EP0269474B1 - Hydrostatic component with axially movable vanes and axial pressing - Google Patents

Description

The present invention relates to a hydrostatic component with axial vanes such as a pump or motor.

A hydrostatic component with axial vanes is formed by two coaxial parts which are free to present a relative speed of rotation about their common axis. One of the parts, called in practice pallet carriers, comprises at least one annular series of housings in which are engaged pallets adapted to slide axially therein. The other of the parts, called track carrier, carries axially opposite the housings an annular guide track against which the pallets are intended to be axially resiliently pressed; this track comprises an annular series of recesses or working chambers alternating with rest surfaces; at the circumferential ends of each chamber open channels ensuring either a supply or a discharge of fluid.

The pressure performance of such a component is in practice limited in particular by the more or less controlled leaks which inevitably occur between the track carrier and the pallet carrier and near the guide track, the pallets and their housings. .

Known pallets are thin parallelepipeds applied by a section on the track, most often by elastic members bearing on the bottom of the housings.

The pallets either retract into the housings when they run along the rest surfaces, or protrude into the working chambers: the track acts on these pallets like cams. In engine speed, pressurized fluid arriving in a chamber acts circumferentially on the sides of the pallets projecting in this chamber, and causes the rotation of the pallet carrier relative to the track carrier, fluid at lower pressure being evacuated to the other end circumferential of the chamber. In pump mode, the rotation of the pallet carrier relative to the track carrier causes, by means of the protruding slabs in a cnambre, a suction of fluid at low pressure at a circumferential end of the chamber and a discharge of fluid to higher pressure at the other circumferential end of this chamber.

In order to keep the pallets perpendicular to the track, it is necessary that they remain permanently engaged in their housing over a significant fraction of their height (dimension oriented perpendicular to the track). As a result, the pallets must have a large height and a large mass: this implies for the pallet carrier sometimes considerable bulk perpendicular to the track, therefore a high mass, and this too can limit the maximum admissible pressure.

However, such pallets have been satisfactory to date.

Such a hydrostatic component is for example described in document DE-A-2,319,496 which relates to a pump with a single track carried by a stator and with axial vanes sliding in a rotor and subjected to the thrust of springs bearing on a surface transverse of this rotor. Axial pressure balancing of the rotor is obtained there for example by the use of axially sliding rear plates on which the springs bear and which separate, behind the rotor, chambers in hydraulic communication with the chambers separated by the pallets. In several embodiments, the pallet housings open radially opposite a stator wall 5.

The present invention aims to overcome the aforementioned drawbacks by ensuring, in a hydrostatic component with axial vanes, an improved seal between the pallet carrier and the track carrier, near the guide track, pallets and their housings.

It thus provides a hydrostatic component comprising in a chamber two coaxial parts admitting relative rotation, including a track carrier on which is formed a generally transverse annular guide track having recesses forming a working chamber, and a pallet holder provided with a bottom determining jointly with the track of the track carrier an annular fluid stream and in which are formed housings opening axially opposite this track. pallets being engaged in the housings and being axially pressed by a slice against the Track by circumferentially dividing the fluid vein, an annular piuîalite of `rear chambers in communication each individually, with the fluid vein through the pallet holder being arranged on a transverse face of this pallet holder opposite to the track carrier and opposite a support flange, characterized in that this support flange is coupled in rotation to the pallet holder, in that this pallet holder comprises annular bearings arranged radially on either side of the annular track and in axial support against the track carrier, and in that each of the rear chambers contains a part comprising, in the direction of the support flange, a basin supported by its edge against the support flange, and in communication via its bottom with said rear chamber, sealing means being interposed between this part and the interior of the rear chamber iere, sealing this chamber vis-à-vis the residual flange / pallet holder interface at least in the direction chamber / residual interface. the total transverse area of this plurality of rear chambers being greater than the transverse area of the fluid stream so that the pallet carrier is pressed against the track carrier by the pressure prevailing in the fluid stream and in the plurality of rear bedrooms.

