FR3084410A1 - HYDRAULIC MACHINE - Google Patents

Abstract

The present invention relates to a hydraulic machine comprising a cylinder block (30) comprising cylinders (32) housing pistons (50), a distributor (60) comprising channels (61, 64) which communicate with the cylinders (32) and comprising two concentric complementary elements (62, 66) capable of relative axial sliding and sealing means (70, 72, 74; 100) arranged in respective grooves between the two concentric complementary elements (62, 66) in which the means of sealing (70, 72, 74) comprise at least two continuous annular seals each comprising a base and at least one lip-shaped fin, adapted to rest elastically against a respective surface of the complementary elements (66, 62) of distributor placed in look and seal at this level, the annular seals being made of a material allowing elastic deformation of the seal allowing the engagement of u joint in the respective associated groove.

Description

TECHNICAL AREA

The invention relates to the field of hydraulic machines.

The invention relates more precisely to hydraulic machines comprising a rotary element, of the type comprising a casing which contains a cylinder block comprising cylinders each housing a respective piston, a distributor comprising channels which communicate with the cylinders of the cylinder block and comprising two elements concentric complementary radially internal and radially external respectively and capable of relative axial sliding and sealing means disposed between the two concentric complementary elements to ensure a seal therebetween.

The distributor is particularly of the type comprising a flat support on the cylinder block, equipped with distribution orifices towards the cylinders, and exerting a thrust on the cylinder block during operation to ensure the sealing of the distribution.

The aforementioned sliding can be sought to guarantee a reliable and permanent contact between the distributor and the cylinder block or also to ensure a coupling and uncoupling function between a shaft and the cylinder block by means of a coupler formed for example by a stack of friction discs.

The desired thrust is exerted either by a specific thrust chamber, or in a preferred manner by a staging of the walls of the distribution grooves, which generates an axial thrust when the grooves are put under pressure. These grooves are framed by the sealing means.

STATE OF THE ART

Many hydraulic machines of the aforementioned type are known, in particular radial piston machines.

These machines can form either motors or pumps.

They form motors when the distributor receives oil from a pressure source and distributes the oil successively in the cylinders of the cylinder block during a relative rotation between the cylinder block and the distributor, making it possible to recover a mechanical energy on a shaft linked to a rotating mobile part of the machine.

They form pumps when mechanical energy is applied to the machine, imposing a relative rotation between the cylinder block and the distributor, so that the distributor collects oil under pressure through its channels communicating with the cylinders.

As indicated previously, the distributor comprises two concentric complementary elements respectively radially internal and radially external and capable of relative axial sliding, at least of a slight axial clearance, to ensure the fluid connection with the cylinders of the cylinder block.

These two elements can be called “main distributor element” and respectively “secondary distributor element” or “secondary fluid connection element”.

One of these elements, which constitutes the main element of the dispenser, has a surface perpendicular to the axis of rotation of the machine, generally called "ice", in contact with a surface facing the cylinder block. This main distributor element comprises channels opening out, generally by means of grooves open on the glass surface, facing supply orifices of the cylinder block. It is the relative sliding of the distributor support plane with respect to the support plane opposite the cylinder block which ensures the cutting of the connection of the supply and exhaust conduits to each cylinder orifice. The permanent balance between the distributor contact pressure and the oil pressure in the conduits guarantees the sealing of the sliding distribution junction. It is therefore necessary that the distributor is always applied to the cylinder block when the engine is running. Leaks that occur reduce the volumetric and mechanical efficiency of the hydraulic machine.

To ensure the axial support of the distributor on the cylinder block, it is therefore necessary to be able to obtain an axial sliding of the distributor.

In addition, during the rotation of the engine, and in particular if the latter is of the type comprising a connection of the cylinder block to the shaft by friction discs, it should be noted that the cylinder block is subjected to slight oscillations, by its deformation, by the deformation of the shaft which carries it or which centers it, by the play of its sliding link if it is supported on discs. So that the distributor is always in plan support on the cylinder block, it must also be able to compensate for these slight oscillations by a slight offset. This implies a clearance between the internal part and the external part of the dispenser, and this consequently implies that the sealing means can absorb a flapping movement from the internal part of the distributor into the external part.

Furthermore, depending on the environment, the machine housing can be fixed or mobile in rotation and conversely a shaft linked to the cylinder block can then be mobile in rotation or fixed.

When the machine casing is fixed and the shaft linked to the cylinder block then mobile in rotation, the fluid connection with the main element of the distributor is operated by this casing, part of which constitutes the secondary distributor element.

When, on the contrary, the machine casing is movable in rotation and the shaft linked to the cylinder block then fixed, the fluid connection with the main element of the distributor is effected by means of a central shaft linked in rotation with the block. cylinders.

There is shown in the appended figure in longitudinal section and in FIG. 1b in cross section, a hydraulic machine with radial pistons of the aforementioned type, for example forming a hydraulic motor, with fixed casing, comprising:

. a casing 10 formed of two lateral casing elements 10a and 10c framing a central annular casing element 10b,. a casing comprising a multi-lobed cam 20 preferably formed on the radially internal surface of the central casing element 10b,. a cylinder block 30 mounted with relative rotation in the casing 10 about an axis O-O, facing the cam 20,. a shaft 40 linked in rotation with the cylinder block 30, for example by means of complementary axial grooves,. pistons 50 guided in radial sliding in respective cylinders 32 of the cylinder block 30 and bearing on the lobes of the cam 20, preferably by means of rollers 52 and. a distributor 60 adapted to ensure a fluid connection with the cylinders 32 of the cylinder block 30 (adapted to successively apply a pressurized fluid to the pistons 50 in the case of an engine or adapted to recover a pressurized fluid from cylinders 32 in the case of a pump), so that the successive pressing of the pistons 50 on the lobes of the cam 20 causes the relative rotation of the cylinder block 30 and of the elements which are linked to it relative to the casing 10, thanks to an asymmetry between the number of lobes of the cam 20 and the number of pistons 50.

More precisely according to the variant embodiment illustrated in FIG. 1, the dispenser 60 comprises two concentric complementary elements 62, 66, respectively radially internal and radially external. These two elements 62, 66 can be indexed for rotation, or linked to rotation by any appropriate means, but they are capable of relative axial displacement. For example in FIG. 1a, a fork-shaped protuberance of the part 62 frames a pin linked to the element 66, which ensures indexing in rotation only of these two parts, without interfering with the other possible movements of the element 62 vis-à-vis element 66. Other means such as Holdhamm seals can be used. The means of indexing in rotation will not be detailed subsequently. In general, the distributor part in contact with the cylinder block must be indexed in rotation relative to the cam of the hydraulic machine.

The radially external distributor element 66 belongs to the casing element 10a according to FIG. La and constitutes “the secondary distributor element” or “secondary fluid connection element”.

The radially internal element 62, which constitutes the main distributor element, has a face 63 transverse to the axis O-O, which constitutes the glass, attached to a face 33 complementary to the cylinder block 30.

Each of these two distributor elements 62, 66 comprises channels intended to ensure the routing of the oil between the cylinders 32 and the exterior of the machine.

Such a machine is described for example in the documents FR 2 651 836, FR 2 582 058 and EP 2 531 720.

The radially external element 66, which constitutes the secondary distributor element, has at least two generally radial channels 67, 68, which open at the interface between the two elements 62 and 66, preferably in annular grooves 71 , 73 formed at this interface between the two elements 62 and 66.

The radially internal element 62, which constitutes the main distributor element, has generally axial channels 61, 64 which open onto the face 63 of the main distributor element forming the ice. These axial channels 61, 64 are extended by any suitable secondary channels, generally generally radial, to ensure a fluid connection between these axial channels 61, 64 and the channels 67, 68 of the element 66.

Sealing means are provided between the two distributor elements 62 and 66. More specifically, it is thus preferably provided at least three seals 70, 72 and 74 distributed axially between the two distributor elements 62 and 66. The pair of seals 70 and 72 frame a groove 71 formed at the interface between the elements 62 and 66 and which provide a connection between the channels 61 and 67, The second pair of seals 72 and 74 frame a groove 73 formed at the level of the interface between the elements 62 and 66 and which provide a connection between the channels 64 and 68.

