WO2017186905A1

WO2017186905A1 - Disengageable hydraulic machine and vehicle provided with such a machine

Info

Publication number: WO2017186905A1
Application number: PCT/EP2017/060182
Authority: WO
Inventors: Ante Bozic; Philippe Lucienne
Original assignee: Poclain Hydraulics Industrie
Priority date: 2016-04-28
Filing date: 2017-04-28
Publication date: 2017-11-02
Also published as: FR3050773A1; FR3050774B1; FR3050773B1; FR3050774A1

Abstract

The present invention relates to a hydraulic machine with radial pistons comprising a casing (110) defining a first assembly and a shaft (130) defining a second assembly, which are rotatably free relative to one another, a multi-lobed cam (114), a manifold (140), and a cylinder block (120), characterised in that the manifold (140) comprises at least one sealing means (146) made up of an open annular segment having two cuts (220, 230) angled relative to the central axis (202) of the segment and relative to the transverse median plane of symmetry thereof (204), the two cuts (220, 230) being offset in the peripheral direction and each covering only one portion of the thickness of the segment.

Description

DEGRASABLE HYDRAULIC MACHINE AND VEHICLE EQUIPPED WITH SUCH A MACHINE

GENERAL TECHNICAL FIELD

The invention relates to the field of disengageable hydraulic machines.

The invention applies in particular to hydraulic machines with radial pistons.

STATE OF THE ART

The disengagement of a hydraulic machine can be sought for different purposes.

For different types of application, it is for example known to use hydraulic machines to generate a torque at the wheels of a vehicle.

This hydraulic assistance is however not always desired and it may be desirable to temporarily set the wheel "free wheel". To this end, there are disengageable hydraulic machines.

FIGS. 1 and 2 show the general structure, according to a longitudinal axial section and a cross section respectively, of an example of a known disengageable hydraulic machine, for example from document WO2014 / 048842.

The hydraulic machine 100 shown in Figures 1 and 2 attached comprises, centered on a longitudinal axis XX, a housing 110, a distributor cover 112, a cylinder block 120, a shaft 130, a distributor 140, a clutch 150 and a cam lobed 114.

The distributor 140 is mounted free of a certain deflection or axial movement to allow disengaging / engaging the engine.

More specifically, the cylinder block 120 preferably comprises a plurality of radial pistons 122 housed in respective cylinders 124 oriented radially relative to the central axis XX. The pistons 122 can move in radial translation in the respective cylinders 124. Each piston carries, at its end adjacent to the lobed cam 114, a roller 126 resting on the lobed cam 114, so that the rollers 126 above roll on the lobed cam 114.

Generally, bearing springs 128, respectively placed in each cylinder 124, continuously push each piston 122 and its associated roller 126 bearing against the lobed cam 114.

Hydraulic machines of the type illustrated in Figures 1 and 2 may be subject to many variants.

They can be either the rotating shaft type or the rotating casing type.

They may also have an outer multilobed cam 114 and a cylinder block disposed on the inside of the cam 114, or conversely an internal multi-lobed cam 114 and a cylinder block disposed on the outside of the cam 114.

The housing 110 and the shaft 130 are always rotatably mounted relative to each other.

In an external cam machine, the cam 114 is connected to the housing 110, while the cylinder block 120 is free with respect to the housing 110 and can be engaged in rotation with the shaft 130. The hydraulic inlets and outlets of the distributor 140 open always in a fixed part.

In one configuration the cam 114 can be secured to the fixed frame and in this case the cylinder block 120 drives the shaft 130 in rotation relative to the fixed frame.

Alternatively the shaft 130 may be secured to the fixed frame and in this case the cylinder block 120 drives the cam 114 and the casing 110 in rotation relative to the fixed frame.

Those skilled in the art knows internal cam configurations and knows how to adapt accordingly the layout of the various elements making up the machine. In some configurations the engagement means are then no longer provided between the cylinder block and the shaft, but between the cam and the shaft.

Whatever the configuration adopted, the cylinder block 120 is rotated relative to the housing 110 during operation. Bearings 115, 116, for example of the tapered roller or ball bearing type, are arranged at the ends of the machine, in order to allow the relative rotation of the shaft 130 and possibly to resume efforts.

The dispenser 140 most often comprises two ducts 142,

144 configured to supply the cylinder block 120 with oil or to discharge the oil from the cylinder block 120. Generally, within these conduits 142, 144, the oil is under a high pressure of about 400 bar when it is the supply pressure, under a low pressure of about 100 bar when it is a discharge pressure, and a feeding pressure of about 20 bars when it is is to force the machine 100 in the moments prior to its operation.

