20  is pressed in sealed contact against the seat  4 B like in the operating configuration shown in  FIG. 1 , this seal prevents the fluid from flowing between the paths  1 A and  1 B, whereas, when the shutter  20  is separated from the seat  4 B as in the operating configurations shown in  FIGS. 4 and 5 , the shutter  20  allows fluid to pass between the paths  1 A and  1 B, which, in the example embodiment defined above, amounts, within the valve  1 , to having at least part of the fluid entering through the path  1 A pass into the outlet of the path  1 B. 
         [0048]    To control the movement of the shutter  20 , the latter is securely fastened to the body  12  of the thermostatic element  10  such that, within the valve  1  when it is in use, the axial movement of the body  12  relative to the casing  4 , resulting from the expansion of the thermodilatable material, causes a corresponding movement of the shutter  20  so as to open the main valve by axial separation of this shutter  20  with respect to the seat  4 B. 
         [0049]    In the embodiment considered in the figures, the main shutter  20  comprises a rigid frame  22 , typically made from metal, which has a stepped annular shape, substantially centered on the axis X-X, and the periphery of which, turned radially opposite the axis X-X, is provided, for example by overmolding, with a flexible sealing gasket  24 , typically made from polymer or rubber. The sealing gasket  24  constitutes the part of the shutter  20  that cooperates with the seat  4 B of the casing  4  in order to open and close the main valve, while the frame  22  constitutes a part of the shutter  20  that cooperates with the body  12  of the thermostatic element  10  for the secure connection of the shutter to this body  12 , in particular by tight fitting around this body  12  of the periphery, turned radially toward the axis X-X, of this frame  22 . Given its embodiment, the shutter  20  considered here is comparable to a gate. 
         [0050]    Irrespective of the embodiment of the main shutter  20 , it will be noted that the latter and thermostatic element  10  are assembled to one another by forming a first module M 1  of the thermostatic device  2 , which differs from the rest of this device in that the assembly connection between the shutter  20  and the thermostatic element  10 , more specifically between the frame  22  of this shutter and the body  12  of the thermostatic element, is independent of the assembly connections between the other components of the device  2 , such that this module M 1  can be manipulated in a single piece, separately from the rest of the device  2 , in particular so that it may be assembled with the rest of this device. 
         [0051]    The thermostatic device  2  further comprises a cradle  30  for supporting the module M 1 , which is designed so that this module M 1  can be removably attached therein. More specifically, in the embodiment considered here, and as clearly shown in  FIG. 3 , the cradle  30  assumes a tubular global shape, the central axis of which is substantially combined with the axis X-X when the module M 1  is attached to this cradle, as clearly shown in  FIG. 2 . At its axial end turned toward the module M 1 , the cradle  30  is axially open, forming an axial access opening  32  to the free inner space of the cradle, while being outwardly surrounded by a crown  34 , substantially coaxial to the rest of the cradle  30  and extending continuously over the entire outer periphery of the cradle. On its axial side turned opposite the rest of the cradle  30 , the crown  34  has a face  34 A designed to provide axial bearing for the sealing gasket  24  of the main shutter  20  when the module M 1  is attached to the cradle  30 . The opening  32  of the cradle  30  is sized to axially engage the body  12  of the thermostatic element  10  therein, as well as at least one peripheral part, turned radially toward the axis X-X, of the frame  22  of the shutter  20 , this engagement being provided with no axial interference that would prevent the creation of axial bearing of the sealing gasket  24  against the face  34 A of the crown  34 . In other words, the cross-section of the opening  32 , i.e., the section of the latter in a geometric plane perpendicular to the axis X-X, is larger than, or optionally adjusted to, the largest of the cross-sections of the body  12  and the frame  22 , which may axially interfere with the cradle  30  when the module M 1  is attached to the cradle and as long as its sealing gasket  24  is not yet axially pressed against the face  34 A of the crown  34 . 
         [0052]    Building on the preceding considerations, and according to one advantageous arrangement that is implemented in the embodiment considered in the figures, the opening  32  of the cradle  30  defines radial wedging surfaces  32 A of the module M 1 , which cooperate by shape matching, in particular by radial bearing, with the frame  22  of the shutter  20  when the module M 1  is attached to the cradle: in other words, in its portions corresponding to the aforementioned wedging surfaces  32 A, the cross-section of the opening  32  is adjusted to that of the part of the frame  22 , arranged across this opening, as clearly shown in  FIG. 1 . 