The channels 67 and 68 form for example a high pressure line and a drain and are for example connected to a source of pressurized fluid and to a pressureless tank, in the case of an engine.

There is shown in Figure 2 appended in longitudinal section, a variant of a hydraulic machine with radial pistons of the aforementioned type with mobile housing for rotation.

This variant may be in accordance with the cross-sectional representation illustrated in FIG. 1b.

Such a machine is described for example in document EP 0 487 393.

The hydraulic machine illustrated in FIG. 2 also includes:

. a casing 10 formed of two lateral casing elements 10a and 10c framing a central annular casing element 10b,. a cam comprising a multilobed cam 20 preferably formed on the radially internal surface of the central casing element 10b,. a cylinder block 30 mounted with relative rotation in the casing 10 about an axis O-O,. a shaft 40 linked in rotation with the cylinder block 30,. pistons 50 guided in radial sliding in respective cylinders 32 of the cylinder block 30 and bearing on the lobes of the cam 20, preferably by means of rollers 52 and. a distributor 60 adapted to ensure a fluid connection with the cylinders 32, for example successively applying a pressurized fluid to the pistons 50 in the case of an engine, so that the successive support of the pistons 50 on the lobes of the cam 20 causes the relative rotation of the cylinder block 30 and of the elements which are linked to it with respect to the casing 10, thanks to an asymmetry between the number of lobes of the cam 20 and the number of pistons 50.

Found in the alternative embodiment illustrated in Figure 2, a distributor 60 comprising two concentric complementary elements 62, 66, respectively radially external and radially internal.

The radially internal distributor element 66 constitutes the secondary distributor element. It is linked to rotation with the shaft 40 hey, moreover itself to rotation with the cylinder block 30, and can even be formed in this shaft 40.

The radially external element 62, which constitutes the main distributor element, has a face 63 transverse to the axis 0-0 which constitutes the glass, attached to a complementary face 33 of the cylinder block 30.

Here again the two elements 62, 66 are linked in rotation by any appropriate means, but they are capable of relative axial displacement along the axis O-O.

Each of these two distributor elements 62, 66 comprises channels intended to ensure the routing of the oil between the cylinders 32 and the exterior of the machine.

The radially internal element 66, which constitutes the secondary distributor element, has at least two generally radial channels 67, 68 which open at the interface between the two elements 62 and 66, preferably in annular grooves 71, 73 formed at this interface between the two elements 62 and 66. These channels 67, 68 communicate with the outside of the machine, typically with a pressure source and a drain, by any appropriate means, preferably by the intermediary channels 670, 680 formed axially in the shaft 40.

The radially external element 62, which constitutes the main distributor element, also has generally axial channels 61, 64 which open on the face 63 of the main distributor element forming the ice. These axial channels 61, 64 are extended by any suitable secondary channels, generally generally radial, to ensure a fluid connection between these axial channels 61, and the channels 67, 68 of the element 66.

Also here again, sealing means are provided between the two distributor elements 62 and 66. More specifically, it is thus preferably provided at least three seals 70, 72 and 74 distributed axially between the two distributor elements 62 and 66. The pair of seals 70 and 72 surround the groove 71 formed at the interface between the elements 62 and 66 and which provide a connection between the channels 61 and 67. The second pair of seals 72 and 74 frame the groove 73 formed at the interface between the elements 62 and 66 and which provide a connection between the channels 64 and 68.

Channels 67 and 68 form for example a high pressure line and a drain and are for example connected to a source of pressurized fluid and to a pressureless reservoir, in the case of an engine, via channels 670 and 680. Channels 67 and 68 can also be the high pressure and low pressure lines of a closed mud circuit.

The sealing means 70, 72 and 74 currently used in hydraulic machines are generally formed of open or split C-shaped metal segments, for example of cast iron segments. More precisely, in order to obtain the seal which a single segment does not make it possible, taking into account the presence of the cut essential for ensuring the engagement of the segments on the dispenser due to their low deformability, the sealing means are generally formed by two associated segments placed respectively in two neighboring housings.

In general, the segments have two unfavorable characteristics. Due to the slot necessary for their assembly, they present leaks. The start-up of the circuit therefore requires a large boost flow rate to compensate for leaks. In addition, being incompressible, it is necessary to provide a clearance between the segment and the groove bottom which houses them, so that the internal and external parts of the distributor can have the beat necessary to follow the oscillations of the cylinder block. One consequence is that the segments cannot support the weight of the distributor, and that the internal part of the distributor falls in contact with the external part. This generates shocks when the machines are in motion, in particular when the engines are not activated, for example during the transport of the machines as spare parts of the machines, or when moving the machines equipped with these hydraulic machines, when the machines are not used. This can be frequent for hydraulic machines intended to make temporary hydrostatic transmissions on vehicles.

There are also known, as described for example in document EP 0 487 393, sealing means formed by association of an annular seal and a biasing member, for example an elastomer O-ring or a cut metal or plastic ring. elastically deformable, intended to deform the seal to apply it to the opposite face of the dispenser.

These known sealing means have already rendered great services.

However, they remain complex, require know-how and do not always ensure optimum sealing. In particular, they are very tight, slide with difficulty. They provide support for the weight of the dispenser, but do not allow sufficient beating, and also very little offset. One consequence is that during the rotation of hydraulic machines, the distributor poorly follows the oscillations of the cylinder block, and this generates leaks through the distribution plane. If this type of seal gives a better seal at the distributor groove joints, it can generate greater leaks at the distribution support plane. Furthermore, when the machines are started up, very high pressure is required for the internal part of the distributor to slide axially in contact with the cylinder block. During this time, the leak penalizes the rise in pressure of the hydraulic lines. The starting of these machines is therefore not immediate, and is not done at low pressure. It is difficult to work or start with these machines at low pressure. One consequence is that the start-up of the circuit comprising these machines requires a large force-feeding rate to compensate for leaks.

BASIS OF THE INVENTION

In this context, the present invention aims to propose new means for improving the state of the art.

The present invention particularly aims to provide means for improving the seal at the interface between the two elements of the dispenser.

Another important object of the invention is to propose means making it possible to make the relative positioning of the two distributor elements more reliable.

Another important object of the invention is to propose means making it possible to authorize a certain displacement in relative inclination, with respect to the axis of the machine, between the two distributor elements, comparable to a swiveling.

Another object of the invention is to provide reliable sealing means without leading to a significant friction force.

Other objects of the invention are to propose means making it possible to start more quickly than with hydraulic machines conforming to the state of the art, making it possible to start correctly with a low pressure, which corresponds to a setting in machine route which can be described as “soft”, well sealed at low pressure and requiring less booster, therefore requiring smaller booster pumps, saving energy on booster and to see more easily the use of electric booster pumps.

These objects are achieved according to the invention thanks to a hydraulic machine comprising. a housing that contains. a cylinder block comprising cylinders each housing a piston,. a distributor comprising channels which communicate with the cylinders of the cylinder block and comprising two concentric complementary elements respectively radially internal and radially external and capable of relative axial sliding, said two complementary distributor elements defining between them at least one hydraulic supply groove of the machine and. sealing means disposed in respective grooves between the two concentric complementary elements to ensure sealing between them by framing said hydraulic supply groove, characterized by the fact that. the sealing means comprise at least two continuous annular seals each comprising a base and at least one lip-shaped fin, adapted to rest elastically against a respective surface of the complementary distributor elements placed facing each other and to ensure sealing at this level, which lip has a conical part of revolution around the axis of the dispenser, biased in radial deformation to be pressed against said facing surface,. said annular seals being axially separated and made of a material. allowing an elastic deformation of the seal allowing the engagement of the seal in the respectively associated groove so that the seal rests against a surface of the groove to ensure a seal,. while ensuring elastic support and centering of the radially internal element in the external distributor element to avoid direct mechanical contact between these two elements.

According to other advantageous but optional features of the invention:

- The base of the seals rests against a radial surface of the groove respectively associated to ensure the seal.

- The lip-shaped fin rests against an axial and peripheral surface of the distributor element placed opposite to ensure sealing.