This results in hydrostatic axial plating of the pallet holder on the track carrier, which is, of course, favorable to good sealing, by bearing on the support flange closing said chambers at the rear of the pallet holder. To make the most of this axial plating, the pallet holder advantageously has an axial clearance. for example by means of grooves.

The hydraulic isolation limited to the residual chamber-interface direction only makes it possible to force-feed the pallet housing.

Experience shows that in practice there is a minimum value for this area deviation. so that the axial plating is done satisfactorily. This minimum value, the determination of which is empirical, takes into account in particular a percentage (for example 50%) of the confrontation area of the pallet carrier against the carrier.

It will be appreciated that it is not the pallet holder but the flange which, according to the invention, undergoes the deformations induced by the pressure differentials. It is the play of the pallet holder with the support flange (watertightness) and not that with the track holder (dynamic sealing) which is increased by these deformations.

Preferably, the plurality of chambers is the same number as the pallets. It can also correspond to a submultiple of this number.

The component is advantageously split in symmetry with respect to a transverse plane passing through the track carrier. Such a component is described in the European patent application of the same day filed under priority of the French application 86-14.385 of October 16, 1986.

• chaque logement de palette débouche dans une desdites chambres, la communication de chaque chambre avec la veine fluide se faisant au travers d'un logement de palette traversant ainsi axialement de part en part le porte-palettes ; l'usinage s'en trouve simplifié et les ressorts d'application des palettes prennent appui sur le flasque d'appui indépendamment du porte-palettes;
• les chambres alternent angulairement avec les logements de palettes, des canaux étant prévus entre les logements pour mettre en communication les chambres et la veine fluide; un trés bon équilibrage est ainsi obtenu;
• la veine fluide est délimitée par un évidement torique du porte-palette dans lequel pénètre une couronne du porte-piste sur laquelle est ménagée la piste ; tout ou partie de la veine fluide peut aussi être ménage dans le porte-piste;
• le porte-palettes est affronté axialement au porte-piste par des portées annulaires coplanaires radialement disposées de part et d'autre de la couronne ; ces portées sont de façon très générale planes ou coniques (effet de centrage), coplanaires ou non.

According to preferred arrangements of the invention:

• each pallet housing opens into one of said chambers, the communication of each chamber with the fluid stream taking place through a pallet housing thus passing axially right through the pallet holder; machining is thereby simplified and the pallet application springs bear on the support flange independently of the pallet holder;
• the chambers alternate angularly with the pallet housings, channels being provided between the housings to connect the chambers and the fluid stream; a very good balance is thus obtained;
• the fluid stream is delimited by a toroidal recess of the pallet holder into which a crown of the track holder enters on which the track is formed; all or part of the fluid stream can also be cleaned in the track carrier;
• the pallet carrier is faced axially with the track carrier by coplanar annular bearings radially arranged on either side of the crown; these spans are generally very flat or conical (centering effect), coplanar or not.

The static sealing of the chambers relative to the residual interface can be obtained, in practice, either by O-rings (with anti-extrusion part if necessary), or by cups with flexible edges forming lips.

The invention also aims to overcome other aforementioned drawbacks by making it possible to lighten the pallets (and therefore to reduce the thrust of the associated springs, the contact pressure of these pallets on the opposite track as well as the mechanical losses by friction in resulting, while increasing the retraction speeds of the pallets in their housings or protruding and therefore reducing the acceleration forces) as well as the associated pallet carrier, to improve the guidance of the pallets during retraction, to allow the use of elastic ramps on the track, to simplify the machining of the pallet carrier, to reduce pressure losses in transfer conduits, to reduce creepage distances and to improve the resistance of the pallets under the pressure.

To this end, the invention proposes, according to an original characteristic in itself, a pallet for hydrostatic component comprising a wafer intended to be applied against a track determining working chambers and to slide along it, characterized in that it has the shape of a C, said edge being formed on a pallet body between two parallel branches oriented perpendicularly to this edge and intended to laterally follow said track on either side thereof.

The invention also provides a hydrostatic component of the aforementioned type including such paddles.

