FR3052528A1 - ANTI-RETURN VALVE AND CIRCUIT AND COOLING DEVICE FOR A VEHICLE COMPRISING SUCH A VALVE - Google Patents

Abstract

A check valve (50) having a fixed housing (52) including an inner conduit extending between a fluid inlet (54) and a fluid outlet (56), and a movable member (58) between a first position shutting said duct and a second open position of said duct, said movable member being configured to be moved from said first position to said second position when a fluid flow greater than a predetermined threshold enters said duct via said inlet, and to be moved from said second position to said first position when said flow rate is below said threshold, characterized in that it further comprises means (80) for immobilizing said member in said second position.

Description

Non-return valve and circuit and cooling device for a vehicle comprising such a valve

TECHNICAL FIELD The invention relates to a non-return valve, a circuit and a cooling device for a vehicle comprising such a valve.

STATE OF THE ART The state of the art includes in particular the document FR-A1-2 913 374. This document describes a cooling circuit of a motor vehicle

Typically, a vehicle cooling circuit is a closed circuit that includes different lines that extend from the engine and the vehicle water pump, defining different loops. A loop extends for example in the vicinity of the passenger compartment of the vehicle to ensure the heating thereof. Other loops include a thermostat, a radiator, a degassing tank, etc.

A vehicle cooling device may include one or more cooling circuits. It may for example comprise a first said high temperature cooling circuit, at least 90 ° C for example, and a second so-called low temperature cooling circuit, of the order of 60-70 ° G for example. This second circuit can be used to cool batteries of an electric vehicle for example.

Several architectures are possible for this device.

In a first case, the circuits may be independent and each comprise a release tank. The device is then equipped with two independent degassing tanks.

In another case, part of the circuits is communalised. It is advantageous to communicate the degassing tank so that the device has only one. This saves space but also facilitates the fluid filling of the circuits since the supply port of the degassing tank can be used to supply the two circuits. However, in practice, the tank is actually used for degassing only the first circuit. The second circuit is connected by a loop to the fluid outlet of the reservoir. The tank serves as a degassing tank for the second circuit only when it is filled. In operation, the tank serves only as an expansion tank in the second circuit, in case of temperature rise of the fluid contained in this circuit.

In yet another preferred embodiment, the degassing tank is connected to the two circuits so as to ensure in operation the degassing function for each of these circuits. In this case, the second circuit is connected by loops to the fluid inlet and outlet of the reservoir, the loop connected to the fluid outlet to be equipped on the one hand with a non-return valve or with a valve to allow filling. of the second circuit and prevent the fluid contained in the second circuit from escaping into the first circuit, and secondly a closing valve (English "on / off") which is controlled for close when the temperature of the fluid in the second circuit reaches a predetermined threshold (for example 60-70 ° C).

However, the juxtaposition of two valves on the loop causes problems including congestion.

The present invention provides a solution to this problem which is simple, effective and economical.

SUMMARY OF THE INVENTION The invention thus proposes a non-return valve, in particular for an automobile, comprising a fixed housing comprising an internal duct extending between a fluid inlet and a fluid outlet, and a movable member between a first shutter position of said duct and a second open position of said duct, said movable member being configured to be moved from said first position to said second position when a fluid flow rate greater than a predetermined threshold enters said duct via said inlet and to be moved from said second position to said first position when said fluid flow rate is below said threshold, characterized in that it further comprises immobilization means, in particular controlled means, of said member in said second position. The invention thus proposes to combine the functions of the check valves and closure of the current technique in a single valve which thus has a dual function. It provides on the one hand the conventional non-return function and is further configured to provide a valve holding function in the closed position. The invention is thus advantageous in terms of compactness and thus space saving.