- each joint is made of a material such that the stiffness of the fin supports the weight of the radially internal distributor element so that it is suspended and centered in a bore of the radially external distributor element with the possibility of axial sliding, even in the state of rest without pressure.

- the base of the seal is clamped in the groove of the distributor and maintains the seal without sliding or rotation of the base relative to the distributor.

- the base of the seal is mounted floating in the groove of the distributor

- a radial clearance exists between the base of the seal and the groove, but the length of the fin allows sufficient centering so that the radially internal distributor element is centered and suspended so as not to touch the bore formed in the radially external distributor element.

- the base of the joint has a rectangular section.

- The joint has the general shape of an L in cross section, comprising two wings formed respectively by the base and by the lip-shaped fin.

- the fin generally extends along a radius from the center of the straight section of the base.

- The base is of generally rectangular or square cross section and the fin extends along a radius from an angle of the straight section of the base.

- The fin protrudes radially with respect to the periphery of the base directed towards the facing surface on which the sealing must be ensured.

- The seal is placed in a groove formed on a radially external surface of one of the distributor elements and the free end of the fin extends radially on the outside of the external periphery of the base.

- The seal is placed in a groove formed on a radially internal surface of one of the distributor elements, the free end of the fin extends radially on the inside of the internal periphery of the base.

- the axial extension of the fin is between two and six times the amplitude of the radial protrusion of the fin relative to the base, preferably the axial extension of the fin is at least equal to 3 times l amplitude of the radial protrusion of the fin relative to the base.

- The joint has the general shape of a U in cross section comprising a central base and two fins.

- The machine comprises a U-shaped joint which has a plane of radial symmetry perpendicular to the axis of rotation 0-0 of the machine and the opening of which is directed radially.

- The machine includes a U-shaped seal which has an axial extension from its middle part between two and six times the amplitude of the radial protrusion of the fin relative to the base, preferably the axial extension of the fin is at least equal to three times the amplitude of its arrow, or a total width of between four and twelve times the amplitude of the arrow, preferably at least equal to 6 times its arrow.

- The joint has the general shape of a U in cross section whose convexity is directed towards the bottom of the groove, comprising a central core forming the base and two lip-shaped fins adapted to rest against the opposite surface.

- The joint has the general shape of a U in cross section whose concavity is directed towards the bottom of the groove, comprising a central core adapted to rest against the opposite surface.

- the lip-shaped fin constitutes a ring of conical shape.

- the fin defines a concavity directed towards an area under pressure.

- the seal is made of plastic.

- The joint is made of a material chosen from the group comprising polyoxymethylene and polyamide.

- the joint is produced by machining.

- The two seals are placed in respective grooves arranged on the opposite axial ends of the dispenser element provided with the grooves.

- The machine comprises a return means of the assembly formed by the main distributor element and the cylinder block, which exerts on the main distributor element an antagonistic force to an axial displacement urged by hydraulic pressure.

the elasticity of the lips of the seals bearing on the facing surface allows the centering of the main distributor element with respect to the cylinder block, and a slight latitude of swiveling movement of the main distributor element with respect to the axis of rotation of the machine so as to always remain applied to a distribution plane of the cylinder block when the latter is rotated when the machine is hydraulically operated, in order to guarantee a good seal on the distribution plane .

- the machine comprises three continuous annular seals adapted to be placed in a respective groove formed in a distributor element and adapted to ensure a seal at this level, the three seals being placed respectively on the axial ends and in the middle part of the distributor elements and framing two by two of the feed grooves of the machine.

- The machine comprises two L-shaped end seals placed in respective grooves provided on the axial ends of the dispenser and a U-shaped central seal placed in a central groove of the dispenser.

- The lip-shaped fins provided on the end joints are directed towards each other, towards the axial center of the dispenser.

each annular seal is made of a material allowing elastic expansion of the seal such that in the expansion position the seal has a diameter greater than the radially internal distributor element in which the groove intended to receive the seal is formed, a part of the seal resting after engagement against a surface of the associated groove to ensure a seal.

- The machine comprises means forming a stop which impose a unique mounting direction for each seal and prohibit mounting in the wrong direction of the seal.

- the pistons are mounted to slide radially in the cylinder block.

- the machine comprises a multilobe cam opposite the cylinder block.

- The casing is fixed and the fluidlque connection with the main element of the distributor is operated by the casing, part of which constitutes the secondary element of the distributor which comprises distribution channels.

the casing is movable in rotation and the fluid connection with the main element of the distributor is effected by means of a central shaft linked in rotation with the cylinder block and which comprises distribution channels,

- The machine comprises three continuous U-shaped annular seals placed respectively on the axial ends and in the middle part of the distributor elements, in respective grooves, and framing two by two of the feed grooves of the machine.

The invention further relates to a distributor for a hydraulic machine comprising two concentric complementary elements, respectively radially internal and radially external and capable of relative axial sliding, said two complementary elements of distributor defining between them at least one hydraulic supply groove for the machine and . sealing means arranged between the two concentric complementary elements to ensure a seal between them by framing said hydraulic supply groove, characterized in that. the sealing means comprise at least two continuous annular seals each comprising a base and at least one lip-shaped fin, adapted to rest elastically against a respective surface of the complementary distributor elements placed facing each other and to ensure sealing at this level, which lip has a conical part of revolution around the axis of the dispenser, biased in radial deformation to be pressed against said facing surface,. said annular seals being axially separated and made of a material. allowing elastic deformation of the seal allowing re-engagement of the seal in the respectively associated groove so that said seal rests against a surface of the groove to ensure a seal,. while ensuring elastic support and centering of the radially internal element in the external distributor element to avoid direct mechanical contact between these two elements.

The present invention also relates to a seal for the implementation of a machine of the aforementioned type, characterized in that it comprises a base and a lip-shaped fin, adapted to rest elastically against respective surfaces facing elements complementary to a dispenser and provide sealing at this level, each annular seal being made of a material allowing elastic deformation of the seal allowing the engagement of the seal in an associated groove so that the seal rests against a surface of the associated groove to ensure a seal while ensuring elastic support and centering of the radially internal element in the external distributor element to avoid direct mechanical contact between these two elements.

QUICK DESCRIPTION OF THE FIGURES

Other characteristics, aims and advantages of the present invention will appear on reading the detailed description which follows and with reference to the appended drawings, given by way of indicative and nonlimiting examples, and in which:

FIGS. 1 a and 1 b previously described respectively in longitudinal section and in cross section, a hydraulic machine in accordance with a first embodiment known from the state of the art,

FIG. 2 also previously described represents a view in longitudinal section of a hydraulic machine in accordance with a second variant embodiment known from the state of the art,

FIG. 3 represents a half view in longitudinal section of a machine according to an embodiment according to the present invention,

FIG. 4 represents a partial view in longitudinal section of a seal in accordance with the present invention,

FIG. 5 represents an axial view of the seal illustrated in FIG. 4,

- Figures 6, 7, 8 and 9 show a partial view in longitudinal section of joints according to four alternative embodiments of the present invention, while Figure 7bis shows a partial view in longitudinal section of a joint according to a variant of realization intended to be placed in a groove formed on a radially internal surface of a distributor element,

FIGS. 8a and 8b show two alternative embodiments of a seal in accordance with the present invention,

- Figure 10 schematically shows, in a side view, a partial view of a machine according to an alternative embodiment of the present invention, illustrating a possibility of swiveling between the two distributor elements, Figure lObis schematically illustrates an inclination of the main distributor element with respect to the auxiliary distributor element made possible within the framework of the present invention

FIG. 11 illustrates a half view in longitudinal section of a machine according to an alternative embodiment in accordance with the present invention comprising polarizing means preventing incorrect mounting of the seals,

FIG. 12 schematically illustrates a hydraulic machine equipped with a coupler based on friction discs,

FIG. 13 schematically illustrates a half view in longitudinal section of a machine according to an alternative embodiment according to the present invention,

FIG. 14 represents a view on an enlarged scale of a U-shaped joint of FIG. 13 in a complementary groove and

- Figure 15 schematically illustrates a half view in longitudinal section of a machine according to another alternative embodiment according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The detailed description which follows essentially relates to the geometry of the seals in accordance with the present invention intended to form the seals 70, 72 and / or 74 illustrated in FIGS. 1 and 2.