         [0053]    Taking the above explanations into account, it is understood that, when the module M 1  is attached to the cradle  30 , the latter is attached thereto removably, in that the connection between the cradle and the module M 1  consists exclusively, or at least essentially, of an axial bearing of the shutter  20  on the crown  34  of the cradle, this axial bearing being freely reversible. The cooperation between the wedging surfaces  32 A of the cradle  30  and the module M 1  makes it possible to avoid a relative misalignment between the cradle and the module M 1  when the latter is attached to the cradle: if applicable, in case of radial interference between these wedging surfaces  32 A and the module M 1 , in the case at hand between these surfaces  32 A and the frame  22  of the shutter  20 , it will be understood that this interference does not permanently connect the module M 1  with the cradle  30 , but causes a low resistance to the release of the module M 1  with respect to the cradle  30  when such a release is desired, for example for maintenance purposes of the device  2 . More generally, building on the preceding considerations, in addition to being connected by axial bearing, the module M 1  and the cradle  30  are optionally connected in another manner, for example by clipping and/or fitting, as long as this other connection is removable, like the connection by axial bearing. 
         [0054]    At its end axially opposite the crown  34 , the cradle  30  includes a solid wall  36 , which extends across the axis X-X, while being substantially centered on this axis, and which, in the embodiment considered in the figures, axially closes the free space inside the cradle  30 . This wall  36  is connected to the crown  34  by a running part  38  of the cradle  30 , which defines the free inner space of the cradle and inside which at least part of the body  12  of the thermostatic element  10  and, if applicable, part of the frame  22  of the shutter  20  when the module M 1  is connected to the cradle  30 , are arranged without interference. Thus, the running part  38  of the cradle  30  is designed to be arranged radially with respect to and at a distance from the body  12  of the thermostatic element, but without preventing the fluid from flowing through it radially with respect to the axis X-X inasmuch as this running part  38  is provided with radially through openings  38 A: in the embodiment considered in the figures, this running part  38  consists of arms  38 B, which extend lengthwise substantially parallel to the axis X-X, while each connecting the crown  34  to the wall  36  of the cradle  30 , and which are distributed regularly around the axis X-X, defining the openings  38 A between them, as clearly shown in  FIG. 3 . 
         [0055]    According to one advantageous arrangement, which is also implemented in the embodiment considered in the figures, the cradle  30  is made in the form of a single-piece part, by molding or machining, in that the crown  34 , the solid wall  36  and the running part  38  are integral with one another. 
         [0056]    The thermostatic device  2  further includes a bracket  40  to which the cradle  30  is movably connected along the axis X-X, typically sliding along this axis. Within the valve  1  when it is in use, the bracket  40  is securely fastened to the casing  6 , the embodiment of this secure connection not limiting the invention. 
         [0057]    In the example considered in the figures, the bracket  40  has a tubular global shape, the central axis of which is substantially combined with the axis X-X when the valve  1  is in use, and which is axially open at its opposite axial ends. 
         [0058]    At its end turned axially opposite the cradle  30 , the bracket  40  thus defines an axial access opening  42  to the free inner space of the bracket and is outwardly surrounded by a coaxial collar  44  continuously running over the entire outer periphery of the bracket. It is also at this end that the bracket  40  is securely connected to the casing  6 , via axial bearing of its collar  44  against a part  6 A of the casing  6 , which is arranged across the axis X-X and through which the path  1 C is provided: as mentioned above, other embodiments can be considered regarding the secure connection between the bracket  40  and the casing  6 , in particular by cooperation between the collar  44  of this bracket and the part  6 A of the casing  6 , this secure connection advantageously being sealed by any appropriate means. In all cases, the opening  42  of the bracket  30  emerges axially in the path  1 C, connecting the latter to the free inner space of the bracket  40 , as clearly shown in  FIG. 1 . 
         [0059]    The opening  42  forms a seat  42 A for cooperation with the wall  36  of the cradle  30  at the ends of the opening and closing of a corresponding valve, other than the aforementioned main valve and qualified in this document as bypass valve, in particular in connection with the example use of the valve  1  set out above. In the example embodiment considered in the figures, the seat  42 A consists of a cylindrical surface defining the opening  42 , the cross-section of the cylindrical surface being adjusted to that of the wall  36  of the cradle  30 : more generally, it will be understood that the seat  42 A is arranged and sized to receive the wall  36  of the cradle  30  along the axis X-X in a complementary manner, like in the operating configuration shown in  FIG. 5 , such that the wall  36  then closes off the fluid passage inside the opening  42 , in other words by closing the aforementioned bypass valve. Of course, when the wall  36  is axially remote from the seat  42 A, the bypass valve is open in that the fluid is free to pass through the opening  42  of the bracket  40 , thus flowing between the paths  1 A and  1 C, like in the operating configurations shown in  FIGS. 1 and 4 . It will therefore be understood that the wall  36  constitutes a shutter of the bypass valve, cooperating, here by sliding axial engagement, with the fixed seat  42 A of the bracket  40  in order to open and close the bypass valve. 