The valve according to the invention may comprise one or more of the following characteristics, taken separately from one another or in combination with each other: the immobilizing means are electrical or pneumatic immobilizing means; said movable member comprises a ferromagnetic body, said immobilization means comprising at least one electrical coil surrounding at least part of said body; said body has an elongated shape and is slidably mounted along its axis of elongation inside said housing; said housing comprises at least one internal cylindrical surface for guiding said body along said axis of elongation; said housing comprises a first cylindrical wall comprising said inner cylindrical surface and an outer cylindrical surface on which said at least one coil is mounted; said at least one coil is surrounded by a second cylindrical wall, which is formed in one piece with or on said first cylindrical wall; said at least one coil is mounted on a support sleeve, itself mounted on said first wall; said housing comprises a portion equipped with means for electrically connecting said at least one coil; said fitted part is formed in one piece with said support sleeve or said second cylindrical wall; said body is cylindrical solid or tubular and defines externally or internally a flow vein of said fluid; - said movable member comprises a head configured to cooperate by pressing and sealing with an inner annular seat of said housing when said member is in its first position; said head has at least partly a spherical or ovoid shape; - Said movable member is biased towards its second position by biasing means such as a compression spring, for example helical; - The return means are configured to be deformed, for example by compression, by applying a force less than 1N, and for example between 0.1 and 0.5N; - The return means are configured to exert a restoring force of less than 1 N, and for example between 0.1 and 0.5N; said return means are mounted coaxially inside or outside said body; said housing comprises an internal chamber configured to be connected to means for supplying air and / or for extracting air; said movable member comprises a first elongated body slidably mounted along its elongation axis inside said housing, at least a portion of said first body extending into said chamber; an elastically deformable membrane is mounted in said chamber and is respectively fixed to said housing and to said portion, said membrane being configured to deform following an activation of said supply and / or suction means for driving or following said first body; from his second position to his first position; said membrane has an annular shape and comprises an inner peripheral edge fixed on said portion and an outer peripheral edge fixed on said casing; said portion comprises an annular surface for supporting and guiding the membrane during its deformations; said movable member comprises a second body independent of said first body and coaxial with the latter, said second body being slidably mounted along said axis of elongation inside said casing between said first and second positions; said first and second bodies are urged at a distance from one another by return means such as a compression spring; said threshold is zero or almost zero; and - said inlets and outlets are substantially aligned or at right angles; alternatively, they are inclined at a given angle.

The present invention also relates to a cooling circuit, in particular a low temperature circuit, for a vehicle, comprising at least one non-return valve as described above.

The circuit may comprise a loop comprising said non-return valve, a water pump and a degassing and expansion tank.

The present invention further relates to a cooling device for a vehicle, comprising a low temperature cooling circuit as described above, a high temperature cooling circuit, and a tank configured to provide degassing and expansion functions for said circuits.

Advantageously, said reservoir comprises a fluid outlet connected to said high temperature cooling circuit, this outlet also being connected to said non-return valve of said low temperature cooling circuit.

BRIEF DESCRIPTION OF THE FIGURES The invention will be better understood and other details, characteristics and advantages of the present invention will appear more clearly on reading the description which follows, given by way of nonlimiting example and with reference to the appended drawings. in which: - Figure 1 is a very schematic view of a cooling device, in particular a vehicle; - Figure 2 is a schematic axial sectional view of a first embodiment of a non-return valve according to the invention, here in the closed position; - Figure 3 is a schematic axial sectional view of the valve of Figure 2, here in the open position; - Figure 4 is a schematic sectional view along the line IV-IV of Figure 3; - Figure 5 is a schematic axial sectional view of a second embodiment of a non-return valve according to the invention, here in the closed position; - Figure 6 is a schematic axial sectional view of the valve of Figure 5, here in the open position; - Figure 7 is a schematic sectional view along the line VII-VII of Figure 6; - Figure 8 is a schematic axial sectional view of a third embodiment of a non-return valve according to the invention, here in the closed position; - Figure 9 is a schematic axial sectional view of the valve of Figure 8, here in the open position; - Figure 10 is a schematic axial sectional view of the valve of Figure 8, here in the locked position; and FIG. 11 is another partial schematic view in axial section of the valve of FIG. 8, and shows an air intake duct.

DETAILED DESCRIPTION

FIG. 1 schematically represents a cooling device 10 for a motor vehicle, this device 10 comprising two interconnected cooling circuits, a main circuit 12 for cooling, said high temperature (for example at least 90 ° C.) and a circuit secondary cooling 14, said low temperature (for example of the order of 60-70 ° C).

The main circuit 12 is well known to those skilled in the art and will not be described in detail. It is schematically represented by a rectangle in dotted lines and comprises a fluid inlet 16 connected to a fluid outlet 18 of a degassing tank 20, and a fluid outlet 22 connected to a fluid inlet 24 of the tank 20.

The secondary circuit 14 comprises a water pump 26, a fluid inlet 28 of which is connected by a pipe 30 to the fluid outlet 18 of the tank 20. The fluid outlet 32 of the water pump 26 is connected to several parallel loops of water. cooling elements 34 of the vehicle, these loops being connected to the fluid inlet 24 of the reservoir 20. These loops are further connected to an input of a thermostat 36 which, depending on the temperature of the fluid in the circuit 14 , either passes the fluid through a radiator 38, or bypasses the radiator and returns to the water pump 26. The radiator outlet is also connected to the inlet 28 of the water pump 26.

