Sealing arrangement for rolling bearings, in particular for a hub bearing unit of vehicles and associated hub bearing unit

Abstract

Sealing arrangement (5; 105; 205) for rolling bearings, in particular for a hub bearing unit (1) of vehicles, which is suitable for being inserted between a first (3) rotating ring during use and a second (2) stationary ring during use, for protection against external contamination of an annular space (7) bounded between the first and second ring, comprising a first annular rigid shield (10) designed to be integrally supported by the first ring, and a second annular rigid shield (11) designed to be integrally supported by the second ring; wherein: i) - the second annular rigid shield (11) is L-shaped in radial section and comprises a radially outer sleeve-shaped insertion section (12) and a flange section (13) which extends radially inwards from a first end (14) of the insertion section towards the side opposite the first annular shield, projecting radially inwards; the second annular rigid shield integrally and radially on its inner side carries a first annular sealing element (15) made of an elastomeric material; and wherein: ii) - the first annular rigid shield (10) is C-shaped in radial section, having a cavity in the direction of the second annular rigid shield (11) and comprising a first radially inner sleeve section (16) defining an insertion section of the first rigid shield, a flange section (17) projecting radially outward from a first end (18) of the first sleeve section in the direction opposite the second annular rigid shield, and a second sleeve section (19) projecting axially from the flange section of the first shield on the same side as the first sleeve section of the first rigid shield; the first and second sleeve sections of the first rigid shield (10) are radially oriented toward each other and coaxial with respect to a common axis of symmetry (A) of the first and second rigid shields; iii) - the first annular sealing element (15) comprises a first elastically deformable annular lip (20; 220) extending axially from the flange section (13) of the second rigid shield towards the first rigid shield to be arranged radially between the first (16) and the second (19) sleeve section of the first rigid shield; and a second elastically deformable annular lip (21; 131; 221) arranged radially on the inside of the first annular lip (20; 220) and extending axially and radially to interact in contact with the first rigid shield, thus defining a sliding seal; iv) - the first annular lip (20; 220) is shaped such that it radially outwards delineates a first annular channel (22) which, at the other end than that of the flange section of the first rigid shield, faces a free edge end (23) of the second sleeve section of the first rigid shield; characterized in that v) - the first annular sealing element (15) comprises a third annular, elastically deformable lip (28) which extends radially and axially projecting from the insertion section (12) of the second rigid shield in the direction of the flange section (17) of the first rigid shield, in order to be arranged between the insertion section (12) of the second rigid shield and the second sleeve section (19) of the first rigid shield, obliquely to the flange section (17) of the first rigid shield; vi) - the third ring-shaped lip (28) is designed to optionally assume: a first configuration, undeformed, in which it does not contact a radially outer surface (29) of the second sleeve section (19) of the first rigid shield, so that a sufficiently small radial clearance is defined to form a first radially oriented labyrinth seal (30); and a second configuration, deformed, in which, in response to the application of an external force to the sealing arrangement, it contacts the radially outer surface (29) of the second sleeve section of the first rigid shield, thereby forming a sliding seal. vii) - the third elastically deformable annular lip (28) is bent radially outwards to allow, by gravity, the outflow of any contaminants that may overcome the first labyrinth seal from at least one collection chamber (37) for the contaminants, which is delimited between the first annular channel (22) and the second sleeve section (19) of the first rigid shield.

Description

Technical field of the invention

[0001] The present invention relates to a sealing arrangement for rolling bearings, in particular for use in a hub bearing unit of vehicles, which is particularly, but not exclusively, usable both on the “outside”, i.e. when used facing the outside of the vehicle body of the unit itself, and on the “inside”, i.e. facing the inside of the vehicle, and has a high sealing effect against external contaminants and low friction, as well as a hub bearing unit which is provided with the same. State of the art

[0002] As is known, vehicle hub bearing units comprise an outer ring, which is stationary during operation, and an inner ring, which is rotating during operation, and a mounting flange for a vehicle wheel, provided on the outside of the hub bearing unit. Sealing assemblies are inserted between the inner and outer rings, one on the outside and one on the opposite side, referred to as the "inner".

[0003] Among the most commonly used sealing arrangements, not only for hub bearing units but for rolling bearings in general, are the so-called "cassette" seals, comprising two rigid L-shaped shields in radial section, one of which is provided with an elastomeric seal that is equipped with a plurality of sliding lips.

