EP3406901B1 - Hydraulic device comprising an improved distributor - Google Patents

Description

FIELD OF THE INVENTION

This presentation concerns hydraulic devices, and more specifically distributors for hydraulic devices.

STATE OF THE PRIOR ART

Several applications are known for hydraulic devices arranged on vehicle axle stub axles, in particular for driving vehicle wheels.

In operation, one of the two parts of the distributor is supported on the cylinder block of the engine, while the other part is carried by the structure of the engine. The relative positioning of the two parts is limited by the support of the distributor on the cylinder block of the engine.

During the assembly of the hydraulic device, a recurring problem arises for the assembly of the distributor. Indeed, the operator must then manipulate the distributor comprising a core and a distribution crown in order to position it in relation to the other components of the hydraulic device, for example at the end of a spindle wheel. However, there is then a risk of the core sliding in the timing ring which then goes beyond its nominal operating position when the core and the timing ring are pressed against other components of the hydraulic device. , which can cause a fall of the sealing segments, insofar as the distributor is then not kept in abutment against other elements of the hydraulic device.

Indeed, the different staggered shapes and conduits arranged in the core and in the distribution ring allow a relative movement of the internal distributor with respect to the distribution ring which can lead to the fall of sealing elements when the distributor n has not yet been assembled with other components forming a hydraulic device. The documents WO 2016/198793 , US 6,494,126 and FR 3030381 present several examples of hydraulic devices comprising distributors presenting such a problem.

The present presentation thus aims to respond at least partially to this problem.

PRESENTATION OF THE INVENTION

To this end, the present description relates to a distributor for a hydraulic device, comprising a core and a distribution crown mounted rotating around the core along an axis defining a proximal end and a distal end, the distribution crown and the core being mounted sliding. '' in relation to each other along the axis,
the core having a plurality of internal grooves opening into an external periphery of the core,
the distribution ring having a plurality of external grooves opening into an internal periphery of the distribution ring,
said internal and external grooves being configured to be placed in fluid communication and to form fluid circulation conduits,
the core comprising a plurality of sealing segments configured so as to isolate each of said fluid circulation conduits,
the core having a decreasing external section from a distal end towards a proximal end,
the distributor being characterized in that one of the core and the distribution crown comprises a stopper configured so as to come into contact with a wall of the other among the core and the distribution crown in order to limit the displacement of the core with respect to the distribution ring in a direction defined by the axis.

Said stopper is configured so as to limit the displacement along the axis of the core with respect to the distribution ring, from the distal end to the proximal end.

Each of said core sealing segments is positioned in a housing arranged in the core, and is in abutment against an internal face of the distribution crown, and the stop is configured so as to limit the displacement of the core relative to the crown distribution in a direction defined by the axis so that the distance between the proximal sealing segment and the proximal clearance of the distribution crown remains non-zero, the proximal sealing segment being the closest sealing segment along the axis of the proximal end of the core, and the proximal clearance of the distribution ring being defined as the first variation in section of the internal surface of the distribution ring bearing against the proximal sealing segment, towards a proximal end of the distribution ring.

Said stopper is typically integral with the distribution ring, and is configured so as to come into contact with a wall of the core.

As a variant, said abutment is integral with the core, and is configured so as to come into contact with a wall of the distribution crown.

The present description also relates to a hydraulic device with radial pistons and multi-lobe cam, comprising a distributor as defined above, in which there is a non-zero clearance along the axis between the stop of the distributor and a surface of the core disposed opposite the stop.

The present disclosure also relates to a method of assembling a hydraulic device on a wheel spindle, in which
a first set of components of the hydraulic device is positioned around an axis of the wheel spindle,
we provide a distributor as defined above,
the distributor is positioned in abutment against components of the first set of components, so as to define a non-zero clearance along an axis of the stub axle between the distributor stop and a surface of the core disposed opposite the stop,
the core is secured to a component of the first set of components,
a second set of components of the hydraulic device is positioned, so as to define an internal casing volume in which the distributor is positioned.

BRIEF DESCRIPTION OF THE DRAWINGS

• la figure 1 représente une vue d'ensemble d'un appareil hydraulique comprenant un distributeur selon un aspect de l'invention,
• les figures 2, 3 et 4 sont des vues détaillées de modes de réalisation du distributeur,
• les figures 5 à 13 sont des variantes de modes de réalisation du distributeur.

