Static seal system in a sealing shield for a rolling bearing and rolling bearing

Abstract

Static sealing system (1) and associated rolling bearing (3), in particular for a vehicle wheel hub unit, for coupling a sealing device (2) to an outer ring (5) of the bearing, the mounting portion (15) of the sealing device comprising a sleeve portion (12) of an annular support (10) and an end portion (14) of an elastomeric sealing element (11) coupled to the sleeve portion and having a radially inner first annular boss (16) configured to be coupled in interference with an annular seat (18) of the outer ring; the end portion of the elastomeric element comprising a second annular boss (20) coupled to the annular seat adjacent to the first annular boss on a side axially opposite a curved end surface (22) of the annular seat and laterally flanked in the radial direction by a radially thinned end (24) of the sleeve portion of the annular support, the first annular boss protruding axially from said end.

Description

Technical Field

[0001] This invention relates to a static sealing system that can be applied to or form part of a sealing shield for a rolling bearing. The invention also relates to a rolling bearing, particularly a rolling bearing integrated into or constituting a vehicle wheel hub unit. Background Technology

[0002] US2015036957A1 discloses a sealing device (such as a seal or plug) mounted on the outer surface of the outer ring of a rolling bearing (particularly a rolling bearing forming part of or constituting a vehicle wheel hub unit).

[0003] These sealing devices are radially connected to the outside of the outer ring, generally fixed to the wheel support flange of the inner ring of the rolling bearing on the side facing the outer ring. Therefore, the static sealing system must be fixed between the sleeve-shaped mounting portion of the sealing device and the annular seat formed on the radially outer lateral surface of the bearing's outer ring.

[0004] Static sealing is ensured by a portion of an elastomeric sealing element that forms part of the sealing device. The elastomeric sealing element is provided with a single annular boss that contacts a curved connecting surface at the end of an annular seat formed on the outer ring.

[0005] An annular elastomeric boss, connected to at least a portion of the aforementioned curved surface via an interference fit, creates a combined axial and radial static seal. (As per the attached...) Figure 3 An example of this type of static seal is schematically depicted in the image. Figure 3 Therefore, it reflects existing technology.

[0006] The drawbacks of this sealing system stem from the machining tolerances required during the production of the outer ring. The radially outer surface of the outer ring, adjacent to the curved end surface of the annular seat, is not machined and therefore has a forging finish. Consequently, the circumferential profile of the outer ring may differ significantly from the design intended profile, negatively impacting the compression of the annular boss, resulting in uneven compression. In fact, even if the axial position and radius of the curved end surface of the annular seat conform to the design, the forged outer profile, due to machining tolerances, produces unintended operating conditions where the sealing element does not function optimally.

[0007] In fact, the following negative effects may occur:

[0008] - The distribution of sealing pressure deviates from the expected conditions, which leads to a decrease in sealing performance.

[0009] - Unexpected reaction forces are generated during the assembly of the sealing device onto the annular seat of the outer ring with an interference fit. This causes irregular deformation of the annular boss, resulting in reduced sealing performance and increased friction. Summary of the Invention

[0010] The present invention aims to provide a static sealing system that can be applied to / form part of a sealing shield for rolling bearings, and does not have the aforementioned disadvantages.

[0011] The present invention also aims to provide a rolling bearing equipped with an improved static sealing system, the rolling bearing forming part of or constituting a vehicle wheel hub unit.

[0012] The present invention provides a static sealing system for a sealing shield for a rolling bearing and an associated rolling bearing having the features set forth in the appended claims. Attached Figure Description

[0013] The invention is described below with reference to the accompanying drawings, which illustrate two non-limiting exemplary embodiments of the invention, in which:

[0014] - Figure 1 The front view and radial section view of a vehicle wheel hub unit are schematically shown. The vehicle wheel hub unit is composed of rolling bearings, which are provided with a pair of opposing mounting flanges and a sealing system according to the invention.