More specifically, the conduits 142, 144 above each comprise a portion disposed between the distributor 140 and the distribution cover 112, acting as a thrust chamber. These portions include an effective S142, S144 section that can generate a longitudinal force when pressure is applied.

The dispenser 140 includes seals 146 at the interface with the dispenser cover 112.

The distributor 140 generally has a stepped shape approaching the cylinder block 120. This stepped shape facilitates the implementation of the aforementioned thrust chambers.

It is thus preferably provided a seal 146 between each stage of the dispenser 140 and the cover of the distributor facing also staggered in a complementary manner.

More precisely according to FIG. 1, there are three joints 146. A rod referenced 148 in FIG. 1 can allow the rotation indexing of the dispenser 140 relative to the dispenser cover 112.

The clutch 150 makes it possible to join or disengage the shaft 130 with the cylinder block 120 and thus to switch respectively between a drive configuration or a freewheel configuration.

The clutch 150 generally comprises a plurality of disks 152 integral with the shaft 130 or a radial extension 132 thereof and a plurality of disks 154 integral with the cylinder block 120.

The disks 152 and 154 are arranged alternately and can, when they are pressed onto each other, transmit a torque.

For this, the cylinder block 120, like the distributor 140, is movable longitudinally in translation which makes it possible to tighten and loosen the clutch 150.

The aforementioned translation is caused by the distributor 140, which itself is movable longitudinally in translation along the axis XX under the effect of the pressure in the conduits 142, 144. Indeed, the thrust chambers of the conduits 142, 144 are designed so that the pressure generates a force exerting in the longitudinal direction X. This is typically the feeding pressure which is used to cause the clutch of the machine 100.

When it is desired to disengage the machine, the conduits 142, 144 are evacuated, that is to say connected to an oil reservoir whose pressure is low. Nevertheless, to ensure that the clutch 150 is discarded, it is known to use a disengagement spring 160 disposed between the cylinder block 120 and the casing 110. This spring 160 tends to move the cylinder block 120 away from the extension radial 132 connected to the shaft 130, to disengage the machine 100.

In known hydraulic machines, the seal between the distributor 140 and the distributor cover 112 or the associated casing member is generally achieved by seals 146 and counter-seals.

Overall hydraulic machines thus formed are satisfactory.

However, they have the disadvantage that the aforementioned seals and counter-joints induce a high coefficient of friction, which implies having to apply a large force to move the distributor 140, and therefore requires to increase the boost pressure compared to conventional machines, not disengaged.

Different solutions have been proposed for this purpose. A solution is for example described in the document FR 3019594. It essentially consists in providing an additional thrust chamber associated with the distributor 140.

The use of such an additional thrust chamber is of interest. However, to limit the force exerted by the dispenser, exposed to the maximum pressure, it is often useful to add an additional valve limiting pressure. This valve, of the reverse selector type, connects the throat of the additional thrust chamber to the low pressure line of the system.

Such a solution therefore has the disadvantage that the addition of the additional thrust chamber, combined with the additional valve, increases the price of the complete system and therefore lower the competitiveness of the system in economic terms.

The problem arises from the fact that in disengageable hydraulic machines of the aforementioned type, the distributor 140 must perform two functions, one which is to ensure the distribution of oil necessary to operate the hydraulic machines and which requires that the leaks are minimized and the other which is to ensure the commitment of the system by an axial movement of the distributor 140 and which requires that the friction forces between the distributor and the dispenser cover or the associated housing element, are also minimized .

PRESENTATION OF THE INVENTION

In this context, the object of the present invention is to improve the state of the art by proposing new means which make it possible both to limit the coefficient of friction between the distributor 140 and the dispenser cover 112 and to improve the hydraulic sealing. The aforementioned objects are achieved within the scope of the present invention by means of a radial piston hydraulic machine comprising:

a housing defining a first assembly,

a shaft defining a second set, said first and second sets being free to rotate with respect to each other,

a multi-lobed cam,

- a distributor,

a cylinder block mounted free to rotate with respect to the first assembly,

characterized in that the distributor comprises at least one sealing means formed of an open annular segment having two sections inclined with respect to the central axis of the segment and with respect to its transverse median plane of symmetry, the two sections being offset to each other in the peripheral direction and each covering only a portion of the thickness of the segment.

