EP2771596A1

EP2771596A1 - Valve, in particular for a motor vehicle engine

Info

Publication number: EP2771596A1
Application number: EP12780237.9A
Authority: EP
Inventors: Grégory HODEBOURG
Original assignee: Valeo Systemes de Controle Moteur SAS
Current assignee: Valeo Systemes de Controle Moteur SAS
Priority date: 2011-10-26
Filing date: 2012-10-11
Publication date: 2014-09-03
Also published as: FR2982005B1; FR2982005A1; CN104067038A; WO2013060963A1; KR20140084262A; JP2014530992A; CN104067038B; US20140367600A1

Abstract

The invention relates to re-circulated exhaust gas valve for a motor vehicle engine, including a flap (2) and a shaft (7) for driving the flap (2) about an axis of rotation, said flap (2) and said shaft (7) being inserted one inside the other in the area of one or more connecting barrels (5) forming a thermal conduction area between the flap (2) and the shaft (7), the valve being characterized in that said valve includes a cavity (28) configured such as to localize the thermal conduction area axially and set back from a first edge of the flap (2) turned toward an axial end of the shaft (7), which is connected to members for driving the valve.

Description

Valve, in particular for a motor vehicle engine

The invention relates to a valve for a motor vehicle engine, and more particularly to a recirculated exhaust gas valve.

It is now well known to recycle the exhaust gases of an engine by connecting the intake circuit and the exhaust pipe of the engine. Such a recycling device allows the reuse of a portion of the exhaust gas in the mixture supplying the engine.

Antipollution standards now make it necessary to recycle a larger share of exhaust gases. However, the current architecture reaches its limits with regard to the amount of exhaust gas that can be recycled. To improve the recycling of the exhaust gas, it has been imagined to connect a recycling device to the low pressure part of the exhaust pipe, that is to say downstream of the gas expansion zone. exhaust, for directing a more substantial portion of the exhaust gas to the intake circuit of the engine.

Thus, there is known a valve mounted on the low pressure portion of the exhaust pipe for directing the exhaust gas to the outside or to the recycling device and comprising a flap, a drive shaft of the flap and an actuating motor and transmission means configured to transmit the movement of the motor to the shaft.

The assembly of the shaft on the body of the valve is performed with games, allowing its rotation. Such games allow a quantity of exhaust gas to flow through the valve towards the transmission and actuation members employed. These gases being liable to damage the drive members, in particular by condensing, a seal is inserted along the shaft to block these gases.

However, in the valve, the flap and the shaft are fitted into each other at one or more connecting barrels which establishes a thermal conduction zone between the flap and the shaft. The flap is exposed directly to the exhaust gases and conducts the heat to the shaft through the barrel or barrels.

Today, it is known to cool the valve which allows to have a shaft whose temperature to the right of the seal is lower than the level of the flap. But this cooling is limited and the seal must withstand heat. It is therefore expensive and complicates the assembly of the valve. Furthermore, in this part of the pipe, the exhaust gas may undergo remediation treatments, including a post-combustion, may raise their temperature further. The valve must be arranged to resist this temperature, which increases the cost and more particularly that of the seal.

One solution would be to move away as much as possible from the transmission and actuation members of the ducts in which the hot exhaust gases circulate. However, it is desirable that the valve has a compact structure and collected on the exhaust manifold to limit its bulk. In such a structure, the length of the drive shaft of the flap is necessarily limited which makes it difficult to cool the valve along it.

The object of the invention is to solve at least part of these disadvantages. For this purpose, it relates to a gas valve, in particular recirculated exhaust gas for motor vehicle engine, comprising a flap and a drive shaft of the flap about an axis of rotation, said flap and said shaft being sheathed one into the other at one or more connecting barrels establishing a heat conduction zone between the flap and the shaft, the valve comprising at least one cavity, in particular a cavity, configured so as to locate the zone thermal conduction axially recessed from a first edge of the flap facing an axial end of the shaft connected to the drive members of the valve.

The cavity thus formed makes it possible to reduce the temperature reached at the joint by moving the central temperature point toward the flap. This allows in particular to use a conventional type of seal, for example rubber, not expensive, without having to lengthen the tree.

Preferably, the cavity is located between the shaft and the flap, in particular radially.

Still preferably, the annular space extends axially from a passage through which the shaft enters a body of the valve.

According to one aspect of the invention, the cavity is delimited by an annular space formed in a side wall of the shaft.

Advantageously, the diameter of the shaft is lower in its portion located at the level of the annular space.