The invention and its advantages will be better understood on reading the detailed description given below of various embodiments of the invention given by way of nonlimiting examples. This description refers to the pages of attached figures, on which:

• the figure 1 shows an overview of a hydraulic device comprising a distributor according to one aspect of the invention,
• the figures 2, 3 and 4 are detailed views of embodiments of the dispenser,
• the Figures 5 to 13 are alternative embodiments of the dispenser.

In all of the figures, the elements in common are identified by identical reference numerals.

DETAILED DESCRIPTION OF EXAMPLES OF EMBODIMENT

The figure 1 shows a hydraulic system comprising a casing 10 in which is disposed a hydraulic device 12, a shaft 14 engaged in the casing 10 and a sealing device 16 between the shaft and the casing. The shaft 14 and the casing 10 are mounted so that they can rotate relative to each other about an axis A. The shaft 14 is typically a spindle wheel of a vehicle, the hydraulic device 12 then typically carrying out the rotational driving of a vehicle wheel.

The hydraulic device 12 as shown comprises a cylinder block 12A, a cam 12B and a fluid distributor 40. Cam 12B can be a multi-lobe cam. It is therefore, with the housing, a hydraulic motor or a pump. This hydraulic device 12 can be in particular with radial pistons.

In a manner known per se, the cylinders of the cylinder block 12A are supplied with fluid from a fluid distributed by the distributor 40, via grooves which will be described later.

The distributor 40 is itself connected to main pipes 1 and 2, respectively for the supply and the exhaust of the hydraulic device 12. In this case, the hydraulic device 12 can be of the cylinder block type 12A fixed and with casing 10 rotating, and the supply and exhaust pipes 1 and 2 pass through the shaft 14 of the wheel stub, in which they are oriented axially, that is to say parallel to the 'axis A of rotation, axis along which the shaft 14 is oriented.

In the example shown, another pipe 3 is pierced axially in the shaft 14. It is a fluid supply pipe, which serves to bring the fluid to the interior space 11 of the casing 10, in particular to put this space under pressure so as to favor the disengagement of the pistons from the hydraulic device, and to evacuate this fluid when the pistons and the cam 12B come into contact.

More precisely, the pipe 3 makes it possible to produce a fluid in the interior space 11 of the casing so as to cause a rise in pressure therein causing a retraction of the pistons in the cylinders of the cylinder block 12A so that the pistons are not no longer in contact with the cam 12B, thus operating what is called a declutching of the hydraulic device 10 and making it possible to put the engine in freewheeling configuration. Conversely, the fact of bringing the pistons into contact with the cam 12B is called a dog clutch or a displacement of the hydraulic device 10. The fluid supplied by the pipe 3 reaches between the opposite faces of the distributor 40 and from the shaft 14 and flows towards the interior space 11 of the casing 10, for example by a dedicated connection, or else by a clearance made on a part of the splines between the shaft 14 and the cylinder block 12A.

It can thus be seen that the shaft has only three axial sections of fluid pipe, namely two main sections which form all or part of the main supply and exhaust pipes 1 and 2 and an auxiliary section which forms all or part of the casing pressure line 3. This auxiliary section typically forms a drain pipe for the internal volume 11 of the casing 10 when the hydraulic device 12 is in operation.

The cam 12B forms a part of the casing 10, which also comprises a cover 10A situated around the distributor 40 and secured to the cam 12B, typically by bolting, and a part 10B forming, for example, a flange for connection with a member driven by the motor, for example the hub of a wheel. On the side opposite to the hydraulic device 12, the casing 10 is extended by a part 10C, which can for example be engaged in the hub of a wheel. The housing 10 and the shaft 14 are mounted in relative rotation. For this reason, they cooperate with each other via bearings 18A and 18B, housed in this case in part 10C of the casing. In known manner, these bearings 18A and 18B can be bearings with tapered bearings. The system can be used for driving a vehicle wheel, in which case the shaft 14 can be a wheel spindle axle.

