Dynamic interference sealing devices and systems with improved contact behavior

Abstract

The sealing system (1) includes an annular support (4), an annular sealing element (5) and an annular shielding element (6); the first lip (11) and the second lip (14) of the sealing element interact slidably with the abutment surface (10) of the shielding element (6) and each includes: a root portion (21) extending perpendicularly in a cantilever manner from the flange portion (9) of the annular support; a flexure portion (22) extending in an inclined direction in a cantilever manner from the root portion (21) and having a thinner radial thickness, defined by an annular inner arc surface (24) facing the abutment surface (10) and an annular outer arc surface (25) facing the support (4) formed by a revolution surface generated by a segment of the circumference; a contact portion (23) including a wedge-shaped overhang (26) and a step portion (27) on the side of the overhang (26), the overhang (26) forming a first angle (α) and a second angle (β) with the abutment surface, the first angle facing the annular support and being smaller than the second angle.

Description

Field of the Invention

[0001] The present invention relates to a dynamic interference sealing device and system having improved contact behavior / performance, which can be applied to, for example, rolling bearings or drive shafts or existing in, for example, rolling bearings or drive shafts, and in each case inserted or insertable between a first and a second mechanically rotating member for protecting an internal cavity defined by the mechanical members and / or the rolling bearings or their rolling elements from external contaminants, while also retaining any lubricant inside. Background Art

[0002] It is well known that, especially in cases involving high-stress applications, such as in drive shafts or power take-off units of agricultural machinery or industrial vehicles and in passenger vehicles, modern industry requires sealing devices or systems with high sealing capabilities, which are typically obtained by using one or more elastically deformable annular lips that interact slidingly with a mating surface with a relatively high degree of interference, the mating surface being formed directly, for example, on one of the relatively rotating members or, more commonly, directly on an annular shielding element mounted in a position facing the sealing device, thereby providing a complex sealing system.

[0003] Sealing devices generally consist of a substantially rigid annular support and an annular sealing element provided with one or more elastically deformable sealing lips, the sealing element being integrally carried by the annular support.

[0004] Typically, the sealing element is integrally formed with the annular support by co-molding and / or bonding (e.g., co-molding and / or bonding performed during vulcanization by known techniques).

[0005] Although using a relatively high design interference degree between the sealing lip and the corresponding mating surface provides the desired sealing effect, it also causes an undesirable deformation of the sealing lip, where the sealing lip "flattens" against the mating surface. In this case, instead of forming a substantially linear contact that would exert a high contact pressure, a flat contact surface is formed, thus reducing the contact pressure and thereby reducing the sealing effect for a given interference degree, and increasing friction, resulting in higher energy consumption and greater wear of the sealing lip. Summary of the Invention

[0006] The object of the present invention is to provide a sealing device and system which do not have the drawbacks of the prior art, are reliable and economical, and in particular make it possible to improve the sealing performance in terms of contact pressure and contact force within a wider design interference ( / interference) range.

[0007] Thus, according to the present invention, there is provided a sealing device and an associated sealing system, the sealing device being capable of being inserted between a first mechanical member and a second mechanical member that rotate relative to each other, for example but not exclusively, the sealing device being capable of being inserted between the rings of a rolling bearing, the device and system having the features set forth in the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The present invention will now be described with reference to the accompanying drawings, which show some non-limiting examples of embodiments of the present invention, in which:

[0009] - Figure 1 A partial view of a three-quarter front view stereoscopic radial section of a sealing system manufactured according to the present invention is schematically shown;

[0010] - Figure 2 A front view radial section view showing in enlarged scale the details of a first embodiment of the sealing device representing the present invention Figure 1 ;

[0011] - Figure 3 A front view radial section view showing in enlarged scale a second embodiment of the sealing device of the present invention which is also applied to the Figure 1 sealing system; and

[0012] - Figure 4 and Figure 5 A front view radial section view of the same details of two preferred embodiments of the sealing device of the present invention which are both applied to the Figure 1 sealing system is schematically shown. DETAILED DESCRIPTION

[0013] Referring to Figure 1 , Figure 1 the overall view of a complex sealing system indicated by the numeral 1 which is capable of being inserted between a first mechanical member 2 and a second mechanical member 3 that can rotate relative to each other is shown, these members being known and only partially schematically shown in dashed lines.