[0015] - Figure 2 Schematally shown at magnified scale Figure 1 Details;

[0016] - Figure 3 A radial cross-sectional view of a sealing system according to the prior art is shown schematically at an enlarged scale;

[0017] - Figure 4 A radial cross-sectional view of a first embodiment of the sealing system according to the invention is shown schematically at enlarged scale; and

[0018] - Figure 5 With Figure 4 A radial cross-sectional view of a second embodiment of the sealing system according to the invention is shown schematically at the same magnification. Detailed Implementation

[0019] Reference Figure 1 and Figure 2 Reference numeral 1 in the figure generally indicates a static sealing system of a sealing device 2 constructed for a rolling bearing 3.

[0020] In the non-limiting example shown, the rolling bearing 3 forms part of the vehicle wheel hub unit 4 (which is known in general), or better constitutes the vehicle wheel hub unit 4.

[0021] Specifically, the rolling bearing 3 includes a radial outer ring 5, a radial inner ring 6, a plurality of rolling elements 7 between the outer ring and the inner ring to enable the outer ring and the inner ring to rotate relative to each other with low friction, a sealing device 2 securely attached to the outer ring 5, a sealing system 1 according to the invention, a first mounting flange 8 and a second mounting flange 8, the first mounting flange 8 being integrally formed with the inner ring 6 on the radially outer side of the inner ring and configured to receive a vehicle wheel (vehicle wheels are known and are not shown for simplicity) in use, and the second mounting flange being integrally formed with the outer ring 5 on the radially outer side of the outer ring and configured to connect to a vehicle suspension pillar (vehicle suspension pillars are known and are not shown for simplicity) in use.

[0022] Essentially, the rolling bearing 3 is of the "double-flanged" type, forming the entire wheel hub unit 4 on its own. However, according to different possible implementations (not shown for simplicity), the wheel hub unit 4 may include a rolling bearing without any flanges or only provided with flanges 9, with flanges 8 firmly formed to a conventional type of spindle, and inner ring 6 angularly and firmly mounted on the spindle. Here and in the following, while maintaining general applicability, reference will be made to the implementation in which the rolling bearing forms the wheel hub unit 4 on its own.

[0023] The sealing device 2 includes an annular support 10 and an annular elastomeric sealing element 11. The annular support 10 is substantially rigid and is typically metallic. The annular elastomeric sealing element 11 is securely attached to the annular support 10, for example, by adhesive during vulcanization.

[0024] The annular support 10 includes ( Figure 2 The sleeve portion 12 is basically cylindrical and the flange portion 13 is radially inward from the sleeve portion 12 on the same side as the flange 8 that the flange portion faces.

[0025] The annular elastomeric sealing element 11 is combined with at least a portion of the annular support 10. The annular elastomeric sealing element 11 is fixed to the annular support 10, and in the non-limiting example shown, the annular elastomeric sealing element 11 together with the annular support 10 forms a labyrinth-type sealing shield constituting the sealing device 2. Figure 1 ).

[0026] The annular elastomeric sealing element 11 includes a radially outer end portion 14, which at least partially engages with a sleeve portion 12 and is fixed to the sleeve portion 12. The end portion 14 and the sleeve portion 12 together form an integral sleeve-shaped mounting portion 15 of the sealing device 2.

[0027] In the non-limiting example shown, the static sealing system 1 is disposed between the sealing device 2 and the outer ring 5 and forms part of both. In other possible embodiments not shown for simplicity, the static sealing system 1 of the present invention cooperates directly or indirectly with the outer ring 5 in any case.

[0028] The end portion 14 of the elastomeric sealing element 11 includes a radially inner first annular boss 16, which protrudes radially inner relative to the sleeve portion 12 of the annular support 10.

[0029] The annular boss 16 is configured to be connected to the annular seat 18 formed on the radially outer surface 19 of the outer ring 5 in an interference fit during use.

[0030] To date, sealing system 1 is similar to Figure 3The prior art sealing system T is schematically shown and for visual comparison only. The sealing system T also includes an end portion 14 of an elastomeric sealing element 11, the end portion 14 having an annular boss B (schematically shown in a non-deformed configuration) on its radially inner side, the annular boss B being connected to an annular seat S formed on the radially outer lateral surface 19 of the outer ring 5.

