FR3047789A1 - IMPROVED SEALING SYSTEM FOR HOUSING AND BEARING OF HYDRAULIC MACHINE - Google Patents

Abstract

Assembly comprising a casing (1) defining an internal volume in which is arranged a hydraulic machine (2), a shaft (3) engaged in the casing (1) and rotatably mounted relative to the casing (1) by means of a bearing (4) comprising rolling elements (43), an inner ring (41, 42) mounted on the shaft (3), and an outer ring (44) mounted on the housing (1), the assembly comprising a device sealing (6, 7) between the internal volume of the housing (1) and the rolling elements (43) of the bearing (4), characterized in that said sealing device (6, 7) is arranged between the ring internal (41, 42) and the outer ring (44) of the bearing (4).

Description

GENERAL TECHNICAL FIELD

The present invention relates to the field of hydraulic devices, and more specifically a sealing system between a hydraulic device and a bearing coupling the housing and the shaft of the hydraulic device.

STATE OF THE ART

The realization of a sealing system for a hydraulic machine mounted on a shaft proves tricky to achieve for certain types of applications, in particular because of tight space constraints, and the constraints imposed due to the presence of other components necessary for the proper functioning of the whole.

Several structures are thus known for producing a seal between a hydraulic machine casing and a shaft associated with such a machine.

The patent application FR 2 967 228 in the name of the Applicant thus has a sealing system comprising two sealing elements; a first sealing member for protecting a second sealing member against pressure peaks that may occur in the interior space of the housing of the hydraulic machine.

These two sealing elements define a discharge chamber which serves as a buffer space, in particular to collect the fluid from leaks at the first sealing member that may occur especially the occasion of such pressure peaks. The connection of the discharge chamber to a drain makes it possible to avoid pressure build-ups in this chamber and thus to further improve the protection of the second sealing element.

Such a sealing structure, however, requires several specific components to allow the implantation and maintenance of the sealing elements, including a joint support and a friction track, which is penalizing in terms of size.

In addition, such a structure requires very low manufacturing tolerances, to ensure the coaxiality of the sealing elements relative to the rotating part of the system, which has a significant impact in terms of manufacturing cost.

The present invention thus aims to at least partially address this problem.

PRESENTATION OF THE INVENTION For this purpose, the present invention proposes an assembly comprising a casing defining an internal volume in which is disposed a hydraulic machine, a shaft engaged in the casing and mounted in relative rotation with respect to the casing by means of a bearing comprising rolling elements, an inner ring mounted on the shaft, and an outer ring mounted on the housing, the assembly comprising a sealing device between an internal volume of the housing comprising the hydraulic machine and the rolling elements of the housing; bearing, characterized in that said sealing device is disposed between the inner ring and the outer ring of the bearing.

According to one example, the inner ring and the outer ring of the bearing extend in a longitudinal direction defined by the shaft, so as to define a housing between the rolling elements and the internal volume of the housing comprising the hydraulic machine, said device sealing being disposed in said housing.

In one example, the sealing device comprises two sealing elements successively arranged between the rolling elements and the internal volume of the casing comprising the hydraulic machine.

Said two sealing elements then typically define between them a discharge chamber, connected to a drain arranged in the shaft.

The discharge chamber is then typically connected to the drain via ducts formed in the inner ring of the bearing.

According to one example, the inner ring and the outer ring of the bearing define a first portion and a second portion in which the first sealing member and the second sealing member are respectively positioned, the first portion and second portion having internal diameters. and / or external ones.

According to a particular embodiment of this example, said two sealing elements comprise a lip seal and a composite seal, the lip seal being disposed between the rolling elements and the composite seal.

The lip seal is then typically disposed in the first portion and the composite seal is typically disposed in the second portion defining the inner ring and the outer ring of the bearing, and the inner diameter of the second portion is then typically less than the inner diameter of the the first portion and / or the outer diameter of the second portion is then typically greater than the outer diameter of the first portion.

The composite seal may comprise a calibrated orifice defining a maximum leakage rate between the internal volume of the casing and the discharge chamber. The calibrated orifice is typically configured so that its jet of fluid in the discharge chamber is not oriented towards the lip seal. The assembly may further comprise a sealing element disposed between the outer ring and the housing, and a sealing element disposed between the inner ring and the shaft. The invention also relates to a vehicle comprising an assembly as defined above, in particular for driving the wheels of such a vehicle.