[0004] The known sealing arrangements are relatively satisfactory, but often have large overall dimensions and relatively high friction. To achieve low friction, the number of sliding lips can be reduced, relying wholly or partially on non-contact labyrinth seals. However, this can reduce the seal's efficiency, as it allows a small portion of contaminants to come into contact with the single sliding lip, leading to premature wear. Additionally, due to both manufacturing tolerances and the so-called "curving" loads during operation, sliding seals, particularly axial ones, may malfunction.

[0005] The described disadvantages are not eliminated by the solution according to EP 1 795 787 A1, which is based on the use of a labyrinth seal between the two shields formed by essentially rigid and opposing elastomeric projections. In fact, contaminants that overcome the labyrinth seal are then difficult to remove from a collecting space within the seal, thus increasing wear on the contacting lip. Furthermore, the "cornering" problem remains unresolved.

[0006] German patent application DE 11 2006 001 262 T5 discloses a sealing device for wheel suspension systems of motor vehicles, in particular for sealing between fixed and rotating components. This device consists of a centrifugal ring and a core metal that secures an elastic sealing element. The centrifugal ring has a cylindrical mating section and an outer flange, while the core metal has a cylindrical mating section that extends, thus forming a tight seal with the fixed component.

[0007] JP 2008 202 737 A discloses a sealing device for applications in motor vehicles. The sealing device features a double-sided lip design that minimizes the generated torque and improves sealing performance. Summary of the invention

[0008] The object of the present invention is to provide a sealing arrangement for rolling bearings, particularly but not exclusively suitable for use in a hub bearing unit of a vehicle wheel, which has excellent hydraulic sealing properties against external contaminants, small overall dimensions and low friction.

[0009] According to the invention, a sealing arrangement for rolling bearings and a hub bearing unit provided with the sealing arrangement are thus provided, which have the features set out in the annexed claims. Brief description of the drawings

[0010] The invention will now be described with reference to the accompanying drawings, which show non-limiting embodiments, wherein: - Fig. Figure 1 schematically shows a radial section view of a part of a vehicle hub bearing unit (partial view or partial section) which is provided with a sealing arrangement designed according to the invention; - Fig. Figure 2 shows a detail of schematically and on an enlarged scale. Fig. 1, showing the shape of a first embodiment of the sealing arrangement according to the invention. - Fig. Figure 3 schematically shows a radial section view of a part of a vehicle hub bearing unit (partial view or partial section) which is provided with a sealing arrangement according to a second embodiment of the invention; - Fig. Figure 4 shows a detail of the schematically and on an enlarged scale. Fig. 3, which shows the shape of the second embodiment of the sealing arrangement according to the invention; and - Fig. Figure 5 shows schematically and on an enlarged scale a third embodiment of the sealing arrangement according to the invention, which is interchangeable with the embodiments of the Fig. 2 and Fig. 4 in the Fig. 1 and Fig. 3 is. Detailed description

[0011] With reference to Fig. Reference numeral 1 as a whole designates a rolling bearing, which in the illustrated example forms a hub bearing unit and comprises an outer ring 2, an inner ring 3, a plurality of rolling elements 4 (of which only one is shown with dashed lines for clarity) arranged between the outer ring 2 and the inner ring 3 to make them rotatable relative to each other about a common axis of rotation A, and a sealing arrangement 5 fitted between the rings 2 and 3, which are shown abbreviated for simplicity, to close an annular space 7, which is radially bounded between the rings 2 and 3 and which accommodates the rolling elements 4.

[0012] In general, rings 2 and 3 can be part of a rolling bearing of any known type, whether or not part of the hub bearing unit 1. In any case, the outer ring 2 is stationary during use, while the inner ring 3 rotates about a common relative axis of rotation A of rings 2 and 3, which is generally also a common axis of symmetry of the sealing assembly 5 and of one or both rings 2 and 3. If rings 2 and 3 are part of a hub bearing unit, the stationary outer ring 2 is, for example, attached to a known column of the vehicle suspension (not shown for simplicity), while the inner rotating ring 3 is integrally formed with a vehicle wheel (also known and not shown for simplicity).

[0013] The sealing arrangement 5 comprises ( Fig. 2) a first rigid annular shield 10, made of metal or plastic or polymer material and designed to be integrally supported during use by a first bearing ring, in this case by the inner ring 3 which rotates during use, and a second rigid annular shield 11, also made of metal or plastic or polymer material and designed to be integrally supported during use by a second bearing ring, in this case by the outer ring 2 which is stationary during use.