[0031] According to the first aspect of the invention ( Figure 2 and Figure 4 The end portion 14 of the elastomeric sealing element 11 includes a second annular boss 20, which is also configured to be connected to the annular seat 18 in an interference fit during use, as explained below.

[0032] Seat 18 is essentially stepped and includes ( Figure 4 and Figure 5 The bottom wall 21 is basically cylindrical and the front end surface 22 is curved, forming a first axial shoulder facing the flange 8.

[0033] According to one aspect of the invention, the second annular boss 20 is configured to be axially farther from the curved end surface or axial shoulder 22 of the annular seat 18 than the first annular boss 16.

[0034] exist Figure 4 In the embodiment, the annular boss 16 is actually configured to contact the shoulder surface 22 in an interference fit both axially and radially, thus being close to the curved surface 22. Figure 5 In one embodiment, where the sealing system of the present invention is indicated by reference numeral 1b, the annular boss 16 is configured adjacent to the curved end surface 22 of the seat 18, but axially spaced from the curved end surface 22. However, in both embodiments, the annular boss 16 is closer in the axial direction to the curved end surface 22 of the seat 18 than the annular boss 20.

[0035] According to another aspect of the invention, the second annular boss 20 is flanked radially outward by the substantially cylindrical end 24 of the sleeve portion 12 of the annular support 10.

[0036] Furthermore, the first annular boss 16 is integrally formed with the end portion 14 of the elastomeric sealing element 11, such that the first annular boss protrudes axially from the end portion 24.

[0037] According to another aspect of the invention, the second annular boss 20 protrudes radially inward from the substantially cylindrical end 24 of the sleeve portion 12 of the annular support 10 toward the surface 25. Figure 4 and Figure 5 It has a radial thickness smaller than that of the first annular boss 16.

[0038] In practice, the second annular boss 20 protrudes radially from the radially inward side of the substantially cylindrical end 24 of the sleeve portion 12 of the annular support 10 toward the surface 25, while the first annular boss 16 protrudes radially relative to the radially inward side of the substantially cylindrical end 24 toward the surface 25, but not from the radially inward side toward the surface 25. The first annular boss 16 is not radially connected to the end 24 and is configured to protrude axially relative to the end 24. Furthermore, the annular boss 16 protrudes radially relative to the lateral surface 25 of the annular support 10 by a greater amount than the radial protrusion of the second annular boss 20.

[0039] In other words, the radial projection of the annular boss 20 relative to the radially inner surface 25 of the tubular end 24 is less than the radial projection of the first annular boss 16.

[0040] Furthermore, the substantially cylindrical end 24 of the sleeve portion 12 of the annular support 10 is radially thinned relative to the rest of the sleeve portion 12 on the side facing the lateral surface 25, presenting a curved axial shoulder surface 26. The curved axial shoulder surface 26 is radially inwardly defined as a portion of the radially thinned end 24 itself and is configured to be adjacent to the second annular boss 20 on the side axially opposite to the first annular boss 16. In fact, the curved axial shoulder surface 26 faces and is opposite to the curved end surface 22 of the annular seat 18.

[0041] The end portion 14 of the elastomeric sealing element 11 completely covers the radially thinned end 24 of the sleeve portion 12 of the annular support 10, so as to be radially located between the end 24 of the sleeve portion 12 and the second annular boss 20, which protrudes radially inside the end portion 14 of the elastomeric sealing element 11 and is formed as a single piece together with the first annular boss 16 through the end portion 14.

[0042] According to a preferred embodiment of the invention, the annular boss 16 includes an annular axial protrusion 27 facing the curved end surface 22 of the annular seat 18, and is defined radially outward and inward by a pair of opposing generally conical surfaces 28 and 29, which converge toward the free end 30 of the annular protrusion 27 to form a continuous annular edge.

[0043] exist Figure 4In one embodiment, the annular protrusion 27 is configured to fluid-tightly engage with the curved end surface 22 of the annular seat 18 during use.