Advantageously, the diameter of the shaft is identical on both sides of said annular space.

In one embodiment of the invention, the flap has a radial offset relative to the axis of rotation. It can then be configured to make a thermal screen for the shaft relative to the flow of gas in the valve.

In this embodiment, alternatively, the connecting barrel or that of the connecting barrels near the first edge is axially set back from said first edge. In other words, there is a portion of the shutter comprising its first edge which comes directly opposite the shaft, without the intermediary of the shaft. The space released by the axial withdrawal of this barrel can then form the cavity.

According to this embodiment, one or more additional cavities may be provided, for example an additional cavity formed in the side wall of the shaft and / or in the wall of the barrel. Along the shaft can thus be provided: the cavity formed by the axial withdrawal of the barrel near the first edge of the flap, and one or more other cavities formed in the shaft and / or in the barrel.

Advantageously, said valve further comprises a second remote connection barrel of the barrel provided near the first edge. In this case, the additional cavity or cavities may be provided at this second barrel.

In an alternative embodiment of the invention, the flap is aligned with the axis of rotation. In such a valve, the barrel is exposed directly to the exhaust gas and conducts the heat received to the drive shaft.

Advantageously, the flap comprises two wings integral with the drum or drums and mounted symmetrically on either side of the drum or barrels with respect to said axis of rotation. It is meant here that the axis of rotation is substantially in the median plane defined by the wings.

In a still preferred manner, the flap has a thickness less than the diameter of the connecting barrel or barrels.

In this embodiment, the cavity is formed between the shaft and the shaft so as to dissipate heat and thus reduce the conduction of heat along the shaft.

In a first variant, the cavity is delimited by an annular space formed in a side wall of the shaft, as in one of the variants associated with the flap having a radial offset.

In another variant, the cavity is delimited by an annular space in the barrel or that of the barrels near the first edge.

Preferably, the drive shaft is then of constant section as it may be the case for valves provided with a radial offset flap and connecting barrel axially set back from the first edge. In a variant, the cavity is formed both in the shaft and in the shaft.

The shaft is preferably substantially cylindrical. The shaft may be of circular, rectangular, square or other section, in one piece or in the form of a set of parts such as a plurality of shafts mounted with each other or stems etc. .

Advantageously, the connecting barrel or barrels are made from the component material.

Other features and advantages of the invention will become apparent from the following description given with reference to the appended figures given by way of non-limiting examples, identical references being given to similar objects, in which:

Figure 1 illustrates in perspective a flap off-axis with respect to its axis of rotation.

Figure 2 illustrates in perspective, partially, a valve provided with the shutter of Figure 1, in the open position.

Figure 3 is a longitudinal sectional view, at the drive shaft of the valve of Figure 2, in the closed position.

Figure 4 is a view similar to that of Figure 3 according to a first embodiment of the invention.

Figure 5 is a view similar to that of Figure 3 according to a second embodiment of the invention.

Figure 6 is a view similar to that of Figure 3 according to a third embodiment of the invention.

Figure 7 illustrates in perspective a partial schematic view of a flap comprising a shaft and two wings, mounted symmetrically on the shaft and diametrically secured to a drive shaft.

FIG. 8 illustrates a cross-sectional view of a valve comprising a shutter according to FIG. 7, in the closed position.

Figure 9 is a longitudinal sectional view of the valve of Figure 8, in the closed position.

Figure 10 is a view similar to that of Figure 9 according to a fourth embodiment of the invention.

Figure 11 is a view similar to that of Figure 9 according to a fifth embodiment of the invention.

Figure 12 is a view similar to that of Figure 9 according to a sixth embodiment of the invention. FIG. 1 shows a flap 2 of a gas valve, in particular recirculated exhaust gas for a motor vehicle engine. The flap 2 and a drive shaft 7 of said flap are fitted into each other at a connecting shaft 5. The flap 2 is oriented substantially parallel to its axis of rotation corresponding to the longitudinal axis of the shaft 7.

In the embodiment of Figure 1, the flap 2 has a radial offset relative to its axis of rotation.

Such a flap comprises, in particular, a first flange 3 integral with a second flange 4 themselves secured to the barrel 5. The flanges 3 and 4 and the barrel 5 may, for example, be from the same material. The wings 3 and 4 are substantially rectangular. The drum 5 is substantially cylindrical and comprises a substantially cylindrical bore 6 which is coaxially arranged in the barrel 5. It will be noted that the wings 3 and 4 may, in an alternative embodiment of the invention, be in the same plane, that is to say, form a single wing, located on both sides of the shaft.

