FR3109615A1 - Sealing device for a rolling bearing - Google Patents

Abstract

The invention relates to a sealing device (6) comprising a first armature (7) and a second armature (8) forming a passage (9) between a rotation interface (3) and the outside, the armature (7 ) having a recumbent U-shaped geometry formed of a radial central wall (7a) and bordered on either side by two axial peripheral walls (7b, 7c), the armature (8) having an axial bottom (8a) and two radial side walls (8b, 8c) respectively on one side of said bottom in order to delimit a basin (10) between them, the frame (8) further having an axial outer wall (8d), being connected by a part to one wall (8b, 8c) and on the other hand forming with the other wall (8b, 8c) an opening (11) for the passage (9), in which one of the walls (7b, 7c) extends to form a baffle along said passage. Picture 1a

Description

Sealing device for a rolling bearing

The invention relates to a sealing device for a bearing comprising two bodies, respectively outer and inner, forming between them an interface of relative rotation around an axis, as well as a bearing, in particular with rolling contact, of which at least one side of the rotation interface is equipped with such a sealing device.

In particular, the invention applies to motor vehicle rolling bearings, in particular to wheel bearings. Advantageously, a bearing according to the invention allows the mounting of a driving or non-driving wheel of a motor vehicle, the inner member being rotating and comprising means for fixing the wheel while the outer member is fixed and comprises fixing means on a suspension element of the vehicle.

Furthermore, to allow the relative rotation of the organs, rolling bodies, in particular in the form of balls, can be arranged in the rotation interface.

To prevent, on the one hand, the leaks of lubricant present in the rotation interface and, on the other hand, the contamination of said interface with external pollutants, at least one side of the rotation interface can be equipped with a device for tightness.

To do this, sealing devices are known comprising two rigid armatures each intended to be associated with a member respectively by forming a passage between the rotation interface and the outside.

In particular, sealing devices are known in which the two armatures each have an axial wall for association by fitting with a member and at least one wall forming with a wall of the other armature a sealing baffle to limit the penetration of external pollutants into the rotation interface.

Furthermore, to further limit the entry of external pollutants into the rotation interface, one of the armatures may be equipped with a sealing element comprising at least one lip arranged in said passage being in frictional contact on a span of the other armature.

However, the friction of the sealing lip induces a torque which depends in particular on the speed of rotation of the sealing element relative to the armature against which said lip is in frictional contact.

Thus, this solution for improving the sealing of a sealing baffle induces a high friction torque which is detrimental to the energy performance of the bearing. In addition, a high rotation speed induces rapid wear of the sealing lip, which has a negative impact on the sealing performance of the device, and therefore on the life of the bearing.

The invention aims to improve the prior art by proposing in particular a sealing device whose sealing baffle is arranged to guarantee improved sealing against the penetration of external pollutants into the rotation interface, in order in particular to be able to limit the friction torque in the case where a friction sealing lip is used.

To this end, and according to a first aspect, the invention proposes a sealing device for a bearing comprising two members forming between them a relative rotation interface around an axis, said device comprising a first armature intended to be associated with one of the members and a second armature intended to be associated with the other member by forming a passage between the rotation interface and the outside, said first armature having a recumbent U-shaped geometry formed of a central wall extending along a radial dimension, said central wall being bordered on either side by two peripheral walls - respectively inner and outer - extending along an axial dimension, said second armature having a bottom extending along an axial dimension and two side walls - respectively internal and external - which extend along a radial dimension respectively on one side of said bottom in order to delimit a basin between them, the second frame further having an external wall which extends along an axial dimension, said outer wall being connected on the one hand to one of said side walls and on the other hand forming with the other of said side walls an opening for passage, one of the peripheral walls of the first frame extending into said opening to form a baffle along said passage.

According to a second aspect, the invention proposes a rolling bearing comprising two members and rolling bodies arranged in a rotation interface formed between said members to allow their relative rotation around an axis, at least one side of the interface of rotation being equipped with such a sealing device, the first armature being associated with one of the members and the second armature being associated with the other member by forming a passage between the rotation interface and the outside.

Other objects and advantages of the invention will appear in the following description, made with reference to the appended figures, in which:

And

are schematic representations in partial axial section of one side of a rolling bearing according to a first embodiment of the invention (FIG. 1a) and of the sealing device fitted to the bearing of FIG. 1a (FIG. 1b);

And

are schematic representations in partial axial section of one side of a rolling bearing according to a second embodiment of the invention (FIG. 2a) and of the sealing device fitted to the bearing of FIG. 2a (FIG. 2b).

