FR3052841A1 - ANTI-ROTATION DEVICE FOR A VALVE AND FLUID CIRCULATION VALVE COMPRISING SAME - Google Patents

Abstract

The subject of the invention is an anti-rotation device (20), in particular for a fluid circulation valve (10), comprising: - a receiving part (22) comprising a receiving groove (26), a rod (18) ) extending along a first axis (z), - a bar (24) integral with the rod (18) and mounted in the receiving groove (26) of the receiving piece (22), in which the receiving groove (26) and the bar (24) are shaped so that the rod (18) is locked in rotation about the first axis (z) relative to the receiving part (22) and movable in translation along the first axis (z). ) relative to the receiving part (22).

Description

The invention relates to an anti-rotation device, in particular intended to be integrated in a valve for a motor vehicle engine, and a fluid circulation valve comprising such a device. anti-rotation device.

In particular, the field of the present invention is that of the equipment for the power supply of the engine, especially the exhaust gas recirculation valves which participate in the operation of the combustion engines.

It is known fluid flow valves, for example for air ducting, having a body having a fluid passage duct, a shutter, for example a valve, a shutter control shaft extending longitudinally along an axis, and free in translation along the longitudinal axis, and a drive member in translation of said control shaft. The translation of the valve to adjust the flow rate of fluid flowing in the conduit, the shutter forms a fluidic control member. The shutter is movably mounted between two extreme positions and is driven between the two extreme positions by a drive motor via the drive member. In particular, the drive member converts the rotational movement of the drive motor into translation motion, and then transmits this translational movement to the shutter control shaft. The transformation of the rotational movement into translational movement can be done by a system of the screw / nut type, the rotation of the nut allowing the translation of the rod of the screw.

In order to guarantee a pure translation movement of the shutter control shaft, the valve may comprise an anti-rotation system generating a force, unilateral or bilateral, on the output shaft. Nevertheless, a unilateral anti-rotation system, which carries out the force recovery on one side of the axis of the shaft, puts mechanical stress on the control shaft and consequently on the guidance of the shaft. control. The level of friction in the mechanism is thus increased, as well as wear. In addition, such a unilateral anti-rotation system has the effect of introducing an axial play at the control shaft of the shutter, which results in a degradation of the seal at the valve.

In addition, a bilateral anti-rotation system, where the recovery of effort is made on either side of the axis of the shaft, reduces the forces applied to the shaft. In order to optimize the axial clearance at the shutter control shaft, precise guidance of the anti-rotation device of the precise control shaft is required. Because of the dispersions existing on the dimensions of the various mass-produced parts, the system may in certain cases have no operating clearance and be hyperstatic.

The present invention aims to remedy these drawbacks by proposing an anti-rotation device, in particular intended to be integrated in a valve for a motor vehicle engine, for self-centering the control shaft of the shutter and to control the axial play present at the control shaft, without introducing a problem of hyper-droop in the device. For this purpose, the subject of the invention is an anti-rotation device, in particular for a fluid circulation valve, comprising: a receiving part comprising a receiving groove, a rod extending along a first axis, a solidarity bar of the rod and mounted in the receiving groove of the receiving piece, wherein the receiving groove and the bar are shaped so that the rod is locked in rotation about the first axis relative to the receiving piece and movable in translation along the first axis relative to the receiving part.

Advantageously, such an anti-rotation device makes it possible to self-center the rod with respect to the receiving part, while avoiding any problem of hyper-droop in the device. In addition, such an anti-rotation device makes it possible to control the axial clearance present between the rod and the receiving groove of the receiving part.