The pipe 30 here comprises two independent valves, a non-return valve 40 and a closure valve 42. The non-return valve 40 opens as soon as the force of the liquid is greater than that of the spring, for example during the phase filling circuit 12 and 14, which is through the outlet 18 of the reservoir 20. This valve 40 isolates the circuit 14 and prevents a passage of the fluid from the circuit 12 to the circuit 14. In the same way, a check valve 44 is provided at the output 22 of the circuit 12 to isolate it and avoid a passage of the fluid from the circuit 12 to the circuit 14.

The closure valve 42 is opened during the temperature rise of the circuit 14 so that, associated with the valves 40 and 44, the reservoir 20 has a degassing and expansion function, and is then closed when the fluid of the circuit 14 reaches a certain temperature. The circuit 14 is then closed, the law of conservation of the flows being such that, in spite of the absence of valve on the connecting pipe of the circuit 14 to the inlet 24 of the tank, the closing of the valve 42 is sufficient to isolate the circuit 14 of the rest of the device. The invention proposes to combine the functions of the valves 40, 42 within the same valve.

Figures 2 to 4 show a first embodiment of a non-return valve 50 according to the invention.

The valve 50 comprises a housing 52, for example made of plastic material, which defines an internal conduit for the circulation of a fluid, from a fluid inlet 54 to a fluid outlet 56.

In the example shown, the inner duct has a generally rectilinear and elongated shape, its inlet 54 being located on the left on the drawing and its output 56 on the right. The axis of elongation of the conduit and the housing 52 is noted A.

The housing 52 is fixed and intended to be fixed on a vehicle element. It comprises a movable member 58 inside the duct, between a first closed position of the duct shown in FIG. 2 and a second open position of the duct shown in FIG. 3. The member 58 is here mounted in a movable manner. in a substantially cylindrical cavity 60 of the duct, coaxial with the fluid inlet and outlet 54, 56. The housing 52 is here formed by two tubular sections 52a, 52b fixed coaxially to one another. Each section 52a, 52b here comprises a first cylindrical wall 52aa, 52ba internally defining the fluid inlet or outlet 54, 56, and a second cylindrical wall 52ab, 52bb internally defining a portion of the cavity 60.

In the example shown, the second wall 52ab, 52bb of a section 52a, 52b has a diameter greater than the first wall 52aa, 52ba of this section. Furthermore, the second wall 52bb of the section 52b has a diameter, in particular internal, slightly greater than that of the second wall 52ab of the other section 52a.

The wall 52ab of the section 52a comprises at its axial end opposite the wall 52aa a radially outer annular flange 52ac axially applied to an outer annular flange 52bc similar to the wall 52bb of the section 52b. These flanges 52ac, 52bc can be fixed together by welding.

The housing 52 comprises inside the conduit, and more precisely the cavity 60, a coaxial finger 62. The finger 62 is connected by spacers 64 to the housing, and more precisely to the junction zone of the walls 52ba, 52bb of the section 52b. The finger 62 extends axially from this zone to substantially half the axial dimension or length of the wall 52bb of this section 52b. The spacers 64 are here three in number (Figure 4). They extend substantially radially with respect to the axis A and are evenly distributed around this axis A. The struts 64, the finger 62 and the section 52b can be made in one piece as in the example shown. The movable member 58 here comprises two elements, a tubular body 58a and a head 58b. The body 58a is defined by a tubular cylindrical wall of axis A. The body 58a is slidably movable along the axis A and is centered and guided inside the cavity 60, by cooperation of its outer cylindrical surface with the internal cylindrical surface of the wall 52bb of the section 52b.

The body 58a extends over 60 to 90% of the length of the cavity 60 in the example shown. The free end of the body 58a, located on the side of the inlet 54 of the duct, is fixed to the head 58b.

The head 58b here has a generally ovoid shape and comprises a free end, located on the side of the inlet 54, as a sphere portion. This free end is intended to cooperate by sealing with an inner ring seat 66 located here in the junction area of the walls 52aa, 52ab of the section 52a. The opposite end of the head 58b, therefore located on the output side 56, comprises a substantially cylindrical housing 68 aligned on the axis A and receiving an axial end of a return spring 70. The opposite axial end of the spring 70 is housed in a cylindrical housing 72 of the axial end of the finger 62 located on the side of the inlet 54. The return spring 70 is here a helical compression spring axis A.

The head 58b comprises radial protrusions 58bb for fixing to the body 58a. The outer radial ends of the excrescences 58bb are located on a circumference of diameter substantially equal to the internal diameter of the wall 52ab of the section 52a. The head 58b is thus centered and guided in translation along the axis A by cooperation of its excrescences 58bb with the inner cylindrical surface of this wall 52ab.