PRESENTATION OF THE FIGURES Other characteristics, objects and advantages of the invention will emerge from the description which follows, which is purely illustrative and nonlimiting, and which should be read with reference to the appended drawings, in which: FIG. 2 is a variant of FIG. 1; FIG. 3 shows another variant of the invention.

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

DETAILED DESCRIPTION

Figure 1 shows an assembly according to one aspect of the invention.

This figure shows an assembly comprising a casing 1 defining an internal volume in which is disposed a hydraulic machine 2, and a shaft 3 inserted in the casing 1.

The hydraulic machine 2 comprises a cylinder block 21, a cam 22 and a distributor 23; it thus forms with the casing 1 a motor or a hydraulic pump, typically with radial pistons.

The operation of such a hydraulic machine 2 is well known, and therefore will not be described in detail here.

In a manner known per se, the cylinders of the cylinder block 21 are supplied with fluid from a fluid dispensed by the distributor 23, via grooves, some of which are shown and designated by the references 23A and 23B. The dispenser 23 is formed of two parts; a counter-distributor 24 in which the grooves 23A and 23B are formed and connected to main conduits for feeding and exhausting fluid (not shown), and a distributor 25 disposed around the counter-distributor 24, and dispensing The supply lines are typically drilled in the shaft 3, connected to the counter-distributor 24 in a sealed manner, and extended by holes through the counter-distributor 24. to debouch in the grooves 23A and 23B. In particular, this hydraulic machine may be of the fixed cylinder block type 21 and rotating casing 1, in which case the supply and exhaust ducts advantageously pass through the shaft 3.

The hydraulic machine 2 is typically a radial piston hydraulic machine, comprising a multilobe cam 22.

The hydraulic machine 1 is for example selectively activated, for example by retracting the pistons in the cylinder block 21, or by disengaging the cylinder block 21 from the shaft 3.

The hydraulic machine 1 typically carries out the driving of the wheels of a vehicle. According to one embodiment, the hydraulic machine 1 rotates at the speed of the wheels of the associated vehicle, or the cam 22 of the hydraulic machine 1 rotates at the speed of the wheels. The housing 12 may for example carry the rim of a wheel of the vehicle.

The housing 1 as shown generally comprises a cover 11 disposed around the distributor 23 of the hydraulic machine 2, and a proximal portion 12, here formed of several parts, arranged around the shaft 3. The cam 22 also forms here a part of the housing 1, and is disposed between the proximal portion 12 and the cover 11 of the casing 1.

A bearing 4 is mounted between the shaft 3 and the housing 1, so that the housing 1 is rotatably mounted relative to the shaft 3, or vice versa. The shaft 3 thus typically forms a wheel spindle, that is to say that the shaft 3 carries the bearing 4 which allows the rotation of a vehicle wheel or machine.

The bearing 4 as presented comprises an inner ring formed of two inner half-rings 41 and 42 mounted around the shaft 4, typically clamped around the shaft 4 or with a clearance, rolling elements 43, here rollers conical, and an outer ring 44 mounted tightly in the housing 1.

The casing 1 typically has two abutment elements which hold the outer ring 44 in position in the axial direction, these two abutment members being positioned on either side of the outer ring 44.

The proximal portion 12 of the casing 1 comprises for example a shoulder or a rib forming a first stop 121, and an elastic ring positioned in a groove of the housing 1 (as shown in Figure 2), or a patch on the proximal portion 12 of the housing 1 (for example by bolting, as shown for example in Figure 1) and bearing against the outer ring 44 can then form the second stop 122.

The inner ring is also maintained in position axially on the shaft 3, for example by means of a shoulder or abutment on the one hand, and an elastic ring or other means on the other hand.

In the case where the inner ring is made of two half-rings (here the two inner half-rings 41 and 42), the means forming abutments then frame the assembly formed by these two half-rings.

In the embodiments shown in the figures, the axial stop of the half-ring 41 is formed by a shoulder 34 on the shaft 3, while the axial stop of the half-ring 42 is produced by means of a groove radial 35 arranged on the shaft 3, receiving two half stop rings 36, held in place by an elastic ring 37 or other suitable means. The axial stop of the internal half-rings 41 and 42 can also be achieved by means of a nut, typically a sealing nut.