In connection with these figures, a rolling bearing is described below, in particular for mounting a driving or non-driving wheel of a motor vehicle.

The bearing comprises two members, respectively outer 1 and inner 2, mounted in relative rotation around an axis via a rotation interface 3 formed between said members. In the description, the terms “exterior” and “interior” are defined with respect to the axis of rotation of the bearing (horizontal in the figures), respectively for a location far from and close to said axis.

In the embodiment shown, the outer member 1 is intended to be fixed, by being associated for example with a suspension element of the vehicle, and the inner member 2 is intended to rotate with the wheel. However, the invention can be applied to another bearing configuration, in particular with rolling contact, comprising two members 1, 2 in relative rotation, possibly intended for an application other than the mounting of a motor vehicle wheel.

The bearing represented comprises rolling bodies, in particular in the form of balls 4, which are arranged in the rotation interface 3 to allow the relative rotation of the members 1, 2. To do this, the rotation interface 3 comprises two tracks of bearing 1a, 2a each formed respectively on a member 1, 2, said tracks forming between them a raceway in which is arranged a row of rolling bodies 4.

However, the invention is not limited to one embodiment of the bearing, in particular with respect to the geometry of the rolling bodies 4, to the geometry and/or to the relative arrangement of the fixed 1 and rotating 2 members.

In particular, according to a variant embodiment not shown, the members 1, 2 can be mounted in relative rotation in a smooth manner, with or without the interposition of a friction washer between them.

At least one side 5 of the rotation interface 3 is equipped with a sealing device 6 to prevent, on the one hand, the leakage of lubricant present in the rotation interface 3 and, on the other hand, the contamination of said interface with external pollutants, in particular based on sludge.

In FIGS. 1a and 2a, side 5 of rotation interface 3 is formed between two substantially axial walls 1b, 2b of respectively a member 1, 2, said walls each extending in the extension of respectively a rolling track 1a, 2a.

The sealing device 6 comprises a first armature 7 intended to be associated with one of the members 1, 2 and a second armature 8 intended to be associated with the other member 2, 1 by forming a passage 9 between the interface of rotation 3 and the outside of the bearing, said fittings possibly being made of metallic material, in particular by bending a stamped sheet.

The first reinforcement 7 has a recumbent U-shaped geometry formed of a central wall 7a extending along a radial dimension, said central wall being bordered on either side by two peripheral walls - respectively inner 7b and outer 7c - s' extending along an axial dimension.

Furthermore, the second frame 8 has a bottom 8a extending along an axial dimension and two side walls - respectively internal 8b and external 8c - which extend along a radial dimension respectively on one side of said bottom, in order to delimit a 10 bowl between them.

In the description, the terms “internal” and “external” are taken with reference to the interior of the rolling bearing, and correspond to provisions located respectively on the left and on the right in the figures.

Advantageously, the bowl 10 forms a zone for recovering the external pollutants entering the passage 9, the length of the bottom 8a and/or the height of the side walls 8b, 8c being large enough to contain the said pollutants in the said zone. , and thus limit their penetration into the rotation interface 3.

The second reinforcement 8 also has an outer wall 8d which extends along an axial dimension, said outer wall being connected on the one hand to one of the side walls 8b, 8c and on the other hand forming with the other side walls 8b, 8c an opening 11 for the passage 9, one of the peripheral walls 7b, 7c of the first frame 7 extending into said opening to form a baffle along said passage.

Such a baffle makes it possible to limit the entry of external pollutants into the passage 9, any pollutants crossing said baffle being moreover collected in the bowl 10 of the second reinforcement 8. Thus, it is possible to obtain a good seal with respect to the outside of the rolling bearing by limiting the use of friction elements by increasing the life of the sealing device 6.

In the embodiments shown, the outer wall 8d extends around the bowl 10 to form the opening 11 between said bowl and the outside. In particular, the outer wall 8d and the corresponding peripheral wall 7b, 7c are arranged to form a baffle upstream of the bowl 10, which makes it possible to limit the quantity of external pollutants flowing into said bowl.

To improve the tightness of the device 6, at least one of the reinforcements 7, 8 can carry a sealing element 12, in particular of elastomeric material, which comprises at least one lip 12a in frictional contact on the other of said reinforcements.

To limit the friction torques, only one of the armatures 7, 8 is equipped with such a sealing element 12, said element further having a limited number of lips 12a, in particular less than or equal to 2, and more particularly a single rubbing lip 12a.