Such a pallet reduces the functional games which generate leaks (it runs along the track on three sides). Deformations of the pallet carrier do not increase leakage at the pallet; moreover, these leaks are further reduced with a one-piece pallet carrier. It should be noted that a single pallet may be sufficient in the working position in each chamber, thereby saving space for the cams, or reducing the number of pallets. This also allows an increase in working pressure.

There is also a possibility of gain in volume displacement (overall displacement / total volume occupied).

Because such a pallet is supported on the pallet carrier on three sides of the fluid stream, there is a need for less material (or height) to ensure proper maintenance of the pallet vis-à-vis of the track. The pallet can be hollowed out at the rear: the volume of the pallet can be little more than the strict necessary for closing the fluid stream in the working chambers.

The reduction in the weight of the pallets reduces the shocks which can occur on cams in several sections in the case of hydrostatic components with variable displacement.

More generally, this reduction in weight allows a reduction in the cam surfaces (with increased passage for the fluid entering and leaving the vein) and a reduction in the force of the veneer springs for the pallets on the track, (d ' where a reduction in the friction torque of empty pallets).

The machining of the pallets according to the invention is simplified thanks to a possible widening of the tolerances (possible clearances of the pallets in their housings); they can be obtained by molding or sintering then rectification on the two support faces in the pallet carrier, and rectification of the support edges on the track carrier. There is also a reduction in the liveliness of several edges or angles.

There is also, during the retraction of the pallets, a reduction in pressure losses in holes advantageously formed perpendicular to the track (for hydrostatic "transparency"): there is less risk of cavitation, especially if the we take advantage of the feeding option indicated above. There is also an improvement in the "drawer" guide of the pallets, hence a reduction in contact pressures, and possible choice of light alloys for the pallets.

• la palette comporte, à sa partie en regard du fond du logement, deux ailes longitudinales d'appui bordant une gorge centrale longitudinale communiquant par des canaux d'équilibrage avec la tranche d'appui contre la piste;
• cette tranche d'appui est localement convexe au voisinage de son raccordement auxdites branches;
• les branches de la palette sont évidées (voire percées) dans leurs faces bordant latéralement le porte-piste.

According to the preferred arrangements of the invention:

• the pallet comprises, at its part opposite the bottom of the housing, two longitudinal support wings bordering a longitudinal central groove communicating by balancing channels with the support edge against the track;
• this support edge is locally convex in the vicinity of its connection to said branches;
• the branches of the pallet are hollowed out (or even drilled) in their faces laterally bordering the track carrier.

Two components of the aforementioned type are advantageously matched so as to include two pallet carriers on either side of a central track carrier (or two track carriers on either side of a central pallet carrier; rooms on the pallet carrier then no longer have a raison d'être but there are some at the rear of the track carrier). Such an application, in the very general context of a hydrostatic differential with variable displacement, is described in a parallel application filed the same day.