As can be seen in the drawings, the member 58 is movable: from the closed position of the valve 50 of FIG. 2, in which it is located at an axial end, here left, of the cavity 60, the spring 70 axially biasing the head 58b and the body 58a axially towards this end and the head 58b being in sealing engagement against the seat 66, - to the open position of Figure 3, in which the member 58 is located the opposite axial end, here right, of the cavity 60, the spring 70 being axially constrained and the head 58b being located at a distance from the seat 66.

In the absence of fluid circulation in the conduit, the valve 50 is closed. The compression spring 70 urges the head 58b against the seat 66. When a fluid enters the valve 50 through its inlet 54, it applies a force on the head 58b. When the fluid flow rate is above a certain threshold, the force applied to the head 58b is such that it is greater than the restoring force of the spring 70 which is compressed axially. The member 58 then moves from its first to its second position. When the fluid flow rate drops below the threshold, the return force of the spring becomes greater than the force exerted by the fluid on the head, which moves from its second to its first position. When a fluid enters the valve through its outlet, it is blocked by the head 58b which bears tightly on its seat 66. With the exception of its protuberances 58bb, the head 58b has a maximum external diameter less than the internal diameter of the wall 52ab and the cavity 60 so that fluid can flow inside the cavity 60, between the head 58b and the housing 52, when the head is not in sealing abutment on the seat 66.

At the inlet 54 of the valve, the fluid passageway has a circular cross section. At the level of the head 58b of the member 58, the passage vein has an annular section upstream, at the level of the excrescences 58bb a sectioned section and then again an annular section downstream of these excrescences. This is also the case at the finger 62 where the vein extends between the finger 62 and the tubular body 58a. This vein is then sectorized at the spacers 64 in three angular sectors (Figure 4). Downstream of the spacers 64, the vein again has a circular shape in section.

The valve 50 further comprises means 80, here electrical, immobilizing the member 58 at least in its first position, that is to say closed.

The means 80 here comprise at least one electrical coil 82 which is mounted coaxially on the wall 52bb of the section 52b. In the example shown, the coil 82 extends over substantially the entire length of this wall 52bb, between the flange 52bc of the section 52b and its junction area of the walls 52ba, 52bb.

The coil 82 is here mounted on a tubular support sleeve 84, which is itself engaged on the wall 52bb. This sleeve 84 has a longitudinal section substantially U-shaped and can be used for the preparation of the coil and in particular the winding of son or son son. The sleeve 84 comprises at an axial end, located on the side of the inlet 54, an outer radial flange 84a applied to the flange 52bc of the section 52b, and an outer radial flange 84b at the opposite end.

The coil 82 is surrounded by a cylindrical wall 86 of an annular cover 88 mounted on the housing 52. The end of the wall 86, located on the inlet side 54 of the valve, is applied to the flange 52bc of the section 52b and fixed to this rim, for example by welding or gluing. The opposite end of the wall 86 is connected to the outer periphery of an inner annular flange 90 of the cover 88, whose inner periphery bears and can be fixed, for example by welding or gluing, on the housing 52. The sleeve support 84 can be held axially clamped between the flange 52bc of the section 52b and the flange 90 of the cover 88.

The cover 88 comprises means for electrical connection of the coil 82 to power supply and electrical control means (not shown). As mentioned in the foregoing, when the temperature of the fluid in the circuit 14 comprising the valve 50 reaches a predetermined threshold, for example 60 or 70 ° C, the coil 82 is electrically powered and generates a magnetic field inside the conduit. . The body 58a, which is here made of ferromagnetic material, is then biased by the magnetic field in the closed position of the valve (Figure 2). The member 58 is then locked in this closed position as the coil 82 is energized.

Figures 5 to 7 show a second embodiment of a non-return valve 150 according to the invention.

The valve 150 comprises a housing 152, for example of plastic material, which defines an internal conduit for the circulation of a fluid, from a fluid inlet 154 to a fluid outlet 156.

In the example shown, the internal duct has a general L shape. The inlet 154 has an axis A and the outlet has an axis B. These axes A, B are substantially perpendicular.

The housing 152 is fixed and intended to be fixed on an element of the vehicle. It comprises a movable member 158 inside the duct, between a first closed position of the duct shown in FIG. 5 and a second open position of the duct shown in FIG. 6. The member 158 is here mounted in a movable manner. in a substantially cylindrical cavity 160 of the duct, coaxial with the inlet 154. The housing 152 is here formed by two tubular sections 152a, 152b fixed to one another.