In particular, in the figures, the sealing lip(s) 12a is (are) positioned in the passage 9 between the bowl 10 and the rotation interface 3, which makes it possible to prevent the external pollutants flowing out of said bowl to enter said rotation interface, but also to limit the risk of lubricant leaks out of said rotation interface.

The first armature 7 is secured to one of the members 1, 2 by fitting one of its peripheral walls 7b, 7c onto the corresponding axial wall 1b, 2b of said member.

Similarly, the second armature 8 is secured to the other member 1, 2 by fitting its bottom 8a or its outer wall 8d onto the corresponding axial wall 1b, 2b of said other member.

Furthermore, at least one of the reinforcements 7, 8 can carry a static sealing element 13 of its association with the corresponding member 1, 2.

In the figures, the armature 7, 8 associated with the outer member 1 carries such a static sealing element 13, said element comprising a bead 13a, in particular made of elastomeric material, which is placed in contact with said outer member to form static sealing.

In particular, the axial wall 8d, 7c fitted to the member 1 has a free end 14, 15 which is offset radially, in order to allow contact between the bead 13a and the outer axial wall 1b which guarantees static sealing. by not imposing excessive deformation of said fitted wall.

In relation to FIGS. 1a and 1b, a first embodiment of the invention is described, in which the first armature 7 in the shape of a recumbent U is associated with the internal member 2 of a rolling bearing via of the inner peripheral wall 7b, the second armature 8 being associated with the outer member 1 of said bearing via the outer wall 8d.

In particular, the outer wall 8d is connected to the inner wall 8b, and the outer peripheral wall 7c is placed in the opening 11, forming along the passage 9 a conduit 16a for baffling with said outer wall and said peripheral wall.

To limit the axial size of the sealing device 6, the free end 14 of the outer wall 8d is arranged in radial alignment with the central wall 7a, forming at their radial interface an opening 17 to the outside.

Advantageously, the second frame 8 comprises a sealing web 18, in particular integral with the static sealing element 13, which extends at least over the entire inner span of the outer wall 8d, in order to reduce the radial dimension of the baffle duct 16a, and thus limit the entry of external pollutants through said duct.

The outer peripheral wall 7c has a free end 19 which is arranged facing axially from the inner wall 8b, forming at their interface a baffling clearance 16b along the passage 9. In the figures, the baffling conduit 16a opens into the clearance baffle 16b upstream of the bowl 10, so that any pollutants crossing said conduit flow directly into said bowl through said clearance.

The bottom 8a is arranged around the inner peripheral wall 7b, forming between them a first baffling conduit 16c along the passage 9, said conduit being formed downstream of the bowl 10. In particular, the inner peripheral wall 7b has one end free 20 which is arranged in the radial alignment of the internal wall 8b, forming at their interface an opening 21 towards the rotation interface 3.

Advantageously, the second reinforcement 8 carries a dynamic sealing element 12 which is associated on the inner surface of the bottom 8a, said element having two sealing lips 12a which extend substantially radially in the first baffling duct 16c to come into frictional contact on the inner peripheral wall 7b.

Thus, the risk of lubricant leaking out of the rotation interface 3 is limited, but also the entry into said interface of any external pollutants overflowing from the bowl 10.

The central wall 7a is arranged axially opposite the outer wall 8c, forming between them a second baffle duct 16d along the passage 9, said second duct opening into the first baffle duct 16c.

In particular, the outer wall 8c has a free end 22 which is arranged radially opposite the outer peripheral wall 7c, forming at their interface a baffling clearance 16e along the passage 9, the second baffling conduit 16d opening into said clearance downstream of the basin 10.

The reinforcements 7, 8 are arranged, in particular by their respective axial dimensions and their relative arrangement in the side 5 of the rotation interface 3, to be able to form a baffling clearance 16b and a second baffling duct 16d with reduced axial dimensions. .

Similarly, the outer wall 8c has a sufficiently large radial dimension to allow the formation of a baffle clearance 16e with a reduced radial dimension at its interface with the outer peripheral wall 7c.

Thus, before being able to reach the rotation interface 3, the external pollutants entering through the opening 17 must first cross the baffling duct 16a, then the baffling clearance 16b which opens into the bowl 10. Then, these pollutants must fill the bowl 10 in order to be able to reach the second baffling duct 16d by passing through the clearance 16e, before being able to flow into the first duct 16c, where their passage through the rotation interface 3 is prevented by the lips 12a d dynamic sealing.