[0014] The sealing system 1 includes a generally rigid annular support 4, an elastic annular sealing element 5 and a generally rigid shielding annular element 6 which can be coaxially coupled to the annular support 4.

[0015] The annular support member 4 and the annular sealing element 5 together form a sealing device 7, and when the sealing device 7 is connected to the shielding element 6, a sealing system 1 is formed.

[0016] In the non - restrictive example shown, the annular support member 4 includes a sleeve portion 8 and a flange portion 9. The sleeve portion 8 is configured to be fixedly attached to the first member 2 in an angled and integral manner. The flange portion 9 extends radially in a cantilever manner from the sleeve portion 8 and integrally carries the annular sealing element 5 as a single piece.

[0017] On the other hand, the annular shielding element 6 is configured to be fixedly attached to the second member 3 in an angled and integral manner, and is provided with an abutment surface 10 for the annular sealing element 5 facing the annular support member 4. In the non - restrictive example shown, the second member 3 is constituted by a shaft.

[0018] For its part, the annular sealing element 5 is provided with at least one elastically deformable annular sealing lip 11, which is configured to interact slidably and interferingly with the abutment surface 10 to form a dynamic seal with the abutment surface 10.

[0019] In a non - restrictive but preferred example of the illustrated embodiment, as Figure 2 more easily seen due to the enlarged scale, the abutment surface 10 includes a first annular portion 12 and a second annular portion 13. The first annular portion 12 is defined by a frustoconical surface having a taper (i.e., the theoretical vertex, that is, the geometric origin of the surface) pointing towards the annular support member 4, and the second annular portion 13 is defined by a flat front surface of the annular shielding element 6 facing and parallel to the flange portion 9 of the annular support member 4.

[0020] The annular sealing element 5 further includes a first lip constituted by the above - mentioned lip 11 and an elastically deformable second annular sealing lip 14.

[0021] The first annular lip 11 is configured to interact with the first annular surface portion 12 of the abutment surface 10, which is conical (or at least inclined / slanted, or "non - linear" in technical language), while the second annular lip 14 is configured to interact with the second annular surface portion 13 of the abutment surface 10, which is a flat surface perpendicular to the axis of symmetry A of the entire sealing system 1, the annular support member 4, the annular sealing element 5, and the shielding element 6.

[0022] According to an aspect of a preferred embodiment of the present invention, the annular support member 4 includes ( Figure 1The first annular coined metal (or cast metal) element, the first annular coined metal element defining a sleeve portion 8 and a flange portion 9 radially inwardly, the flange portion 9 being shaped in a radial cross-section in the form of a chair and facing the annular shielding element 6.

[0023] The annular support 4 further comprises ( Figure 1 ) a second annular element 16 made of a synthetic plastic material, the second annular element 16 being co-molded radially on the outside of the annular metal element 15 to define, together with the annular metal element 15, the sleeve portion 8.

[0024] The annular element 16 of synthetic plastic material is further provided, on the side facing the annular shielding element 6, with a generally cylindrical overhang 18 which radially surrounds the outside of the annular shielding element 6 and is coaxial with the annular shielding element 6.

[0025] In a preferred embodiment, the shielding element 6 is generally shaped in a radial cross-section as a reverse C-shape facing the annular support 4, such that the sleeve portion 19 of the shielding element, radially outside the abutment surface 10, is coaxially inserted inside the generally cylindrical overhang 18 of the second annular element 16 made of a synthetic plastic material.

[0026] Preferably, the overhang 18 is integrally provided, towards the annular shielding element 6, with an annular lip fin 20 which extends radially towards the sleeve portion 19 of the annular shielding element 6 and is configured to form a labyrinth seal with the sleeve portion 19.

[0027] According to a first aspect of the invention, both the first annular lip 11 and the second annular lip 14 each combinatorially comprise a root portion 21, a flexure portion 22 and a contact portion 23, the root portion 21 being adjacent to the flange portion 9, the flexure portion 22 extending immediately from the root portion 21 in a cantilever manner in a direction inclined (i.e., oblique) with respect to the flange portion 9, and the flexure portion 22 being directed such that the flexure portion 22 extends at least partially towards the sleeve portion 8 of the annular support 4, the contact portion 23 extending immediately from the flexure portion 22 in a cantilever manner in a direction parallel to the root portion 21.