The distributor 40 comprises a distribution crown 60 and a core 50, the distribution crown 60 and the core 50 are in relative displacement in rotation. The distribution ring 60 has a relative displacement in rotation relative to the cylinder block 12A, while the core 50 is secured to the shaft 14, typically by bolting.

The figures 2 and 3 are detailed views of the dispenser 40 shown in the figure 1 .

A proximal end 40P and a distal end 40D are defined for the distributor 40, the proximal end 40P being defined arbitrarily as being the end of the distributor 40 closest to the shaft 14. Likewise, the core 50 and for the distribution ring 60 a proximal end 50P, 60P and a distal end 60P, 60D. In the example shown in the figures, the proximal end 50P of the core 50 forms the proximal end 40P of the distributor 40, and the distal end 60D of the distribution crown 60 forms the distal end 40D of the distributor 40.

The core 50 is inserted via its proximal end 50P into the distribution ring 60 from the distal end 60D, and slides in an internal volume of the distribution ring 60 in the direction of the proximal end 60P, for example until protrusion from its proximal end 60P. The core 50 thus has a decreasing external section from its distal end 50D towards its proximal end 50P, while the distribution ring 60 defines an internal housing delimited by an internal section whose section decreases from the distal end 60D towards the end proximal 60P. These shapes typically make it possible to obtain an axial thrust, and therefore the support of the surface 60P of the timing ring 60 on the cylinder block 12A, when the grooves 60A and 60 B are put under hydraulic pressure. The distributor 40 comprises supply conduits 41 and 42 arranged in the core 50, which are only primed in the figures, and which, on the one hand, open onto the radial face of the internal distributor 50 facing the shaft 14 , so as to be opposite the ends of the pipes 1 and 2 located at this end of the shaft 14 and which, on the other hand, are connected to distribution grooves arranged in the core 50 and in the distribution crown 60. Distribution conduits open radially on the face forming the end proximal 60P of the distribution ring 60 so as to connect the external grooves 60A and 60B to the cylinder block 12A of the hydraulic device 12, so as to selectively supply each chamber of the cylinder block 12A of the hydraulic device 12 during its rotation.

The core 50 thus has internal grooves 50A and 50B opening into its external periphery, and connected to the supply conduits 41 and 42. The distribution ring 60 has external grooves 60A and 60B opening into the internal periphery of the ring distribution 60, and configured so as to each be placed in fluid communication with at least one internal groove of the core 50.

The external grooves 60A and 60B arranged in the distribution ring 60 are connected to conduits opening on the radial face of the distribution ring 60 facing the cylinder block 12A, so as to supply and discharge fluid.

The communication between the main pipes 1 and 2 and the supply pipes 41 and 42 is sealed off from the rest of the system by any suitable sealing means, for example by annular seals 31 and 32 arranged between the faces opposite the core 50 and the shaft 14, or the segments, or even the compositions of joints and segments.

In known manner, the core 50 comprises a plurality of grooves 51 in which are arranged segments 52 ensuring a sealed contact between the core 50 and the distribution ring 60, and thus making it possible to isolate the various conduits produced in the distributor 40 the relative to each other, and relative to the environment outside the gorges. Each groove of the distributor 40 is therefore surrounded by segments. In the example shown, each internal groove 50A and 50B of the core 50 is surrounded by two pairs of grooves 51 and segments 52.

The sealing means 52 are typically placed for mounting in the grooves 51 by stretching them to increase their diameter. Then they are placed in the grooves 51. Next, the core 50 is placed in the crown 60, and the sealing means 52 are supported on the internal wall of the crown 60. This allows movement, in particular essentially axial sliding along the axis AA between the core and crown, while obtaining the watertightness of the grooves 50A and 50B.

As indicated in the preamble to this patent application, a recurring problem during the assembly of the hydraulic device is the maintenance in position of the segments 52 in the grooves 51 when the distributor 40 is handled individually, or more generally when the distributor 40 is not mounted in abutment against other components of a hydraulic device. Indeed, it is understood that if the core 50 slides in the distribution crown 60 during its manipulation to put it in position, there is a risk that segments come out of the internal volume defined by the distribution crown 60, and disengage , in particular at the level of the proximal end 50P of the core 50.

