Dynamically acting seals especially for rolling bearings

Abstract

The sealing device (8) comprises a first annular element (9) which can be connected to a first fixed mechanical component (6) and a second annular element (13) which can be connected to a second rotating mechanical component (5) for protecting an annular compartment (7) defined between the components; the first element is provided with at least one annular sealing lip (18) which is configured to interact with the second element, the second element having a radial edge (22) of a flange portion (15) arranged at an edge (23) of a sleeve portion (10) of the first element, thereby forming a radial gap (24) configured as a labyrinth seal with the sleeve portion of the first element; the radial gap of the flange portion of the second annular element carries a plurality of recesses (25), which are arranged in the crown, spaced adjacent to each other at the radial gap and are configured to generate a dynamic effect (F) due to the rotation of the second element, for repelling any contaminants pushed towards the radial gap.

Description

Technical Field

[0001] The present invention relates to a sealing device with dynamic action, particularly suitable for being inserted between a first mechanical component and a second mechanical component rotating relative to each other or being present in a rolling bearing (for example comprising an inner ring and an outer ring of a rolling bearing), for the purpose of protecting the bearing and / or the rolling elements of the bearing from external contaminants, while keeping any grease inside. Background Art

[0002] As is known, the industry now requires that sealing devices should have greater sealing capacity and lower friction torque than in the past, which are called "pack seal" type, for example, for insertion between two components that rotate relative to each other. The demand for seals with low friction without reducing their fluid tightness is also increasing.

[0003] There are many known ways to reduce friction: the simplest is to reduce the number of sealing lips in sliding contact with one of the two relatively rotating components, or to form one or more lips configured to provide a non-sliding labyrinth seal, but this generally results in a reduced sealing ability of the sealing arrangement. Summary of the invention

[0004] The object of the present invention is to provide a sealing device which does not have the disadvantages of the prior art and is at the same time reliable and economical, and in particular a sealing device which allows the friction generated by the sealing device in use to be reduced, and therefore the friction torque and the energy consumption which are associated therewith, to be reduced by reducing the number of sealing lips which are constructed to be slidingly connected to one of two components moving relative to each other in use, but without losing sealing capacity, or, conversely, a sealing device which allows the sealing capacity to be increased without increasing the friction torque or in the presence of lips which are constructed only for labyrinth sealing.

[0005] Therefore, according to the present invention, a sealing device that can be inserted between a first mechanical component and a second mechanical component that rotate relative to each other (for example, between the rings of a rolling bearing) and an associated sealing system are provided, the sealing device comprising: a first annular element having a first sleeve portion and a first flange portion, the first sleeve portion being configured to be integrally angularly connected to a first mechanical component that is stationary in use among the mechanical components during use, the first flange portion extending in a cantilevered manner from a first end of the first sleeve portion along a first radial direction; and a second annular element being coaxially arranged with the first annular element and comprising a second sleeve portion and a second flange portion, the second sleeve portion being configured to be integrally angularly connected to a second mechanical component that rotates in use among the mechanical components during use, the second flange portion extending in a cantilevered manner from a first end of the second sleeve portion along a second radial direction opposite to the first radial direction, the second flange portion being configured to face the first flange portion; the first annular element is provided with at least an annular sealing lip, the annular sealing lip being elastically deformable and configured The second annular element is configured to cooperate with the front surface of the second annular element facing the first annular element in a sliding manner or by using a labyrinth seal; the second annular element is configured to cooperate with the first annular element so that the radial edge of the second flange portion configured at the second end of the first sleeve portion forms a radial annular gap with the second end of the first sleeve portion, and the radial annular gap is configured to provide a labyrinth seal between the first annular element and the second annular element; the radial edge of the second flange portion carries a plurality of recesses, which are arranged in the crown, sequentially spaced adjacent to each other along the entire radial edge of the second flange portion, and are arranged at the radial annular gap, directly facing and adjacent to the second end of the first sleeve portion of the first annular element and configured on the side opposite to the first flange portion of the first annular element; the recesses are configured to produce a dynamic effect in response to the rotation of the second annular element and the cooperation with the second end of the first sleeve portion, and the dynamic effect is designed to repel any contaminants directed toward the radial annular gap. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The invention will now be described with reference to the accompanying drawings, which show some non-limiting examples of embodiments of the invention, in which:

[0007] Figure 1 schematically shows a three-quarter front perspective view and a radial cross-sectional view of a sealing device according to the present invention; and

[0008] Figures 2 to 7 Various embodiments of the sealing device of the invention are schematically shown in the same three-quarter front perspective view, in a radial cross-section and in a view that is cut off for simplicity. DETAILED DESCRIPTION

[0009] Reference Figure 1 , reference numeral 8 denotes a sealing device as a whole, which can generally be inserted between a first annular mechanical component 5 and a second annular mechanical component 6 (shown purely schematically and only partially shown in dotted lines), which components are assembled in a relatively rotatable manner in a known manner (not shown for the sake of simplicity), component 5 being a component that rotates around its own axis of symmetry and component 6 being a fixed component; for example, components 5 and 6 can be the rotating inner ring and the fixed outer ring of a rolling bearing, respectively, or can be two mechanical components that rotate relative to each other with a rolling bearing interposed therebetween.

[0010] In order to protect the annular compartment 7 defined between the relatively rotatable components 5 and 6 from any external contaminants and / or to retain any lubricating fluid in the annular compartment 7, for example inside a rolling bearing, a sealing device 8 is inserted between the components 5 and 6 coaxially with these components, as shown in a non-limiting manner.

[0011] In fact, the sealing device 8 can be inserted between any two annular members that are rotatable relative to each other, so that the following description refers purely by way of example to the mechanical members 5 and 6 , without thereby losing its generality.

[0012] The sealing device 8 includes a first annular element 9, which has a first sleeve portion ( / first bushing portion) (sleeve portion) 10 and a first flange portion ( / first rim portion) (flange portion) (flange portion) 11. The first sleeve portion 10 is a radially outer portion in the example shown, and is configured to be connected to a component 6 that is stationary in use in an angularly fixed manner during use. The first flange portion 11 extends from a first edge 12 of the sleeve portion 10 in a cantilevered manner along a first radial direction, and the first radial direction extends radially inside the sleeve portion 10 in the example shown.

[0013] The sealing device 8 also includes a second annular element 13, which is coaxially positioned with the first annular element 9 and includes a second sleeve portion 14 and a second flange portion 15. The second sleeve portion 14 is a radially inner portion in the example shown and is configured to be connected to a component 5 that rotates in use in an angularly fixed manner during use. The second flange portion 15 protrudes from a first edge 16 of the second sleeve portion 14 opposite to the edge 12; the flange portion 15 extends in a protruding manner along a radial direction opposite to the radial direction in which the flange portion 11 extends in a protruding manner; in the example shown, the second radial direction extends radially outside the sleeve portion 14.

[0014] The second flange portion 15 faces the first flange portion 11 , and more generally, the second annular element 13 is inserted into the first annular element 9 , radially inside the first annular element 9 and coaxially therewith.

[0015] The first element 9 is provided with at least one elastically deformable annular sealing lip 18, which, in the non-limiting preferred example shown, is configured to interact slidably with a frontal surface 19 of the second element 13 facing the first element 9. As another option, the annular sealing lip 18 can be configured to be non-sliding, but to form a labyrinth seal with the frontal surface 19.

[0016] Obviously, as will be seen, it is possible and generally preferred that there are a plurality of annular sealing lips 18 which are configured to form a radially sliding or axially sliding seal or a labyrinth seal which, depending on the configuration, is known as a whole and is therefore not shown for the sake of simplicity.

[0017] In the non-limiting example shown, the annular element 9 is formed by an annular sealing element 20 and an annular reinforcing element or support 21 , preferably made of metal, fixed to the annular sealing element 20 , preferably by bonding during vulcanization.