         [0060]    At its end axially opposite that defining the opening  42 , the bracket  40  defines an axial access opening  46  to the free inner space of the bracket. This opening  46  is suitable for receiving the cradle  30 , so as to arrange and allow the axial movement of the shutter  36  and the running part  38  of the cradle  30  in the free inner space of the bracket  40 . 
         [0061]    The opposite axial ends of the bracket  40  are connected to one another by a running part  48  of the bracket, which is provided with free flow passages  48 A for the fluid so as to allow the fluid to flow through this running wall  48 , radially with respect to the axis X-X: when the bypass valve is open, the fluid passing through the opening  42  can thus rejoin or come from the outside of the bracket  40 , via these free passages  48 A. In the embodiment considered in the figures, this running part  48  of the bracket  40  consists of arms  48 B, which extend lengthwise substantially parallel to the axis X-X while connecting the opposite axial ends of the bracket, and which are distributed regularly around the axis X-X, as clearly shown in  FIG. 3 . Advantageously, these arms  48  define, on their face turned toward the axis X-X, surfaces  48 C for guiding axial sliding of the cradle  30 , these surfaces  48 C being adjusted to the cross-section of the shutter  36  of the cradle, as clearly shown in  FIG. 3 . Subject to their connection to the seat  42 A, it will be understood that these surfaces  48 C guide the shutter  36  over its axial movement travel with respect to the bracket  40  in order to open and close the bypass valve. 
         [0062]    The thermostatic device  2  further comprises a spring  50 , which, within the valve  1  when the latter is in use, is provided to return the body  12  of the thermostatic element  10  toward the piston  14  of the thermostatic element during a contraction of the thermodilatable material, so as to command the closing of the main valve via the driving, by the body  12 , of the shutter  20  with respect to the seat  4 B. To that end, the spring  50  is functionally interposed between the body  12  and the piston  14  of the thermostatic element  10  so as to be compressed in the axis X-X when the body  12  and the piston  14  move axially away from one another. More specifically, the spring  50  is physically interposed, in the axis X-X, between the cradle  30  and the bracket  40 , while axially interposing the cradle between this spring and the module M 1 , and while axially interposing the bracket between this spring and the casing  6 . Thus, within the valve  1 , the spring  50  bears, by one of its axial ends, against the bracket  40 , the bearing forces being reacted by the casing  6 , whereas, by its opposite axial end, the spring  50  bears against the cradle  30 , the corresponding bearing force being transmitted to the module M 1 . 
         [0063]    In the example considered in the figures, an end turn  52  of the spring  50  is pressed against the collar  44  of the bracket  40 , more specifically against the face of this collar, opposite the part  6 A of the casing  6 , while the opposite end turn  54  of the spring  50  bears against the crown  34  of the cradle  30 , more specifically against the face  34 B of this crown, axially opposite its face  34 A. According to one advantageous arrangement, which is implemented in the embodiment considered in the figures, the face  34 B of the crown  34  is configured to center the end turn  54  of the spring  50 , while defining a housing  34 C for receiving and centering this end turn  54 . In all cases, it will be understood that when the cradle  30  is moved axially relative to the bracket  40  so as to bring its crown  34  closer to the collar  44  of this bracket and therefore so as to bring its shutter  36  axially closer to the seat  42 A, the spring  50  is axially compressed. 
         [0064]    Furthermore, the cradle  30  and the bracket  40  are assembled to one another, with axial interposition of the spring  50  as explained above, so as to keep this spring compressed between them. To that end, the cradle  30  is kept permanently at the bracket  40 , limiting the amplitude of its axial mobility when the crown  34  moves away from the collar  44 . In practice, various embodiments can be configured to thus permanently retain the cradle  30  and the bracket  40  relative to one another when the latter are separated from one another with a distance considered to be maximal, as is the case in  FIGS. 2 and 3 . In the example embodiment considered in the figures, the opening  46  of the bracket  40  is provided with hooks  46 A, the recess of which is both axially open toward the opening  42  and substantially complementary with corresponding portions of the periphery of the shutter  36  of the cradle  30 . 
         [0065]    Taking the above explanations into account, it will be understood that the cradle  30 , the bracket  40  and the spring  50  are assembled to one another while forming a module M 2 , which is shown alone in  FIG. 3  and which is separate from the module M 1  described above. Indeed, the assembly of the cradle  30 , the bracket  40  and the spring  50  to one another is independent of the assembly of the thermostatic element and the shutter  20  to one another, having recalled that the module M 1 , formed by the assembly of the thermostatic element  10  and the shutter  20 , is provided, within the device  2 , to be removably attached to the cradle  30 , in particular by connecting this module M 1  to the cradle  30  essentially, or even exclusively, by axial bearing. In other words, the module M 2  constitutes a sort of spring box on which the module M 1  is removably attached so as together to make up the device  2 , the modules M 1  and M 2  next being jointly arranged in the casings  4  and  6  to form the valve  1 , as in  FIGS. 1, 4 and 5 . Because the modules M 1  and M 2  are separate, resulting from respective assemblies done independently of one another, it will be understood that each of these modules M 1  and M 2  benefits from greater design freedom, in particular compared to a situation where the device  2  is fully integrated. In particular, for the module M 1 , this makes it possible to use pre-existing parts for the thermostatic element  10  and/or for the shutter  20 . Inasmuch as, within the module M 2  considered alone, the spring  50  is kept compressed, the device  2  associating this module M 2  and the module M 1  remains easy to place within the valve  1 , in that it is not necessary to use specialized tooling seeking to compress this spring during commissioning of the valve. 