In other words, according to the invention the segment comprises a beveled cut in two planes.

In the context of the invention, the machine may also comprise means for engaging the cylinder block in rotation with respect to the second assembly, the distributor being capable of translation relative to the casing in order to provide a clutch and respectively a clutch release function. engagement means so as to engage and respectively disengage the cylinder block in rotation with the second assembly. However this provision is not imperative. PRESENTATION OF FIGURES

Other features, objects 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 non-limiting examples and in which:

FIG. 1 previously described represents a view in longitudinal axial section of the general structure of a hydraulic machine disengageable according to the state of the art, but whose general structure can be used in the context of the invention,

FIG. 2 also previously described represents a cross-sectional view of the same machine that can be used in the context of the invention, according to a transverse section plane at the level of the cylinder block,

FIG. 3 represents a general perspective view of a sealing segment according to the present invention,

FIG. 4 represents an enlarged partial view of the detail identified IV in FIG. 3, of a sealing segment according to the present invention at its cutting,

FIG. 5 represents a view similar to FIG. 4, but with partial tearing of the material of the segment on a zone referenced A in order to better illustrate the geometry of the cut,

FIG. 6 represents a radial sectional view of the segment along the section plane referenced VI-VI in FIG. 3;

FIG. 7 represents a view similar to FIG. 4 of a variant of a segment according to the present invention comprising a structure of hooks facilitating installation,

FIG. 8 represents the variant of FIG. 7 in the closed position of the segment by engagement of the hooks,

FIG. 9 represents an alternative embodiment of a segment according to the present invention having another embodiment of hook structure facilitating installation, in an open position similar to FIG. 7,

FIG. 10 represents the variant of FIG. 9 in the closed position of the segment by engagement of the hooks,

FIGS. 11 and 12 represent two partial perspective views of another variant embodiment of a segment according to the present invention,

FIGS. 13a, 13b, 13c and 13d schematically represent a manufacturing process of the segment according to the present invention, FIG. 14 represents a view in longitudinal axial section similar to FIG. 1 of a variant according to the invention according to which the segments are placed in grooves formed in the distributor cover and not in grooves of the distributor,

FIG. 15 represents a general perspective view similar to FIG. 3 of another variant embodiment of a segment according to the present invention, comprising hook structures and

FIG. 16 represents a partial view of a sealing segment according to another embodiment of the present invention also comprising a structure of hooks and

- Figure 17 shows a half longitudinal sectional view of a portion of a hydraulic machine according to the present invention illustrating the engagement of a distributor equipped with segments according to the present invention on a distributor cover.

DETAILED DESCRIPTION

The general structure of the disengageable hydraulic machine according to the invention can be the subject of many variants and is preferably of the type shown in Figure 1. It will therefore not be described in detail later. The entirety of the foregoing description made with reference to FIGS. 1 and 2 must be considered as applicable to the machines in accordance with the invention and consequently incorporated in the description of the invention.

The invention, however, preferably applies to the machines with multi-lobed outer cam 114 connected to the casing 110 and to inner cylinder block 120 connected to the shaft 130 by means of engagement means, the machine being in addition to shaft rotating or rotating case.

In the following description, we will focus on describing the structure of the segment 200 according to the invention.

This segment 200 may be used to replace at least one of the seals 146, and preferably the three seals 146, shown in FIG. 1, arranged in grooves formed on the outer surface of the dispenser 140 and therefore resting on the surface facing the dispenser cover 112.

Alternatively, the segment (s) 200 according to the invention can be placed in a groove or groove formed on the inner surface of the dispenser cover 112 and resting on the surface. external to the dispenser 140, as illustrated in Figure 14. In this case the opening of the segment 200 is used to temporarily expand the diameter of the segment 200, once placed in the grooves or grooves formed on the inner surface dispenser cover 112, to allow the engagement of the dispenser, then elastically release the diameter of the segment 200 to allow to seal it against the external surface of the dispenser 140.

The segment 200 shown in the appended FIG. 3, according to the present invention, is formed of a ring centered around a central axis 202. This axis 202 is coaxial with the main X-X axis of the machine when in use. The segment 200 has a mean transverse plane of symmetry 204 perpendicular to the axis 202. The segment 200 is not closed. It is instead open on part of its periphery in the form of a through cut 210.

The term "through" means that the cutout 210 covers the entire radial extension of the ring 200 as well as the entire height or longitudinal thickness parallel to the axis 202 of the ring 200.