The sealing device 6 thus represented therefore makes it possible to guarantee optimum sealing with respect to the outside of the rolling bearing, and this by minimizing the number of sealing lips 12a necessary, which also makes it possible to limit the torques of friction and ensure good performance for the rolling bearing.

In relation to FIGS. 2a and 2b, a second embodiment of the invention will now be described, in which the first armature 7 in the shape of a recumbent U is associated with the external member 1 of a rolling bearing by the through the outer peripheral wall 7c, the second frame 8 being associated with the inner member 2 of said bearing via the bottom 8a.

The outer wall 8d is connected to the outer wall 8c, the inner peripheral wall 7b being disposed in the opening 11 by forming along the passage 9 a baffling conduit 23a between said outer wall and said inner peripheral wall.

The outer peripheral wall 7c is arranged around the outer wall 8d, forming between them an outer baffling duct 23b along the passage 9. In particular, to limit the axial size of the sealing device 6, the free end 15 of the outer peripheral wall 7c is arranged in radial alignment with the outer wall 8c, to form at their interface an opening 24 to the outside.

The outer wall 8d has a free end 25 which is arranged axially opposite the central wall 7a, forming at their interface a baffling clearance 23c along the passage 9, the outer baffling conduit 23b emerging via said clearance upstream of the conduit of chicanery 23a.

Similarly, the inner peripheral wall 7b has a free end 26 which is arranged axially opposite the outer wall 8c, forming at their interface a baffling clearance 23d along the passage 9, the baffling conduit 23a opening into said clearance in upstream of the basin 10.

Advantageously, the first reinforcement 7 comprises a sealing web 27, in particular integral with the static sealing element 13, which extends at least along the baffling ducts 23a, 23b and the baffling clearances 23c, 23d located respectively upstream and downstream of conduit 23a.

Such an arrangement makes it possible to reduce the radial dimensions of the conduits 23a, 23b and the axial dimensions of the baffling clearances 23c, 23d, and thus to limit the entry of external pollutants via the path thus formed upstream of the bowl 10.

The inner wall 8b also has a free end 28 which is arranged radially opposite the inner peripheral wall 7b, forming at their interface a baffling clearance 23e which opens downstream of the rotation interface 3.

In the figures, the baffling clearance 23e is formed downstream of the bowl 10. In particular, to limit the axial size of the sealing device 6, the internal wall 8b is arranged in the radial alignment of the central wall 7a , in order to form the 23rd clearance in said radial alignment.

The internal wall 8b has a radial dimension which is large enough to form a clearance 23e of reduced radial dimension, in order to limit the entry of external pollutants into the rotation interface 3, but also to limit the leakage of lubricant from said rotation interface.

Furthermore, the first armature 7 comprises a dynamic sealing element 12, in particular integral with the web 27, said element having a lip 12a which extends from an inner bearing surface of the inner peripheral wall 7b to come into frictional contact against the inner wall 8b just below the baffle clearance 23e, in order to limit leaks through said clearance of any external pollutants flowing out of the bowl 10.

Thus, before being able to reach the rotation interface 3, the external pollutants entering through the opening 24 must first pass successively through the external baffling conduit 23b, the baffling clearance 23c, the baffling conduit 23a and the baffle 23d upstream of the basin 10. Then, these pollutants must fill the basin 10 in order to be able to reach the baffle clearance 23e, the crossing of which is prevented by the dynamic sealing lip 12a.

The static 13, 13a and dynamic 12, 12a sealing elements, as well as the sealing webs 18, 27, can be made from nitrile butadiene copolymer (NBR), possibly mechanically reinforced with fillers such as carbon black. carbon, hydrogenated NBR (HNBR), fluoropolymer or polyacrylate.

Claims (22)