The hydraulic machines in accordance with the present invention may moreover comply with all of the provisions previously described with reference to FIGS. 1 and 2. These provisions will therefore not be repeated in the detailed description which follows. The entire description previously presented with regard to FIGS. 1 and 2 must however be considered as applying to the invention.

In the following description, the annular seals in accordance with the present invention are referenced 100. They can be used in place of one of the seals referenced 70, 72 and / or 74 in FIGS. 1 and 2.

As indicated above, according to the invention, the hydraulic machines comprise sealing means formed by at least two continuous annular seals 100 each comprising a base 110 adapted for example to be placed in a respective groove 600, 602 or 604 formed in the one of the complementary elements of distributor 62 or 66 and a fin 130 in the form of a lip adapted by example to rest elastically against a surface of the other complementary element of distributor 66 or 62 placed opposite and ensuring a seal at this level.

As a variant, as will be seen later, in particular for a U-shaped cross section joint, the lip-shaped fin 130 can be adapted to rest elastically against a surface of the groove to ensure a seal at this level, while the base 110 rests on a facing surface to also ensure a seal at this level.

The lip 130 has a conical part 132 of revolution around the axis 0-0 of the distributor, biased in radial deformation to be pressed against said facing surface. This conical part has a radial component and an axial component. The axial component allows a large latitude of motion compensation and in particular allows swiveling and offsetting. Note that the point of contact between the fin 130 and a surface of the other complementary distributor element 66 or 62 placed opposite is axially offset relative to the position of the base 110 in the groove 600, 602. In other words preferably the point of contact of the fin 130 on the facing surface is not exactly opposite the groove which receives the seal 100.

It will be noted on examining FIGS. 3 and 11 that preferably the two distributor elements 62 and 66 are not of constant cross section, but are stepped radially. Thus the two feed grooves 71 and 73 are not formed on distributor sections of the same diameter, but on the contrary on distributor sections having different diameters. Similarly the grooves 600, 602 and 604 are preferably formed on distributor sections having different diameters and increasing from an axial end of the distributor to the opposite axial end.

The fin 130 generally extends along a radius relative to the center of the cross section of the base 110.

In the case of a base 110 of rectangular or square cross section, the fin 130 thus extends along a radius from an angle of the cross section of the base 110.

The fin 130 thus protrudes radially relative to the periphery of the base 110 directed towards the facing surface on which the sealing must be ensured.

In the case where the seal 100 is placed in a groove formed on a radially external surface of one of the distributor elements, the free end of the fin 130 extends radially on the outside of the external periphery of the base 110 as illustrated in FIGS. 4, 7 and

9.

On the contrary when the seal 100 is placed in a groove formed on a radially internal surface of one of the distributor elements, the free end of the fin 130 extends radially on the inside of the internal periphery of the base. 110 as illustrated in Figure 7bis.

Preferably the axial extension L2 of the fin 130 is between two and six times the amplitude of the radial protrusion H2 of the fin 130 relative to the base 110, preferably the axial extension L2 of the fin 130 is at least equal to 3 times the amplitude of the radial protrusion H2 of the fin 130 relative to the base 110.

The fin 130 forms a scraper which guarantees sealing.

In the context of the invention, the term "continuous" means that the seals 100 are continuous O-rings, that is to say closed, without 360 ° rupture and not open rings at C.

Preferably the conical part 130 of the lip-shaped fin 130 is oriented so that it is biased in radial deformation to be pressed against the facing surface during the application of oil pressure.

According to the invention the two annular seals 100 are separated axially and made of a material which allows elastic deformation of the seal 100 allowing the engagement of the base 110 in the respectively associated groove 600, 602 or 604 so that said base 110 rests against a surface of the groove 600, 602 or 604 to ensure a seal, while ensuring support and elastic centering of the radially internal element 62 or 66 in the external distributor element 66 or 62, to avoid mechanical contact direct between these two elements.

The two seals 100 are placed in respective grooves 600, 604 arranged on the opposite axial ends of the distributor element 62 or 66 provided with grooves 600 and 604.

As illustrated in FIG. 3, according to the invention, the machine preferably comprises three continuous annular seals 100 each comprising a base 110 adapted to be placed in a respective groove 600, 602 and 604 formed in a distributor element 62 or 66 and a lip-shaped fin 130 adapted to rest elastically against a surface placed opposite the other distributor element 66 or 62 and to ensure a seal at this level, the three seals 100 being placed respectively on the axial ends and in middle part of the distributor elements, to frame two by two respectively the aforementioned grooves 71 and 73.

The machine thus preferably comprises two L-shaped end seals 100 placed in respective grooves 600, 604 provided on the axial ends of the dispenser and a U-shaped central seal 100 placed in a central groove 602 of the dispenser.

The lip-shaped fins 130 provided on the end seals placed in the grooves 600 and 604 are directed towards each other, towards the axial center of the distributor, as seen in FIG. 3.

In the context of the invention, preferably the seals 100, in particular the base 110 of the seals, rest against a radial surface of the respective associated groove 600, 602 or 604, as seen in FIG. 3, to ensure the seal.

Furthermore, in the context of the invention, preferably the lip-shaped fin 130 rests against an axial and peripheral surface of the distributor element placed opposite to ensure sealing. The term “axial and peripheral surface” means a surface defined by a generator parallel to the axis O-O.

According to a first embodiment in accordance with the present invention, which preferably applies to the seals 100 intended to be placed on the axial ends of the dispenser, in the grooves 600 and 604, the seal 100 has the general shape of an L in cross section, comprising two wings formed respectively by the base 110 and by the lip-shaped fin 130.

Such a seal is shown in Figures 4, 7 and 9.

The lip-shaped fin 130 constitutes a ring of conical shape. Its concavity is directed towards an area under pressure.

As indicated above, preferably the axial extension L2 of the fin 130 is between two and six times the amplitude of the radial protrusion H2 of the fin 130 relative to the base 110, preferably the axial extension L2 of l the fin 130 is at least equal to 3 times the amplitude of the radial protrusion H2 of the fin 130 relative to the base 110.

According to a second embodiment in accordance with the present invention, which preferably applies to the seals 100 intended to be placed in the central groove 602 of the dispenser, the seal 100 has the general shape of a U in cross section. The opening of the U is directed radially. The U-shaped joint thus has a plane of radial symmetry perpendicular to the axis of rotation O-O.

Such a seal is shown in Figures 6 and 8.

Preferably, this U-shaped joint 100 corresponds to the same ratio between its axial extension and its radial extension or deflection as that mentioned above for a 100-L joint.

Thus the U-shaped joint 100 has an axial extension L2 from its median part of between two and six times the amplitude of the radial protrusion H2 of the fin 130 relative to the base 110, preferably at least equal to three times the amplitude of its arrow H2, ie a total width L3 of the U-shaped joint 100 between four and twelve times the amplitude of the arrow H2 and preferably at least equal to 6 times its arrow H2.

As shown in FIGS. 3 and 6, the joint 100 of U-shaped cross section may have its concavity directed towards the bottom of the groove 602, comprising a central core 120 adapted to rest against the opposite surface.

However as a variant as shown in FIG. 8, the joint 100 of U-shaped cross section may have its convexity directed towards the bottom of the groove, comprising a central core 120 forming the base 110 and two fins 130 in the form of a lip adapted to rest against the facing surface.

According to another alternative embodiment shown in FIG. 8a, the aforementioned U-shaped seal 100 can be replaced by two L-shaped seals 100 of the aforementioned type mounted in a common central groove (602) and whose respective fins 130 are directed in directions axially opposite, forming in combination a U-shaped joint.

According to yet another alternative embodiment shown in FIG. 8b, the same assembly can be envisaged with a seal 100 comprising a single base 110 and two fins 130 in accordance with the aforementioned arrangements of the invention, each in an axial direction, that is that is to say extending in opposite axial directions, so as to make a central joint operating with a pressure established on one side or the other.