The term "average plane of symmetry" means that the segment 200 comprises two parts located respectively on either side of the plane 204 transverse to the axis 202 and that these two parts are symmetrical to each other, except at the cutting level. 210.

The ring 200 when it is tightened and that the edges of the cutout 210 are contiguous, takes a closed position tightened 360 °. However, at rest, the ring takes an expanded position in which the cutout 110 is open. Segment 200 is thus likely to change as to the value of its outer radius, which makes it possible to press the segment 200 against the surface opposite and thus to ensure tightness.

The segment 200 is preferably made of metal.

Alternatively, the segment 200 is made of plastic, composite or elastomer.

Its cross section, along a radial plane passing through the axis 202, can be the subject of many variants. If necessary, this cross section could be rounded, for example circular. However, preferably, as shown in FIG. 6, the straight section of the segment 200 is formed of a polygon, more precisely still of a square or rectangular section whose main edges are respectively parallel to the axis 202 for the facets cylindrical respectively radially inner 240 and radially outer 242 and parallel to the transverse median plane 204 above and therefore orthogonal to the axis 202 for the axial facets 244, 246 shaped crown.

As previously indicated, according to the invention, the cutout 210 is formed not of a simple cutout in a radial plane passing through the axis 202, but is formed of two oblique cuts 220, 230 inclined with respect to the central axis 202 and relative to the transverse median plane 204.

The term "cut inclined relative to the central axis 202" means that each section 220 and 230 is inclined relative to a radial plane passing through the axis 202 as will be specified later. However each section 220, 230 is preferably defined by a respective generator parallel to the central axis 202 of the segment.

Moreover, the two sections 220, 230 are offset with each other in the peripheral direction.

The facets formed by the cutout 220 on the ends facing the segment are referenced 222 and 224.

The facets formed by the cutout 230 on the ends facing the segment are referenced 232 and 234.

Each of the two facets 222, 224 and 232, 234, respectively, of the two sections 220, 230 may be planar or not, by examples curved, convex or concave and preferably respectively complementary. In the constricted position of the segment 200, the two facets 222, 224 and 232, 234 of each section 220, 230 are contiguous and preferably perfectly complementary. Thus the facet 222 is complementary to the facet 224 and in the constricted position of the segment 200, the facet 222 rests on the facet 224. Respectively the facet 232 is complementary to the facet 234 and in the constricted position of the segment 200, the facet 232 rests on facet 234.

Each of the two cutouts 220, 230 extends over only a portion of the thickness of the segment, but over the entire radial extension of the segment.

Typically, each of the two oblique cuts 220, 230 extends over half the thickness of the segment 200.

And the two oblique cuts 220, 230 are interconnected by a section, preferably flat and located in the median plane of symmetry 204.

Due to the peripheral angular offset defined between the two sections 220, 230 and the median section which connects them, it is formed on the respective ends of the segment 200 two bars 228, 238 generally parallel to each other which end respectively with the facets 222 and 234 above.

As seen in Figures 4 and 5, it is thus formed between the two blanks 220, 230 facets 250, 252 opposite, in the form of ring sectors centered around the axis 202.

These facets 250 and 252 delimit the aforementioned bars 228 and

238.

Those skilled in the art will understand that the particular segment structure according to the invention provides effective barrier against leakage and thus ensures a good seal.

On the one hand, the cooperation defined between the facets 222, 224 and respectively 232, 234 opposite each cutout 220, 230 allows to define a peripheral barrier to the fluid regardless of the opening angle of the segment.

On the other hand, the peripheral angular offset defined between the two cutouts 220, 230 forming two facing bars 228, 238 defines an axial barrier to the fluid.

In other words, the combination of the two cutouts 220, 230 and the peripheral and axial offset defined therebetween, generates a labyrinth with regard to the possible fluid flows on the periphery of the dispenser 140. Indeed, thanks to the particular cutting structure according to the invention, there is no direct passage for the fluid.

In the figures reference is made to the inclination of the section 220 with respect to a radial plane passing through the axis 202 and reference is made to β the inclination of the section 230 with respect to a radial plane passing through the axis 202 .

These angles a and β of inclination of the facets 222, 224 and respectively 232, 234 of the sections 220 and 230 with respect to a radial plane may be identical for the two cuts or different.

Preferably, the cutting facets 222, 224 and respectively 232, 234 are inclined with respect to a radial plane, at an angle of between 10 and 45 °, very advantageously of the order of 30 °.