• la figure 1 est une vue en coupe axiale partielle d'un composant hydrostatique conforme à l'invention selon la ligne I de la figure 2A;
• la figure 2A en est un quart de coupe transversale selon la ligne II-II de la figure 1;
• la figure 2B est un quart de vue du porte-piste tel qu'il est vu du porte-palettes;
• la figure 2C est un quart de vue du porte-palettes tel qu'il est vu du porte-piste avec une seule palette représentée;
• la figure 3 en est une vue en coupe transversale selon la ligne III de la figure 2A;
• la figure 4 est une vue en perspective d'une palette mise en oeuvre dans le composant hydrostatique des figures 1 à 3, avec des pièces complémentaires disposées derrière celle-ci, dans un logement du porte-palettes et la chambre dans laquelle débouche ce logement;
• la figure 5 en est une vue en perspective en configuration d'engagement partiel dans le porte-palettes des figures 1 à 3;
• la figure 6 est une vue en perspective de la palette de la figure 4 dans un autre porte-palettes;
• la figure 7 est une vue en perspective partielle d'une autre palette;
• la figure 8 est une vue en perspective partielle d'encore une autre palette;
• la figure 9 est une vue en coupe pseudo-diamétrale du seul-porte-palette;
• la figure 10 est une vue en coupe longitudinale d'une palette avec des pièces complémentaires disposées derrière celle-ci, selon une variante de réalisation de la figure 4;
• la figure 11 est une demie vue transversale d'un autre mode de réalisation du porte-palette tel qu'il est vu du porte-piste;
• la figure 12 est une demie vue arrière de ce porte-palette, analogue à la figure 2A;
• la figure 13 en est une vue en coupe pseudo-diamétrale, selon la ligne brisée XIII-XIII de la figure 12.
• la figure 14 est une vue en coupe longitudinale d'une palette de ce porte-palette prenant appui sur le fond de son logement;
• la figure 15 est une vue en coupe longitudinale d'une coupelle de ce porte-palette;
• la figure 16 est une demie vue transversale d'une variante de réalisation du porte-palette de la figure 2C;
• la figure 17 est une demie vue arrière de ce porte-palette;
• la figure 18 en est une vue en coupe pseudo-diamétrale;
• la figure 19 est une vue en coupe longitudinale d'une palette associée à ce porte-palette avec des pièces complémentaires disposées derrière celle-ci;
• la figure 20 est une vue partielle en coupe circonférentielle développée du porte-palette et du porte-piste dans le mode de réalisation des figures 1 à 10 et 16 à 19; et
• la figure 21 est une vue partielle analogue correspondant au mode de réalisation des figures 11 à 15.

Objects, characteristics and advantages of the invention appear from the description which follows, given by way of nonlimiting example with reference to the appended drawings in which:

• Figure 1 is a partial axial sectional view of a hydrostatic component according to the invention according to line I of Figure 2A;
• Figure 2A is a quarter cross section along the line II-II of Figure 1;
• Figure 2B is a quarter view of the track carrier as seen from the pallet carrier;
• Figure 2C is a quarter view of the pallet carrier as seen from the track carrier with a single pallet shown;
• Figure 3 is a cross-sectional view along line III of Figure 2A;
• Figure 4 is a perspective view of a pallet used in the hydrostatic component of Figures 1 to 3, with complementary parts arranged behind it, in a housing of the pallet holder and the chamber into which opens this housing ;
• Figure 5 is a perspective view in partial engagement configuration in the pallet carrier of Figures 1 to 3;
• Figure 6 is a perspective view of the pallet of Figure 4 in another pallet carrier;
• Figure 7 is a partial perspective view of another pallet;
• Figure 8 is a partial perspective view of yet another palette;
• Figure 9 is a pseudo-diametral sectional view of the single pallet carrier;
• Figure 10 is a longitudinal sectional view of a pallet with complementary parts arranged behind it, according to an alternative embodiment of Figure 4;
• Figure 11 is a half cross-sectional view of another embodiment of the pallet carrier as seen from the track carrier;
• Figure 12 is a half rear view of this pallet holder, similar to Figure 2A;
• FIG. 13 is a pseudo-diametrical sectional view thereof, along the broken line XIII-XIII of FIG. 12.
• FIG. 14 is a view in longitudinal section of a pallet of this pallet holder bearing on the bottom of its housing;
• Figure 15 is a longitudinal sectional view of a cup of this pallet holder;
• Figure 16 is a half transverse view of an alternative embodiment of the pallet holder of Figure 2C;
• Figure 17 is a half rear view of this pallet holder;
• Figure 18 is a pseudo-diametrical sectional view;
• Figure 19 is a longitudinal sectional view of a pallet associated with this pallet holder with complementary parts arranged behind it;
• FIG. 20 is a partial view in circumferential section developed of the pallet holder and of the track holder in the embodiment of FIGS. 1 to 10 and 16 to 19; and
• FIG. 21 is a similar partial view corresponding to the embodiment of FIGS. 11 to 15.

Figures 1 to 3 show a hydrostatic component with axial vanes suitable for operating as a motor or pump. In fact this component can, in a variant not shown, constitute only a hydrostatic module within a more complex hydrostatic component.