When the seal 100 is L-shaped, the base 110 of the seal 100 can be clamped in the groove 600 or 604 of the dispenser to maintain the seal without sliding or rotation of the base 110 relative to the dispenser.

However as a variant, the base 110 of the seal 100 can be mounted floating in the groove 600 or 604 of the dispenser.

In this case, preferably, a radial clearance exists between the base 110 of the seal 100 and the bottom of the groove, but the length of the fin 130 is adapted to allow sufficient centering for the radially internal distributor element 62 or 66 either centered and suspended so as not to touch the bore formed in the radially external distributor element 66 or 62.

The base 110 of the seal 100 preferably has a generally rectangular radial cross section. The angles of this section can however be rounded to limit the risks of rupture under stress and facilitate the engagement of the seal 100 in the associated grooves 600, 602 and 604.

In the case of L-shaped seals 100 as illustrated in FIGS. 4, 7 and 9, the radial surface of the seal intended to rest against a radial surface of the respective associated groove 600, 602 or 604, to ensure sealing, is the radial surface 102 of the base directed opposite the fin 130 as illustrated in FIG. 3.

In the case of U-shaped seals 100 as illustrated in FIGS. 6 and 8, the radial surfaces of the seal intended to rest against radial surfaces of the associated groove 602, for sealing, are the radial surfaces 104 present on the ends of the fins 130 as illustrated in FIG. 3.

The seals 100 according to the invention are made of a material such that the stiffness of the fin 130 supports the weight of the radially internal distributor element 62 or 66 so that it is suspended and centered in a bore of the radially external distributor element 66 or 62 with the possibility of axial sliding along the axis OO, even in the rest state without pressure.

More precisely according to the invention, the seal 100 is preferably made of plastic, very preferably of a material chosen from the group comprising polyoxymethylene and polyamide.

Furthermore, in the context of the invention, the seal 100 is preferably produced by machining, for example by turning in a plastic plate or bar. The realization of a seal by machining makes it possible to guarantee the optimum geometry and dimensions of the seal, on the one hand allowing the engagement of the seal on the distributor and on the other hand guaranteeing sealing at the interface between the main distributor element 62 and the auxiliary distributor element 66.

According to an implementation variant in accordance with the invention, the elasticity of the lips 130 of the seals 100 bearing on the facing surface allows the centering of the main distributor element 62 to be compared to the cylinder block 30, and a slight latitude of swiveling movement of the main distributor element 62 relative to the axis of rotation 0-0 of the machine, so that the main distributor element 62 remains always applied on the distribution plane 33 of the cylinder block 30 , by its glass 63, during the relative rotation of the cylinder block 30, when the machine is operated hydraulically, in order to guarantee a good seal at the distribution plane.

This variant is shown diagrammatically in FIG. 10.

There is shown diagrammatically in this FIG. 10 a main distributor element 62 centered and suspended inside the bore formed in a secondary distributor element 66 radially external, by the two seals 100 respectively disposed near the two axial ends of the main distributor element 62, even when the machine is not supplied with pressurized oil, to avoid any direct mechanical contact between the two distributor elements 62 and 66.

FIG. 10 also shows diagrammatically a radial support zone 112 of the seals 100 in their complementary groove 600, 604 and at 114 a sliding zone formed on the external face of the fins 130 at their free end.

In ia FIG. 10 there is shown diagrammatically in broken lines under the reference 100a the shape of a seal 100 "empty", that is to say before its engagement in the secondary distributor element 66 resulting in stress reduction of its outside diameter.

In FIG. 10, there is also shown diagrammatically a conduit 61 opening into a groove 71 diagrammatically represented between the two seals 100 and also opening onto the ice surface 63 transverse to the axis 0-0 in contact with the facing surface 33 of the cylinder block.

In ia FIG. 10, the arrow F represents a return force exerted by any suitable return means on the main distributor element 62 towards the cylinder block, to exert on this element a force opposing an axial displacement requested by the hydraulic pressure cylinder block supply. By "antagonistic force" is meant here an opposite force in direction, but of lower intensity than the hydraulic thrust when the machine is activated.

It will be observed on examining FIG. 10 that according to the invention preferably the outer face of the fins 130, at their free end opposite the base 110, asymptotically tangent the opposite surface 65 formed on the secondary element distributor 66.

It is noted that the configuration of the seals to their environment or to the swiveling movements is done by bending the fins 130 in the axial direction more than by compression.

The two seals 100 behave like sliding springs in the form of bells which support the main distributor element 62 at the center of the secondary distributor element 66 while avoiding any direct contact between these two elements while allowing relative sliding between these two elements.

Stressing at least two seals 100 defines centering and long guidance with possible axial sliding.

The radial tightening in the bore of the secondary distributor element 66 coupled to a radial or axial support in the grooves 600 and 604 makes it possible to guarantee sealing at the level of said grooves.

Preferably within the framework of the invention, the respective diameters of the main distributor element 62 and of the secondary distributor element 66, as well as the stiffness of the seals 100 are such that they allow the element to be swiveled. main distributor 62 relative to the axis 0-0 and relative to the secondary distributor element 66, of the order of 0.25 °.

Such authorized swiveling ensures that the face 63 of the distributor 60 always remains in very reliable abutment against the facing surface 33 of the cylinder block 30.

The main distributor element 62 can therefore take a certain angle relative to the axis 0-0 and to the secondary distributor element 66, without loss of sealing since the seals 100 make it possible to guarantee sealing in the range of the aforementioned inclination.

According to other advantageous characteristics of the invention, according to a particular embodiment in accordance with the present invention, the clearance RI defined between the main distributor element 62 and the secondary distributor element 66 is of the order of 0 , 06mm at the level of the large diameter groove 604 and of the order of 0.13mm at the level of the small diameter groove 600, for an axial distance between the two grooves 600 and 604 of 46.8mm.

FIG. 10A thus illustrates the main distributor element 62 inclined at an angle a with respect to the secondary distributor element 66, in a swiveling position which nevertheless allows the sealing to be maintained. As indicated above, this angle a can reach for example 0.25 °. It is deliberately exaggerated in FIG. 10A to explain the possibility of swiveling. In this figure, it is understood that it is the support of the distributor 60 on the cylinder block 30 at the surface 63 which imposes the angle of the distributor 60, while the distributor 60 is also generally supported and centered in its bore. by the seals 100. The distributor element 62 never directly touches the element 66, except for the means necessary for indexing in rotation, not shown.

It will be observed that the preferred range presented previously in accordance with the invention of axial extension L2 of the fin 130 at least equal to 3 times the amplitude of the radial protrusion H2 of the fin 130 relative to the base 110, allows a large radial clearance, for example of the order of (1 - 0.8) mm, or 0.2mm. Such a clearance defines the authorized angle for the distributor, ie + 0.2mm on one side and -0.2mm on the other side, over the length of the distributor, which allows a significant angle without loss of tightness.

Is shown in Figure 11 attached an alternative embodiment of a hydraulic machine according to the invention which comprises means 150 forming a stop which impose a single mounting direction for the L-shaped end joints and prohibit mounting in the direction wrong seal. The purpose of these means 150 is to impose an assembly of the L-shaped seals such that the concavity of the conical part delimited by the fin 130 is well directed towards the origin of the pressure applied and not opposite. This ensures that the applied pressure tends to deform the fin in extension and thus to press the end of the fin against the facing surface.

Such polarizing means 150 can be the subject of numerous embodiments.

They are preferably formed of an annular ring adjacent to the grooves 600 and 604 and comprising a radial extension on the outside of the grooves 600 and 604 whose radial dimension is greater than that of the lip-shaped fin 130. This ring can be attached or machined in the mass of the distributor 62, 66. Thus the lip 130 cannot be placed on the side of this radial extension, external to the grooves 600 and 604. In other words the lip 130 cannot be directed axially outward. On the contrary, the lip 130 can only be installed by being directed axially towards the interior of the distributor 60. The seal 100 must therefore imperatively be oriented so that the lip 130 is directed towards the central or central part of the distributor 60 .

In FIG. 11, the sketched representations of the seals 100 made impossible by the presence of the polarizing means 150 are crossed out by the symbol "X".