The section 152a comprises a first cylindrical wall 152aa of axis A and internally defining the fluid inlet 154, and a second cylindrical wall 152bb of axis A and internally defining a portion of the cavity 160.

The section 152b comprises a first cylindrical wall 152ba of axis B and internally defining the fluid outlet 154, and connected at right angles to a second substantially cylindrical wall 152bb of axis A. This second wall 152bb comprises a first front portion 152bba or upstream part forming the cavity 160 and a bend 15bbb connecting this cavity 160 to the outlet 156. The second wall 152bb further comprises a second rear portion 152bbc or downstream axis A and having two coaxial cylindrical walls respectively radially internal 152bbc1 and external 152bbc2.

In the example shown, the second wall 152ab of the section 152a has a diameter greater than the first wall 152aa of this section. Furthermore, the wall 152aa and the portion 152bbc have substantially the same diameter and the upstream end of the 52bba portion has an inner diameter substantially equal to that of the wall 152ab.

The wall 152ab of the section 152a comprises at its axial end opposite the wall 152aa a radially outer annular flange 152ac axially applied to an outer annular flange 152bc similar to the wall 152bb of the section 152b. These flanges 152ac, 152bc can be fastened together by welding. The movable member 158 here comprises two elements, a cylindrical body 158a and a head 158b. The body 158a is slidably movable along the axis A and is centered and guided inside the cavity 160, by cooperation of its outer cylindrical surface with the internal cylindrical surface of the wall 152bbc1. This wall 152bbc1 here defines a cylindrical housing for guiding the body 158, which is closed at its axial end opposite the inlet 154 by a radial wall 161. The free end of the body 158a, situated on the side of the inlet 154 of the led, is attached to the head 158b.

The head 158b here has a generally ovoid shape and comprises a free end, located on the side of the inlet 154, as a sphere portion. This free end is intended to cooperate by sealing with an inner ring seat 166 located here in the junction area of the walls 152aa, 152ab of the section 152a. The opposite end of the head 158b, therefore located on the output side 156, comprises a substantially cylindrical housing 168 of axis A in which is received an axial end of the body 158a. A return spring 170 is mounted around the body 158a and bears axially on this end of the head 158b. The other end of the spring 170 is axially supported on a radial end face of the wall 152bbc1. The return spring 170 is here a helical compression spring axis A.

The head 158b includes radial protuberances 158bb. The outer radial ends of the protuberances 158bb are located on a circumference of diameter substantially equal to the internal diameter of the wall 152ab of the section 152a. The head 158b is thus centered and guided in translation along the axis A by cooperation of its protuberances 158bb with the internal cylindrical surface of this wall 152ab.

As can be seen in the drawings, the member 158 is mobile: from the closed position of the valve 150 of FIG. 5, in which it is located at an axial end, here left, of the cavity 160, the spring 170 axially biasing the head 158b and the body 158a axially towards this end and the head 158b being in sealing abutment against the seat 166, - to the open position of FIG. 6, in which the member 158 is located at the opposite axial end, right here, of the cavity 160, the spring 170 being axially constrained and the head 158b being located at a distance from the seat 166.

In the absence of fluid circulation in the conduit, the valve 150 is closed. The compression spring 170 urges the head 158b against the seat 166. When a fluid enters the valve 150 through its inlet 154, it applies a force on the head 158b. When the fluid flow rate is above a certain threshold, the force applied on the head 158b is such that it is greater than the restoring force of the spring 170 which is compressed axially. The member 158 then moves from its first position to its second position. When the fluid flow rate drops below the threshold, the return force of the spring becomes greater than the force exerted by the fluid on the head, which moves from its second to its first position. When a fluid enters the valve through its outlet, it is blocked by the head 158b which bears tightly on its seat 166. With the exception of its protuberances 158bb, the head 158b has a maximum external diameter less than the internal diameter of the wall 152ab and the cavity 160 so that fluid can flow inside the cavity 160, between the head 158b and the housing 152, when the head 158b is not in sealing abutment on the seat 166.

At the inlet 154 of the valve, the fluid passageway has a circular cross section. At the head 158b of the member 158, the passage vein has an annular section upstream, at the level of the protuberances 158bb a sectioned section and then again an annular section downstream of these excrescences. Each vein sector extends between two protuberances of the head 158b. Downstream of the spacers, the vein again has a circular shape in section.

The valve 150 further comprises means 180, here electrical, immobilizing the member 158 at least in its first position, that is to say closed.

The means 180 here comprise at least one electrical coil 182 which is mounted coaxially on the wall 152bbc1, and more exactly in the annular space extending between the walls 152bbc1 and 152bbc2. In the example shown, the coil 182 extends over substantially the entire length of the wall 152bbc1.