This component has two coaxial parts 1 and 2 adapted to have a relative rotation relative to their common axis. Part 1, called pallet carrier, is here coupled in rotation to an outer casing 3 by means of grooves 4 allowing an axial play of the pallet carrier. This envelope has a cylindrical wall 5 and a transverse flange 6. The part 2, called track carrier, here is integral with a shaft or axis 7 and the envelope is held axially in position relative to the track carrier 2 by means not shown of any known type, or by simple symmetry.

The track carrier 2 has a transverse face with respect to which a ring 8 projects axially in the pallet carrier. This transverse face is thus divided into two annular surfaces 9 and 10. The crown 8 has a generally transverse face 11 called track, which has in known manner, parallel to the axis, an annular series of recesses or pressure chambers 12 (see FIG. 2B ), in the circumferential ends of which open 12ʹ channels for supplying or discharging fluid from a hydraulic circuit internal to the track carrier of any known type (not shown).

As can be seen from FIG. 2B, a chamber 12 has a bottom 12A connected to plates 12B, circumferentially separating the chambers 12, by ramps 12 C inclined relative to the axis, arranged radially on either side cavities 12D into which the channels 12ʹ open. This track is connected to surfaces 9 and 10 by lateral faces 13 and 14, here cylindrical.

The pallet carrier 1 has a toroidal recess 15 of complementary cross section, apart from clearances, to the cross section of the crown 8 outside a recess. This toroidal recess has a bottom 16 and two side walls 17 and 18, here cylindrical, along the side faces 13 and 14.

This recess 15 is bordered radially by two transverse annular bearings 19 and 20 adapted to come axially into abutment against the surfaces 9 and 10 of the track carrier.

In this pallet carrier (see Figure 9) are housed 21 which pass through it right through and which are regularly distributed angularly. These housings have a radial dimension greater than the width of the toric recess and therefore extend towards the track carrier, on either side radially of this toric recess, by facing grooves or grooves 22 and 23 whose depth radial is less than the radial dimension of the annular bearings 19 and 20.

On the transverse face 24 of the pallet carrier opposite the track carrier are formed chambers 25 of larger cross section than the housings. These chambers are each and individually in hydraulic communication with the transverse bottom of the toroidal recess 15, here through the associated housing 21.

The total cross-sectional area of this series of chambers 25 is greater than the cross-sectional area of the bottom of the toroidal recess as a result of which, whatever the local value, high or low, of the pressure, there is plating without deformation of the pallet carrier on the track carrier by the transverse annular bearings 19 and 20 also forming sealing surfaces for the fluid stream, a possible deformation being in fact transferred to the flange 6 of the envelope, without consequences for leaks.

Each chamber 25 is sealed with respect to the residual flange 6 / pallet carrier interface by a seal 27 associated with an anti-extrusion part 26 provided with a recess 41. This part 26 comprises blind holes 40 whose role will appear more far and a flange 42 projecting laterally from the recess which prevents the seal from extruding out of the chamber 25. This chamber is at variable pressure while the flange interface 6 / pallet carrier 1 is at the drainage pressure ; this part is pierced with at least one hole 43 establishing in a basin 44 provided at the rear of the part 26 the same pressure as in the housing: this prevents the part 26 from sinking into the housing 21 in if the drainage pressure comes to be higher than that of the housing. After reversing the pressure, the pressure drop in this bore produces a rapid priming of the sealing plating of the collar 42 on the flange 6.

In the housings 21 are engaged pallets 29 of C shape pressed elastically against the crown 2 by springs 29A bearing in the blind holes 40.

As shown in more detail in FIG. 4, a pallet 29 has two parallel branches 30 adapted to slide in the grooves 22 and 23, connected by a pallet body 31. The spacing of the branches 30 is equal to the radial width of the 'O-ring recess 15 (see Figure 2C).

The pallet body 31 comprises a section 32 intended to come into abutment against the track and has curved chamfers 33 near the branches 30 facilitating the circumferential sliding of the pallet on the inclined ramps 12C. In certain components with variable displacement, these ramps may be inserts, preferably elastic (in spring steel for example).