FIG. 2 illustrates a valve 1 in the form of a casing 10 in which the shutter 2 is mounted. This is a valve that makes it possible to selectively direct exhaust gases either outwards or to a recycling circuit.

The drive shaft 7 comprises an end 22 connected to an actuating motor 20 by transmission means (not shown) configured to transmit the movement of the motor to the flap 2 via the shaft 7.

The housing 10 comprises a flange 11 in which is formed an opening 12 delimited by tabs 13, 14, 15, 16 projecting into the opening 12 and on which the valve 1 is mounted so as to allow the tilting of the flap 2 between a plurality of open position and a closed position of the opening 12.

The tabs 13, 14, 15, 16 are configured to seal the valve 1 in the closed position of the shutter 2.

As illustrated in FIG. 3, the housing 10 comprises a duct 25, here closed by the shutter 2 in contact with the flange 1 1. This means that the fluid flowing through the valve circulates in the duct 25 between an inlet and a first valve outlet, not shown. On the contrary, when the flap is in the open position, the fluid flows in the inlet valve to a second outlet, also not shown, or both to the first and second outlets.

At one of its ends, the shaft 7 opens through a passage 26 formed in the housing 10 towards the transmission means. Said valve may comprise a first level 21 for the rotation of the shaft at said passage 26. At its other end, the shaft 7 is also mounted in the housing 10, in particular via a second bearing 21. Various axial stops may also be provided for positioning said shaft along the axis of rotation.

In order to prevent the flow of exhaust gases along the shaft 7 towards said transmission means, a seal 24 is arranged in the passage 26, around the shaft 7.

When the exhaust gas comes into contact with the shutter 2, it directs their heat through the wings 3, 4, the shaft 5 and the shaft 7 towards the transmission means. In the valve illustrated in FIG. 3, the heat of the exhaust gases is transmitted by the shaft 5 to the shaft 7 by the zone of thermal conduction existing between the shaft and the shaft to the vicinity of the passage 26, without possibility of dissipation upstream, causing the presence of high temperatures in the portion of the shaft 7 passing through said passage 26.

According to the invention, in order to reduce the heat conduction between the shutter 2 and the shaft 7, the valve 1 comprises a cavity configured so as to locate the thermal conduction zone axially set back from a first edge of the shutter. 2 facing an axial end of the shaft 7 connected to the transmission means and / or the actuating motor of the valve, that is to say, here, the edge of the flap facing the passage 26 and / or the seal 24. In this way, the temperature is reduced at a given point along the shaft 7.

According to the embodiment illustrated in FIG. 4, the cavity is in the form of an annular space 28 formed by machining a portion of the outer wall of a portion 30 of length L of the shaft 7 so that that the diameter of the shaft at the portion 30 is less than the diameter of the shaft in a portion 32 of the shaft, said mounting, the mounting portion 32 being substantially the same diameter as the bore 6 made in the barrel 5 so as to allow the shaft 7 to be secured in the bore 6 of the barrel 5.

In an alternative embodiment illustrated in FIG. 5, the first of the connecting barrels 5, located near the first edge of the flap, that is to say the one on the right in the figure, is axially recessed. said first edge.

The cavity, here marked 34, is in this way formed in the drum 5 and forms a thermal break along the shaft 7 towards the end of the shaft facing the seal 24.

In order to improve the heat dissipation, a cavity 36, in the form of an annular space, is, in addition, formed substantially in a median portion of the flap 2 between the first connecting barrel and a second barrel of link 5, located on the left in the figure. Alternatively, the barrel 5 is continuous along the shaft, while having its end facing the housing 26 axially set back from said first edge of the flap.

In another embodiment of the invention, illustrated in FIG. 6, combining the two embodiments described above, a cavity, here marked 42, is formed both by machining the shaft 7 and axial offset of the shaft. 5 closest to passage 26.

FIG. 7 shows a flap 2 presenting a variant of shape.

Such a flap comprises a first flange 3 and a second flange 4 integral with a drum 5 and mounted symmetrically on either side thereof, that is to say in the same plane further comprising the axis the shaft or axis of rotation of the flap.

The wings 3 and 4 are here two portions of a circle configured so as to give the contour of the flap substantially a circle shape. The wings 3 and 4 and the barrel 5 may, for example, be from the same material.

The barrel 5 is substantially cylindrical and comprises a substantially cylindrical bore which is coaxially arranged in the barrel 5.