Furthermore, the angular offset Θ existing between the two sections 220, 230 with respect to the axis 202 is preferably between 5 and 20 °, very preferably of the order of 10 °.

More specifically, as seen in Figures 4 and 5, preferably the two sections 220, 230 are of opposite inclination.

By "opposite" is meant the fact that according to the representation given in FIG. 4, a first section 220 converges towards the radially outer face 242 in the trigonometric direction whereas the facets 232, 234 of the second section 230 converge towards the same radially outer face 242 in the direction of clockwise. FIGS. 7 and 8 show an alternative embodiment according to which the segment 200 comprises structures 260 in the form of complementary hooks on the facing facets 250 and 252 of the bars 228 and 238.

Such hook-shaped structures can be the subject of many embodiments.

According to the non-limiting embodiment given in the accompanying FIGS. 7 and 8, a polygonal casing recess 262 is formed on the facet 252 and an additional projection 264 on the facet 250, respectively.

In the constricted position of the segment, the projection 264 can be placed in the recess 262, in order to keep the segment in a tight position and thus facilitate the mounting of the segment on the dispenser 140 or on the facing lid 112.

The structures 260 in the form of hooks constituting a projection

264 and a recess 262 illustrated in Figures 7 and 8 are defined by generatrices transverse to the central axis 202 of the segment.

FIGS. 9 and 10 show an alternative embodiment of structures 270 in the form of hooks defined on the cutting facets 222, 224 and 232, 234, respectively, by generatrices parallel to the central axis 202.

According to FIGS. 9 and 10, these structures 270 are in the form of a hemicylindrical cap. However, the invention is not limited to this particular geometry. The structures 270 may for example be polygonal sections.

It is thus formed according to FIGS. 9 and 10, a concave hemicylindrical cavity 272 on the cutting facets 224 and 232 and convex hemicylindrical projections 274 respectively on the facing facets 222 and 234.

This solution is advantageous for mounting. Indeed the projections 274 / hollow 272 can maintain the constricted shape of the segment during assembly so that the segment remains in his throat and does not rub. And when first put into use, the pressure causes both ends of the segment to unclip and the segment rubs against the bore that receives it.

As shown in FIGS. 11 and 12, the facing facets 250 and 252 formed between the two cutouts 220, 230 and perpendicular to the axis 202 can be extended by slots 280, 282 extending in a mean plane perpendicular to the central axis 202. The slots 280 and 282 extend over the entire radial extension of the segment 200.

These slots 280, 282 make it possible to separate at mid-thickness each of the two ends of the segment in the form of two distinct elements juxtaposed axially, allowing independent deformation of these two end elements, and consequently improving the tightness of the system, in particular to improve the reduction of axial leaks, but also radial.

By way of non-limiting example, each slot 280, 282 may cover an angle of the order of 5 to 45 °, preferably 5 to 20 °, with respect to the central axis 202.

According to the embodiments illustrated in Figures 3 to 8, the cutting facets 222, 224, 232, 234 are generally planar.

FIGS. 11 and 12 also show an alternative embodiment according to which these cutting facets 222, 224, 232, 234 are concave. More precisely still, preferably, according to FIGS. 11 and 12, the curve of the facets 222, 224, 232, 234 is not symmetrical with respect to a median plane pm parallel to the central axis 202 and orthogonal to an external envelope ee planar plane corresponding to the plane facets illustrated in FIGS. 4 to 8 (in FIG. 11 is shown diagrammatically under the reference "ee" such a theoretical planar outer envelope and under the reference "pm" said aforementioned plane parallel to the central axis and orthogonal to the envelope ee): according to FIGS. 11 and 12, the facets 222, 224, 232, 234 of the cuts are connected substantially tangentially to the external envelope ee said theoretical plane on the end side of the segment segments and instead connect substantially perpendicular to the outer envelope ee said theoretical plane on the opposite side of the segment directed towards the solid part thereof.

The above non-planar but concave arrangement of the cutouts 222, 224, 232, 234 makes it possible to guarantee a good filling of the end of the segment in the case of a molding embodiment.

Furthermore, the concave shapes of the cutting facets 222, 224, 232, 234 make it possible to reinforce the labyrinth effect defined by the complementary cooperation of the ends of the segment 200 and consequently to reinforce the reduction of leaks.

The various cutouts mentioned above 220, 230 and where appropriate

280 and 282, necessary to form a segment 200 according to the invention, can be formed by laser cutting.