[0014] The second annular shield 11 is shaped in radial section like an inverted L facing the outside of the bearing 1, i.e., facing away from the annular space 7, and comprises a radially outer sleeve-shaped insertion section 12 and a flange section 13 extending from a first end 14 ( Fig. 2) of the insertion section projecting radially inwards, facing the side opposite the first annular shield 10 and extending in the direction of the inside of the bearing 1.

[0015] The annular shield 11 also integrally and radially carries on its inner side an annular sealing element 15 made of elastomeric material, which has been integrally and inseparably (unless broken) produced with the shield 11 during vulcanization using a known method.

[0016] According to a first aspect of the invention, in combination with the described structure of the shield 11, the first annular shield 10 is shaped like a C in radial section, the cavity of which faces the annular shield 11 and points in the direction of the annular space 7 and thus in the direction of the inside of the bearing 1;The first shield 10 comprises a first radially inner sleeve section 16, defining the insertion section of the shield 10, a flange section 17 extending radially outward from a first end 18 of the sleeve section 16, the end 18 facing the side opposite the first annular shield 11, and a second radially outer sleeve section 19 extending axially outward from the flange section 17 on the same side as the first sleeve section 16, to which the sleeve section 19 is radially oriented and to which it is coaxial with respect to a common axis of symmetry A of the shields 10, 11, which coincides with the relative axis of rotation between the rings 2 and 3.

[0017] Always in combination with what has already been described, the annular sealing element 15 has a first annular lip 20 which extends axially from the flange section 13 of the shield 11 in the direction of the shield 10 rotating in operation, also known as the "sling", so that it is arranged radially between the first radially inner sleeve section 16 and the second radially outer sleeve section 19 of the shield 10, radially closer to the radially outer sleeve section 19 than to the radially inner sleeve section 16.

[0018] The sealing element 15 also comprises a second annular, elastically deformable lip 21, which is arranged radially on the inside of the first annular lip 20 and which extends axially and radially (i.e. is inclined in relation to the axis A) in order to interact with the first rigid shield 10 with a certain, albeit reduced, overlap, in particular according to the non-limiting embodiment shown, with the sleeve section 16, with which it forms a sliding seal, which in the illustrated embodiment is a radial sliding seal.

[0019] In combination with this configuration, the annular lip 20 is shaped such that it radially delimits on the outside a first annular channel 22 which faces a free end edge 23 of the radially outer sleeve section 19 of the C-shaped shield 10; the free edge 23 is on the opposite side from the flange section 17 of the first shield 10.

[0020] According to the non-restrictive embodiment shown in the Fig. 1 and Fig. 2, carries the first shield 10 integrally on the flange section 17 and on the side facing the second shield 11 a second annular sealing element 24, made of elastomeric material and comprising a third annular lip 25, which extends axially projecting from the shield 10 and towards the shield 11 and which is arranged radially between the lip 20 and the lip 21.

[0021] The annular lip 25 is shaped such that it has a second annular channel 26 on its outer side, facing a free end 27 of the annular lip 20 ( Fig. 2) radially limited.

[0022] In this way, the shield 10 in radial section together with the annular sealing element 24 defines an E-shaped element whose prongs or arms, defined by the two sleeve-shaped sections 16 and 19 and by the annular lip 25, are arranged radially alternating with the lips 20 and 21, thus forming a radial labyrinth path.

[0023] According to a further important aspect of the invention, the annular sealing element 15 further comprises a further annular lip 28, which extends radially and axially from the insertion section 12 of the shielding 11 in the direction of the flange section 17 of the shielding 10, so that it is arranged between the insertion section 12 and the radially outer sleeve-shaped section 19 of the shielding 10, adjacent in the radial direction to the outside of the same and obliquely to the flange section 17 of the first rigid shielding 10.

[0024] The annular lip 28 is elastically deformable and designed to assume either a first or a second, different configuration; in the first configuration, it is undeformed and in Fig. Figure 2 shows the annular lip 28 in its normal operating state, in which the lip 28 is not subjected to any external loads and is therefore not elastically deformed; in such a first configuration, in normal operating use, the lip 28 touches a radially outer surface 29 ( Fig. 2) of the sleeve-shaped section 19 does not, but instead defines a sufficiently small radial clearance to form a first radially directed labyrinth seal 30; in the second configuration, deformed and not shown for the sake of simplicity, the lip 28, in response to an external force applied to the sealing arrangement 5, touches the radially outer surface 29 to form a sliding seal.