The coil 182 is here mounted on a tubular support sleeve 184, which is itself engaged on the wall 152bbc1. This sleeve 184 has a longitudinal section substantially U-shaped and can be used for the preparation of the coil and in particular the winding of son or son son. The sleeve 184 comprises at an axial end, located on the side of the inlet 154, an outer radial flange 184a applied to a cylindrical surface 185 of the wall 152bbc1, and an outer radial flange 184b at the opposite end.

The coil 182 is surrounded by the cylindrical wall 152bbc2, which can bear on the flanges 184a, 184b of the sleeve 184. In the example shown, the sleeve 184 is formed in one piece with an annular cover 188 attached to the housing 152. The cover 188 comprises a radial wall, which here coincides with the flange 184b, and which is engaged in the free end of the wall 152bbc2. This radial wall comprises a central orifice 192 traversed by a finger 194 projecting from the housing, extending downstream along the axis A from the radial wall 161. This finger 194 is crimped to immobilize the cover 188 on the 152. The support sleeve 184 is thus kept axially clamped between the bearing 185 and the finger 194 crimped.

The cover 188 comprises electrical connection means of the coil 182 to power supply and electrical control means (not shown). As mentioned above, when the temperature of the fluid in the circuit 14 comprising the valve 150 reaches a predetermined threshold, for example 160 or 170 ° C, the coil 182 is electrically powered and generates a magnetic field inside the conduit. . The body 158a, which is made here of ferromagnetic material, is then biased by the magnetic field in the closed position of the valve (Figure 6). The member 158 is then locked in this closed position as the coil 182 is energized.

Figures 8 to 11 show a third embodiment of a non-return valve 250 according to the invention.

The valve 250 comprises a housing 252, for example of plastic material, which defines an internal conduit for the circulation of a fluid, from a fluid inlet 254 to a fluid outlet 256.

In the example shown, the inner duct has a general L shape. The inlet 254 has an axis A and the outlet has an axis B. These axes A, B are substantially perpendicular.

The housing 252 is fixed and intended to be fixed on an element of the vehicle. It comprises a movable member 258 inside the duct, between a first closed position of the duct shown in FIG. 5 and a second open position of the duct shown in FIG. 6. The member 258 is in this case mounted movably. in a substantially cylindrical cavity 260 of the duct, coaxial with the inlet 254. The housing 252 is here formed by two tubular sections 252a, 252b fixed to one another.

The section 252a comprises a first cylindrical wall 252aa of axis A and internally defining the fluid inlet 254, and a second cylindrical wall 252ab of axis A and internally defining a portion of the cavity 260.

The section 252b comprises a first cylindrical wall 252ba of axis B and internally defining the fluid outlet 254, and connected at right angles to a second substantially cylindrical wall 252bb of axis A. This second wall 252bb comprises a first front portion 252bba or upstream part forming the cavity 260 and a 252bbb elbow connection of this cavity 260 at the outlet 256.

In the example shown, the second wall 252ab of the section 252a has a diameter greater than the first wall 252aa of this section. Furthermore, the wall 252aa and the wall 252bb have substantially the same diameter and the upstream end of the portion 252bba has an inner diameter substantially equal to that of the wall 252ab.

The wall 252ab of the section 252a comprises at its axial end opposite the wall 252aa a radially outer annular flange 252ac axially applied to an outer annular flange 252bc similar to the wall 252bb of the section 252b. These flanges 252ac, 252bc can be fastened together by welding. The movable member 258 here comprises three elements, a cylindrical body 258a in two parts 258a1,258a2, and a head 258b. The body 258a is slidably movable along the axis A and is centered and guided inside the cavity 260, by cooperation of its outer cylindrical surface with an inner cylindrical surface of axis A of the wall 252bb.

The head 258b here has a generally ovoid shape and comprises a free end, located on the side of the inlet 254, as a sphere portion. This free end is intended to cooperate by sealing with an inner ring seat 266 located here in the junction area of the walls 252aa, 252ab of the section 252a.

Parts 258a1, 258a2 of the body are coaxial and arranged one behind the other along the axis A. They each have a portion slidably engaged in the wall 252bb.

The portion 258a1 of the body is attached to the head 258b and is formed integrally with the head 258b in the example shown. This portion 258a1 comprises, at its opposite end of the head 258b, a substantially cylindrical housing 268 for receiving an axial end of a return spring 270 of axis A. The other end of the spring 270 is received in a housing cylindrical 272 facing the other part 258a2 of the body. The return spring 270 is here a helical compression spring axis A.