[0018] In the example shown, the element 9 is provided with a plurality of annular sealing lips, consisting in the example shown of three annular sealing lips 18 of known type and construction, which extend radially and / or axially from the flange portion 11 in a cantilevered manner.

[0019] The lip 18 is formed as an integral part of the annular sealing element 20 and is preferably configured to interact slidingly and with slight interference on the annular elements or shields 9 and 13, which are connected to the flange portion 14 by two radially inner lips 18 and to the sleeve portion 15 by a radially outer lip 18, all on the front surface 19. As another option, one or more of the lips 18 can be configured to interact with the flange portion 14 and / or with the sleeve portion 15 without sliding, but to interact closely with these parts to form a labyrinth seal. In both cases, the annular element 13 thus serves as an additional component, which serves as a counter-face to the annular sealing element 20.

[0020] According to a configuration known but forming an integral part of the present invention, in combination with what has been described above, the second annular element 13 is constructed to interact with the first annular element 9, the elements 9 and 13 being coaxially connected (moreover, in the non-limiting example shown, as described above, the second annular element is inside the first annular element), so that the radial edge 22 of the second flange portion 15 is located at the second edge 23 of the first sleeve portion 10, so as to form an annular radial gap 24 with the second edge 23, and the annular radial gap 24 is constructed to form a labyrinth seal between the first annular element 9 and the second annular element 13.

[0021] According to the first aspect of the invention, the radial edge 22 of the flange portion 15 has a plurality of recesses 25, which are arranged in the crown, sequentially spaced adjacent to each other along the entire radial edge 22 and located at the radial gap 24, directly facing and adjacent to the edge 23 of the sleeve portion 10 of the element 9. In addition, the recesses 25 face in the opposite direction to the flange portion 11 of the element 9, and in particular, the recesses 25 are formed on a front surface 26 of the element 13 that is opposite to the front surface 19 and belongs to the flange portion 15.

[0022] The recess 25 is constructed to generate a dynamic centrifuging effect F by interacting with the second edge 23 of the sleeve portion 10 due to the rotation of the second annular element or shield 13 relative to the first annular element or shield 9 and due to the presence of the radial gap 24. The dynamic centrifugal effect F is, for example, directed not only in the tangential direction but also in the axial direction and / or radial direction, and is capable of repelling any contaminants pushed towards the radial gap 24 so that they cannot reach the radial gap 24, thereby eliminating the risk that any contaminants may penetrate the labyrinth seal formed by the gap 24 and enter the annular space between the shields 9 and 13, thereby reaching the sealing lip 18 closest to the flange portion 10, which in the example shown is a radial outer lip.

[0023] Due to the presence of the recess 25, this dynamic centrifugal effect F is greatly improved in force, direction and path compared to, for example, conventional centrifugal elements, because it can throw any solid contaminants away from the gap 24, while the contaminants are intercepted by the recess 25, and when liquid or similar contaminants (such as water, mud, etc.) are present, this flow is deflected by the recess 25, which acts like the blades of a turbine.

[0024] According to another aspect of the invention, the recesses 25 alternate with solid circumferential portions 27 without interruption of the radial edge 22 , these portions 27 being spaced from the edge 23 of the sleeve portion 10 by an amount equal to the gap 24 .

[0025] According to one aspect of the present invention, on the side opposite to (opposite to) the front surface 19, the recess 25 is also formed to span (across) the radial edge 22 of the flange portion 15 to partially extend on a surface 26 correspondingly facing in a direction opposite to the first element 9.

[0026] According to another aspect of the present invention, the profile of the recess 25 is such that the recess 25 forms corresponding relative lead angles α and β with the radial edge 22 of the flange portion 15 on the surface 26. Figure 3 ).

[0027] These angles α and β may preferably be symmetrical to each other so that the dynamic effect F generated by the recess 25 is the same regardless of the direction of relative rotation between the first element 9 and the second element 13; alternatively, the relative advance angles α and β are asymmetrical to each other so that the intensity of the dynamic effect F generated by the recess 25 varies with the direction of relative rotation between the first element 9 and the second element 13. The latter characteristic may be useful when the rotating member 5 has a preferred direction of rotation.