The anti-rotation device according to the invention may also include one or more of the following features, considered individually or in any combination possible; the bar is free in translation along a second axis relative to the receiving part and locked in translation along a third axis relative to the receiving part, the first axis, the second axis and the third axis being orthogonal to each other; and / or the stiffness of the bar is strictly less than the stiffness of the receiving piece; and / or - in a section perpendicular to the first axis, the bar has a general shape of "S", and in a section perpendicular to the second axis at one end of the bar, the bar has a general shape of "C" " and / or - in a section perpendicular to the first axis, the bar has a general shape of "S", and in a section perpendicular to the second axis at one end of the bar, the bar has a general shape of "M" layer " ; and / or - the receiving part is made of plastic or metal material; and / or the bar is made of plastic or metal material; and / or the plastic material comprises a low coefficient of friction material, especially PTFE; and / or the plastics material comprises at least 10% of its PTFE mass; and / or the rod is made of metallic material; and / or the rod comprises a slot, a portion of the bar being mounted in the slot of the rod so that the bar is secured to the rod in translation along the first axis; and / or the bar is asymmetrically mounted in the slot of the rod; and / or the receiving groove extending longitudinally along the second axis, and wherein the slot of the rod extends in a plane containing the axis of the rod and being non-parallel to the longitudinal direction of the receiving groove ; and / or - the bar being welded in the slot of the rod; and / or the rod is fixed to the bar, in particular by welding or keying or clipping to the bar; and / or - the central part of the bar is cylindrical, and is slid into a cylindrical bore made in the rod; and / or the rod is movable in translation along the first axis with respect to the receiving part between a first position and a second position; and / or the receiving piece is a fluid circulation valve cover; and / or the receiving piece is a valve body. The invention also relates to a fluid circulation valve comprising: a valve body delimiting a fluid circulation duct, a shutter movable in translation between an open position allowing the passage of fluid in the duct and a closing position preventing the passage of fluid in the conduit, an anti-rotation device according to the invention, wherein the rod is attached to the shutter.

Advantageously, such a fluid circulation valve ensures sealing at the shutter.

The fluid circulation valve according to the invention may also comprise one or more of the following characteristics, considered individually or according to all possible combinations: the valve is a valve is of the exhaust gas recirculation valve type, in particular of the high type pressure; and / or the first position of the rod is the open position of the valve, and the second position of the rod is the closed position of the valve; and / or the shutter is a valve. Other features and advantages of the present invention will appear on reading the detailed description of embodiments given as non-limiting examples, accompanied by the following figures: FIG. 1 is a sectional view along a first axis of FIG. A fluid circulation valve according to the invention, - Figure 2 is a perspective view of an assembly comprising a rod and a bar according to one embodiment of the invention, and - Figures 3 and 4 show sectional views respectively along a second axis and a third axis of an anti-rotation device according to the invention.

It should be noted that these drawings have no other purpose than to illustrate the text of the description and do not constitute in any way a limitation of the scope of the invention.

In the various figures, the analogous elements are designated by identical references. In addition, the various elements are not necessarily represented on the scale in order to present a view making it easier to understand the invention. The invention relates to a fluid circulation valve, in particular of exhaust gas recirculated between the exhaust circuit and the intake circuit of a heat engine, for a motor vehicle. Figure 1 illustrates such a valve, here a valve valve 10 configured to adjust the flow of recirculated exhaust gas. In the example described, the valve is of the "high pressure" type, that is to say that the exhaust gases are recirculated between a point of the exhaust circuit located upstream of the turbine of a turbocharger, and a point of the intake circuit located downstream of the compressor.

A valve 10 of fluid circulation comprises a valve body 12 having a conduit 14 for the passage of fluid and a fluidic regulating member, for example a shutter 16, mounted movably between two positions. The fluidic control member is driven between the two positions by a drive motor via a drive member.

The drive motor is for example a DC type electric motor. The driving member converts the rotational movement of the drive motor into translational movement, via a nut and a screw, not shown. The rotation of the nut causes the translation of the screw and thus of the control shaft. The shutter 16 is fixedly mounted on the control shaft, for example the rod 18 extending longitudinally along a first axis, noted (z) in Figure 1, free in translation along the axis (z). More specifically, the control shaft is moved, driving the valve, by the drive motor via the drive member.

In the case of a valve valve as shown in Figure 1, the fluidic control member is a shutter 16 of the linear type, for example a valve. One of the extreme positions corresponds to a position where the conduit 14 of the valve 10 is completely open and allows the recirculated exhaust gas to pass through, and the other extreme position corresponds to a position where the conduit 14 of the valve 10 is completely closed thus blocking the passage of recirculated exhaust gases. In other words, the shutter is movable in translation between an open position of the valve, said first position, allowing the passage of fluid in the conduit and a closed position of the valve, said second position, preventing the passage of fluid in the conduit 14.