[0028] The description given from this point onwards of the lips 11 and 14 of the sealing device 7 belonging to the sealing system 1 applies equally to Figure 3 、 Figure 4 and Figure 5 the embodiments of the invention shown in, which relate only to two different embodiments of the sealing device, respectively by Figure 3 and Figure 5 7b in and Figure 4The indication of 7c in it. For simplicity, other details similar or identical to those previously described or to be described hereinafter with reference to the sealing system 1 are indicated by the same reference numerals.

[0029] The root portion 21 extends vertically from the flange portion 9 in a cantilever manner and has a first predetermined radial thickness HT in a direction perpendicular to the sleeve portion 8 ( Figure 4 ); this applies not only to the sealing device 7, but also to Figure 4 the sealing device 7c shown in which has only one sealing lip 11 and Figure 3 and Figure 5 the sealing device 7b which has only one sealing lip 14. For example, the root portion 21 may have a first predetermined radial thickness HT in the radial direction.

[0030] The flexure portion 22 has a radial thickness thinner than that of the root portion 21 and is bounded by an annular inner arc surface 24 facing the abutment surface 10 and an annular outer arc surface 25 facing the sleeve portion 8, both of which are formed by a revolved surface generated by a segment of a circumference.

[0031] The contact portion 23 is configured to interact in contact with the abutment surface 10, and according to an aspect of the present invention, the contact portion 23 includes ( Figures 2 to 5 ) a first annular portion 26 and a second annular portion 27, the first annular portion 26 is shaped as a cantilever projecting towards the abutment surface 10 with a wedge-shaped radial cross-section, and the second annular portion 27 is adjacent to the side surface of the first annular portion 26 on the side of the sleeve portion 8 facing the annular support 4 to form a thickening of the contact portion 23 on the side facing the sleeve portion 8.

[0032] According to an aspect of the present invention, the second annular portion 27 is stepped and is bounded by a first annular surface 28 and a second annular surface 29 ( Figure 2 and Figure 3 ), the first annular surface 28 and the second annular surface 29 are adjacent to each other and are substantially perpendicular to each other, both facing the opposite direction of the flange portion 9; in particular, the surface 28 faces the abutment surface 10 axially, and the surface 29 faces the outside radially.

[0033] In addition, the wedge portion or the cantilever 26 has a free end formed by a wedge vertex at an acute angle δ ( Figure 2 and Figure 3 ), and when the lips 11, 14 are in a non-deformed state, this free end forms ( Figure 4 and Figure 5 ) a first angle α and a second angle β with the abutment surface 10, and the first angle α and the second angle β are complementary to the acute angle δ formed by the wedge vertex.

[0034] According to one aspect of the present invention, a first angle α is formed on the side facing the sleeve portion 8 and is always smaller than a second angle β, which is formed on the side opposite to the first angle α.

[0035] Furthermore, according to another aspect of the present invention, in the sealing device 7 having two lips and in the sealing device 7c having only one lip, the contact portion 23 of the lip 11 has a second predetermined radial thickness LT greater than the first predetermined radial thickness HT of the root portion 21 in a direction perpendicular to the sleeve portion 8 ( Figure 4 ).

[0036] Similarly, in the sealing device 7 having two lips and in the sealing device 7b having only one lip, the contact portion 23 of the lip 14 has a second predetermined radial thickness LT in a direction perpendicular to the sleeve portion 8, and the second predetermined radial thickness LT is smaller than the first predetermined radial thickness of the root portion 21 (which is indicated by HT2 in Figure 5 ), but is still greater than the radial thickness of the flexure portion 22 (which is indicated by HT1 in Figure 5 ).

[0037] Finally, according to another aspect of the present invention, in the two embodiments 7 and 7c of the sealing device of the present invention, the radius of curvature R2 of the annular outer arc surface 25 of the lip 11 is greater than the radius of curvature R1 of the annular inner arc surface 24 of the same lip 11.

[0038] However, in the two embodiments 7 and 7b of the sealing device of the present invention, the radius of curvature R2 of the annular outer arc surface 25 of the lip 14 is smaller than the radius of curvature R1 of the annular inner arc surface 24 of the same lip 14.