The pallet body 31 includes, behind this edge 32, a longitudinal groove 34 bordered by flanks 35 and 36 intended to guide the pallet in a housing 21 and to obstruct the fluid stream. Ports or channels 37 allow a transfer of hydraulic oil during the axial movements of the pallet in its housing: they connect the edge 32 to the groove 34. They also reduce the placing of the pallets against the track by means of hydraulic balancing.

In FIG. 5 where, for reasons of readability, the crown 8 has not been shown and where the pallet carrier is assumed to be transparent, a pallet 29 is shown in a projecting configuration: the hatching oriented downwards to the right designate section 32, the tight hatching designates the support area of the pallet in the housing and the grooves of the pallet carrier (it is supported on three sides of the fluid stream), and the hatching oriented downwards at left designating faces 30A of the branches which run along the lateral faces of the crown 8 (not shown).

Assuming that the pallet is subjected to a high pressure HP on the left in this figure 5, this high pressure is found in the grooves and at the rear of the palette due to the plating of the latter on the right. The faces 30A of the branches ensure the radial guidance of the pallet but also and above all participate in the sealing. Indeed, the pallet being in circumferential support in the pallet carrier on three sides, if there were no branches 30, there would be a leak from corner to corner between the grooves 22 and 23 er the chambers 12 of the fluid vein to be closed. The convex chamfering chamfers 33 (not shown in this figure) make the C-shape of the pallets according to the invention interesting even if they a priori harm, to a certain extent, the sealing.

Recesses 38, or even holes 39 can be made in the branches 30 of the pallets (see FIGS. 7 and 8) to reduce the force of radial plating of these branches against the crown 8 and the deformation of these branches under the effect of pressure.

It is indeed desirable to obtain a small leakage clearance between the pallets and the crown 8 without generating untimely friction.

When the pallets slide in their housings they are hydraulically balanced making the seal between successive chambers 12 or at the bottom thereof. The phases of axial movement of the pallets in their housings are thus well dissociated from the phases of obstruction of the fluid stream.

Figure 6 describes an alternative embodiment of the pallet carrier where the grooves 22ʹ and 23ʹ do not open on the runway side so as not to affect the seal.

In the variant shown in FIG. 10, the O-ring and the associated anti-extrusion part are replaced by a sealing cup 50 provided with a flexible peripheral edge forming a lip 51 extending towards the pallet 52 and the door -track, adapted to be pressed towards the wall of the chamber 25, as well as lugs 53 adapted to engage inside the springs 29 A. It comprises also at least one bore 55 and a rear chamber 54. The pallet 52 has parallel rear flanks and have holes 39 in its branches.

In the variety of pallet holder 1ʹ, represented in FIGS. 11 to 15, the housings 21ʹ of the pallets (here closed at their rear part) and the chambers 25ʹ, provided with parts 50ʹ, are angularly offset, the latter being directly supplied with pressure by conduits 60 opening into the bottom 16 of the toroidal recess 15. This results in better balancing in deformation of the pallet holder (bending in a transverse plane). The pallets 52 are not supported on the parts 50ʹ, but on the bottom of the housings 21ʹ provided with ergors 53.

Figures 16 to 19 show a variant of Figures 1 to 10 (with the addition of the index ʺ to the corresponding reference figures) in which the pallets 70 have no branches and have a radial dimension equal to that of the crown 8 or the O-ring recess 15. There are no longer grooves 22 or 23 running along the crown 8.

We can easily deduce a variant of Figures 11 to 15 using these same palettes.

Figures 20 and 21 show the pressure distributions within the pallet carriers of the above embodiments. It is checked that the pallets in the retraction phase are axially balanced while, because the overall section of the chambers 25 or 25ʹ is greater than that of the bottom 16 of the toroidal recess 15, there is axial plating at any point of the pallet carrier against the track carrier, without significant local contact pressure.

It goes without saying that the foregoing description has been offered only by way of non-limiting example and that numerous variants can be proposed by those skilled in the art without departing from the scope of the invention.