The fluid circulation valve 10 may also comprise a position sensor for detecting the position of the fluidic control member 16. For example, in the case of a valve gate as illustrated in FIG. Position sensor is a linear position sensor.

The fluid circulation valve 10 comprises an anti-rotation device 20 for self-centering the control shaft of the valve.

Such an anti-rotation device 20 comprises a reception piece 22, the rod 18 and a bar 24, as represented in FIG.

The receiving part may be a valve cover, as shown in Figure 1, or a valve body.

The receiving part 22 comprises a receiving groove 26. The bar 24 is mounted in the receiving groove 26 of the receiving part 22. In other words, the receiving part 22 surrounds the bar 24.

The rod 18 extends longitudinally along the axis (z) and is integral with the bar 24. In other words, a translational movement of the rod 18, in particular along the axis (z), causes a translational movement of the bar 24, and vice versa.

Preferably, the receiving groove 26 of the receiving piece 22 has a generally hollow parallelepipedal shape extending longitudinally along a second axis, noted (x) in Figure 1, substantially perpendicular to the axis (z).

The receiving groove 26 and the bar 24 are shaped so that the rod 18 is locked in rotation about the axis (z) relative to the receiving part 22 and movable in translation along the axis (z) relative to to the receiving member 22. In other words, the translation along the axis (z) of the assembly comprising the bar 24 and the rod 18 relative to the receiving part 22 is free, while a rotational movement around the axis (z) of the assembly relative to the intermediate piece 22 is blocked.

The bar 24 mounted in translation along the axis (z) in the receiving groove 26 of the receiving part 22 guides the translation along the axis (z) of the rod 18 relative to the receiving part 22 , and thus guide the shutter 16 between its two extreme positions. In other words, the rod 18 is movable in translation along the axis (z) with respect to the receiving part 22 between a first position and a second position.

The stiffness of the bar 24 may be strictly less than the stiffness of the receiving part 22. For example, the bar 24 may be made of a material having, also taking into account its dimensions, an elasticity greater than the elasticity of the In particular, the stiffness of the receiving part 22 and the bar 24 in a load application direction substantially perpendicular to the axis (z) takes into account the dimensioning of the anti-rotation device 20.

Advantageously, the stiffness of the bar 24 less than the stiffness of the receiving part 22 allows the bar 24 to absorb shocks due to the opening and closing of the valve 10 and to eliminate the hyper-droop of the device anti-rotation 20. In addition, the elasticity of the bar 24 allows self-positioning of the bar 24 in the receiving part 22.

The respective stiffnesses of the receiving part 22 and of the bar 24 are adapted such that when the valve reaches its seat with the maximum closing speed, an elastic deformation of the bar 24 makes it possible to reduce the severity of the impact and to dissipate some of the energy. The constraints on the various parts of the control mechanism, in particular the teeth, are thus reduced. During the most severe shocks, the central portion 28 of the bar 24 can, for a short time, rotate 10 ° relative to its rest position, the angle of rotation being observed in the plane perpendicular to the axis of the valve. This rotation is permitted by an elastic deformation of the zone between the connection with the valve stem and each end portion 30.

The bar 24 may be a folded blade, as shown in Figure 2, and in particular a folded sheet when the bar 24 is made of metallic material.

According to a section perpendicular to the axis (z), particularly shown in Figure 3, the bar 24 may have a general shape of "S". The bar 24 comprises a central portion 28 and two end portions 30.

The central portion 28 of the bar 24 cooperates with the rod 18 so that the bar 24 and the rod 18 are integral. As shown in Figures 2 and 3, the central portion 28 has a wavy shape. More specifically, the central portion 28 represents the spine of the "S", that is to say the curved central portion of the shape of "S". In particular, the central portion 28 connects the two extremal parts.