[0028] Reference Figures 2 to 7 , these figures schematically show various embodiments of the invention described so far, indicated by reference numerals 8a to 8f. For simplicity, details similar or identical to previously described details are indicated with the same reference numerals.

[0029] like Figure 5 , Figure 6 and Figure 7 As shown, the recessed portion 25 and the solid portion 27 are defined by a wave-shaped profile 28 carried by the radial edge 22 of the flange portion 15 on the side opposite to the flange portion 11 of the first element 9 .

[0030] However, according to Figure 2 , Figure 3 and Figure 4 In the variant shown in , the recesses 25 are formed on or in the edge 22 and are spaced apart at constant intervals to leave between them a solid portion 27 consisting of an intact portion 27 of the edge 22 .

[0031] According to 8( Figure 1 ), 8a, 8b, 8d, 8e indicate a preferred embodiment, the second element 13 ( Figure 1 , Figure 2 , Figure 3 , Figure 5 and Figure 6) comprises a substantially rigid annular reinforcing element 29, preferably made of metal, delimiting both the flange portion 15 and the sleeve portion 14, and an annular insert 30, made of a synthetic or elastic plastic material, preferably bonded or co-molded as a single piece on the annular reinforcing element 29 on the side opposite to the first element 9 during vulcanization. As a further alternative, the annular insert 30 can also be simply bonded to the annular reinforcing element 29, or can be fixed to the annular reinforcing element 29 by a snap fit.

[0032] The insert 30 together with the annular reinforcement element 29 forms the radial edge 22 of the second flange portion 15 of the second annular element 13 .

[0033] According to these embodiments of the invention, the recess 25 is formed only on a first radial edge portion 31 of the insert 30 facing towards the sleeve portion 10 of the first element 9 , which first radial edge portion 31 is the radially outer portion in the example shown.

[0034] According to the embodiments shown by 8, 8a and 8d ( Figure 1 , Figure 2 and Figure 5 ), according to the example shown, the annular insert 30 extends over the entire front surface 26 of the flange portion 15 of the element 13, which is opposite to the element 9. The insert 30 may also extend only over an annular portion of the front surface 26, which in this case is the radially outer portion.

[0035] In the non-limiting embodiment shown above, the insert 30 includes not only the radial edge portion 31, but also a second radial edge portion 32, which faces in the direction opposite to the sleeve portion 10 of the first element 9 ( / away from the sleeve portion 10 of the first element 9). In the example shown, the second radial edge portion 32 is a radially inner portion formed as a single piece with the first radial edge portion 31.

[0036] According to the preferred but non-limiting embodiment shown, the radial edge portion 32 is configured to form an encoder element of known type, which comprises a circumferential sequence of radial portions 33 having physical or magnetic discontinuities, which, in the example shown, are magnetized with opposite polarities N (North) and S (South). If the insert 30 is not required to function as an encoder, it is clear that these physical or magnetic discontinuities are not present even when the annular insert 30 extends over the entire front face 26 according to the example shown.

[0037] Finally, in implementations 8c and 8f ( Figure 4 and Figure 7 ), the second element 13 is formed solely by a substantially rigid annular element 34 , preferably made of metal, defining both the flange portion 15 and the sleeve portion 14 .

[0038] In this case, the flange portion 15 comprises a protruding annular radial portion 35 which protrudes in a cantilevered manner in the axial direction on the side opposite to the first element 9 and delimits / defines the radial edge 22 of the flange portion 15 .

[0039] According to these embodiments 8 c , 8 f , the recess 25 is formed on the protruding annular radial portion 35 on the side opposite to the first flange portion 11 .

[0040] exist Figure 4 In embodiment 8c, the recess 25 is formed by hollow portions or indentations produced by plastic deformation of the circumferential portion of the annular radial portion 35 , alternating with undeformed portions that thus form the solid portion 27 .