[0039] Furthermore, in both embodiments 7 and 7c, the contact portion 23 of the lip 11 is bounded radially inwards and outwards by respective opposing conical surfaces 30, 31 that bifurcate from each other on opposite sides of the abutment surface 10 ( Figure 2 ).

[0040] In embodiments 7 and 7c, the acute angle δ of the wedge-shaped annular overhang 26 of the lip 11 and the angles α and β formed by the overhang 26 of the lip 11 of the sealing device 7 with the conical annular portion 12 of the abutment surface 10 (or, in the case of the sealing device 7c, directly with the abutment surface 10 (in this case the abutment surface 10 is conical, Figure 4 )) that are complementary to the acute angle δ are respectively between 58° and 66°, between 50° and 60°, and between 53° and 67°.

[0041] In Embodiments 7 and 7b, the acute angle δ of the wedge-shaped annular overhang 26 of the lip 14 and the angles α and β complementary to the acute angle δ, formed by the overhang 26 of the lip 14 of the sealing device 7 with the flat annular portion 13 of the abutment surface 10 (or, in the case of the sealing device 7b, directly with the abutment surface 10 (in this case the abutment surface 10 is flat, Figure 5 )) are respectively between 40° and 55° (α), between 70° and 80° (β), and between 50° and 60° (δ).

[0042] In addition, in both Embodiments 7 and 7b, the contact portion 23 of the lip 14 is bounded radially on the side opposite to the sleeve portion 8 by a continuous extension of the inner arc surface 24 of the flexure portion 22.

[0043] Based on the above description, it is evident that the present invention relates both to Figure 1 and Figure 2 the complex sealing system 1 of the encapsulated type shown therein, and to the simple sealing devices 7, 7b or 7c having two lips 11, 14 (as in the device 7) or having a single lip 11 (device 7c) or 14 (device 7b), the sealing devices 7, 7b or 7c being able to be coupled to a shielding element 6 such as shown (or, to a variant of the shielding element, having a conical surface such as 12 as its entire abutment surface 10 in the case of the application of the device 7c, or having a flat surface such as 13 in the case of the application of the device 7b) or directly to a simple (only conical or flat) or hybrid (having conical surface portions and flat surface portions) abutment surface 10 formed, for example, directly on the mechanical member 3.

[0044] In this last-mentioned case, the sealing devices 7, 7b or 7c will be able to be directly inserted between the relatively rotatable first mechanical member 2 and the second mechanical member 3.

[0045] In the non-limiting embodiments shown, the sealing devices 7b and 7c differ from the sealing device 7 of the sealing system 1 described above first in that they only include one of the two axial lips 11, 14. However, like the rest of the sealing device 7, these lips can include other sealing lips capable of forming a labyrinth seal of a known type, whether sliding or non-sliding, such as the radial lip 32.

[0046] In addition, the sealing devices 7b and 7c differ from the sealing device 7 in that the sealing devices 7b and 7c each include the same generally rigid annular support 4b or 4c, the support 4b or 4c only at Figure 3(Sealing device 7b) is shown integrally, and the support members 4b or 4c are each formed only by coined annular metal elements 15b or 15c, but still include a sleeve portion 8 and a flange portion 9. The sleeve portion 8 is configured to be joined to the first mechanical member 2 in an angled and integral manner, and the flange portion 9 extends perpendicularly from the sleeve portion 8 in a cantilever manner and integrally carries the annular sealing element 5. As described above, at least one elastically deformable annular lip 11 or 14 projects from the flange portion 9 in a cantilever manner.

[0047] If desired, in the case of devices 7b and 7c, the shape of the annular metal elements 15b or 15c can be different from Figure 1 the shape of the annular metal element 15; for example, in the case of devices 7b and 7c, the sleeve portion 8 projects from the flange portion 9 towards the abutment surface 10, while in the case of device 7, the sleeve portion 8 projects from the flange 9 in the opposite direction, and there is a cylindrical overhang 18.

[0048] In other respects, the sealing devices 7b and 7c are the same as the previously described sealing device 7, and details similar or identical to those previously described are indicated by the same reference numerals. Therefore, for devices 7b and 7c, reference should be made to the foregoing description provided for device 7.