Bearing 4 is typically lined with grease.

Sealing means are disposed between the shaft 3 and the casing 1, typically between the proximal portion 12 of the housing 1 and the shaft 3, so as to protect the bearing from the outside environment by preventing the infiltration of external elements. In the examples illustrated in the figures, a sealing element 31 is thus disposed between the shaft 3 and the proximal portion 12 of the casing 1.

This embodiment is only illustrative; the structure of the outer and inner rings can be modified to suit the system requirements and the type of rolling elements. The outer ring can thus be formed of two half-rings, while the inner ring can be formed in one piece.

The system further comprises a sealing device 5 between the internal volume of the casing 1 comprising the hydraulic machine 2 and the rolling elements 43 of the bearing 4 in order to protect them against pressure variations within the internal volume of the casing 1 which can be caused in particular by the operation of the hydraulic machine 2.

The sealing device 5 is here mounted in the bearing 4, between the inner ring and the outer ring, so as to be interposed between the rolling elements 43 of the bearing and the internal volume of the casing 1 in which the machine is arranged. hydraulic 2.

Sealing elements are also arranged between the bearing 4 and the casing 1 on the one hand, and between the bearing 4 and the shaft 3 on the other hand.

In the example illustrated in Figure 1, a groove 46 is formed in the outer ring 44 of the bearing 4, and an O-ring 47 is disposed in the groove 46. The groove 46 is covered by the outer ring 44 during its assembly , so as to provide a tight connection between the outer ring 44 and the proximal portion 12 of the casing 1 on which the outer ring 44 is mounted.

In the embodiment illustrated in Figure 2, the groove 46 is formed in the proximal portion 12 of the casing 1 and not in the outer ring 44 of the bearing 4. The function is then identical.

In the example illustrated in Figure 1, a groove 48 is formed in the shaft 3, and an O-ring 49 is disposed in this groove 48. The groove 48 is covered by the inner ring (here the inner half-ring 42 ) during its assembly, so as to provide a tight connection between the inner ring (here the inner half-ring 42) and the shaft 3 around which the inner ring is mounted. The groove 48 is then typically made downstream of the groove 83 which will be described later.

In the embodiment illustrated in Figure 2, the sealing element between the shaft 3 and the inner ring is disposed at the contact between the two inner half-rings 41 and 42. The latter have two bevelled ends, so as to form a housing delimited by the shaft 3 and the two inner half-rings 41 and 42. An O-ring 45 is then disposed in this housing, so as to provide a tight connection between the two inner half-rings 41 and 42 and the shaft 3. The seal between the bearing 4 and the housing 1 or the shaft 3 can also be achieved via specific stop means, for example by means of a sealing nut thus achieving a dual function of stopping in translation and sealing.

The inner ring and the outer ring of the bearing 4 thus each have an axial bearing, respectively an inner axial bearing surface 51 and an outer axial bearing surface 52, defining a housing extending in the longitudinal direction defined by the shaft 3.

The internal axial bearing surface 51 and the external axial bearing surface 52 are configured so that the housing is formed between the rolling elements 43 of the bearing and the internal volume of the housing 1 in which the hydraulic machine 2 is arranged.

The sealing device comprises a first sealing element 6 and a second sealing element 7 successively arranged in the housing defined by the inner and outer rings of the bearing 4, so that the first sealing element 6 is closer rolling elements 43 that the second sealing element 7. The second sealing element 7 is thus interposed between the first sealing element 6 and the internal volume of the casing 1 in which the hydraulic machine 2 is arranged.

The two sealing elements 6 and 7 define between them a discharge chamber 8.

The inner ring and / or the outer ring of the bearing 4 may comprise ribs and / or ribs provided with elastomer rings in order to hold the sealing elements 6 and / or 7 in position.

The sealing device thus makes it possible to isolate the rolling elements 43 of the bearing 4 from the internal volume of the casing 1 in which the hydraulic machine 2 is arranged, and thus to protect the rolling elements 43 of the bearing 4 from pressure variations that can This casing of the hydraulic machine is typically filled with hydraulic fluid or oil, and may be subject to pressure peaks. The bearing 4 is in turn lined with oil or grease, and must be preserved from such pressure peaks. The insertion of the sealing device in the housing defined by the bearing 4 has several advantages over conventional structures.