[0044] In this embodiment, the static sealing system 1 according to the invention further includes an annular chamfer 31, which is machined on the radially outer surface 19 of the outer ring 5 of the rolling bearing at a position adjacent to the curved end surface 22 of the annular seat 18 and on the radially outer side of the curved end surface.

[0045] The annular chamfer 31 faces the end portion 14 of the elastomeric sealing element 11 and converges toward the first annular boss 16.

[0046] As is clear from the foregoing, the present invention relates to a rolling bearing, particularly a rolling bearing (such as bearing 3) forming part of or constituting a vehicle wheel hub unit 4. The rolling bearing includes a radial outer ring 5, a radial inner ring 6, a plurality of rolling elements 7 between the outer ring 5 and the inner ring 6, a sealing device 2 securely supported by the outer ring 5 and configured to protect the rolling elements 7, and a static sealing system 1. The static sealing system 1 is configured between the sealing device 2 and the outer ring 5 and includes elements forming part of both. The sealing device 2 substantially includes an annular support 10 and an elastomeric sealing element 11 securely connected to the annular support 10. The sealing system 1 includes:

[0047] - An annular seat 18 is machined at the first end 32 of the outer ring on the radial outer surface 19 of the outer ring 5. Figure 1 and Figure 2 The annular seat 18 includes a curved end surface 22, which is axially disposed on the side opposite to the first end 32 of the outer ring 5 and faces the first end 32 of the outer ring 5; and

[0048] - The sleeve-shaped mounting portion 15 of the sealing device 2 includes an end portion 14 of the elastomeric sealing element 11 and a sleeve portion 12 of the annular support 10. The sleeve portion 12 firmly supports the end portion 14 of the elastomeric sealing element 11. The end portion 14 of the elastomeric sealing element 11 itself includes a first annular boss 16, which protrudes from the sleeve portion 12 of the annular support 10 and is connected to the annular seat 18 in an interference fit.

[0049] According to the present invention, the end portion 14 of the elastomeric sealing element 11 includes a second annular boss 20 that is connected to the annular seat 18 in an interference fit manner, and the second annular boss 20 is configured to be axially spaced from the curved end surface 22 of the annular seat 18, while a first annular boss 16 is axially located between the curved end surface 22 of the annular seat 18 and the second annular boss 20.

[0050] Furthermore, the second annular boss 20, which forms part of the bearing 3, is radially outwardly connected to the substantially cylindrical end 24 of the sleeve portion 12 of the annular support 10, and the first annular boss 16 protrudes axially from the end 24.

[0051] The radial thickness of the second annular boss 20 is less than the radial thickness of the first annular boss 16. As indicated, the second annular boss protrudes radially from the radially inward side of the substantially cylindrical end 24 of the sleeve portion 12 of the annular support 10 toward the surface 25. In combination, the first annular boss 16 protrudes radially toward the surface 25 relative to the radially inward side of the substantially cylindrical end 24 of the sleeve portion 12 of the annular support 10 by a greater radial protrusion than the second annular boss 20, but does not overlap with the end 24 radially.

[0052] Therefore, the first annular boss 16 is not flanked on the radially outer side by the substantially cylindrical end 24 of the sleeve portion 12 of the annular support 10, so that the end portion 14 of the elastomeric sealing element 11 can freely and elastically deform in the radial direction at the first annular boss 16.

[0053] The substantially cylindrical end 24 of the sleeve portion 12 of the annular support 10 is radially thinned relative to the rest of the sleeve portion 12 of the annular support 10 to present a curved axial shoulder surface 26, which is radially inwardly defined on a portion of the radially thinned end 24 and is disposed adjacent to the second annular boss 20 on the side axially opposite to the first annular boss 16.

[0054] According to a preferred embodiment, as already indicated, the first annular boss 16 includes an annular axial protrusion 27 facing the curved end surface 22 of the annular seat 18 and defined radially outward and inward by a pair of opposing generally tapered surfaces 28 and 29 that converge toward the free end 30 of the annular protrusion 27 to form an annular edge.