FIG. 8 illustrates a valve 1 in the form of a housing 10 in which the shutter 2 is mounted. It is here a metering valve allowing the duct 25 to be closed more or less along which the shutter 2 has climbed. As in the previous valve, the shaft 7 comprises an end 22 mounted connected to the actuating motor 20, either directly or via transmission means. A passage 26 allows the passage of the shaft of the conduit 25 to the motor and / or the transmission means. It is equipped with a bearing 21.

Sealing means 18, here in the form of a lip seal, make it possible to prevent the exhaust gases, flowing in the clearances provided between the flap 2, the housing 10 and the shaft 7 from penetrating in a housing housing in the housing 10 to reach the actuating motor 20 and / or the transmission means, through the passage 26.

However, when the exhaust gas comes into contact with the flap 2, it directs their heat through the flanges 3, 4, the barrel 5 and the shaft 7 towards the actuating motor. The problem is thus the same as in the valve of FIG.

FIG. 10 illustrates a solution according to the invention and similar to that of FIG. 5. The cavity is here in the form of an annular space 28 formed by machining a portion of the outer wall of a portion 30 length L of the shaft 7 so that the diameter of the shaft at the portion 30 is less than the diameter of the shaft in the shaft mounting portion 32, the mounting portion 32 being substantially same diameter as bore 6 realized in the barrel 5 so as to allow the shaft 7 to be secured in the bore 6 of the barrel 5.

It can be seen here that, as in the embodiment of FIG. 4, the diameter of the shaft is identical on either side of the portion 30 having the annular space 28.

In an alternative embodiment illustrated in FIG. 11, the cavity is formed in the drum 5. It is configured so as to form a heat shield along the shaft 7 in the direction of the end of the shaft located on the shaft. side of the passage 26.

The cavity is here in the form of an annular space 36 formed by machining a portion of the barrel 5.

In another embodiment of the invention, illustrated by FIG. 12, combining the two previously described embodiments, a cavity 36 is machined both in the barrel 5 and in the shaft 7.

In these different modes, it is found that the cavity extends, on the one hand, axially from a zone of the shaft penetrating into the passage 26, this towards a central part of the conduit 25, and, on the other hand, part, radially between the shutter 2 and the shaft 7.

Claims

A gas valve, in particular a recirculated exhaust gas for a motor vehicle engine, comprising a flap (2) and a drive shaft (7) for the flap (2) around an axis of rotation, said flap ( 2) and said shaft (7) being fitted into each other at one or more connecting barrels (5) establishing a thermal conduction zone between the flap (2) and the shaft (7), the valve (1) comprising at least one cavity (28, 34, 36, 42) located radially between the shaft (7) and the flap (2) and configured to locate the axially indented thermal conduction zone of a first edge of the flap (2) facing an axial end of the shaft (7) connected to the drive members of the valve.

2. Valve according to claim 1, wherein the flap (2) has a radial offset relative to the axis of rotation and wherein the connecting barrel or the connecting barrels (5) near the first edge of the flap. is axially set back from said first edge, the space released by this axial withdrawal forming the cavity (34).

3. Valve according to claim 2, further comprising a second shaft remote connection barrel provided near the first edge.

4. Valve according to claim 1, wherein the flap (2) is aligned with the axis of rotation and the cavity is delimited by an annular space (36) formed in the barrel or that of the barrels (5) near the first edge.

5. Valve according to claim 4, wherein the flap (2) has a thickness less than the diameter of the connecting shaft (5).

6. Valve according to one of claims 2 to 5, wherein the drive shaft (7) is of constant section.

The valve of claim 1, wherein the cavity extends axially from a passage (26) through which the shaft enters a valve body (10).

8. Valve according to claim 1 or 7, wherein the cavity is defined by an annular space (28) formed in a side wall of the shaft (7).

9. Valve according to claim 8, wherein the diameter of the shaft (7) is lower in its portion located at the annular space (28).

10. Valve according to one of claims 8 or 9, wherein the diameter of the shaft (7) is identical on either side of said annular space (28).

11. Valve according to claim 1 or 7, wherein the flap (2) is aligned with the axis of rotation.

12. Valve according to claim 1, wherein the flap (2) is aligned with the axis of rotation and the cavity is delimited by an annular space (36) formed in the barrel or that of the barrels (5) near the first edge.

13. Valve according to claim 12, wherein the flap (2) has a thickness less than the diameter of the connecting shaft (5).

14. Valve according to claim 1, wherein the cavity (36, 42) is formed both in the shaft (5) and in the shaft (7).

15. Valve according to one of the preceding claims, wherein the barrel or barrels are derived from material flap (2).