The head 258b comprises radial excrescences 258bb. The outer radial ends of the protuberances 258bb are located on a circumference of diameter substantially equal to the internal diameter of the wall 252ab of the section 252a. The head 258b is thus centered and guided in translation along the axis A by cooperation of its excrescences 258bb with the inner cylindrical surface of this wall 252ab.

As can be seen in the drawings, the member 258 is movable: from the closed position of the valve 250 of FIG. 5, in which it is located at an axial end, right here, of the cavity 260, the spring 270 axially biasing the head 258b and the body 258a axially towards this end and the head 258b being in sealing engagement against the seat 266, - to the open position of Figure 6, wherein the member 258 is located the opposite axial end, left here, of the cavity 260, the spring 270 being axially constrained and the head 258b being located at a distance from the seat 266.

In the absence of fluid circulation in the conduit, the valve 250 is closed. The compression spring 270 urges the head 258b against the seat. When a fluid enters the valve 250 through its inlet 254, it applies a force on the head 258b. When the fluid flow rate is above a certain threshold, the force applied on the head 258b is such that it is greater than the restoring force of the spring 270 which is compressed axially. The member 258 then moves from its first to its second position. When the fluid flow rate drops below the threshold, the return force of the spring becomes greater than the force exerted by the fluid on the head, which moves from its second to its first position. When a fluid enters the valve through its outlet, it is blocked by the head 258b which bears tightly on its seat 266. With the exception of its protuberances 258bb, the head 258b has a maximum external diameter less than the internal diameter of the wall 252ab and the cavity 260 so that fluid can flow inside the cavity 260, between the head 258b and the housing 252, when the head 258b is not in sealing abutment on the seat 266.

At the inlet 254 of the valve, the fluid passageway has a circular cross section. At the level of the head 258b of the member 258, the passage vein has an annular section upstream, at the level of the protuberances 258bb a sectioned section and then again an annular section downstream of these excrescences. Each vein sector extends between two protuberances of the head 258b. Downstream of the spacers, the vein again has a circular shape in section.

The valve 250 further comprises means 280, here pneumatic, immobilizing the member 258 at least in its first position, that is to say closed.

The means 280 here comprise at least one elastically deformable membrane 282, which is mounted in an internal chamber 296 of the housing 252.

In the example shown, the chamber 296 is delimited by the rear or downstream end of the wall 252bb, and in particular a radial face 252bb1 of this wall, and an annular cover 288 attached and fixed on this wall. The cover 288 has a substantially U-shaped axial section and comprises a cylindrical wall 288a of axis A whose axial end located on the side of the inlet 254 is fixed on the wall 252bb and whose opposite axial end is connected. at a radial wall 288b. More specifically, the cover 288 comprises at the free end of its wall 288a a cylindrical rim 288aa centering and fixing to be engaged and fixed, for example by welding, on a cylindrical rim 252bb1 of the wall.

The membrane 282 has an annular or disk shape in the stress-free position. Its outer periphery is clamped between the flanges 288aa, 252bb1. Its inner periphery is tightly mounted on the axial end of the portion 258a2 of the body opposite the head 258b. This portion 258a2 of the body comprises a radial flange 259 for axial support of the diaphragm 282. This radial flange 259 extends radially outwards to its outer periphery which is curved and oriented towards the inlet 254 of the valve . The membrane 282 conforms to the shape of this collar, as can be seen in FIGS. 9 and 10.

The membrane 282 divides the chamber 296 into two parts sealed against each other, respectively upstream and downstream. The flange 259 is located in the downstream part of the chamber 296. The wall 252bb of the housing 252 comprises at least one internal air intake channel 298 in the downstream part of the chamber, in which the radial flange 259 is located ( Figure 11). This channel 298 opens here on the radial face 252bb1.

When the immobilizing means 280 are not activated, the compression spring 270 biases the membrane 282 in a natural or unconstrained position shown in FIGS. 8 and 9, regardless of the position of the member 258 in the conduit. In this position, the free end of the portion 258a2 of the body bears axially on the radial wall 288b of the cover 288. The membrane 282 retains this position as long as the immobilizing means 280 are not activated. When they are activated, the air contained in the part of the downstream chamber in which this channel opens 298 is sucked by the channel 298 (arrow 300 of FIG. 11), which causes a depression in this part, which has tendency to reduce its volume. The reduction of its volume is obtained by the displacement of the portion 252a2 of the body until its flange 259 bears axially against the radial face 252bb1 of the wall 252bb, as well as by the deformation of the membrane 282 (FIG. ). The membrane 282 then adopts a deformed shape under stress. The head 258b is then held in abutment against its seat 266 by the restoring force exerted by the spring 270 in the constrained position, and / or by axial support of the free end of the portion 258a2 of the body on the free end facing of the part 258a1 of the body, as can be seen in FIG.