In order to respond to such a problem, the distributor 40 as proposed comprises a stop 65 formed in or carried by the core 50 or by the distribution crown 60, configured so as to limit the displacement of the core relative to the distribution crown in a direction defined by the axis A. We will generally refer thereafter to a stop 65. It is understood that the distribution ring 60 may have a single stop, several similar stops arranged around the axis A, or another annular, the operation then remaining unchanged.

This stop 65 extends from the internal surface of the distribution ring 60, so as to come into contact with a wall of an internal groove 50A or 50B of the core 50 and thus limit the displacement of the core 50 relative to the distribution ring 60 along the axis A in a direction going from the distal end 40D towards the proximal end 40P of the distributor 40.

The stop 65 is typically a rib or a shoulder extending from the internal surface of the distribution ring 6.

The stop is typically an insert, such as a pin, inserted in an internal groove of the core 50 as will be seen below with reference to the various embodiments.

In the example shown on the figures 2 and 3 , the stop 65 is a shoulder formed in the internal wall of the distribution ring 60, configured so as to extend in the internal groove 50B when the core 50 is inserted in the distribution crown 60.

The stop 65 is configured so as not to come into contact with the core 50 once the hydraulic device is assembled. More precisely, the stop 65 is thus configured so as to be able to come into contact with the core 50 only during assembly of the hydraulic device comprising the distributor 40.

The figure 2 is thus a detailed view of the distributor 40 shown in the figure 1 , while the figure 3 is a view of the distributor 40 taken in isolation.

As seen on the figure 2 , a non-zero functional clearance J remains between the stop 65 and the surface of the core 50 opposite the stop 65, here a wall of the internal groove 50B. This functional clearance results from the different contact surfaces of the core 50 and the distribution ring 60 with the other elements of the hydraulic device 12, in particular with the shaft 14 and the cylinder block 12A.

Conversely, when the distributor 40 is taken in isolation as shown in the figure 3 , the core 50 is no longer limited in translation by its contact with the shaft 14. The stop 65 then makes it possible to limit the displacement of the core 50 relative to the distribution ring 60 in a direction going from the distal end 60D towards the proximal end 60P of the distribution crown 60. More specifically, if we consider the position of the distributor 40 shown on the figure 2 , an additional displacement corresponding to the functional clearance J can occur when the distributor 40 is taken in isolation.

The stop 65 is configured so as to limit the displacement of the core 50 relative to the distribution crown 60 in order to prevent a segment 52 of the core 50 from passing beyond the proximal end 60P of the distribution crown 60, or more precisely does not come out of the timing ring 60.

More specifically, the sealing segment 52 closest to the proximal end 50P of the core 50 is considered here. The distribution ring 60 has an internal surface opposite this segment 52. This internal surface of the ring is defined for this distribution 60 a proximal clearance 63, corresponding to the first variation in section of the internal surface of the distribution ring opposite the segment 52, towards the proximal end 60P of the distribution ring 60.

In practice, this proximal clearance 63 thus corresponds to a section of the distribution ring 60 not necessarily ensuring that the segment 52 is maintained in its housing 51 of the core 50.

The stop 65 is configured so that the distance measured along the axis A between the proximal clearance 63 and the closest segment (along the axis A) of the proximal end 50P of the core 50 remains non-zero, and therefore of so that the segment 52 cannot go beyond the proximal clearance 63. Thus, the segment 52 closest to the proximal end 50P of the core 50 remains held in place by the internal surface of the distribution crown 60.

In certain embodiments, the proximal clearance 63 corresponds to the proximal end 60P of the distribution crown 60. The stop 65 is then configured so that the length (measured along the axis A) of the portion of the core 50 which may project from the proximal end 60P of the distribution crown 60 is strictly less than the distance (measured along the axis A) between the proximal end 50P of the core 50 and the segment 51 closest to said end proximal 50P of the nucleus 50.

Indeed, during mounting of the distributor 40 against the shaft 14 and against the cylinder block 12A, the user will hold the distributor 40 by its distal end 40P in order to come to rest it against the shaft 14 and against the block 12A cylinders. The user thus prevents disengagement via the distal end 40D, while the stop 65 prevents disengagement via the proximal end 40P. The user can then secure the core 50 to the shaft 14, for example by bolting, which fixes the distributor 40 and then prevents any subsequent risk of falling before positioning the remaining elements of the system.

