SEAL FOR WHEEL BEARINGS

Description

[0001] The present invention relates to a seal for sealing a wheel bearing for a motor vehicle, in particular for a passenger car and / or a truck. State of the art

[0002] Seals for sealing wheel bearings are well known in the art. For example, so-called cassette seals are used to seal wheel bearings in cars and trucks. These seals serve to protect the rolling element chamber of the wheel bearing against external contaminants such as water, dirt particles, etc. The seals are usually designed as two-part assemblies. The first assembly is a sheet metal ring connected to a stationary element of the wheel bearing, such as the inner ring. The second assembly is a sealing arrangement with sealing lips connected to an element rotatably mounted on the wheel bearing, such as a wheel hub. At least one of the sealing lips is in sealing contact with the sheet metal ring.

[0003] It has now become apparent that there is a further need to improve a known seal for sealing a wheel bearing. In particular, there is a further need to provide a seal for sealing a wheel bearing that makes it difficult or even impossible for foreign substances to penetrate the wheel bearing and enables friction-reduced operation. A seal of this type is known from DE 11 2016 004199 T5.

[0004] Against this background, it is an object of the present invention to provide an improved seal for sealing a wheel bearing for a motor vehicle, in particular for a passenger car and / or a truck, which in particular makes it more difficult or prevents the ingress of foreign substances, such as water, dirt particles, etc., and enables friction-reduced operation. Disclosure of the invention

[0005] These and other problems, which will be mentioned in the following description or which can be recognized by a person skilled in the art, are solved by the subject matter of the independent claims. Advantageous embodiments and further developments can be found in the dependent claims and the following description.

[0006] The seal according to the invention for sealing a wheel bearing for a vehicle, in particular for a passenger car or a truck, comprises a guide plate and a sealing assembly. The guide plate is configured to be rotationally fixed to a radially inner, in particular stationary, component of a wheel bearing, such as an axle journal or an inner ring of the wheel bearing. The sealing assembly is configured to be rotationally fixed to a radially outer, in particular rotatable, component of the wheel bearing, such as a wheel hub. The sealing assembly comprises a sealing plate and a radially circumferential sealing element with at least one axial sealing lip, wherein the sealing element is attached to the sealing plate, e.g., vulcanized on, and the axial sealing lip extends substantially axially in the direction of the guide plate.In this arrangement, a radially outer end section of the sealing plate and a radially outer end section of the running plate form an axial opening gap that leads into a collection chamber. The collection chamber is designed as a space between the running plate and the sealing assembly. Specifically, the collection chamber is bounded radially on the inside by the axial sealing lip. An axial gap is formed between the axial sealing lip and the running plate, and the running plate has a diversion section designed to guide or lift any foreign matter, such as dirt, water, etc., through the gap between the axial sealing lip and the running plate into the collection chamber. Furthermore, the sealing assembly has a guide section designed to direct the foreign matter out of the collection chamber by means of a rotational movement of the seal.

[0007] The advantage of the solution according to the invention lies particularly in the fact that the axial sealing lip does not rest against the running plate, thus preventing friction in this area of ​​the seal. Furthermore, the diversion section ensures that foreign substances, such as water, dirt, etc., which enter the seal through the opening gap, are directed into the collection chamber via the gap between the axial sealing lip and the running plate, thereby preventing further penetration of these foreign substances into the seal. This reduces friction within the seal during operation, while still ensuring the seal's tightness and sealing function.

[0008] The collection chamber is designed such that centrifugal forces generated by the rotational movement of the seal, particularly the sealing assembly, transport the foreign matter radially outwards, where it encounters the guide section. The guide section is designed such that the foreign matter transported to it by the centrifugal forces is guided along the guide section to the opening gap, through which it exits the collection chamber. Furthermore, the opening gap is designed to be as narrow as possible to reduce, and ideally minimize, the ingress of foreign matter into the seal. The opening gap may also feature radial centrifugal channels that assist, and in particular improve, the removal of foreign matter from the collection chamber.In particular, a plurality of axially extending rubber extensions can be formed on the rotating sealing plate, which can extend especially to the radial outer surface of the radially outer end section.

[0009] In other words, the specific arrangement of the opening gap, the collection chamber, the diversion section, and the guide section makes it difficult for foreign substances, such as water, dirt, etc., to penetrate the seal, and in particular prevents deeper penetration. Therefore, this specific arrangement can be described as forming a type of labyrinth seal designed to reduce the ingress of foreign substances and to expel any foreign substances that do enter the seal as efficiently and / or with as little friction as possible.