At least one of the parts 258a1, 258a2 may be equipped with a seal intended to cooperate with the inner surface of the wall 252bb. A seal may for example be mounted in an outer annular groove 302 of the portion 258a1, as in the example shown (Figure 9).

The chamber 296 may comprise biasing means, such as a compression spring 304, for biasing the membrane 282 in its unstressed position. This spring can be aligned on the axis A, and bear axially respectively on the upstream face of the flange 259 and on the downstream radial face 252bb1 of the wall 252bb.

Claims (17)

A nonreturn valve (50, 150, 250), particularly for a motor vehicle, having a fixed housing (52, 152, 252) comprising an inner conduit extending between a fluid inlet (54, 154, 254) and a fluid outlet (56, 156, 256), and a movable member (58, 158, 258) between a first closed position of said duct and a second open position of said duct, said movable member being configured to be moved from said first position to said second position when a fluid flow rate greater than a predetermined threshold enters said conduit via said inlet, and to be moved from said second position to said first position when said flow rate is below said threshold, characterized in that it further comprises means (80, 180, 280) for immobilizing said member in said second position. 2. Non-return valve (50, 150, 250) according to the preceding claim, wherein the immobilizing means are electrical immobilization means (80,180) or pneumatic (280). 3. Non-return valve (50, 150) according to the preceding claim, wherein said movable member (58,158) comprises a ferromagnetic body (58a, 158a), said immobilizing means comprising at least one electrical coil (82, 182) surrounding at less in part said body. 4. Non-return valve (50, 150) according to the preceding claim, wherein said body (58a, 158a) has an elongated shape and is slidably mounted along its axis of elongation (A) inside said housing (52, 152). 5. Non-return valve (50, 150) according to the preceding claim, wherein said housing (52, 152) comprises at least one inner cylindrical surface for guiding said body (58a, 158a) along said axis of elongation (A ). 6. Non-return valve (50, 150) according to the preceding claim, wherein said housing (52, 152) comprises a first cylindrical wall (52bb, 152bbc1) having said inner cylindrical surface and an outer cylindrical surface on which is mounted said at least one coil (82, 182). The nonreturn valve (50, 150) according to claim 6, wherein said at least one coil (82, 182) is surrounded by a second cylindrical wall (86, 152bbc2), which is integrally formed with said first cylindrical wall (52bb, 152bbc1) or reported thereon. 8. Non-return valve (50, 150) according to the preceding claim, wherein said at least one coil (82, 182) is mounted on a support sleeve (84, 184), itself mounted on said first wall (52bb, 152bbc1). 9. Non-return valve (50, 150) according to one of claims 3 to 8, wherein said housing (52, 152) comprises a portion (88, 188) equipped with electrical connection means of said at least one coil (82.182). 10. A check valve (50, 150) according to the preceding claim, dependent on claim 7 or 8, in said portion (88.188) equipped is formed integrally with said support sleeve (84, 184) or said second cylindrical wall (86,152bbc2). The check valve (250) according to claim 1 or 2, wherein said housing (252) comprises an inner chamber (296) configured to be connected to air supply and / or suction means of air. 12. Non-return valve (250) according to the preceding claim, wherein said movable member (258) comprises a first body (258a) of elongate shape and slidably mounted along its axis of elongation (A) inside. said housing (252), at least a portion of said first body extending into said chamber (296). 13. Non-return valve (250) according to the preceding claim, wherein a resiliently deformable membrane (282) is mounted in said chamber (296) and is respectively fixed to said housing (252) and said portion, said membrane being configured to deforming following activation of said supply and / or suction means for driving or following said first body (258a) from its second position to its first position. 14. Non-return valve (250) according to the preceding claim, wherein said movable member (258) comprises a second body (258b) independent of said first body and coaxial therewith, said second body being slidably mounted along said axis elongation (A) within said housing (252) between said first and second positions. 15. Non-return valve (250) according to the preceding claim, wherein said first and second bodies (258a, 258b) are solicited at a distance from each other by return means (270) such as a spring compression. 16. Cooling circuit (14), in particular low temperature, for a vehicle, comprising at least one non-return valve (50, 150, 250) according to one of the preceding claims. 17. Cooling device (50) for a vehicle, comprising a low temperature cooling circuit (14) according to the preceding claim, a high temperature cooling circuit (12), and a reservoir (20) configured to perform degassing functions. and expansion for said circuits.