[0055] The conical surface 29, which is arranged radially inward, is configured to facilitate an interference fit between the annular seat 18 and the sleeve-shaped mounting portion 15 of the sealing device 2. When the sealing device 2 as a whole is inserted into the seat 18 by sliding and in a radial interference fit on one side of the first end 32, the conical surface 29 serves as an "invitation" for elastic deformation.

[0056] The sealing system 1 according to the invention has the following advantages due to its feature of having two annular bosses 16 and 20 arranged in axial sequence:

[0057] • Improve sealing performance;

[0058] • Ensure the proper installation of the sealing device 2 (especially the sealing system 1) so that no deformation occurs during installation, thereby achieving improved sealing performance, that is, improving the hydraulic seal between the sealing device 2 and the outer ring 5;

[0059] • The reduced risk of deformation eliminates the need for sealing device 2 to work with other sealing elements (such as oil slinger ring 33) (other sealing elements are known to be...). Figure 1 And to prevent unintended contact between the flanges 8 and the bearing 3, and to ensure low friction.

[0060] With Figure 4 The chamfer 31 in the embodiment is or Figure 5 In the embodiments described, the different positions of the curved shoulder surface 22 relative to the annular boss 16, and the static seal applied by the sealing system 1 of the present invention are not subject to the machining tolerances of the outer ring 5.

[0061] Or the forging process of the outer ring may be affected.

[0062] Therefore, all the objectives of this invention have been achieved.

Claims

1. A static sealing system (1) for a sealing device (2) for a rolling bearing (3), particularly for a vehicle wheel hub unit (4), the static sealing system (1) comprising a sleeve-shaped mounting portion (15) of the sealing device (2), the mounting portion (15) comprising an end portion (14) of an elastomeric sealing element (11) and a sleeve portion (12) of an annular support (10), the annular support (10) being securely coupled to the elastomeric sealing element (11) such that together they constitute the sealing device (2); the end portion (14) of the elastomeric sealing element (11) comprising a first annular boss (16) radially inwardly projecting relative to the sleeve portion (12) of the annular support (10) radially inwardly projecting relative to the sleeve portion (12) of the annular support (10), and configured to, in use, be coupled in an interference fit with an annular seat (18) formed on a radially outwardly facing surface (19) of the outer ring (5) of the rolling bearing; characterized in that, The end portion (14) of the elastomeric sealing element (11) includes a second annular boss (20), which is also configured to be connected to the annular seat (18) in use with an interference fit. The second annular boss (20) is axially farther from the curved end surface (22) of the annular seat (18) than the first annular boss (16). The second annular boss (20) is radially outwardly connected to the substantially cylindrical end (24) of the sleeve portion (12) of the annular support (10), and the first annular boss (16) protrudes axially from the end (24).

2. The static sealing system according to claim 1, characterized in that, The second annular boss (20) protrudes less from the radially inner surface (25) of the substantially cylindrical end (24) of the sleeve portion (12) of the annular support (10) than the first annular boss (16), which is not radially adjacent to the substantially cylindrical end (24) of the sleeve portion (12) of the annular support.

3. The static sealing system according to claim 1 or 2, characterized in that, The substantially cylindrical end (24) of the sleeve portion (12) of the annular support (10) is radially thinned relative to the rest of the sleeve portion (12) of the annular support, so as to present a curved axial shoulder surface (26), which radially inwardly defines a portion of the radially thinned end (24) of the sleeve portion (12) of the annular support and is disposed adjacent to the second annular boss (20) on the side axially opposite to the first annular boss (16).

4. The static sealing system according to claim 3, characterized in that, The end portion (14) of the elastomeric sealing element (11) completely covers the radially thinned end (24) of the sleeve portion (12) of the annular support (10), such that it is located radially between the radially thinned end (24) and the second annular boss (20), which protrudes radially inside the end portion (14) of the elastomeric sealing element (11) and is integrally formed with the first annular boss (16) through the end portion.

5. The static sealing system according to any one of the preceding claims, characterized in that, The first annular boss (16) includes an annular axial protrusion (27) facing the curved end surface (22) of the annular seat (18) and defined radially outward and inward by a pair of opposing substantially conical surfaces (28, 29) that converge toward the free end (30) of the annular protrusion (27) to form an annular edge.