Sealing device (6) for a bearing comprising two members (1, 2) forming between them an interface (3) of relative rotation about an axis, said device comprising a first armature (7) intended to be associated with the one of the members (1, 2) and a second armature (8) intended to be associated with the other member (1, 2) by forming a passage (9) between the rotation interface (3) and the exterior , said first reinforcement having a recumbent U-shaped geometry formed of a central wall (7a) extending along a radial dimension, said central wall being bordered on either side by two peripheral walls - respectively inner (7b) and outer (7c) - extending along an axial dimension, said second frame having a bottom (8a) extending along an axial dimension and two side walls - respectively internal (8b) and external (8c) - which extend along a radial dimension respectively on one side of said bottom in order to delimit a basin (10) between them, said sealing device being characterized in that the second armature (8) also has an outer wall (8d) which extends along an axial dimension, said outer wall being connected on the one hand to one of said side walls and on the other hand forming with the other of said side walls an opening (11) for the passage (9), one of the walls peripherals (7b, 7c) of the first armature (7) extending into said opening to form a baffle along said passage. Sealing device (6) according to claim 1, characterized in that the outer wall (8d) extends around the bowl (10) to form the opening (11) between the bowl (10) and the exterior . Sealing device (6) according to one of Claims 1 or 2, characterized in that at least one of the armatures (7, 8) carries a sealing element (12) which comprises at least one lip ( 12a) in frictional contact on the other of said armatures. Sealing device (6) according to Claim 3, characterized in that the sealing lip (12a) is positioned in the passage (9) between the bowl (10) and the rotation interface (3). Sealing device (6) according to any one of Claims 1 to 4, characterized in that the outer wall (8d) is connected to the inner wall (8b), the outer peripheral wall (7c) being arranged in the opening (11) by forming along the passage (9) a baffling duct (16a) with said outer wall and said peripheral wall. Sealing device (6) according to Claim 5, characterized in that the outer peripheral wall (7c) has a free end (19) which is arranged facing axially from the inner wall (8b) by forming at their interface a clearance chicanery (16b) along the passage (9). Sealing device (6) according to Claim 6, characterized in that the baffling duct (16a) opens into the baffling clearance (16b) upstream of the bowl (10). Sealing device (6) according to any one of Claims 5 to 7, characterized in that the bottom (8a) is arranged around the inner peripheral wall (7b) forming between them a first baffling duct (16c) along the passage (9), said conduit being formed downstream of the bowl (10). Sealing device (6) according to any one of Claims 5 to 8, characterized in that the central wall (7a) is arranged axially facing the outer wall (8c) forming between them a second baffling duct ( 16d) along the passage (9). Sealing device (6) according to Claim 9, characterized in that the outer wall (8c) has a free end (22) which is arranged radially opposite the outer peripheral wall (7c) by forming at their interface a clearance chicanery (16th) along the passage (9). Sealing device (6) according to any one of Claims 5 to 10, characterized in that the outer wall (8d) has a free end (14) which is arranged in radial alignment with the central wall (7a) by forming an opening (17) to the outside. Sealing device (6) according to any one of Claims 1 to 4, characterized in that the outer wall (8d) is connected to the outer wall (8c), the inner peripheral wall (7b) being arranged in the opening (11) by forming along the passage (9) a baffling conduit (23a) between said outer wall and said peripheral wall. Sealing device (6) according to Claim 12, characterized in that the inner peripheral wall (7b) has a free end (26) which is arranged facing axially from the outer wall (8c) by forming at their interface a clearance chicanery (23d) along the passage (9). Sealing device (6) according to Claim 13, characterized in that the baffling duct (23a) opens into the baffling clearance (23d) upstream of the bowl (10). Sealing device (6) according to any one of Claims 12 to 14, characterized in that the outer peripheral wall (7c) is arranged around the outer wall (8d) forming between them a baffling conduit (23b) along the passage (9). Sealing device (6) according to Claim 15, characterized in that the outer wall (8d) has a free end (25) which is arranged facing axially from the central wall (7a) by forming at their interface a set of chicanery (23c) along the passage (9). Sealing device (6) according to any one of Claims 12 to 16, characterized in that the internal wall (8b) has a free end (28) which is arranged radially opposite the internal peripheral wall (7b) in forming at their interface a chicanery game (23e) along the passage (9). Sealing device (6) according to Claim 17, characterized in that the baffling clearance (23e) is formed downstream of the bowl (10). Sealing device (6) according to one of Claims 17 or 18, characterized in that the internal wall (8b) is arranged in radial alignment with the central wall (7a). Rolling bearing comprising two members (1, 2) and rolling bodies (4) arranged in a rotation interface (3) formed between said members to allow their relative rotation around an axis, at least one side (5) of the rotation interface (3) being equipped with a sealing device (6) according to any one of claims 1 to 19, the first armature (7) being associated with one of the members (1, 2) and the second armature (8) being associated with the other member (1, 2) by forming a passage (9) between the rotation interface (3) and the outside. Rolling bearing according to Claim 20 when dependent on Claim 5, characterized in that the first armature (7) is associated with an internal member (2) via the internal peripheral wall (7b), the second frame (8) being associated with an outer member (1) via the outer wall (8d). Rolling bearing according to Claim 20 when dependent on Claim 12, characterized in that the first armature (7) is associated with an external member (1) via the external peripheral wall (7c), the second armature (8) being associated with an interior member (2) via the bottom (8a).