[0010] According to the invention, the diversion section is designed at an angle such that an imaginary extension of the diversion section does not intersect the outer diameter of the axially extending sealing lip, and in particular, extends radially outside the outer diameter of the axially extending sealing lip. The term "angled" here refers in particular to an angular course relative to the main direction of extension of the running plate, especially relative to the radial direction of the seal. Thus, the diversion section allows foreign matter that enters the seal via the opening gap to be diverted into the collection chamber. This makes it possible to form a gap between the axial sealing lip and the running plate without impairing the sealing effect of the seal. Due to the gap between the axial sealing lip and the running plate, the axial sealing lip does not touch the running plate, is therefore contactless, and thus friction-free.

[0011] According to one embodiment, the diversion section, viewed in longitudinal section, has a straight contour or a curved contour formed by at least one radius.

[0012] Furthermore, the contour of the diversion section in longitudinal section can be formed from several radii, particularly according to a logarithmic function. The imaginary extension of the curved contour is preferably the imaginary extension of one end of the diversion section facing the axial sealing lip.

[0013] According to one embodiment, the guide section, which is arranged particularly on a radially outer inner diameter of the sealing assembly, is designed as a slope inclined radially outwards towards the opening gap and is configured to guide foreign matter to the opening gap. In particular, the guide section can be formed from the sealing element attached to the sealing plate. The inclination of the guide section towards the opening gap is selected such that the foreign matter is transported along the guide section to the opening gap by the centrifugal forces resulting from the rotational movement of the seal.

[0014] According to another embodiment, the slope is essentially non-parallel to the sealing plate. In one embodiment, the slope has an inclination of approximately 10° to 40°, particularly approximately 12° to 25°, and further, particularly approximately 15° to 20°, to the longitudinal axis of the seal. This allows the slope to be designed essentially independently of the inclination of the sealing plate.

[0015] According to one embodiment, the radially outer end section of the sealing plate extends radially and is arranged essentially parallel to the radially outer end section of the guide plate. This allows the opening gap to be long and narrow. Furthermore, the radially outer end section of the sealing plate serves as a stop, simplifying the positioning of the sealing assembly, particularly in the axial direction, on the radially outer component.

[0016] According to an alternative embodiment, an end face of the radially outer end section of the sealing plate is arranged essentially parallel to the radially outer end section of the running plate. This simplifies the manufacture of the sealing plate.

[0017] According to one embodiment, the gap between the axial sealing lip and the running plate is up to 1 mm, in particular about 0.1 mm to 0.5 mm. In particular, the gap between the axial sealing lip and the running plate is large enough to reduce, in particular to avoid, friction between the axial sealing lip and the running plate, and small enough to make it difficult for foreign substances, such as water, dirt, etc., to penetrate.

[0018] According to one embodiment, the inclined surface of the guide section extends substantially to the radially outer end section of the sealing plate. Thus, foreign matter is guided by centrifugal forces along the guide section to the opening gap. According to an alternative embodiment, the sealing arrangement further comprises a cylindrical seat on the radially outer inner diameter, particularly in the region of the radially outer end section, with the inclined surface of the guide section extending substantially to the cylindrical seat. The cylindrical seat serves to simplify the manufacture and / or assembly of the sealing arrangement.

[0019] According to a further embodiment, the sealing arrangement can also have two radial sealing lips. A first of the two radial sealing lips is in sealing contact with an axially extending mounting section of the guide plate, wherein the first radial sealing lip and / or the mounting section has a friction-reducing material at least in the contact area, and a second of the two radial sealing lips is arranged radially outside the mounting section of the guide plate such that a radial gap is formed between the mounting section of the guide plate and an inner diameter of the second radial sealing lip. This significantly reduces friction during the seal's operation, while still ensuring the sealing function of the seal.

[0020] The second radial sealing lip, which can also be referred to as the grease lip, does not touch the mounting section, thus preventing frictional losses due to contact friction. The distance or gap between the second radial sealing lip and the mounting section is specifically chosen to make it difficult, and in particular to prevent, the ingress of foreign substances, especially lubricating grease, into the seal. Furthermore, the lack of contact reduces wear on the second radial sealing lip and thus extends its service life.

[0021] The first radial sealing lip is designed to ensure the sealing function of the seal and is therefore in sealing contact with the mounting section of the running plate.

[0022] The friction-reducing material present in the contact area between the first radial sealing lip and the mounting section reduces the friction generated during operation without impairing the sealing function of the seal. Due to the reduced friction, wear of the first radial sealing lip is also reduced, thus extending its service life.

[0023] According to one embodiment, the first radial sealing lip further comprises a spring element that biases the first radial sealing lip towards the mounting section of the guide plate. This improves the sealing function of the seal. Furthermore, this extends the service life of the seal, as the spring element keeps the first radial sealing lip in constant contact with the mounting section, even if the first radial sealing lip already exhibits wear, which can be caused in particular by contact friction.