A form of mounting ramp can be provided to assist in mounting the seal 100. This shape is on the mounting side of the seal, and therefore opposite the polarizing means 100 relative to the grooves 600, 604.

When the body in which the grooves 600, 602 and 604 are formed is radially stepped, the abovementioned mounting ramp is directed towards the section of smaller diameter adjacent to said groove. In FIGS. 3 and 11 such shapes constituting mounting ramps are formed of frustoconical surfaces of revolution referenced 601, 603 and 605.

This shape 601, 603, 605 allows progressive expansion of the seal 100 until it enters the associated groove 600, 602, 604, during the mounting operation. If this shape is not provided, a removable tool can be provided which takes its place. This tool must be installed before presenting the seal 100, then removed after having placed the seal in its groove.

The seal 100 illustrated in FIG. 9 differs essentially from the seal 100 illustrated in FIG. 7 by the fact that it comprises an annular recess 132 of circular outline on the concave side of the interface between the base 110 and the fin 130 , in order to facilitate the articulation of the fin 130 and limit the risks of rupture of the fin 130 at this level.

Figure 12 attached shows an embodiment of a variant of hydraulic machine according to the present invention comprising a coupler 80 based on friction discs.

The general structure of this hydraulic machine known per se will not be described in detail below.

This machine is for example described in the documents FR 2 996 267 and FR 2 996 268.

All of the embodiments described in these documents FR 2 996 267 and FR 2 996 268 are compatible with the present invention. In other words, all of the embodiments described and represented in the documents FR 2 996 267 and FR 2 996 268 may comprise a joint structure as described in the present patent application.

It will be recalled that the document FR 2 996 267 describes a hydraulic machine in which the multi-lobe cam 20 is linked in rotation with one of two assemblies formed respectively by the casing and by a shaft and the machine further comprises an actuator suitable for, selectively immobilize the cylinder block with respect to the other of the two assemblies.

It is also recalled that the document FR 2 996 268 describes a machine comprising return means tending to disengage the rotating cylinder block from the assemblies formed by the casing and the shaft, for example by displacement of the cylinder block, and the distributor is configured to, when applying pressure, engage the cylinder block in rotation relative to one of these assemblies.

The invention thus advantageously applies to hydraulic machines with radial pistons 50, comprising:

a casing 10 defining a first set,

a shaft 40 defining a second set, said first and second sets being free to rotate relative to one another,

a multilobe cam 20 linked in rotation with one of the two assemblies,

a cylinder block 30 mounted freely in rotation relative to the first and second sets, and comprising a plurality of cylinders 32 in which are arranged pistons 50 guided with radial sliding in the respective cylinders of the cylinder block 30 and bearing on the lobes of cam 20, and

- An actuator 80 adapted to selectively immobilize the cylinder block 30 relative to the other of said first and second assemblies.

The invention also advantageously applies to hydraulic machines with radial pistons 50, comprising:

a casing 10 defining a first set,

a shaft 40 defining a second set, said first and second sets being free to rotate relative to one another,

a multilobe cam 20 linked in rotation with one of the two assemblies,

- a distributor 60,

a cylinder block 30 mounted freely in rotation relative to the first and second sets, and comprising a plurality of cylinders 32 in which are arranged pistons 50 guided with radial sliding in the respective cylinders of the cylinder block 30 and bearing on the lobes of the cam 20, the cylinder block comprising means for engaging in rotation relative to the other of the two assemblies and

- return means tending to disengage the cylinder block 30 in rotation relative to the other of two sets, while the distributor is configured to, when applying pressure, engage the cylinder block 30 in rotation by compared to the other of the two sets.

More precisely in FIG. 12, given by way of nonlimiting example of an embodiment of a selective mechanical coupler, the shaft 40 is linked in rotation to the cam 20.

The main distributor element 62 is mounted fixed in rotation on the shaft 40, around the shaft 40, typically by means of grooves arranged on the surface of the shaft 40 cooperating with ribs produced in a bore of this main element distributor 62.

A distributor cover forming part of the casing 10a and constituting the secondary distributor element 66 is mounted to rotate around the main distributor element 62 and is linked in rotation to the rest of the casing 10.

The cylinder block 30 is arranged so that the pistons 50 are in the ring forming the cam 20 and are kept in contact with the cam 20 by means of springs 54.

The cylinder block 30 is associated with a disc holder 34 to which it is linked in rotation, this disc holder 34 comprising a plurality of regularly spaced discs 82.

The distributor cover 10a also further comprises a plurality of complementary discs 84 which are arranged alternately with the discs 82 of the disc holder 34.

The two disk groups 82 and 84 are configured to alternate between a configuration in which they are not in contact and thus leave the distributor cover 10a and the cylinder block 30 free to rotate with respect to each other, and a configuration in which they are in contact and thus immobilize the distributor cover 10a and the cylinder block 30 relative to one another under the effect of friction.

We also see in Figure 12 a support element 90 disposed around the shaft 40, between the shaft 40 and the main distributor element 62, The support element 90 comprises a thrust spring 92 positioned so as to carry out a thrust force on the main distributor element 62 against the cylinder block 30, thus providing a sealed support between the main distributor element 62 and the cylinder block 30.

An elastic washer 94, which constitutes the abovementioned return means, is positioned in abutment on the shaft 40 and acts on the bearing element 90 in opposition to the thrust force exerted by the thrust spring 92, thus allowing to return to the disengaged position of the discs 82 and 84, that is to say the position of the machine in which the cylinder block 30 is free to rotate relative to the main distributor element and therefore relative to the housing 10.

Of course the present invention is not limited to the embodiments which have just been described but extends to all variants in accordance with its spirit.

The grooves 600, 602 and 604 intended to receive the seals 100 can be formed on a radially external surface of one of the distributor elements or on a radially internal surface of one of the distributor elements.

When the grooves 600, 602 and 604 intended to receive the seals 100 are formed on a radially external surface of one of the distributor elements, each annular seal 100 concerned is made of a material allowing elastic expansion of the seal 100 such that in expansion position the seal has an internal diameter greater than the radially internal distributor element 62 or 66 in which is formed the groove 600, 602 or 604 intended to receive the base 110 of the seal, the base 110 of the seal resting after the engagement against a surface of the associated groove 600, 602 or 604 to ensure a seal.

On the contrary when the grooves 600, 602 and 604 intended to receive the seals 100 are formed on a radially internal surface of one of the distributor elements, each annular seal 100 is made of a material suitable for allowing an elastic retraction of the seal 100 such that in the retraction position, the seal 100 has an outer diameter smaller than the radially outer distributor element in which the groove 600, 602 or 604 is formed, intended to receive the base 110 of the seal, the base 110 of the seal resting after re-engagement against a surface of the associated groove 600, 602 or 604 to ensure a seal.

The present invention offers numerous advantages over solutions known from the prior art.

The distributor 60 slides easily, because the lip 130 is quite flexible, which allows the distributor 60 to be supported at a very low pressure. It is therefore possible to lower the booster pressure of the machine according to the invention compared to solutions known from the prior art. This makes it easier to use an electric booster pump.

The rings 100 are uninterrupted, and therefore very waterproof. There are few leaks. The shape of the lips 114 which includes an axial component allows a large latitude of swiveling of the distributor which also guarantees a good seal of the distributor against the oscillations of the cylinder block. The hydraulic machines according to the invention have better performance than the machines known from the state of the art.

The rings 100 touch both the bottom of the groove 600, 602 or 604 which carries them, and the facing wall 65. The space is filled and there is little leakage. In addition, this form makes it possible to center a part of the distributor 62 relative to the other 66. This form allows both easy sliding of the distributor and a suspension which avoids impacts between the internal part relative to the external part.

The lip 130 is applied more against the facing surface 65 when the pressure increases, for a good seal.

This type of sealing can be applied to a wide range of motors with a rotary distributor, beyond the motors which require significant translation of the distributor 60.

The assembly has three seals shown in Figure 3 is waterproof even if the pressure direction is reversed (that is to say even if for example the groove 71 High Pressure becomes a Low Pressure line)

The manufacture of seals 100 is simple.