The components of FIGS. 1 and 3, and 7 and 8 have been represented and described very schematically for all that relates to their characteristics known per se which do not interact with the invention. In advantageous embodiments not shown, such modules are paired so as to comprise two pallet carriers on either side of a central track carrier with two tracks, the vertical lines in dashed lines bordering on the right the figures. 1 and 3, in particular corresponding to planes of symmetry. More generally, a plurality of hydrostatic modules of the type shown between the vertical dashed lines in these figures can be combined as desired.

Claims (12)

1. A hydrostatic component comprising, in an enclosure (3), two coaxial parts (1. 1', 1", 2) allowing relative rotation, which consist of a track-carrier (2), on which a generally transverse annular guide track (11) comprising openings forming working chambers (12) is formed, and a blade-carrier (1, 1', 1") equipped with a base (16), which defines conjointly with the track of the track-carrier an annular channel for fluid (15), and in which axially opening housings (21, 21', 21") are formed facing the track, blades (29, 52, 70) being engaged in the housings and being axially pressed with an edges against the track, thus dividing the channel for fluid circumferentially, and an annular plurality of rear chambers, each individually in communication through the blade-carrier with the channel for fluid, being formed on a transverse face of the blade-carrier on the opposite side to the track-carrier and facing a bearing flange, characterized in that the bearing flange (6) is fixed in rotation to the blade-carrier, the blade-carrier comprises annular bearing surfaces (19, 20) disposed radially on either side of the annular track and in annular bearing against the track-carrier, each of the rear chambers contains an element (26, 50) comprising a basin (44, 54), open towards the bearing flange, which bears by means of its edge against the bearing flange and is in communication through its base with the said rear chamber, sealing means (27, 51) being interposed between this element (26, 50) and the interior of the rear chamber, isolating this chamber in a sealed manner from the residual flange/blade-carrier interface, at least in the chamber/residual interface direction, the total transverse area of this plurality of chambers being greater than the transverse area of the channel for fluid in such a way that the blade-carrier is applied against the track-carrier by the pressure existing in the channel for fluid and in the plurality of rear chambers.
2. A component according to claim 1, characterized in that the annular plurality of rear chambers, which are regularly distributed angularly, and the blades are equal in number.
3. A component according to claim 2, characterized in that each blade housing (21, 21") opens into one of the said rear chambers (25, 25"), the communication between each chamber and the channel for fluid being made through a blade housing, thus passing axially completely through the blade-carrier (1, 1").
4. A component according to claim 2, characterized in that the rear chambers (25') alternate angularly with the blade housings (21'), channels (60) being provided between the housings to put the chambers in communication with the channel for fluid.
5. A component according to any one of claims 1 to 4, characterized in that each chamber is sealed by a toroidal seal cooperating with an anti-extrusion element.
6. A component according to any one of claims 1 to 4, characterized in that each chamber is sealed by a dished element (50) comprising a supple edge (51) forming a lip.
7. A component according to any one of claims 1 to 6, characterized in that the channel for fluid is delimited by a toroidal recess (15, 15', 15") in the blade-carrier into which a protruding ring (8) of the track-carrier on which the track is formed projects.
8. A component according to claim 7, characterized in that the annular bearing surfaces (19, 20) by means of which the blade-carrier (1, 1', 1") is butted axially against the track-carrier are coplanar.
9. A component according to any one of claims 1 to 8, characterized in that the blade housings (21, 21") are extended on either side of the toroidal recess by grooves (22, 23), the blades (29, 52) are C-shaped, the said edge (32) being made on a blade body (30) between two parallel arms directed perpendicularly to this edge which are adapted to slide in the grooves and to extend laterally against the said protruding ring (8).
10. A component according to claim 9, characterized in that each blade comprises, on the opposite side to the said edge, two longitudinal bearing wings (35, 36) bordering a central longitudinal groove (34) communicating with the edge by means of hydraulic transfer and equilibrating channels (37).
11. A component according to claim 9 or claim 10, characterized in that the opposite faces (30a) of the arms of the blade are hollowed out (38) or pierced through (39) parallel to the said edge.
12. A component according to any one of claims 1 to 11, characterized in that the blade-carrier allows an axial movement relative to the bearing flange (6) by means of axial splines (4).

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