[0049] The difference between the sealing devices 7b and 7c is that in device 7b, the predetermined radial thickness of the contact portion 23 in the direction perpendicular to the sleeve portion 8 is less than the first predetermined radial thickness of the root portion 21, while in the sealing device 7c, the predetermined radial thickness of the contact portion 23 in the direction perpendicular to the sleeve portion 8 is greater than the predetermined radial thickness of the root portion 21.

[0050] Another difference is that in the sealing device 7b, the radius of the annular outer arc surface 25 is less than the radius of the inner arc surface 24, and this feature is obtained in combination with the fact that the predetermined radial thickness of the contact portion 23 in the direction perpendicular to the sleeve portion 8 is less than the predetermined radial thickness of the root portion 21.

[0051] On the other hand, in the sealing device 7c, the radius of the annular outer arc surface 25 is greater than the radius of the inner arc surface 24, and this feature is obtained in combination with the fact that the predetermined radial thickness of the contact portion 23 in the direction perpendicular to the sleeve portion 8 is greater than the predetermined radial thickness of the root portion 21.

[0052] In addition, in the sealing device 7b, the wedge-shaped overhang 26 of the contact portion 23 is formed at an acute angle between 50° and 70°, preferably between 50° and 60°, with respect to the abutment surface, while in the sealing device 7c, the wedge-shaped overhang 26 of the contact portion 23 is formed at an acute angle still between 50° and 70°, preferably between 58° and 66°, with respect to the abutment surface.

[0053] In all cases, compared to those in currently known solutions, the newly designed axial lips 11 and / or 14 as described can operate on non-linear surfaces, such as curved or slightly inclined or beveled surfaces, under more extreme interference ( / interference fit) conditions. This is made possible by the shape of the lips 11 / 14 for the following reasons:

[0054] 1 - In the contact area, the angle between the operating counter-face 10 and the lips 11 / 14 increases, also forming a region with a convex curvature. These two characteristics allow for a more uniform distribution of pressure and delay the effect of the "flattening" of the contact surface of the lips against the abutment surface 10. The curved geometry of the lips 11 / 14 can better counteract the deformation that the lips experience during operation, thus creating more stable conditions.

[0055] 2 - In the flexure area 22 located in the lower part of the lips 11 / 14 opposite to the contact area 23, material is added to compensate for the removal that occurs in the contact area 23. Thus, for a wide range of interference tolerances ( / interference fit tolerances), the peak pressure remains at an optimal value.

[0056] Therefore, the proposed solution improves the following factors:

[0057] 1 - It increases the stability of the contact pressure at a higher interference interval ( / interference fit interval).

[0058] 2 - It delays the effect of the "flattening" of the contact surface of the lips, thus increasing the interference ( / interference fit) range.

[0059] 3 - It produces a more constant contact force effect while remaining within an acceptable limit of force.

[0060] Thus, all the objects of the present invention are achieved.

Claims

1. A sealing device (7; 7b; 7c) capable of being inserted between a first mechanical component (2) and a second mechanical component (3) that are rotatable relative to each other, the sealing device (7; 7b; 7c) comprising a substantially rigid annular support (4; 4b; 4c) and a sealing annular element (5) made of elastic material and obtained as a whole piece with the annular support; the annular support comprising a sleeve portion (8) and a flange portion (9), the sleeve portion (8) being configured to be integrally connected to the first mechanical component at an angle, the flange portion (9) extending vertically from the sleeve portion in a cantilevered manner and integrally carrying the sealing annular element, at least a first elastically deformable annular lip (11; 14) protruding from the flange portion (9) in a cantilevered manner, the first elastically deformable annular lip (11; 14) being configured to abut against an annular abutment surface (10) integral with the second mechanical component in use, so as to achieve a dynamic sliding seal with the annular abutment surface (10); characterized in that The first annular lip (11; 14) extends from the flange portion in a cantilevered manner from a side facing the abutment surface in use and extends in a direction substantially perpendicular to the flange portion so as to be coaxial with the sleeve portion; The first annular lip comprises in combination: i) a root portion (21) adjacent to the flange portion, the root portion extending vertically from the flange portion in a cantilever manner, the root portion having a first predetermined radial thickness in a direction perpendicular to the sleeve portion; ii) a flexure (22) extending immediately from the root portion in a cantilevered manner in a direction inclined relative to the flange portion and directed toward the sleeve portion, the flexure having a radial thickness thinner than that of the root portion and being defined by an inner arc annular surface (24) facing the abutment surface and an outer arc annular surface (25) facing the sleeve portion; iii) a contact portion (23) extending immediately from the flexure portion in a cantilever manner in a direction parallel to the root portion and configured to engage with the abutment surface (10), the contact portion comprising a first annular portion (26) and a second annular portion (27), the first annular portion (26) having a wedge-shaped radial cross section and forming an overhang of the contact portion (23) protruding toward the abutment surface, the second annular portion (27) being located immediately on the side of the first annular portion from one side of the sleeve portion of the support member, so that a thickening of the contact portion (23) is formed on one side of the sleeve portion (8); iv) The second annular portion (27) is stepped and is defined by a first annular surface (28) and a second annular surface (29) adjacent and perpendicular to each other and both facing generally towards opposite sides of the flange portion.