We will now give an example of an embodiment of the seal 100 illustrated in FIG. 4. width L1 of base 110: 0.8 +/- 0.1mm. length L2 of the fin 130: 6 +/- 0.12mm. height H2 of protrusion of the fin 130 relative to the base, which corresponds to the deflection of the fin 130: 2 +/- 0.15mm,

We will now give an example of an embodiment of the seal 100 illustrated in FIGS. 6 and 8:

. thickness of the fin 130: 0.8 +/- 0.1mm. H2 arrow of fin 130: 0.9 +/- 0.15mm. . axial width L3 of the joint: 6.6 +/- 0.1mm.

We will now give an example of an embodiment of the seal 100 illustrated in FIG. 7:

. width L1 of base 110: 3 +/- 0.15mm. height H1 of base 110: 2.8 +/- 0.15mm. length L2 of the fin 130: 3 +/- 0.15mm. thickness of the fin 130: 0.8 +/- 0.05mm. height H2 of the fin 130 protruding from the base: 1 +/- 0.05mm.

As indicated above, the two distributor elements 62, 66 are preferably indexed in rotation, that is to say linked in rotation. In certain configurations, however, they may be subject to relative rotation, for example for motors mounted on a fixed wheel shaft. Generally, the distributor part 62 in contact with the cylinder block 30 must be indexed in rotation relative to the cam 20 of the hydraulic machine.

FIG. 13 shows a variant embodiment of the machine comprising three continuous U-shaped annular seals 100 placed respectively in the grooves 600, 602 and 604 on the axial ends and in the middle part of the elements 62, 66 of the distributor and framing two by two the feed grooves 71, 73 of the machine.

The U-shaped seals 100 used in the variant embodiment illustrated in FIG. 13 can conform to all of the arrangements described above, in particular with regard to FIG. 6. Their geometry will therefore not be described in detail below.

It is recalled, however, that these U-shaped seals comprise a central core 110 and two fins 130 which extend in axially opposite directions, starting from the core 110.

The concavity of the seals 100 shown in FIG. 13 is directed towards the bottom of the grooves 600, 602 and 604.

This arrangement has the advantage that an oil pocket is thus formed in the concave part of the U-shaped seals directed towards the bottom of the grooves 600, 602 and 604, which limits the deformation of the seals during the pressure rise of the machine and contributes to ensuring a good seal of the system.

The inventors have found by tests that this arrangement makes it possible to ensure satisfactory sealing.

They also found that during the evolution of the pressure in the machine, each seal 100 is capable of moving at least slightly within its respective groove 600, 602 and 604, while maintaining the seal.

The central core 110 remains in contact with an axial and peripheral surface facing.

However, the ends of the fins 130 can rest on radial and / or axial surfaces depending on the positioning of the seals and the pressures applied.

FIG. 14 shows an annular seal, a fin 130 of which rests on an axial and peripheral surface, in this case the bottom of a groove, on the side of the pressure applied, while the second fin 130 rests on a radial surface of the groove.

The axial dimensions of the seals 100, that is to say the axial dimension separating at rest the ends of the two fins 130, can be complementary to the axial length of the grooves 600, 602 and 604 so that the seals 100 are mounted without play in the grooves

600, 602 and 604, while adapting to the facing surfaces under the pressure applied to guarantee the seal, or be at least slightly less than the axial length of the grooves 600, 602 and 604 to leave a clearance between the seals 100 and grooves 600, 602 and 5,604.

FIG. 15 shows another alternative embodiment of a machine according to the present invention, also comprising three continuous U-shaped annular seals 100 placed respectively in grooves 600, 602 and 604 on the axial ends and in part 10 middle of the elements 62, 66 of distributor to frame two by two the feed grooves 71, 73 of the machine, which is distinguished from the embodiment illustrated in Figure 13 only by the orientation of the U-joints. in the case of FIG. 15 the U-joints have their convexity directed towards the bottom of the grooves. The core 110 of the U-joints 15 then rests on a surface of the grooves 600, 602 and 604 while the ends of the fins 130 rest on a surface 65 of the element 66 opposite.

Claims (41)