An end portion 30 comprises two lateral portions 32 connected by an upper portion 34.

The lateral portions extend longitudinally along the axis (z). The lateral portions 32 of the end portion 30 are in contact with the receiving part 22. As shown in FIG. 4, in a section perpendicular to a second axis, denoted (x), at an end portion 30 of the bar 24, the bar 24 may have a general shape of "C". The lateral portions 32 and the upper portion 34 are substantially perpendicular.

In a section perpendicular to the axis (x) at one end of the bar 24, the bar 24 may have a general shape of "M". Specifically, the bar 24 may have a general shape of "lying M", that is to say a general shape of "M" turned 90 ° relative to the axis (x).

Preferably, the blade forming the bar has a thickness of between 0.3 mm and 0.8 mm, and more preferably a thickness of 0.5 mm.

The rod 18 comprises a slot 36, in particular visible in FIGS. 2 and 3. A portion of the bar 24, in particular a portion of the central portion 28, is mounted in the slot 36 of the rod 18 so that the bar 24 is secured to the rod 18 in translation along the axis (z).

As shown in Figure 3, the slot 36 of the rod 18 may extend in a plane containing the axis of the rod 18 and being non-parallel to the axis (x). In other words, the slot 36 of the rod 18 extends transversely with respect to the longitudinal direction of the receiving groove 26.

Advantageously, the slot extending in a plane transverse to the longitudinal direction of the receiving groove makes it easier to position the bar when mounting the valve.

Thus, when at mounting the bar is inserted into the slot 36, the bar can move slightly with respect to the rod, in the direction of the axis (x) and in the direction of the axis (y). The bar will not be constrained against the receiving room. The dispersions of dimensions of the different parts can thus be compensated, and it is possible to provide nominal dimensions with little play. After assembly, once the positioning of the bar 24 has been achieved, the bar 24 can be placed asymmetrically with respect to to the rod 18. In other words, the bar 24 can be mounted asymmetrically in the slot 36 of the rod 18.

Preferably, a clearance of the order of ten microns remains between the walls delimiting the slot 36 of the rod 18 and the bar 24, once the latter is inserted into the slot 36 of the rod 18.

This play value makes it possible to fix the bar 24 in the slot of the rod 18 by laser welding. Alternatively, the rod 18 can be fixed to the bar 24 by keying, or by clipping.

Preferably, the fixation of the rod 18 to the bar 24 is carried out following the mounting of the bar 24 in said receiving groove 26. In a variant, the fixing may be carried out prior to the mounting of the bar 24 in the receiving groove 26 of the reception room 22.

The bar 24 may be free in translation along the axis (x) with respect to the receiving part 22 and locked in translation along a third axis, denoted by (y), substantially perpendicular to the axes (x) and (z), by relative to the receiving part 22. In other words, the translation along the axis (x) of the assembly comprising the bar 24 and the rod 18 relative to the receiving part 22 is free, while a translation movement along the axis (y) of the assembly relative to the intermediate piece 22 is blocked.

Advantageously, the translation movement of the assembly along the axis (x) relative to the receiving part 22 reduces the mechanical stresses applied to the assembly without introducing hyper-droop into the anti-rotation device 20.

Preferably, the (x), (y) and (z) axes are orthogonal.

The receiving part may comprise pads, not shown, for example four pads, extending longitudinally along the axis (x) from the receiving part towards the bar.

In particular, the pads can be positioned vis-à-vis the lateral portions of the bar, so that the bar is slidably mounted on the pads. In other words, the bar is inserted by sliding in the receiving groove of the receiving part.

A pad may have a generally parallelepipedal, or cylindrical, or conical, or conical-truncated, or pyramidal, or pyramidal-truncated, or semi-spherical shape. The surface of the or each pad in contact with the bar, in particular in contact with a lateral portion of the bar, may be flat or curved.

Alternatively, the pads can be made on the bar, the surface of the receiving part then being flat.

Preferably, the receiving part 22 and the bar 24 are made of plastic or metal material. In particular, the receiving part 22 and the bar 24 are made of materials for which a deformation is reversible.

In general, the rod 18 is made of metallic material.