2. The sealing device according to claim 1, characterized in that The contact portion (23) has a second predetermined radial thickness (LT) in a direction perpendicular to the sleeve portion, the second predetermined radial thickness (LT) being greater than the radial thickness of the flexure portion (22) and greater than or less than the first predetermined radial thickness of the root portion (21).

3. The sealing device according to claim 2, characterized in that The outer arc annular surface (25) and the inner arc annular surface (24) include revolving surfaces generated by circumferential segments. When the first preset radial thickness is less than the second preset radial thickness, the radius of the outer arc annular surface (25) is greater than the radius of the inner arc annular surface (24). When the first preset radial thickness is greater than the second preset radial thickness, the radius of the outer arc annular surface (25) is less than the radius of the inner arc annular surface.

4. The sealing device according to any one of the preceding claims, characterized in that The wedge-shaped overhang (26) of the contact portion (23) forms an acute angle comprised between 50° and 70° towards the abutment surface.

5. The sealing device according to any one of claims 1 to 3, characterized in that When the first lip is in a non-deformed state, the wedge-shaped overhang (26) forms a first angle (α) and a second angle (β) with the abutment surface, the first angle (α) and the second angle (β) being complementary to an acute angle (δ) formed by the overhang toward the abutment surface; the first angle being formed on one side of the sleeve portion and being smaller than the second angle, and the second angle being formed on the side opposite to the first angle.

6. A sealing system (1) capable of being inserted between a first mechanical component (2) and a second mechanical component (3) that are rotatable relative to each other, the sealing system (1) comprising a substantially rigid annular support (4) and a substantially rigid annular shielding element (6) and an elastic sealing annular element (5) that can be coaxially connected to the annular support (4); the annular support comprises a sleeve portion (8) and a flange portion (9), the sleeve portion (8) being configured to be fixed integrally with the first mechanical component, the flange portion (9) being suspended The arm extends radially from the sleeve portion and carries the sealing annular element in an integral piece; the annular shielding element (6) is configured to be fixed integrally with the second mechanical component and is provided with an abutment surface (10) for the sealing annular element facing the annular support, the sealing annular element is provided with at least one elastically deformable annular sealing lip (11; 14), the annular sealing lip (11; 14) being configured to slide and interfere with the abutment surface to achieve dynamic sealing with the abutment surface; wherein: - the abutment surface comprises a first annular portion (12) defined by a frustoconical surface and a second annular portion (13) defined by a flat front surface facing the flange portion (9) of the annular support and parallel to said flange portion (9); - the sealing annular element (5) comprises a first elastically deformable annular sealing lip (11) and a second elastically deformable annular sealing lip (14), wherein the first elastically deformable annular sealing lip (11) is configured to cooperate with the first annular portion (12) of the abutment surface, and the second elastically deformable annular sealing lip (14) is configured to cooperate with the second annular portion (13) of the abutment surface; characterized in that the first annular lip (11) and the second annular lip (14) each comprise in combination: i) a root portion (21) adjacent to the flange portion, the root portion extending vertically from the flange portion in a cantilever manner, the root portion having a first predetermined radial thickness in a direction perpendicular to the sleeve portion; ii) a flexure (22) extending immediately from the root portion in a cantilevered manner in a direction inclined relative to the flange portion and directed toward the sleeve portion, the flexure having a radial thickness thinner than that of the root portion and being defined by an inner arc annular surface (24) facing the abutment surface and an outer arc annular surface (25) facing the sleeve portion, the inner arc annular surface (24) and the outer arc annular surface (25) both being formed by surfaces of revolution generated by circumferential segments; iii) a contact portion (23) extending immediately from the flexure portion in a cantilever manner in a direction parallel to the root portion and configured to engage with the abutment surface, the contact portion comprising a first annular portion and a second annular portion (27), the first annular portion being formed as an overhang (26) having a wedge-shaped radial cross-section and protruding toward the abutment surface, the second annular portion (27) being located immediately on the side of the first annular portion on one side of the sleeve portion of the annular support so as to form a thickened contact portion on one side of the sleeve portion; iv) the second annular portion (27) is stepped and defined by a first annular surface (28) and a second annular surface (29) adjacent to each other and substantially perpendicular to each other and both facing opposite sides of the flange portion; v) a wedge-shaped overhang (26) having a free end formed by an acute-angled apex of the wedge-shaped overhang (26), and when the lip is in a non-deformed state, the free end forms a first angle (α) and a second angle (β) with the abutment surface, the first angle (α) and the second angle (β) being complementary to the acute angle formed by the apex of the wedge-shaped overhang (26), the first angle (α) being formed on one side of the sleeve portion and being smaller than the second angle (β), and the second angle (β) being formed on the side opposite to the first angle; vi) the contact portion (23) of the first lip (11) has a second predetermined radial thickness in a direction perpendicular to the sleeve portion, the second predetermined radial thickness being greater than the first predetermined radial thickness of the root portion (21); vii) The contact portion (23) of the second lip (14) has a second predetermined radial thickness in a direction perpendicular to the sleeve portion, the second predetermined radial thickness being smaller than the first predetermined radial thickness of the root portion (21) and larger than the radial thickness of the flexure portion (22).