[0041] exist Figure 7 In the embodiment 8f, the recess 25 is formed by the trough of the wave profile 28, while the peaks form a solid portion 27 without discontinuity. The wave profile 28 is formed by plastic deformation of the entire edge 22 (for example, by molding / embossing).

[0042] Similarly, in Figure 5 In embodiment 8d, in this case, the recess 25 is also formed by the trough of the wave profile 28, while the wave crest forms a solid part 27 without interruption, and the wave profile 28 is formed by injection moulding or compression directly on the insert 30 during the step of molding the insert.

[0043] Finally, it is apparent from the above description that the present invention also relates to a sealing system 36 ( Figure 1 ), comprising a sealing device 8 according to any one of the embodiments described above and a first annular mechanical component and a second annular mechanical component (such as components 5, 6) coupled together so as to be relatively rotatable, wherein:

[0044] - a first element 9 is attached in an angularly fixed manner to the annular member 6 which is stationary in use,

[0045] - a second element 13 is attached in an angularly fixed manner to the annular member 5 which rotates in use,

[0046] - the first element 9 is housed in an annular compartment 7 which, in the non-limiting example shown, is delimited between a first annular member numbered 5 and a second annular member numbered 6,

[0047] On the side opposite to the first element 9 , the second element 13 is positioned radially inside the first element 9 and towards the outside of the annular compartment 7 , so that its flange 15 substantially closes the compartment 7 (except for the gap 24 ) from the external environment.

[0048] Due to the favorable phenomena present in the generation of the dynamic effect F, and according to other possible embodiments, the outer lip 18 can even be eliminated to reduce friction (if a sliding lip is present), or, as another option, again with the purpose of reducing friction, even without changing the number of lips 18, the interference found during the design phase between the lip 18 and its sliding surface 19 can be reduced.

[0049] All objects of the invention are thus achieved.

Claims

1. A sealing device (8) capable of being inserted between two relatively rotatable mechanical parts (5, 6), comprising: A first annular element (9) having a first sleeve portion (10) and a first flange portion (11), wherein the first sleeve portion (10) is configured to be integrally angularly coupled to a first mechanical component (6) that is stationary in use among the mechanical components, the first flange portion (11) extending in a cantilevered manner from a first end (12) of the first sleeve portion (10) in a first radial direction; and a second annular element (13) arranged coaxially with the first annular element (9) and comprising a second sleeve portion (14) and a second flange portion (15), wherein the second sleeve portion (14) is configured to be integrally angularly coupled to a first mechanical component (6) that is stationary in use among the mechanical components, the first flange portion (11) extending in a cantilevered manner from a first end (12) of the first sleeve portion (10) in a first radial direction. The second mechanical component (5) is connected to the mechanical component at an angle and rotates in use, the second flange portion (15) extending from the first end (16) of the second sleeve portion (14) in a cantilevered manner in a second radial direction opposite to the first radial direction, and the second flange portion (15) is configured to face the first flange portion (11); the first annular element (9) is provided with at least an annular sealing lip (18), the annular sealing lip (18) being elastically deformable and being configured to slide or utilize a labyrinth seal to engage with a front surface (19) of the second annular element facing the first annular element. ); the second annular element (13) is configured to cooperate with the first annular element so that a radial edge (22) of the second flange portion (15) arranged at the second end (23) of the first sleeve portion (10) forms a radial annular gap (24) with the second end (23) of the first sleeve portion (10), and the radial annular gap (24) is configured to provide a labyrinth seal between the first annular element and the second annular element; characterized in that the radial edge (22) of the second flange portion (15) carries a plurality of recesses (25), and the plurality of recesses (25) are arranged in The recess (25) is sequentially spaced adjacent to each other in the crown portion along the entire radial edge (22) of the second flange portion, and is arranged at the radial annular gap (24), directly facing and adjacent to the second end (23) of the first sleeve portion of the first annular element and configured on the side opposite to the first flange portion (11) of the first annular element; the recess (25) is configured to produce a dynamic effect (F) in response to the rotation of the second annular element and in cooperation with the second end (23) of the first sleeve portion, and the dynamic effect (F) is designed to repel any contaminants directed toward the radial annular gap; The profile of the recess (25) is such that, on a surface (26) arranged on the side of the second flange portion opposite to the first annular element, respective relative advance angles (α, β) are formed with the radial edge (22) of the second flange portion which are asymmetrical with each other, so that the dynamic effect (F) generated by the recess has different intensities depending on the rotation direction of the second annular element.