As a variant, these cutouts 220, 230 and, where appropriate, 280 and 282 may be formed by mechanical cuts.

FIG. 13a shows a cutting step using a blade 300 moved at mid-thickness of the segment in a direction perpendicular to the central axis 202, radially with respect thereto, for producing the facets 250, 252 and, where appropriate, slots 280, 282.

The leading edge of the blade 300 may be concave 302, rectilinear 304 or convex 306.

FIG. 13b shows the step of making the oblique cutout 220 using a tool 310 moved parallel to the central axis 202 up to half the thickness of the segment.

FIG. 13c shows the step of producing the second oblique cutout 230 using a tool 320 moved parallel to the central axis 202 on the opposite side up to half the thickness of the segment.

FIG. 13d shows the segment obtained at the end of the aforementioned mechanical cutting steps. Figure 13d shows cutouts 220, 230 and slots 280 and 282.

The present invention also relates to vehicles equipped with a machine according to the invention. Of course, the present invention is not limited to the particular embodiments that have just been described, but extends to any variant within his mind.

FIG. 15 shows an alternative embodiment of the segment according to the present invention which comprises a hook structure 260 oriented in the axial direction with reference to the central axis 202 of the segment 200. The general structure of the two sections 220, 230 delimiting facets 222, 224, respectively 232, 234, as well as two bars 228, 238 respectively defined between the facets 222 and 232, respectively 224 and 234 and forming the facets 250, 252 in the form of rings centered around the axis 202, illustrated in Figure 15, are in accordance with the previously described arrangements with reference to Figures 3 and 4 and will therefore not be described in more detail later. It is simply recalled that preferably the cutouts 220 and 230 are preferably defined by generatrices parallel to the axis 202, located in planes inclined both with respect to radial planes passing through this axis 202, (typically at an angle between 10 ° and 45 °), and with respect to the transverse median plane 204 (typically orthogonal to this transverse median plane 204), as well as typically angularly offset between them at an angle between 5 ° and 20 °.

More precisely according to FIG. 15, the bar 228 is provided on the end of its facet 250 adjacent to the facet 222 with a pin or projection 266 oriented axially or substantially parallel to the axis 202 and adapted to penetrate into position reserrée segment, in a housing or complementary cavity 268, also oriented axially or substantially parallel to the axis 202, formed near the end of the facet 252 adjacent to the facet 224.

More precisely still the pin or projection 266 and the housing or complementary cavity 268 are formed of a generatrix parallel to the axis 202. The pin or projection 266 and the housing or complementary cavity 268 have identical axial extensions. The pin or projection 266 and the complementary housing or cavity 268 may have an axial extension equal to the thickness of the bar 238, ie half of the axial thickness of the segment 200. In this case the housing or cavity 268 would cover the entire thickness of the bar 238 and extend from both sides. other of it. However, as illustrated in FIG. 15, preferably the pin or projection 266 and the complementary housing or cavity 268 preferably cover only a part of the thickness of the bar 238, typically half this thickness, being generally a quarter of the thickness of the bar. axial thickness of the segment 200.

More precisely still the pin or projection 266 and the housing or complementary cavity 268 are formed near the radially internal cylindrical surface 240 of the segment 200. The complementary housing or cavity 268 also opens on this radially inner cylindrical surface of the segment 200. The fact that the housing or complementary cavity 268 opens on the radially inner cylindrical surface of the segment 200 facilitates the engagement of the pin or projection 266 in the housing or complementary cavity 268, by radial deformation of the bar 228. It is even to disengage the pin or projection 266 from the housing or complementary cavity 268.

It will be observed, however, that according to the precise embodiment shown in FIG. 15, the complementary housing or cavity 268 is not strictly adjacent to the facet 224, but formed at a slight distance from this facet 224, whereas the pawn or projection 266 is adjacent to the facet 222. This latter arrangement facilitates the engagement of the peg or protrusion 266 in the housing or complementary cavity 268.

FIG. 16 shows another alternative embodiment of the segment according to the present invention which comprises a hook structure 270 oriented in the radial direction with reference to the central axis 202 of the segment 200. The general structure of the two sections 220 , 230 delimiting facets 222, 224, respectively 232, 234, as well as two bars 228, 238 defined respectively between the facets 222 and 232, respectively 224 and 234 and forming the facets 250, 252 in the form of rings centered around the axis 202, illustrated in Figure 16, are also in accordance with the previously described arrangements with reference to Figures 3 and 4 and will therefore not be described in more detail later. It is simply recalled that again preferably the cuts 220 and 230 are preferably defined by generatrices parallel to the axis 202, located in inclined planes both with respect to radial planes passing through this axis 202, (typically according to an angle between 10 ° and 45 °), and with respect to the transverse median plane 204 (typically orthogonal to this transverse median plane 204), as well as typically angularly offset between them at an angle of between 5 ° and 20 °.