1. Hydraulic machine including. a housing (10) which contains. a cylinder block (30) comprising cylinders (32) housing pistons (50),. a distributor (60) comprising channels (61, 64) which communicate with the cylinders (32) of the cylinder block (30) and comprising two concentric complementary elements (62, 66) respectively radially internal and radially external and capable of relative axial sliding , said two complementary distributor elements (62, 66) defining between them at least one groove (71, 73) for hydraulic supply of the machine and. sealing means (70, 72, 74; 100) disposed in respective grooves between the two concentric complementary elements (62, 66) to seal between them by framing said feed groove (71, 73) hydraulic, characterized in that. the sealing means (70, 72, 74; 100) comprise at least two continuous annular seals (100) each comprising a base (110) and at least one lip-shaped fin (130), adapted to rest elastically against a respective surface (65) of the complementary elements (66, 62) of distributor placed facing each other and ensuring a seal at this level, which lip (130) has a conical part of revolution around the axis of the distributor (OO), biased in radial deformation to be pressed against said facing surface (65),. said annular seals (100) being axially separated and made of a material. allowing elastic deformation of the seal (100) allowing engagement of the seal (100) in the respective associated groove (602, 604, 606) so that the seal (100) rests against a surface of the groove (602, 604, 606) to ensure a seal,. while ensuring support and elastic centering of the radially internal element (62, 66) in the external element (66, 62) of the dispenser to avoid direct mechanical contact between these two elements. 2. Machine according to claim 1, characterized in that the base (110) of the seals (100) rests against a radial surface of the respective associated groove (600, 602, 604) to ensure the seal. 3. Machine according to one of claims 1 or 2, characterized in that the lip-shaped fin (130) rests against an axial and peripheral surface (65) of the distributor element placed opposite to ensure the seal. 4. Machine according to one of claims 1 to 3, characterized in that each seal (100) is made of a material such that the stiffness of the fin (130) supports the weight of the radially internal distributor element of so that it is suspended and centered in a bore of the radially external distributor element with the possibility of axial sliding, even in the state of rest without pressure. 5. Machine according to one of claims 1 to 4, characterized in that the base (110) of the seal (100) is clamped in the groove of the dispenser (600, 602, 604) and maintains the seal (100) without sliding nor rotation of the base (110) relative to the distributor (60). 6. Machine according to one of claims 1 to 4, characterized in that the base (110) of the seal (100) is mounted floating in the groove of the distributor (600, 602, 604). 7. Machine according to claim 6, characterized in that a radial clearance exists between the base (110) of the seal (100) and the groove (600, 602, 604), but the length of the fin (130) allows sufficient centering so that the radially internal distributor element (62, 66) is centered and suspended so as not to touch the bore formed in the radially external distributor element (66, 62). 8. Machine according to one of claims 1 to 7, characterized in that the base (110) of the seal (100) has a rectangular section. 9. Machine according to one of claims 1 to 8, characterized in that the seal (100) has the general shape of an L in cross section, comprising two wings formed respectively by the base (110) and by the fin (130) in the shape of a lip. 10. Machine according to one of claims 1 to 9, characterized in that the fin (130) extends generally along a radius relative to the center of the cross section of the base (110), for example when the base (110) is of generally rectangular or square cross section, the fin (130) extends along a radius from an angle of the cross section of the base (110). 11. Machine according to one of claims 1 to 10, characterized in that the fin (130) protrudes radially relative to the periphery of the base (110) directed towards the facing surface on which the seal must be ensured . 12. Machine according to one of claims 1 to 11, characterized in that the seal (100) is placed in a groove formed on a radially external surface of one of the distributor elements and the free end of the fin (130) extends radially on the outside of the outer periphery of the base (110). 13. Machine according to one of claims 1 to 11, characterized in that the seal (100) is placed in a groove formed on a radially internal surface of one of the distributor elements, the free end of the fin (130) extends radially over the interior of the internal periphery of the base (110). 14. Machine according to one of claims 1 to 13, characterized in that the axial extension (L2) of the fin (130) is between two and six times the amplitude of the radial protrusion of the fin relative to at the base, preferably the axial extension of the fin is at least equal to 3 times the amplitude of the radial protrusion (H2) of the fin (130) relative to the base (110). 15. Machine according to one of claims 1 to 14, characterized in that the seal (100) has the general shape of a U in cross section comprising a base (110) and two fins (130). 16. Machine according to one of claims 1 to 15, characterized in that it comprises two seals (100) in L mounted in a common groove (602) and whose respective fins (130) are directed in axially opposite directions , forming in combination a U-shaped joint. 17. Machine according to one of claims 1 to 15, characterized in that it comprises a seal (100) comprising a single base (110) and two fins (130), extending in opposite axial directions, so to make a central joint operating with a pressure established on one side or the other. 18. Machine according to one of claims 1 to 17, characterized in that it comprises a U-shaped seal (100) which has a plane of radial symmetry perpendicular to the axis of rotation 0-0 of the machine and whose l opening is directed radially. 19. Machine according to one of claims 1 to 18, characterized in that it comprises a U-shaped seal (100) which has an axial extension (L2) from its middle part between two and six times the amplitude of the radial protrusion of the fin relative to the base, preferably at least equal to three times the amplitude of its arrow (H2), or a total width (L3) of between four and twelve times the amplitude of the radial protrusion of the fin relative to the base, preferably at least equal to 6 times its arrow (H2). 20. Machine according to one of claims 17 to 19, characterized in that the seal (100) has the general shape of a U in cross section whose convexity is directed towards the bottom of the groove (600, 602, 604 ), comprising a central core forming the base (110) and two lip-shaped fins (130) adapted to rest against the facing surface (65). 21. Machine according to one of claims 17 to 19, characterized in that the seal (100) has the general shape of a U in cross section whose concavity is directed towards the bottom of the groove (600, 602, 604 ), comprising a central core adapted to rest against the facing surface (65). 22. Machine according to one of claims 1 to 21, characterized in that the lip-shaped fin (130) constitutes a ring of conical shape. 23. Machine according to one of claims 1 to 22, characterized in that the fin (130) defines a concavity directed towards a pressurized area. 24. Machine according to one of claims 1 to 23, characterized in that the seal (100) is made of plastic, for example of a material chosen from the group comprising polyoxymethylene and polyamide. 25. Machine according to one of claims 1 to 24, characterized in that the two seals (100) are placed in respective grooves (600, 604) disposed on the opposite axial ends of the distributor element provided with the grooves. 26. Machine according to one of claims 1 to 25, characterized in that it comprises a means for returning the assembly formed by the main distributor element (62) and the cylinder block (30), which exerts on the main distributor element (62) an antagonistic force to an axial displacement requested by hydraulic pressure. 27. Machine according to one of claims 1 to 26, characterized in that it comprises a multilobe cam (20) linked in rotation with one of two assemblies formed respectively by the casing or by a shaft and the machine comprises in in addition to an actuator adapted to selectively immobilize the cylinder block with respect to the other of the two assemblies, as well as return means tending to disengage the rotating cylinder block from the assemblies formed by the casing or the shaft, and the distributor is configured to, when applying pressure, engage the cylinder block in rotation relative to one of these assemblies. 28. Machine according to one of claims 1 to 27, characterized in that the elasticity of the lips (130) of the seals (100) bearing on the facing surface (65) allows the centering of the main distributor element (62) relative to the cylinder block (30), and a slight latitude of swiveling movement of the main distributor element (62) relative to the axis of rotation (OO) of the machine, so as to always remain applied to a distribution plane (33) of the cylinder block (30) during the rotation thereof when the machine is operated hydraulically, in order to guarantee a good seal at the distribution plane. 29. Machine according to one of claims 1 to 28, characterized in that it comprises three continuous annular seals (100; 70, 72, 74) adapted to be placed in a respective groove (600, 602, 604) formed in a distributor element (62, 66) and provide a seal at this level, the three seals (100; 70; 72, 74) being placed respectively on the axial ends and in the middle part of the distributor elements (62, 66) and two by two framing the feed grooves of the machine (600, 602, 604). 30. Machine according to one of claims 1 to 29, characterized in that it comprises two end seals (100; 70, 74) L-shaped placed in respective grooves (600, 604) provided on the ends axial of the dispenser and a U-shaped central seal (100; 72) placed in a central groove (602) of the dispenser. 31. Machine according to one of claims 29 or 30, characterized in that the lip-shaped fins (130) provided on the end seals (100) are directed towards each other, towards the axial center from the distributor. 32. Machine according to one of claims 1 to 28, characterized in that the machine comprises three continuous U-shaped annular seals (100) placed respectively on the axial ends and in the middle part of the distributor elements (62, 66) , in respective grooves (600, 602, 604) and framing two by two of the grooves (71, 73) supplying the machine. 33. Machine according to claim 32, characterized in that the three U-shaped seals (100) have their concavity directed towards the bottom of the respective grooves (600, 602, 604). 34. Machine according to one of claims 32 or 33, characterized in that the central core (110) of the U-joints rests on an axial and peripheral surface (65) of a distributor element (66) placed opposite , for example a cover, while the ends of the fins (130) rest against surfaces of the respective associated groove (600, 602, 604) to seal. 35. Machine according to one of claims 1 to 34, characterized in that each annular seal (100) is made of a material allowing elastic expansion of the seal such that in the expansion position the seal has a diameter greater than the Radially internal distributor element (62, 66) in which the groove (600, 602, 604) is formed intended to receive the seal, a part of the seal resting after engagement against a surface of the groove (600, 602, 604 ) associated to ensure a seal. 36. Machine according to one of claims 1 to 35, characterized in that it comprises means (150) forming a stop which impose a unique mounting direction for each seal (100) and prohibit mounting in the wrong direction of the seal. 37. Machine according to one of claims 1 to 36, characterized in that the two complementary elements (62, 66) concentric respectively radially internal and radially external and capable of relative axial sliding, of the distributor, are linked in rotation. 38. Machine according to one of claims 1 to 37, characterized in that the grooves (600, 602, 604) intended to receive a seal (100) are formed on the external surface of a distributor element (62, 66 ). 39. Machine according to one of claims 1 to 38, characterized in that the main distributor element (62) comprises a surface (63) perpendicular to the axis of rotation (OO) of the machine and in contact with a supply face (33) of the cylinder block. 40. Distributor for hydraulic machine comprising two complementary elements (62, 66) concentric respectively radially internal and radially external and capable of relative axial sliding, said two complementary elements of distributor (62, 66) defining between them at least one groove (71, 73) hydraulic supply to the machine and. sealing means (70, 72, 74; 100) disposed in respective grooves between the two concentric complementary elements (62, 66) to seal between them by framing said feed groove (71, 73) hydraulic, characterized in that. the sealing means (70, 72, 74; 100) comprise at least two continuous annular seals (100) each comprising a base (110) and at least one lip-shaped fin (130), adapted to rest elastically against a respective surface of the complementary elements (66, 62) of distributor placed facing each other and ensuring a seal at this level, which lip (130) has a conical part of revolution around the axis of the distributor (OO), biased in radial deformation for be pressed against said facing surface (65),. said annular seals (100) being axially separated and made of a material. allowing elastic deformation of the seal (100) allowing engagement of the seal in the respective associated groove (602, 604, 606) so that the seal (110) rests against a surface of the groove (602, 604, 606) to ensure a seal,. while ensuring support and elastic centering of the radially internal element (62, 66) in the external element (66, 62) of the dispenser to avoid direct mechanical contact between these two elements. 41. Annular seal for the implementation of a machine according to one of claims 1 to 39, characterized in that it is formed of a continuous seal and that it comprises a base (110) and a fin in the form of a lip (130), adapted to rest elastically against respective facing surfaces (65) of complementary elements of a dispenser and to ensure a seal at this level, each annular seal (100) being made of a material allowing a elastic deformation of the seal allowing the engagement of the seal in the associated groove (600, 602, 604) so that the seal rests against a surface of the associated groove to provide a seal while ensuring elastic support and centering of the seal radially internal element (62, 66) in the external distributor element (66, 62) to avoid direct mechanical contact between these two elements.