In this way, the segments 52 are held sandwiched between the core 50 and the distribution ring 60, which prevents any risk of loss or accidental fall of a segment.

The figure 4 presents a variant of the embodiment shown in figure 3 .

The stop 65 is here a shoulder extending from a radial wall of an external groove 60A. As for the embodiment described with reference to the figure 3 , the stop 65 comes into contact with a radial wall of an internal groove, here the internal groove 50A in order to limit the displacement of the core 50 relative to the distribution ring 60 in a direction going from the distal end 60D towards the proximal end 60P of the distribution crown 60.

The Figures 5 to 9 are alternative embodiments of the dispenser.

The figure 5 shows a variant in which the stop 65 is formed by a shoulder extending from the outer periphery of the core 50 of the distributor 40. This shoulder forming a stop 65 then comes into abutment against a radial surface of the distribution ring 60, in order to limit the displacement of the core 50 relative to the distribution crown 60 in a direction going from the distal end 60D towards the proximal end 60P of the distribution crown 60. The shoulder as shown is formed adjacent to the internal groove 50B , it is understood that it can also be formed adjacent to the internal groove 50A, the function then being carried out identically.

The figure 6 shows another variant in which the stop 65 is formed at the proximal end 60P of the distribution ring 60. This stop 65 thus limits the movement of the core 50, a radial wall of which comes into contact with the stop 65. Operation remains unchanged. It is noted that the stop 65 forms the proximal clearance 63, but ensures by its location that the segments cannot leave the distribution ring 60 through the proximal end.

The figure 7 represents another variant in which the stop 65 is formed by a screw inserted in a hole 66 formed in the distribution ring 60. The hole 66 is made so that the screw forming the stop can be inserted in an internal groove, here the internal groove 50B. The end of the screw entering the internal groove here defines a limited axial clearance of the core 50 relative to the distribution ring 60 in both directions of the axis A. In such an embodiment, once the distributor 40 positioned, the screw can be held in position or be removed by the operator, and the hole 66 is then closed. This variant is particularly advantageous in that the distributor 40 cannot be disassembled, in particular in the case of a use as a spare part which was assembled before transport, which then facilitates mounting on the hydraulic device. Sealing elements such as seals (not shown) are typically provided between the screw and the bore 66. A functional clearance is typically provided radially between the free end of the screw forming the stop 65 and the axial wall of the groove associated.

The figure 8 shows another variant in which a shoulder extends from the distal end 50D of the core 50. This shoulder forms the stop 65, and is configured to come into abutment against a radial surface of the distribution ring 60 forming its distal end 60D , or near the distal end 60D.

The figure 9 shows another variant in which the stop 65 is formed by an insert positioned in a housing 67 formed in an internal groove, here the internal groove 50B. The insert is for example a circlip, a ring, ring segment or half-ring, a pin or any other suitable element. In the embodiment shown in the figure 9 , the stop 65 is formed by a pin. As for the embodiments described above, this insert forms a stop 65 making it possible to limit the displacement of the core 50 relative to the distribution crown 60 in a direction going from the distal end 60D towards the proximal end 60P of the crown distribution 60. A functional clearance is provided radially between the free end of the insert forming the stop and the axial wall of the associated groove.

It will be understood from reading the above that the stop 65 is formed on one of the core 50 and the distribution ring 60, and is adapted to come into contact with one surface of the other among the core 50 and the timing ring 60. The stop 65 is only used during the assembly of a hydraulic device. More generally, the stop 65 can be qualified as internal to the distributor 40, in that it does not require elements external to the distributor 40 to perform its function. Once the hydraulic device has been assembled, the stop 65 is no longer in contact with the core 50 in order to avoid generating additional friction between the core 50 and the timing ring 60.

It is thus understood that the different embodiments shown in the figures 1 to 6 limit the relative movement of the core 50 relative to the distribution ring 60 in a given direction, namely a displacement of the core 50 in the direction going from the distal end 60D of the distribution crown 60 towards the proximal end 60P of the distribution crown 60.