More precisely according to FIG. 16, the facet 222 is provided, in the vicinity of its end adjacent to the radially internal cylindrical surface 240 of the segment 200, with a pin or projection 276 oriented radially outwards and adapted to penetrate, in a constricted position. of the segment, in a housing or complementary cavity 278 formed near the end of the facet 224 adjacent to the radially inner cylindrical surface 240 of the segment 200.

More specifically still the pin or projection 276 and the housing or complementary cavity 278 are formed of a generatrix parallel to the axis 202. They cover both preferably the entire width of the facets 222 and 224 parallel to the 202 axis is half the axial thickness of the segment 200.

The housing or complementary cavity 278 opens again on the radially inner cylindrical surface 240 of the segment 200, which again makes it possible to facilitate the engagement of the pin or projection 276 in the complementary housing or cavity 278, by radial deformation of the bar 228. It is the same to disengage the pawn or projection 276 from the housing or complementary cavity 278.

The attachment provided in the context of the present invention thanks to the different hook structures described above makes it possible to have a constrained diameter (when the hooks are engaged) less than a corresponding chamfer diameter on the distributor cover and thus facilitate the establishment of the segment.

By "complementary" is meant that the geometry and the dimensions, both axial and radial, of the receptacles or cavities, 262, 272, 268 or 278 of hook reception are in principle identical, with the necessary clearance necessary to ensure engagement and disengagement, the geometry and dimensions both axial and radial hooks 264, 274, 266 or 276 intended to be inserted into these housings or cavities.

However according to an advantageous characteristic and a variant of the invention, the dimensions of the housing or cavity, 262, 272, 268 or 278 for receiving the hook, in particular its width, may be wider than the corresponding size of the hook 264, 274 , 266 or 276 to allow some deflection.

Preferably, the hook receiving housings or cavities 262, 272, 268 or 278 are formed of grooves with parallel or diverging edges and not of converged edge grooves and symmetrically the pion or projection structures 264, 274, 266 or 276. forming hooks are formed of convex hull structures without concave clearance.

An embodiment comprising such a hook allows a simplification of the mounting operations of the dispenser 140 inside the dispenser cover 112, by relative translation of the dispenser 140 in the dispenser cover 112 as shown schematically in FIG. 17.

For this purpose, the segment 200 is dimensioned so that in the "attached" position, that is to say when a hook 264, 274, 266 or 276 is engaged in the housing or complementary cavity, 262, 272, 268 or 278, the outer diameter of the segment 200 is smaller than the input diameter of the corresponding chamfer in the distributor cover 112 and greater than the output diameter of said chamfer.

For an embodiment as shown in FIG. 1, the distributor cover 112 comprises 3 chamfers 1120, 1121 and 1122 cooperating during assembly with the 3 segments 200 of the distributor 140. The 3 chamfers 1120, 1121 and 1122 are formed by oblique or rounded surfaces at a reduction of the edges defined between sections of the distributor cover 112 of diameter successively descending.

A method of mounting such a set is as follows:

Inserting the segments 200 with the hooks 264, 274, 266 or 276 attached to the associated housing or complementary cavity, 262, 272, 268 or 278, in the corresponding grooves of the distributor 140,

- Insertion of the distributor assembly 140 equipped with segments 200 in the distributor cover 112, the segments 200 cooperating with the chamfers 1120, 1121 and 1122 to be able to reduce their diameter a little more (interest of having a housing 262, 272, 268 or 278 hook wider than the size of the hook 264, 274, 266 or 276) to allow to introduce the distributor 140 in the stepped portion of the cover 112.

Once inserted, the elasticity / tension of the segment 200 makes it possible to seal.

This type of assembly avoids the breakage of the segment 200 during the insertion of the dispenser 140 in the cover of the dispenser 112 and makes it easy to insert segments 200 in areas inaccessible for an external tool.

The hook 264, 274, 266 or 276 can be made on both "ends of the segment 200. Alternatively, the segment 200 has only one hook 264, 274, 266 or 276 at one of its ends. .