7. The sealing system according to claim 6, characterized in that: viii) the radius of curvature of the outer arc annular surface (25) of the first lip (11) is greater than the radius of curvature of the inner arc annular surface (24) of the first lip; ix) The curvature radius of the outer arc annular surface (25) of the second lip (14) is smaller than the curvature radius of the inner arc annular surface (24) of the second lip.

8. The sealing system according to claim 6 or 7, characterized in that The contact portion (23) of the first lip is delimited radially inwardly and outwardly by respective opposite conical surfaces (30, 31) diverging from each other on the side opposite to the abutment surface (10); the acute angle of the wedge-shaped overhang (26) of the first lip (11) and the first angle (α) and the second angle (β) formed by the overhang and the first annular portion of the abutment surface, which are complementary to the acute angle, are respectively comprised between 58° and 66°, between 50° and 60° and between 53° and 67°.

9. The sealing system according to claim 6 or 7, characterized in that The contact portion (23) of the second lip (14) is defined radially from the opposite side of the sleeve portion of the support by a continuous extension of the inner arc surface (24) of the flexure (22); the acute angle of the wedge-shaped overhang (26) of the second lip (14) and the first angle (α) and the second angle (β) formed by the overhang and the second annular portion of the abutment surface, which are complementary to the acute angle, are respectively included between 50° and 60°, between 40° and 55° and between 70° and 80°.

10. The sealing system according to claim 6 or 7, characterized in that The annular support (4) comprises: a first coined metal annular element (15) radially delimiting the sleeve portion and the flange portion on the inner side, the flange portion being chair-shaped in radial section and facing the annular shielding element (6); and a second annular element (16) made of a co-molded synthetic plastic material located radially on the outer side on the metal annular element so as to define the sleeve portion (8) together with the metal annular element; the second annular element (16) made of synthetic plastic material is provided with a substantially cylindrical overhang (18) on one side of the annular shielding element radially surrounding the annular shielding element (6) on the outer side; the annular shielding element (6) is substantially shaped in radial section into an inverted C-shape facing the annular support, so that the sleeve portion (19) of the annular shielding element radially outside the abutment surface is coaxially inserted into the interior of the substantially cylindrical overhang (18) of the second annular element of synthetic plastic material.

11. The sealing system according to claim 10, wherein: The overhang portion (18) is integrally provided with an annular lip winglet (20) toward the annular shielding element. The annular lip winglet (20) extends radially toward the sleeve portion (19) of the annular shielding element and is configured to form a labyrinth seal with the sleeve portion (19).

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