[0025] For this purpose, the annular lip 28 extends projecting from an axially central position of the insertion section 12 of the second rigid shield 11, so that a first annular recess 32 is defined radially on the outside of the annular lip 28 between the lip 28 and the insertion section 12, this first recess increasing radially in the axial direction towards the flange section 17 of the first rigid shield 10.

[0026] In the non-restrictive embodiment shown, the lip 28 extends projecting from an axially central position of a first section 31 of the elastomeric sealing element 15, which covers at least a part of the insertion section 12 of the shield 11 on the inside, so that the first recess 32 between the lip 28 and the section 31 of the annular sealing element 15 is limited radially on the outside of the annular lip 28.

[0027] In the non-restrictive embodiment of the Fig. 1 and Fig. 2. There is also a sufficiently small radial clearance between the section 31 of the elastomeric sealing element 15, which, as illustrated in the non-limiting example, completely covers the entire insertion section 12 radially on the inside, and the sleeve-shaped section 19, defining a second radial, axially extending labyrinth seal 33.

[0028] The labyrinth seal 33 extends axially over at least one section of the axial extent of the sleeve section 19.

[0029] In the preferred embodiment shown, the sleeve section 19 comprises ( Fig. 2), starting at the flange section 17, a first annular section 34, a second annular section 35 and a third annular section 36.

[0030] The first annular section 34 is straight and arranged parallel to the annular lip 25, the second annular section 35 is inclined so that it is further away from the axis of symmetry A on the side facing away from the first section 34, and the third annular section 36, progressing in an axial direction, is first radially bulged on the outside, then becoming thinner in a radial direction towards the free end edge 23 of the sleeve-shaped section 19.

[0031] In the example shown, the labyrinth seal 33 extends axially over at least part of the axial extent of the third section 36.

[0032] According to one aspect of the invention, the first and second annular channels 22 and 26 are designed to capture and collect all external contaminants that may overcome the first labyrinth seal 30 and also any additional labyrinth seal 33; furthermore, between the annular channel 22 formed by the lip 20 and the sleeve section 19, a first annular chamber 37 is arranged downstream of the labyrinth seal 33 for collecting said contaminants ( Fig. 2) limited, and between the lip 20 and the lip 25 a second annular chamber 38 for collecting the impurities is limited. Therefore, the labyrinth seal 33 is arranged upstream of the chambers 37 and 38, taking into account the direction of incidence of the impurities.

[0033] According to one aspect of the invention, the lip 28 is designed to be radially curved outwards (also due to the presence of the ring recess 32) to allow a simple and quick drainage of the contaminants from the collection chambers 37, 38 due to gravity.

[0034] Preferably, the annular shield 10 is arranged axially on the inside of the annular shield 11, so that a second end 39 of the insertion section 12 is covered at the other end 14 and in this case completely by the section 31 of the elastomeric sealing element 15, and a second annular recess 40 is axially defined on the outside of the shield 10, in front of and on the other side than that of the flange section 13.

[0035] According to a further aspect of the invention, the lips 20 and 25 each have a corresponding free end, namely the already described end 27 for the lip 20 and an end 41 for the lip 25, which are bent radially outwards and in the direction of the sleeve section 19; a first radial annular space 42 and a second radial annular space 43 are delimited between the end 27 and the sleeve section 19 and between the end 41 and the lip 20, each having substantially similar dimensions.

[0036] The first annular sealing element 15 also includes a fifth annular lip 44, which extends inwards and radially projecting from a radially inner edge 45 of the flange section 13 and which interacts with the sleeve-shaped section 16 of the shield 10 to define a third labyrinth seal.

[0037] In this way, the contacting sealing lip 21 is well protected from external contaminants; in the case of particularly heavy flows of contaminants, the lip 28 bends inwards and closes, preventing the inflow of contaminants, then gradually opens and allows the removal of said contaminants by gravity, which may have previously entered and collected in the channels 22 and 26 and in the chambers 37 and 38. Furthermore, the sealing lip 21 and the entire sealing assembly 5 are insensitive to any axial displacements between the shields 10, 11 with respect to the designed, expected position, both as a result of manufacturing tolerances and of deformations during operation, for example, when cornering.