As a variant of these different embodiments already described, the distributor 40 as proposed may also include a secondary stop such as an elastic ring or a cover in order to limit the relative displacement of the core 50 relative to the distribution crown 60 in the other direction, namely a displacement of the core 50 in the direction going from the proximal end 60P of the distribution crown 60 towards the distal end 60D of the distribution crown 60. The secondary stop is typically removable.

The figures 10 and 11 thus present two variants comprising such a secondary stop in the form of an elastic ring 7.

The figure 10 is a variant of the figure 4 , in which an elastic ring 7 is inserted in a groove 67 arranged near the distal end 60D of the distribution ring 60. Such elastic rings are commonly designated by the name "circlip".

The elastic ring 7 here defines a stop limiting the relative displacement of the core 50 relative to the distribution ring 60 in the direction from the proximal end 60P of the distribution ring 60 towards the distal end 60D of the ring distribution 60; the distal end 50D of the core 50b then abuts against the elastic ring 7.

The figure 11 is another variant of the figure 4 , in which the elastic ring 7 is here positioned in a groove 57 arranged in the core 50, near its proximal end 50P. As before, the elastic ring 7 defines a stop limiting the relative displacement of the core 50 relative to the distribution ring 60 in the direction going from the proximal end 60P of the distribution ring 60 towards the distal end 60D of the timing ring 60; the elastic ring 7 then abuts against the proximal disengagement 63 of the distribution ring 60.

The figures 10 and 11 previously described thus present different embodiments for the addition of a secondary stop 7. It is understood that these embodiments have been presented as variants of the figure 4 , but that the different arrangements of an elastic ring 7 forming such a secondary stop can also be applied for the other embodiments already described with reference to the other figures, the location of the secondary stop 7 being determined in particular as a function of that of stop 65.

The figure 12 presents another embodiment of the secondary stop 7, which here has the shape of a cap. The distribution ring 60 has an external groove 68 typically extending over its entire external periphery, in which are engaged fixing lugs 71 of the cover 7. The cover 7 here at least partially covers the distal end 60D of the ring distribution 60, so as to define a stop limiting the relative displacement of the core 50 relative to the distribution ring 60 in the direction from the proximal end 60P of the distribution ring 60 towards the distal end 60D of the ring distribution 60, the distal end 50D of the core 50 then coming into contact with the cap 7. The cap 7 typically has one or more openings in order to allow the passage of bolts, in particular for the assembly of the core 50 and the crown of distribution 60 on the other components of a hydraulic device while keeping the cap 7 in place, the latter then being removed following this assembly. The figure 13 is an example of an embodiment of such a cap 7.

Just as the embodiments comprising an elastic ring 7 forming the secondary stop, it is understood that the embodiment in which the secondary stop 7 is formed by a cap has been described with reference to the figure 4 , but that this embodiment can be used for the various embodiments of the stop 65.

In order to assemble a hydraulic device as presented on the figure 1 , an operator will firstly position the bearings 18A and 18B as well as the housing segment 10C around the shaft 14, then the housing segment 10B. If the operator performs the assembly directly on a vehicle, the above elements are already assembled and constitute a wheel spindle on a hub. The operator will then place the cylinder block 12A and the cam 12B. It will then bring the distributor 40 in order to position it in abutment against the shaft 14 and against the cylinder block 14A as indicated previously (having optionally removed the secondary stop 7), the stop 65 then ensuring a function of maintaining in position of the segments 52 by keeping them sandwiched between the core 50 and the distribution ring 60. The operator then positions cover 10A which will hold the distributor 40 in position.

The distributor 40 as proposed thus makes it possible to facilitate the assembly operations of a hydraulic device comprising such a distributor, and thus avoids the risks of loss of time or damage to the distributor 40 resulting from a loss of segment 52 linked excessive movement of the core 50 relative to the distribution ring 60 while the distributor 40 has not yet been assembled with other components of the hydraulic device. These advantages also apply more generally for any transport operation, or involving manipulation of the dispenser 40 before mounting.

Although the present invention has been described with reference to specific exemplary embodiments, it is obvious that modifications and changes can be made to these examples without departing from the general scope of the invention as defined by the claims. In particular, individual features of the different illustrated / mentioned embodiments can be combined in additional embodiments. Therefore, the description and the drawings should be considered in an illustrative rather than restrictive sense.