The device presented thus makes it possible to apply a hydraulic pressure continuously or discontinuously, during a phase of use of the machine, in the internal volume of the machine 2, via a drain channel 85.

Hydraulic pressure can also be established in the internal volume of the machine 2, according to the different phases of use of the machine.

This structure makes it possible to exploit the concentricity between the inner and outer rings of the bearing 4, and thus to make the sealing device more reliable and to limit its wear. Indeed, the sealing elements 6 and 7 are here mounted directly on the elements that define the axis of rotation, which significantly reduces the dispersion compared to conventional assemblies.

In addition, this arrangement has the advantage of using the material of the inner and outer races, which is a very hard steel and very good surface, which avoids reporting friction tracks on the shafts. Indeed, the shafts or wheel flares, and the casings are typically made of less hard materials than the bearing rings. These properties related to the materials used for producing the bearing rings, namely a high hardness and a very good surface condition, are highly advantageous for producing friction tracks for seals.

This structure makes it possible to limit the number of components of the system. Indeed, elements already present in the system are used instead of adding additional elements to form the housing for receiving the sealing device. The cost of the system is reduced, its assembly is simplified, and its size is also reduced.

In addition, the mounting of the sealing system is also simplified, in that it can be carried out jointly with the mounting of the bearing 4.

Moreover, the very good surface condition of the bearing rings makes it possible to reduce the wear of the various sealing elements with respect to conventional surfaces.

In the example shown, the first sealing element 6 is a lip ring, comprising a structural reinforcement 61, an elastic coating 62, and a reinforcing ring 63 which holds the first sealing element 6 pressed against the axial bearing. internal 51. In a known manner, the first sealing member 6 can be placed by force-feeding in the outer ring 44. A stop (not shown) can be provided in the outer ring 44 so that the first element sealing 6 does not go beyond a certain position during assembly.

The first sealing element 6 is rigidly mounted and rotates with the outer ring 44, and is sliding in rotation on the inner ring 44. By sliding in rotation, it is meant that the first sealing element is mounted rotating in rotation relative to to the inner ring, while achieving a dynamic seal with this same inner ring

In the example shown, the second sealing element 7 is a composite seal, comprising an annular ring 71 mounted tightly in the outer ring 44 of the bearing 4, and defining a housing on its inner periphery. The annular ring 71 is fixedly supported by the outer ring 44 and rotates therewith.

An annular pad 72 is mounted tightly but slidably around the internal axial bearing 51 of the inner ring of the bearing 4, and is surmounted by an O-ring 73. The annular pad 72 and the O-ring 73 are arranged in the housing of the annular ring 71, so that the O-ring 73 is compressed between the annular ring 71 and the annular pad 72. The annular pad 72 is thus the part that performs the rotational friction on the inner ring 42, thus preserving the O-ring 73 wear due to such friction. By way of example, the O-ring 73 can contribute to the clamping of the shoe 72 on the inner ring 42. The inner ring 72 is typically made of a material such as steel, cast iron, a synthetic plastic material suitable for friction, bronze, or brass, which are very rigid materials compared to the material of which is formed the O-ring 73, for example rubber. Due to the rigidity of the pad 72, and its positioning in the groove of the annular ring 71, the pad 72 can not deform under the effect of pressure to pass between the piece 7 and the inner ring 42, and remains therefore in the groove of the annular ring 71. Thus, when the sealing member 7 is placed around the inner ring 42, it is impossible for the annular pad 72 to come out of its housing. For example, the material of which is formed the pad 72 is still chosen so as to allow its deformation to be introduced into the groove of the annular ring 71 during assembly. The shoe 72 and the O-ring 73 are then placed in the groove of the annular ring 71 before the second sealing element 7 is positioned around the inner ring 42 or in the outer ring 44.

The O-ring 73 typically makes it possible to perform the rotational drive between the annular pad 72 and the annular ring 71.

The second sealing element 7 can be placed by force-feeding in the outer ring 44. An abutment shape, not shown, can be provided in the outer ring 44 so that the second sealing element 7 does not move axially when it is subjected to the pressure of the internal volume of the machine. A complementary static sealing element, not shown, such as an O-ring placed in a groove, can be placed between the annular ring 71 and the outer ring 44.