Preferably, the plastic material chosen comprises a low-friction material, in particular polytetrafluoroethylene (PTFE), advantageously at least 10% of the mass of the plastic material being PTFE.

Advantageously, an anti-rotation device element made of plastic material comprising PTFE has an improved flexibility with respect to an element of the device made of plastics material not comprising PTFE. This improved flexibility allows shock absorption generated during the opening and closing of the valve, and remove the hyper-droop in the anti-rotation device.

The receiving part 22 and the bar 24 may be made of plastic, the plastic material of the receiving part 22 or the bar 24 comprises PTFE.

The receiving part 22 and the bar 24 may be made of plastics material comprising PTFE.

According to an embodiment not shown, the central portion 28 of the bar 24 is cylindrical, and is slid into a cylindrical bore formed in the valve stem 18. The bar 24 is then made in two parts, a first part being first slid into the valve stem, then assembled with the second part. The two parts of the bar 24 can be assembled by brazing.

The anti-rotation device according to the invention has been described in the context of a high-pressure type valve exhaust gas recirculation valve for a motor vehicle engine. Of course, the invention is not limited to the embodiments described and illustrated, which have been given only as examples. On the contrary, other applications of the anti-rotation device according to the invention are also possible without departing from the scope of the invention.

In addition, the described anti-rotation device can be integrated into any linearly actuated actuator, such as a turbocharger discharge valve actuator, or a variable geometry turbine actuator. Similarly, the anti-rotation device can be integrated in an actuator for controlling a shutter, such as a shutter for adjusting the flow of gas through a heat exchanger and the flow avoiding this heat exchanger.

Claims (10)

Anti-rotation device (20), in particular for a fluid circulation valve (10), comprising: a receiving part (22) comprising a receiving groove (26), a rod (18) extending according to a first axis (z), a bar (24) integral with the rod (18) and mounted in the receiving groove (26) of the receiving piece (22), in which the receiving groove (26) and the bar ( 24) are shaped so that the rod (18) is locked in rotation about the first axis (z) relative to the receiving piece (22) and movable in translation along the first axis (z) relative to the piece of reception (22). 2. An anti-rotation device according to claim 1, wherein the bar (24) is free in translation along a second axis (x) relative to the receiving part (22) and locked in translation along a third axis (y). relative to the receiving part (22), the first axis (z), the second axis (x) and the third axis (y) being orthogonal to one another. 3. anti-rotation device according to one of claims 1 or 2, wherein the stiffness of the bar (24) is strictly less than the stiffness of the receiving part (22). 4. An anti-rotation device according to claim 2 or claim 3 when dependent on claim 2, wherein in a section perpendicular to the first axis (z), the bar (24) has a general shape of "S", and in a section perpendicular to the second axis (x) at one end of the bar (24), the bar (24) has a general shape of "C". Anti-rotation device according to one of the preceding claims, wherein the rod (18) comprises a slot (36), a portion of the bar (24) being mounted in the slot (36) of the rod (18). so that the bar (24) is integral with the rod (18) in translation along the first axis (z). Anti-rotation device according to the preceding claim, wherein the bar (24) is asymmetrically mounted in the slot (36) of the rod (18). An anti-rotation device according to claim 5 when dependent on claim 2 or claim 6, the receiving groove (26) extending longitudinally along the second axis (x), and wherein the slot (36) the rod (18) extends in a plane containing the axis of the rod (18) and is non-parallel to the longitudinal direction of the receiving groove (26). Anti-rotation device according to one of the preceding claims, wherein the receiving piece (22) is a fluid circulation valve cover. 9. Fluid flow valve (10) comprising; a valve body (12) defining a conduit (14) for fluid circulation, - a shutter (16) movable in translation between an open position allowing the passage of fluid in the conduit (14) and a closing position preventing the passage of fluid in the conduit (14), - an anti-rotation device (20) according to one of the preceding claims, wherein the rod (18) is fixed to the shutter (16). 10. Valve according to claim 9, wherein the valve (10) is a valve is of the exhaust gas recirculation valve type, including the high pressure type.