It is also obvious that all the characteristics described with reference to a process can be transposed, alone or in combination, to a device, and conversely, all the characteristics described with reference to a device can be transposed, alone or in combination, to a process.

Claims (8)

1. A distributor (40) for a hydraulic apparatus, comprising a core (50) and a distribution ring (60) rotatably mounted around the core (50) along an axis (A) defining a proximal end (40P) and a distal end (40D), the distribution ring (60) and the core (50) being slidably mounted relative to each other along the axis (A),
   the core (50) having a plurality of inner grooves (50A, 50B) opening into an outer periphery of the core (50),
   the distribution ring (60) having a plurality of outer grooves (60A, 60B) opening into an inner periphery of the distribution ring (60),
   said inner (50A, 50B) and outer (60A, 60B) grooves being configured so as to be brought into fluid communication and form fluid circulation ducts,
   the core (50) comprising a plurality of sealing segments (52) configured so as to isolate each of said fluid circulation ducts,
   the core (50) having an outer section decreasing from a distal end (50D) towards a proximal end (50P),
   wherein one among the core (50) and the distribution ring (60) comprises an abutment (65) configured so as to come into contact with a wall of the other among the core (50) and the distribution ring (60) in order to limit the movement of the core (50) relative to the distribution ring (60) along a direction defined by the axis (A), from the distal end (60D) towards the proximal end (60P),
   each of said sealing segments (52) of the core (50) being positioned in a housing (51) arranged in the core (50), and bearing against an inner face of the distribution ring (60),
   the distributor (40) being characterized in that:

   the abutment (65) is configured so as to limit the movement of the core (50) relative to the distribution ring (60) along a direction defined by the axis (A) so that the distance between the proximal sealing segment (52) and the proximal clearance (63) of the distribution ring (60) remains a non-zero distance,

   the proximal sealing segment (52) being the closest sealing segment (52) along the axis (A) of the proximal end (50P) of the core (50), and

   the proximal clearance (63) of the distribution ring (60) being defined as the first variation in section of the inner surface of the distribution ring (60) bearing against the proximal sealing segment (52) towards a proximal end (60P) of the distribution ring (60).
2. The distributor according to claim 1, wherein said abutment (65) is secured to the distribution ring (60), and is configured so as to come into contact with a wall of the core (50).
3. The distributor according to claim 1, wherein said abutment (65) is secured to the core (50), and is configured so as to come into contact with a wall of the distribution ring (60).
4. The distributor according to any of claims 1 to 3, further comprising a secondary abutment (7) assembled on the core (50) or on the distribution ring (60), so that the movement of the core (50) relative to the distribution ring (60) along a direction defined by the axis (A) is limited in one direction by the abutment (65), and in the other direction by the secondary abutment (7).
5. The distributor according to claim 4, wherein the secondary abutment (7) is an elastic ring mounted in a groove (57, 67) arranged in the core (50) or in the distribution ring (60).
6. The distributor according to claim 4, wherein the secondary abutment (7) is an element forming a cover, mounted around the distal end (60D) of the distribution ring (60), said element forming a cover having a surface forming an abutment during the movement of the core (50) relative to the distribution ring (60) along the axis (A) in a direction from the proximal end (60P) towards the end distal (60D) of the distribution ring (60).
7. A hydraulic radial-piston and multilobe-cam apparatus, comprising a distributor (40) according to any of the preceding claims, wherein there is a non-zero gap (J) along the axis (A) between the abutment (65) of the distributor (40) and a surface of the core (50) disposed opposite the abutment (65).
8. A method for assembling a hydraulic apparatus on a wheel spindle, wherein
   a first set of components of the hydraulic apparatus is positioned about an axis (14) of the wheel spindle,
   a distributor (40) is provided according to any of claims 1 to 6,
   the distributor (40) is positioned bearing against components of the first set of components, so as to define a non-zero gap (J) along an axis (A) of the wheel spindle between the abutment (65) of the distributor and a surface of the core (50) disposed opposite the abutment (65),
   the core (50) is secured to a component of the first set of components
   a second set of components of the hydraulic apparatus is positioned, so as to define an inner casing volume in which the distributor (40) is positioned.

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