[0038] Now, with reference to the Fig. 3 and Fig. Figure 4 shows a sealing arrangement 105 according to the invention. Details that are similar or identical to those already described are provided with the same reference numerals for the sake of simplicity.

[0039] The sealing arrangement 105 is essentially identical to the sealing arrangement 5 already described, except that it lacks a sealing element 24 with lip 25 and lips 21 and 44. Instead, the sealing element 15, in combination with what has been described, comprises an elastically deformable annular lip 131, which replaces lip 21. The lip 131 is arranged radially within the annular lip 20 and extends axially beyond the lip 20 to interact with the flange section 17 of the rotating shield 10, with which it defines an axial sliding seal according to this embodiment of the invention.

[0040] The annular lip 131 according to the preferred but not limiting illustrated embodiment is shaped like an open V in radial section and has a root section 132, immediately adjacent to the flange section 13 of the shielding 11 and an end section 133 arranged obliquely with respect to the axis A, in order to run away from the sleeve-shaped section 16 of the shielding 10 as it approaches the flange section 17 of the shielding 10.

[0041] The lip 131 has a free end 134 at its end section 133, which interacts in contact with the flange section 17; similarly, the lip 20 has the free end 27, which is bent radially outwards and in the direction of the sleeve section 19, so that it is inclined with respect to the axis A at an inclination substantially equal to that of the section 133 of the lip 131.

[0042] The free ends 134 and 27 define a first radial annular space 136 in between, with dimensions essentially similar to those of the radial annular space 42, which is delimited between the free end 27 and the sleeve-shaped section 19 of the shield 10, which allows the spaces to be optimized and facilitates the emptying of the collection chamber 37 during operation.

[0043] The described shape of section 19 is a further barrier against the ingress of contaminants into chamber 37 and into the collecting channel 222 and facilitates emptying by gravity by defining a kind of “expanded” guide in the direction of chamber 37, i.e. by enlarging in the direction of chamber 37.

[0044] The ring-shaped sealing element 15 preferably also includes ( Fig. 4) a further annular lip 138 extending radially inwards from the lip 131, from a point between the root section 132 and the end section 133 of the annular lip 131, and interacting radially outwards with the flange section 16 of the shield 10, thus defining a second labyrinth seal 139.

[0045] In the event of strong external pressure or during cornering of the vehicle equipped with the hub bearing unit 1, the lip 28 comes into contact, so that the friction is only temporary and slight (due to reduced engagements that are generated), but the sealing and protective effect of the lip 131 is drastically increased.

[0046] These advantages are ultimately also achieved thanks to the fact that the sliding seal achieved by the lip 131 is an axial seal and by the fact that the free end 134 of the lip 131 is arranged radially on the outside of a second annular collecting chamber 144 for the external contaminants, which is arranged between the lips 131 and 20 and in which the channel 22 opens from the free end 27, which serves as a weir or drain for any possible excess of contaminants that are in the chamber 37, without the latter affecting the free sealing end 134 of the lip 131.

[0047] With reference to Fig. Reference numeral 205 in Figure 5 shows a further and preferred embodiment of the sealing arrangement according to the invention. Details similar or identical to those already described are designated with the same reference numerals for the sake of simplicity.

[0048] The sealing arrangement 205 is similar to the sealing arrangement 5, from which it differs only in the shape of the sleeve section 19, which is simplified and simply cylindrical, and in the shape of the first elastically deformable annular lip, designated 220, which has a circular arc and defines the first annular channel 22 with its own curvature, which faces the second sleeve section 19 of the first rigid shield 10; the first annular lip 220 has such a curvature as to delimit, together with the second sleeve section 19 and with the first elastically deformable annular lip 28, a collecting space 237 for possible contaminants that pass over the first labyrinth seal 30.

[0049] The collection chamber 237 is shaped like a C in the direction of the first rigid shield 10 and, in the radial direction, has a depth essentially equal to or greater than its own width in the axial direction.

[0050] The first elastically deformable annular lip 220 extends axially on the same side as the annular lip 28 and axially over the latter, forming either a sliding seal or a labyrinth seal with the flange section 17 of the first rigid shield 10.