         [0066]    The operation of the valve  1  will now be described in light of  FIGS. 1, 4 and 5 , in the context of the usage example of this valve mentioned above. 
         [0067]    In the operating configuration shown in  FIG. 1 , the fluid entering through the path  1 A is both prevented from flowing in the path  1 B due to the closing of the main valve and sent in full to the path  1 C owing to the opening of the bypass valve, the fluid flowing by passing successively through the free passages  48 A and the opening  42  of the bracket  40 . Taking the preceding into account, it will be understood that the passage section of the fluid at the bypass valve can be adjusted as needed, by modifying the diameter of the opening  42  and/or by modifying the axial dimension of the free passages  48 A. 
         [0068]    If the temperature of the fluid supplying the path  1 A increases, the thermodilatable material of the thermostatic element  10  expands, the heat from the fluid being transmitted to this thermodilatable material because the body  12  is swept by fluid currents flowing through the openings  38 A of the cradle  30 . The axial movement of the body  12  relative to the piston  14 , which is stationary relative to the casings  4  and  6 , drives the corresponding axial movement of the shutter  20 , and thus of the cradle  30 , against which the shutter  20  is axially pressed. As shown in  FIG. 4 , the main valve then opens gradually, by axial separation of the shutter  20  with respect to the seat  4 B, whereas, at the same time, the bypass valve gradually closes, by bringing the shutter  36  axially closer to the seat  42 A. The fluid allowed in the path  1 A is then distributed between the path  1 B and the path  1 C. 
         [0069]    If the temperature of the fluid supplying the path  1 A continues to increase, the main valve opens more, while the bypass valve closes more in a corresponding manner, until, if applicable, it is completely closed, by sealing of the seat  42 A by the shutter  36 , as shown in  FIG. 5 . 
         [0070]    If the temperature of the fluid supplying the path  1 A next decreases, the thermodilatable material of the thermostatic element  10  contracts and, under the decompression effect of the spring  50 , the cradle  30 , and thus the module M 1 , are driven axially so as to gradually open the bypass valve and gradually close the main valve. 
         [0071]    Various arrangements and alternatives to the device  2  and valve  1  described thus far may be considered. As examples:
       rather than forming a single piece like in the embodiment shown in  FIGS. 1 to 5 , the shutter of the bypass valve may, like in the alternative of the module M 2  shown in  FIGS. 6 and 7 , in which this shutter is referenced  36 ′, include both a part  36 ′A that is stationary relative to the rest of the cradle  30  and that cooperates with the seat  42 A of the bracket  40  in order to open and close the bypass valve in a manner functionally similar to the shutter  36 , and a deballasting part  36 ′B that is movable relative to the stationary part  36 ′A and that is designed so as, during an overpressure of the fluid on this moving part  36 B, as indicated by the arrows S in  FIG. 7 , to move against a dedicated return spring  36 ′C integrated in the cradle  30 ; more generally, it will be understood that, within the module M 2 , the shutter of the bypass valve can therefore incorporate a deballasting function;   rather than securely connecting the piston  14  of the thermostatic element to the casing  4 , the body  12  of this thermostatic element may be provided to be stationary relative to the casing, the piston  14  then constituting the moving part of the thermostatic element, while performing the driving function described for the body  12  in light of  FIGS. 1 to 5 ;   rather than being securely connected to the moving part of the thermostatic element, the shutter  20  may be mounted on this moving part with a free movement along the axis X-X, on the condition that it is associated with a dedicated return spring; the shutter  20  then incorporates a deballasting function in case of overpressure at the main valve;   embodiments other than the hooks  46 A can be considered to permanently keep the cradle  30  and the bracket  40  assembled movably along the axis X-X; in particular, the retaining can be provided by fitting, bayonet coupling, etc.;   the materials making up the different parts of the device  2  are not limiting;   in order to reinforce the sealing, gaskets or similar sealing parts may be added at least at some of the contact interfaces between the parts of the device  2 ; and/or   the embodiment of the thermostatic element  10  is not limiting, inasmuch as this element may optionally be controlled, i.e., incorporate a heating electric resistance, or may assume various diameters, etc.