2. The sealing device according to claim 1, characterized in that: The recesses (25) alternate with circumferential solid extensions (27) without discontinuity of the radial edge (22) of the second flange portion, the extensions (27) being spaced from the second end (23) of the first sleeve portion by an amount equal to the radial annular gap (24).

3. The sealing device according to claim 1 or 2, characterized in that: The recess (25) is formed across the radial edge (22) of the second flange portion so as to partially extend on a surface (26) of the second flange portion (15) disposed on the side opposite to the first annular element (9).

4. The sealing device according to claim 1 or 2, characterized in that: The recess (25) is defined by a wave-shaped profile (28) carried by a radial edge (22) of the second flange portion (15) on the side opposite to the first flange portion (11) of the first annular element.

5. The sealing device according to claim 1 or 2, characterized in that: The second annular element (13) comprises a substantially rigid annular reinforcing element (29) and an annular insert (30) delimiting the second flange portion (15) and the second sleeve portion (14), the annular insert (30) being made of a synthetic or elastomeric plastic material and integrally fastened to the annular reinforcing element (29); the recess (25) being formed exclusively on a first radial end (31) of the insert (30) facing the first sleeve portion (10) of the first annular element.

6. The sealing device according to claim 5, characterized in that: The annular insert (30) extends over the entire front face (26) of the second flange portion (15) of the second annular element (13) opposite to the first annular element or over an annular portion of the second flange portion (15) of the second annular element (13), and the annular insert (30) includes a second radial end (32), which is arranged on the side opposite to the first sleeve portion (10) of the first annular element and is formed integrally with the first radial end (31).

7. The sealing device according to claim 6, characterized in that: The second radial end (32) is configured to produce an encoder element comprising a circumferential sequence of radial portions (33) having physical or magnetic discontinuities.

8. The sealing device according to claim 1 or 2, characterized in that: The second annular element (13) is composed of a substantially rigid annular element (34) and defines the second flange portion (15) and the second sleeve portion (14); the second flange portion (15) includes a protruding annular radial extension portion (35), which protrudes in a cantilever manner in the axial direction on the side opposite to the first annular element (9) and defines the radial edge (22) of the second flange portion; the recess (25) is formed on the protruding annular radial extension portion (35) on the side opposite to the first flange portion.

9. The sealing device according to claim 5, characterized in that: The substantially rigid annular reinforcing element (29) is made of metal.

10. The sealing device according to claim 5, characterized in that: The annular insert (30) is co-molded on the annular reinforcing element (29) on the side opposite to the first annular element and defines, together with the annular reinforcing element (29), the radial edge (22) of the second flange portion of the second annular element.

11. The sealing device according to claim 8, characterized in that: The substantially rigid annular element (34) is made of metal.

12. A sealing system (36) comprising a sealing device (8) according to any one of the preceding claims and a first mechanical part (6) and a second mechanical part (5), the first mechanical part (6) and the second mechanical part (5) being coupled to each other such that the second mechanical part is rotatable when the first mechanical part is stationary, characterized in that The first annular element (9) is integrally fixed at an angle to the first mechanical component (6) which is stationary during use, and the first annular element (9) is accommodated inside an annular compartment (7) defined between the first mechanical component and the second mechanical component; and the second annular element (13) is integrally fixed at an angle to the second mechanical component (5) which rotates during use, and on the side opposite to the first annular element (9), the second annular element (13) is radially arranged inside the first annular element (9) and toward the outside of the annular compartment (7).

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