[0051] Furthermore, the second annular lip 21 is replaced by an elastically deformable lip 221, which slidably interacts with the first sleeve section 16 of the first rigid shield 10 by means of a free end 234 of the same, having in radial section a thickness D greater than the thickness d of the foot section 235 of the annular lip 221 in the direction towards the flange section 13 of the second rigid shield 11.

[0052] This shape of the lip 221 allows for greater flexibility of the same and at the same time a wider contact area between the lip 221 and the outer surface of the sleeve section 16, improving the sealing effect.

[0053] All objectives of the invention are thus achieved.

Claims

[1] Sealing arrangement (5; 105; 205) for rolling bearings, in particular for a hub bearing unit (1) of vehicles, suitable for being inserted between a first (3) rotating ring during use and a second (2) stationary ring during use, for protection against external contamination of an annular space (7) bounded between the first and second ring, comprising a first annular rigid shield (10) designed to be integrally supported by the first ring, and a second annular rigid shield (11) designed to be integrally supported by the second ring; wherein: i) - the second annular rigid shield (11) is L-shaped in radial section and comprises a radially outer sleeve-shaped insertion section (12) and a flange section (13) which extends radially inwards from a first end (14) of the insertion section towards the side opposite the first annular shield, projecting radially inwards; the second annular rigid shield integrally and radially on its inner side carries a first annular sealing element (15) made of an elastomeric material; and wherein: ii) - the first annular rigid shield (10) is C-shaped in radial section, having a cavity in the direction of the second annular rigid shield (11) and comprising a first radially inner sleeve section (16) defining an insertion section of the first rigid shield, a flange section (17) projecting radially outward from a first end (18) of the first sleeve section in the direction opposite the second annular rigid shield, and a second sleeve section (19) projecting axially from the flange section of the first shield on the same side as the first sleeve section of the first rigid shield; the first and second sleeve sections of the first rigid shield (10) are radially oriented toward each other and coaxial with respect to a common axis of symmetry (A) of the first and second rigid shields; iii) - the first annular sealing element (15) comprises a first elastically deformable annular lip (20; 220) extending axially from the flange section (13) of the second rigid shield towards the first rigid shield to be arranged radially between the first (16) and the second (19) sleeve section of the first rigid shield; and a second elastically deformable annular lip (21; 131; 221) arranged radially on the inside of the first annular lip (20; 220) and extending axially and radially to interact in contact with the first rigid shield, thus defining a sliding seal; iv) - the first annular lip (20; 220) is shaped such that it radially outwards delineates a first annular channel (22) which, at the other end than that of the flange section of the first rigid shield, faces a free edge end (23) of the second sleeve section of the first rigid shield; characterized by , that v) - the first annular sealing element (15) comprises a third annular, elastically deformable lip (28) which extends radially and axially projecting from the insertion section (12) of the second rigid shield in the direction of the flange section (17) of the first rigid shield, in order to be arranged between the insertion section (12) of the second rigid shield and the second sleeve section (19) of the first rigid shield, obliquely to the flange section (17) of the first rigid shield; vi) - the third ring-shaped lip (28) is designed to optionally assume: a first configuration, undeformed, in which it does not contact a radially outer surface (29) of the second sleeve section (19) of the first rigid shield, so that a sufficiently small radial clearance is defined to form a first radially oriented labyrinth seal (30); and a second configuration, deformed, in which, in response to the application of an external force to the sealing arrangement, it contacts the radially outer surface (29) of the second sleeve section of the first rigid shield, thereby forming a sliding seal. vii) - the third elastically deformable annular lip (28) is bent radially outwards to allow, by gravity, the outflow of any contaminants that may overcome the first labyrinth seal from at least one collection chamber (37) for the contaminants, which is delimited between the first annular channel (22) and the second sleeve section (19) of the first rigid shield. [2] Sealing arrangement according to claim 1, characterized by , that the third annular lip (28) extends projecting from an axially central position of the insertion section (12) of the second rigid shield (11), such that, radially on the outside of the third annular lip (28) a first annular recess (32) is defined between it and the insertion section (12), the first recess increasing radially in the axial direction towards the flange section (17) of the first rigid shield. [3] Sealing arrangement according to claim 1 or 2, characterized by, that the third annular lip (28) extends projecting from a first section (31) of the first elastomeric sealing element (15), which radially inwards covers at least part of the insertion section (12) of the second rigid shield, defining the first annular recess (32) between the third annular lip (28) and the first section (31) of the