According to another embodiment of the segment according to the present invention illustrated in the accompanying figures can be achieved by axial juxtaposition of two open elementary rings whose openings are angularly offset.

The segments 200 according to the present invention may be of interest for a rotating machine and fixed housing machine distributor, but also in the case of a machine with fixed shaft and rotating housing.

Claims

1. Hydraulic radial piston machine comprising:

a housing (110) defining a first assembly,

a shaft (130) defining a second set, said first and second sets being free to rotate with respect to each other,

a multilobed cam (114),

a distributor (140),

a cylinder block (120) rotatably mounted relative to the first assembly,

characterized in that the distributor (140) comprises at least one sealing means (146) formed of an open annular segment having two sections (220, 230) inclined with respect to the central axis (202) of the segment and relative to its transverse plane of symmetry (204), the two sections (220, 230) being offset in the peripheral direction and each covering only a portion of the thickness of the segment.

2. Machine according to claim 1, characterized in that the cutting angles (α, β) of the two sections (220, 230) are identical.

3. Machine according to claim 1, characterized in that the cutting angles (α, β) of the two sections (220, 230) are different.

4. Machine according to one of claims 1 to 3, characterized in that each cutting facet (222, 224, 232, 234) is inclined relative to a radial plane, a value between 10 and 45 ° , advantageously of the order of 30 °.

5. Machine according to one of claims 1 to 4, characterized in that the two cuts (220, 230) are offset by an angle (Θ) of 5 to 20 °, preferably of the order of 10 °.

6. Machine according to one of claims 1 to 5, characterized in that each cut (220, 230) extends over only a portion of the thickness of the segment, preferably substantially over half the thickness of the segment.

7. Machine according to one of claims 1 to 6, characterized in that the inclinations (α, β) of the two sections (220, 230) are opposite.

8. Machine according to one of claims 1 to 7, characterized in that the segment has hooks (260, 262, 264, 270, 272,

274; 266, 268; 276, 278) at its cuts (220, 230).

9. Machine according to claim 8, characterized in that the hook structures (260, 262, 264, 270, 272, 274, 266, 268, 276, 278) at the cuts (220, 230) are oriented in the axial direction with reference to the central axis (202) of the segment (200).

10. Machine according to claim 8, characterized in that the hook structures (260, 262, 264, 270, 272, 274, 266, 268, 276, 278) at the sections (220, 230) are oriented in the radial direction with reference to the central axis (202) of the segment (200).

11. Machine according to one of claims 8 to 10, characterized in that the hook structures (260, 262, 264, 270, 272, 274, 266, 268, 276, 278) at the sections (220, 230) comprise a housing or cavity (268, 278) forming a groove which opens onto the radially inner surface (240) of the segment (200).

12. Machine according to one of claims 8 to 11, characterized in that the hooking of the hooks (260, 262, 264, 270, 272, 274, 266, 268, 276, 278) defines a constrained diameter, when the hooks are engaged, less than a corresponding chamfer diameter on a dispenser cover (140).

13. Machine according to one of claims 8 to 12, characterized in that the hooks (260, 262, 264, 270, 272, 274, 266, 268, 276, 278) comprise at least one pin or projection (264 , 274, 266 or 276) and at least one complementary receiving housing or cavity (262, 272, 268 or 278) and that the receiving housing or cavity (262, 272, 268 or 278) dimensions are wider than the corresponding footprint of the pawn or projection (264, 274, 266 or 276) to allow a certain deflection.

14. Machine according to one of claims 1 to 13, characterized in that the facets (222, 224, 232, 234) of each section (220, 230) are concave.

15. Machine according to one of claims 1 to 14, characterized in that facets (250, 252) orthogonal to the central axis (202) separating the two sections (220, 230), are extended by slots ( 280, 282) separating in thickness each of the two ends of the segment in the form of two distinct elements juxtaposed axially, allowing independent deformation of these two end elements.

16. Machine according to one of claims 1 to 15, characterized in that each section (220, 230) is defined by a respective generator parallel to the central axis (202) of the segment.

17. Segment according to one of claims 1 to 16 consisting of an open ring having two sections (220, 230) inclined relative to the central axis (202) of the segment and relative to its transverse median plane of symmetry (204), the two cuts (220, 230) being offset in the peripheral direction and each covering only a portion of the thickness of the segment.

18. Vehicle characterized in that it comprises a hydraulic machine according to one of claims 1 to 16.