It is well understood that such an embodiment is not limiting, and that the second sealing element 7 can also be made for example in an inverted configuration, in which the annular pad 72 would be mounted tight but sliding tightly in the outer ring 44 of the bearing 4, while the annular ring 71 is fixedly supported by the inner ring of the bearing 4 and rotates therewith. The function is then unchanged.

The second sealing element 7 is thus a sealing element able to withstand significant variations in pressure, and in particular to withstand higher pressures than those supported by the first sealing element 6. In particular, the second element of sealing 7 is able to withstand high pressures without deformation, and without leaving its location.

In operation, the second sealing element 7 thus makes it possible to protect the first sealing element 6 from excessive pressures generated by the hydraulic machine 2.

In case of leakage of the second sealing element 7, the fluid is collected in the discharge chamber 8 formed between the first sealing element 6 and the second sealing element 7. The pressure of the fluid within this chamber discharge 8 remains low, at least in ranges of acceptable values for the first sealing element 6.

In order to allow the evacuation of the fluid which would then accumulate in the discharge chamber 8, the system comprises a drain 82, for example arranged in the shaft 3, typically when the latter is fixed, connected to the discharge chamber 8.

In the example shown, the drain 82 comprises an axial portion 82A arranged in the shaft 3, in the longitudinal direction of the shaft 3, and a radial portion 82B opening radially from the shaft 3.

The inner ring of the bearing 4, here the inner half-ring 42 of the bearing 4 comprises a groove 83 arranged on the inner periphery of the internal axial bearing 51 of the inner half-ring 42, this groove being made to be aligned with the radial portion 82B of the drain 82. One or more bores 84 are also formed in the internal axial surface 51 of the inner half-ring 42, and allow to connect the discharge chamber 8 to the groove 83. These holes 84 are open, and are typically made radially, through the inner ring of the bearing 4, so as to be aligned with the groove 83.

Thus, the fluid reaching the discharge chamber 8 can be discharged through the holes 84, then the groove 83, the radial portion 82B of the drain 82, and finally the axial portion 82A of the drain 82. The shaft 3 can also have a second drain channel 85. The shaft 3 may for example comprise a drain channel 85 of the internal volume of the hydraulic machine, and a separate drain channel 82.

Such a drain channel 85 of the internal volume of the machine is typically pierced in the shaft 3, and connected to an internal space between the shaft 3 and the counter distributor 24. It can collect any leaks that occur between the distributor 25 and the cylinder block 21 on the side of the shaft 3, and also any other internal leakage of the hydraulic machine in the internal volume via a passage not shown between the block 21 and the shaft 3 or via an additional hole no represented by counter dealer 24.

Despite this drain channel 85, pressure peaks may occur in the crankcase of the hydraulic machine, or a permanent pressure may become established. It is also known to, via this drain channel 85 coupled to pressure regulating means (not shown), voluntarily establish a permanent pressure in the internal volume of the hydraulic machine.

The drain 82 makes it possible to preserve the sealing element 6 of such pressure within the internal volume of the hydraulic machine, or pressure peaks.

According to a particular embodiment shown in FIG. 3, the second sealing element 7 comprises a calibrated orifice 74 thus forming a nozzle, defining a constant calibrated leakage of the internal volume of the casing 1 towards the discharge chamber 8. The orifice calibrated 74 is typically made so that the fluid entering the discharge chamber 8 is not oriented towards the first sealing member 6, which improves the strength and reliability. The calibrated orifice 74 is then typically inclined with respect to the longitudinal direction defined by the shaft 3. The calibrated orifice 74 typically has a section less than or equal to the section of the bore 84, thereby avoiding accumulation in the discharge chamber 84. The calibrated orifice 74 may be in the form of a bore in the second sealing element 7, or a part inserted into the second sealing element 7.

Such a calibrated orifice 74 can be made whatever the structure of the assembly, particularly on the embodiments shown in FIGS. 1 and 2.

In the examples shown in the figures, the inner axial span 51 and the outer axial span 52 have a constant diameter, and the first and second sealing elements 6 and 7 therefore have identical inner and outer diameters.

The inner axial span 51 and / or the outer axial span 52 may be staggered, and thus have portions of different dimensions. The first and the second sealing element 6 and 7 may therefore have different internal and / or external diameters. In this way, it is possible to use different dimensions of joints, for example by choosing existing dimensions, or by adjusting the space between the internal axial surface 51 and the external axial surface 52 to facilitate the passage of a tool of mounting.