first annular sealing element. [4] Sealing arrangement according to claim 2 or 3, characterized by, that there is a sufficiently small radial clearance between the first section (31) of the first elastomeric sealing element (15), which radially inwards covers at least part of the insertion section of the second rigid shield, and the second sleeve section (19) of the first rigid shield, to define a second radial labyrinth seal (33) with axial design; the second labyrinth seal extends axially over at least a distance of the axial extent of the second sleeve section (19) of the first rigid shield. [5] Sealing arrangement according to one of the preceding claims, characterized by, that the first rigid shield (10) on the flange section (17) and extending laterally towards the second rigid shield (11) integrally carries a second annular sealing element (24) which is made of an elastomeric material and includes a fourth annular lip (25) which extends axially outwards from the first rigid shield (10) and towards the second rigid shield (11), and which is arranged radially between the first (20) and the second (21) annular lip; the fourth annular lip (25) is shaped such that it radially outwards delineates a second annular channel (26) which faces a free end (27) of the first annular lip (20). [6] Sealing arrangement according to one of the preceding claims, characterized by, that the second sleeve section (19) of the first rigid shield, starting from the flange section (17) of the first rigid shield, comprises a first, a second and a third annular section (34, 35, 36); the first annular section (34) is straight, the second annular section (35) is inclined so that it is further away from the axis of symmetry (A) on the side facing away from the first section, and the third annular section (36), progressing in the axial direction, is first radially curved outwards and then becomes thinner in the radial direction towards a free edge end (23) of the second sleeve section;The first, second and third annular sections in the direction of the insertion section (12) of the second rigid shield define a second labyrinth seal (33) which extends axially over at least part of the axial extent of the third section (36) of the second sleeve section of the first shield and which is arranged upstream of the at least one collection chamber (37) for the contaminants. [7] Sealing arrangement according to one of the preceding claims, characterized by , that the first annular shield (10) is arranged axially within the second annular shield (11), such that a second end (39) of the insertion section (12) of the second rigid shield, at the other end of the insertion section, extends outwards from the first rigid shield, in front of and on the other side than the flange section of the second rigid shield, axially delineates a second annular recess (40). [8] Sealing arrangement according to one of the preceding claims, characterized by , that the second elastically deformable annular lip (131) extends axially beyond the first annular lip (20) to interact in contact with the flange section (17) of the first rigid shield, with which it defines an axial sliding seal; the second annular lip (131) is designed in radial section like an open V and comprises a root section (132) and an end section (133) arranged obliquely with respect to the axis of symmetry (A) immediately adjacent to the flange section of the second rigid shield, which extends away from the first sleeve section (16) of the first rigid shield and approaches the flange section (17) of the first rigid shield. [9] Sealing arrangement according to any one of claims 1 to 5, characterized by, that the first elastically deformable annular lip (220) has an arc of a circular shape and defines the first annular channel (22) with its own concavity, which faces the second sleeve section (19) of the first rigid shield (10); the first annular lip (220) has a curvature such that it, together with the second sleeve section (19) and with the first elastically deformable annular lip (28), delimits a collection chamber (237) for possible contaminants that pass through the first labyrinth seal (30), the collection chamber (237) being C-shaped in the direction of the first rigid shield (10) and having a depth in the radial direction substantially equal to or greater than its own width in the axial direction. [10] Sealing arrangement according to claim 9, characterized by, that the first elastically deformable annular lip (220) extends axially on the same side as the third annular lip (28) and axially beyond the latter to form either a sliding seal or a labyrinth seal with the flange section (17) of the first rigid shield (10); the second elastically deformable annular lip (221) slidably interacts with the first sleeve section (16) of the first rigid shield (10) by means of a free end (234), the end having in radial section a thickness (D) greater than the thickness (d) of a root section (235) of the second annular lip (221) in the direction towards the flange section (13) of the second rigid shield (11). [11] A hub bearing unit (1) for vehicles, comprising an outer ring (2) that is stationary during use, an inner ring (3) which rotates about a common relative axis of rotation (A) of the inner and outer rings during use, a plurality of rolling elements (4) arranged between the inner and outer rings and in an annular space (7) which is radially bounded between the inner and outer rings, and at least one sealing arrangement (5; 105; 205) which is arranged to close the annular space containing the rolling elements (4), and which is realized according to one of the preceding claims.

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