6. The static sealing system according to claim 5, characterized in that, The annular protrusion (27) is configured to fluid-tightly connect with the curved end surface (22) of the annular seat (18) during use.

7. The static sealing system according to claim 6, characterized in that, The static sealing system further includes an annular chamfer (31) machined on the radially outer surface (19) of the outer ring (5) of the rolling bearing at a position adjacent to the curved end surface (22) of the annular seat (18) and radially outer of the curved end surface. The annular chamfer (31) faces the end portion (14) of the elastomeric sealing element (11) so as to converge toward the first annular boss (16).

8. A rolling bearing (3), particularly a rolling bearing forming part of or constituting a vehicle wheel hub unit (4), the rolling bearing (3) comprising a radial outer ring (5), a radial inner ring (6), a plurality of rolling elements (7) between the outer ring (5) and the inner ring (6), a sealing device (2) securely supported by the outer ring (5) and configured to protect the rolling elements (7), and a static sealing system (1) disposed between the sealing device (2) and the outer ring (5), the sealing system (1) comprising: - An annular seat (18), machined at the first end (32) of the outer ring on the radial outer surface (19) of the outer ring (5), the seat including a curved end surface (22) disposed on a side opposite to the first end (32) of the outer ring (5) and facing the first end (32) of the outer ring (5); and - The sleeve-shaped mounting portion (15) of the sealing device (2), the mounting portion including the end portion (14) of the elastomeric sealing element (11) and the sleeve portion (12) of the annular support (10), the annular support (10) firmly supporting the end portion (14) of the elastomeric sealing element (11), the end portion (14) of the elastomeric sealing element (11) including a first annular boss (16), the first annular boss (16) protruding from the sleeve portion (12) of the annular support (10) and connected to the annular seat (18) in an interference fit; characterized in that, in combination: a) The end portion (14) of the elastomeric sealing element (11) includes a second annular boss (20), which is connected to the annular seat (18) in an interference fit. b) The second annular boss (20) is configured to be axially spaced from the curved end surface (22) of the annular seat, and the first annular boss (16) is axially located between the curved end surface (22) of the annular seat and the second annular boss (20). c) - The second annular boss (20) is radially outwardly connected to the substantially cylindrical end (24) of the sleeve portion (12) of the annular support (10), and the first annular boss (16) protrudes axially from the end (24).

9. The rolling bearing according to claim 8, characterized in that, The radial thickness of the second annular boss (20) is less than that of the first annular boss (16). The second annular boss (20) protrudes radially from the radially inner surface (25) of the substantially cylindrical end (24) of the sleeve portion (12) of the annular support (10), and the first annular boss (16) protrudes radially more than the radially inner surface (25) of the substantially cylindrical end of the sleeve portion of the annular support relative to the second annular boss (20). The first annular boss (16) is not radially adjacent to the substantially cylindrical end (24) of the sleeve portion (12) of the annular support, such that at the first annular boss (16), the end portion (14) of the elastomeric sealing element (11) is freely elastically deformable in the radial direction.

10. The rolling bearing according to claim 8 or 9, characterized in that, The substantially cylindrical end (24) of the sleeve portion (12) of the annular support (10) is radially thinner relative to the remainder of the sleeve portion (12) of the annular support, such that it presents a curved axial shoulder surface (26), which radially inwardly defines a portion of the radially thinned end (24) of the sleeve portion of the annular support and is disposed adjacent to the second annular boss (20) on the side axially opposite to the first annular boss (16); and the first annular boss (16) includes an annular... An annular axial protrusion (27) faces the curved end surface (22) of the annular seat (18) and is defined radially outward and inward by a pair of opposing substantially tapered surfaces (28, 29) that converge toward the free end (30) of the annular protrusion (27) to form an annular edge; the radially inwardly arranged tapered surface (29) is configured to facilitate an interference fit connection between the annular seat (18) and the sleeve-shaped mounting portion (15) of the sealing device (2).

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