An increasing staging of bearings in the direction from the rolling elements 43 to the cylinder block 23, at the fitting of the first and second sealing elements 6 and / or 7, to the internal axial bearing 51 or the axial bearing external 52, thus allows for example to achieve a hunting abutment of the first and second sealing elements 6 and / or 7 respectively. By way of example, if we consider the sealing elements 6 and 7 as represented in FIGS. 1 and 2, it is possible to define a first portion of the span defined by the inner ring 42 and the outer ring 44 in which is arranged the first sealing element 6, and a second portion of the span in which is disposed the second sealing element 7.

The first portion can then form an axial abutment for the insertion of the first sealing element 6. The second portion then for example has an internal diameter and / or an outer diameter respectively greater than the internal diameter and / or the external diameter of the second portion, so as to also form an axial abutment for the insertion of the second sealing element 7. For example, the first portion and the second portion may have an identical internal diameter, but the second portion then has a outer diameter greater than the outer diameter of the first portion.

Also by way of example, the first portion and the second portion may have an identical outer diameter, but the second portion then has an internal diameter smaller than the internal diameter of the first portion.

For example, the second portion may have an outer diameter greater than the outer diameter of the first portion, and the second portion may have an inner diameter smaller than the inner diameter of the first portion.

Claims (12)

claims 1. An assembly comprising a casing (1) defining an internal volume in which a hydraulic machine (2) is arranged, a shaft (3) engaged in the casing (1) and mounted relative to the casing (1) by means of rotation relative to the casing (1). a bearing (4) comprising rolling elements (43), an inner ring (41, 42) mounted on the shaft (3), and an outer ring (44) mounted on the housing (1), the assembly comprising a sealing device (6, 7) between an internal volume of the housing (1) comprising the hydraulic machine (2) and the rolling elements (43) of the bearing (4), characterized in that said device sealing (6, 7) is arranged between the inner ring (41, 42) and the outer ring (44) of the bearing (4). 2. The assembly of claim 1, wherein the inner ring (41, 42) and the outer ring (44) of the bearing (4) extend in a longitudinal direction defined by the shaft (3), so as to define a housing between the rolling elements (43) and the internal volume of the housing (1) comprising the hydraulic machine (2), said sealing device (6, 7) being disposed in said housing. 3. Assembly according to one of claims 1 or 2, wherein the sealing device (6, 7) comprises two sealing elements (6, 7) arranged successively between the rolling elements (43) and the internal volume. housing (1) comprising the hydraulic machine (2). 4. The assembly of claim 3, wherein said two sealing elements (6, 7) define between them a discharge chamber (8), connected to a drain (82) arranged in the shaft (3). 5. The assembly of claim 4, wherein the discharge chamber (8) is connected to the drain (82) via conduits (83, 84) formed in the inner ring (42) of the bearing (4). 6. An assembly according to one of claims 3 to 5, wherein the inner ring (41, 42) and the outer ring (44) of the bearing (4) define a first portion and a second portion in which are respectively positioned first sealing member (6) and the second sealing member (7), the first portion and second portion having distinct internal and / or external diameters. 7. Assembly according to one of claims 3 to 6, wherein said two sealing elements (6, 7) comprise a lip seal (6) and a composite seal (7), the lip seal (6) being disposed between the rolling elements (43) and the composite seal (7). 8. Assembly according to claims 6 and 7 taken in combination, wherein the lip seal (6) is disposed in the first portion and the composite seal (7) is disposed in the second portion defined the inner ring (41, 42). and the outer ring (44) of the bearing (4), and wherein the inner diameter of the second portion is smaller than the inner diameter of the first portion and / or the outer diameter of the second portion is greater than the outer diameter of the first portion. portion. 9. Assembly according to one of claims 7 or 8, wherein the composite seal (7) comprises a calibrated orifice (74) defining a maximum leakage rate between the internal volume of the housing (1) and the discharge chamber (8). ). 10. The assembly of claim 9, wherein the calibrated orifice (74) is configured so that its jet of fluid in the discharge chamber (8) is not oriented towards the lip seal (6). 11. Assembly according to one of the preceding claims, further comprising a sealing element disposed between the outer ring (44) and the housing (1), and a sealing element disposed between the inner ring (41, 42). and the shaft (3). 12. Vehicle comprising an assembly according to one of claims 1 to 11.