[0024] According to one embodiment, the first radial sealing lip has an inlay made of a friction-reducing material, e.g., PTFE, or the first radial sealing lip has a coating of the friction-reducing material, at least in the contact area with the mounting section. The inlay is received in the first radial sealing lip in such a way that it is in sealing contact with the mounting section. This reduces friction during the seal's operation. Furthermore, this significantly reduces, and in some cases even prevents, wear of the first radial sealing lip. The inlay can also be received in the first radial sealing lip in such a way that it is replaceable. This makes it possible to replace the inlay as a wear part and extend the overall service life of the seal.The coating of the first radial sealing lip with the friction-reducing material can be applied easily, and is therefore easier and / or more cost-effective to manufacture.

[0025] According to one embodiment, the mounting section has a coating of the friction-reducing material, e.g., PTFE, at least in the contact area with the first radial sealing lip. The coating of the mounting section with the friction-reducing material can be provided in addition to or as an alternative to the inlay or coating of the first radial sealing lip. By coating the mounting section with the friction-reducing material, the friction between the first radial sealing lip and the mounting section can be (further) reduced without impairing the sealing function of the gasket.

[0026] According to one embodiment, the radial gap between the second radial sealing lip and the mounting section is up to 1 mm, in particular 0.1 mm to 0.5 mm. This gap is sufficiently large to reduce or prevent friction between the second radial sealing lip and the mounting section. Furthermore, the gap is also sufficiently narrow to make it difficult, and in particular even prevent, the ingress of foreign substances, especially lubricating grease from the wheel bearing.

[0027] According to one embodiment, the first radial sealing lip is positioned closer to a substantially radial section of the guide plate than the second radial sealing lip. This allows the first radial sealing lip to prevent foreign matter that has entered the seal through the gap between the second radial sealing lip and the mounting section from penetrating deeper into the seal. Furthermore, the sealing contact between the first radial sealing lip and the mounting section can be considered a kind of partition separating a so-called grease zone of the seal from a so-called water zone. The grease zone is understood to be the area of ​​the seal that, in the operating state, faces the wheel bearing, in particular the bearing housing, and is thus designed to substantially prevent lubricating grease from escaping the bearing.The water area refers to the area of ​​the seal that, in the operating state, is located away from the wheel bearing and is thus designed to essentially prevent foreign substances, such as water or dirt, etc., from penetrating the bearing from the outside.

[0028] According to one embodiment, the mounting section extends axially at least to the level of the second radial sealing lip. Such an extended mounting section reduces, and in particular prevents, foreign substances, such as water, dirt, etc., from penetrating the wheel bearing via a static sealing surface to the first component, e.g., the inner ring of the wheel bearing. Furthermore, the extended mounting section can prevent the first radial sealing lip from accidentally slipping off the mounting section during assembly and / or transport.

[0029] According to one embodiment, the assembly section is designed to be mounted, or to be mountable, onto the radially inner component by means of a press fit.

[0030] This makes mounting the seal, especially the guide plate, onto the radially inner component simple and cost-effective.

[0031] According to one embodiment, the mounting section has a coating on its inner side, i.e., the side facing the radially inner component, which has a static sealing effect. This improves the seal between the guide plate and the radially inner component.

[0032] Furthermore, the invention also relates to a wheel bearing for a vehicle, such as a passenger car and / or a truck, comprising an axle stub, a wheel hub, and a wheel bearing. The wheel hub is rotatably mounted on the axle stub via the wheel bearing. The wheel bearing also includes a seal according to the invention, which is arranged for sealing the wheel bearing, in particular on the inside of the wheel. Detailed description based on drawing

[0033] Further measures improving the invention are described in more detail below, together with a description of a preferred embodiment of the invention, with reference to the figure. It shows: Fig. 1 is a schematic representation of a seal according to an embodiment of the invention in a longitudinal section view.

[0034] The figure is purely schematic and serves only to illustrate the invention. The same elements are labelled with the same reference symbols.

[0035] Fig. 1 Figure 1 shows a seal 1 in a schematic longitudinal section. The seal 1 has a guide plate 2 and a sealing assembly 3. The guide plate 2 has a substantially axially extending, sleeve-like mounting section 4 and a substantially radially extending sealing section 5. The guide plate 2 is designed to be mounted, with the mounting section 4, in a rotationally fixed manner onto a radially inner component of a wheel bearing (not shown). Typically, the guide plate 2 is designed as a static component that does not rotate during the operating state of the seal 1. The mounting section 4 extends substantially over the entire axial length of the sealing assembly 3, thereby improving the assembly and / or transport of the seal 1 as well as ensuring a static seal between the seal 1 and the radially inner component of the wheel bearing.

[0036] The sealing assembly 3 comprises a sealing plate 6 and a sealing element 7, which is attached to the sealing plate 6. The sealing plate 6 is designed to be mounted on a radially outer component of the wheel bearing (not shown). The sealing assembly 3 is typically designed as a dynamic component that rotates during the operating state of the seal 1. The sealing element 7 has an axial sealing lip 8, a first radial sealing lip 9, and a second radial sealing lip 10.

[0037] The first radial sealing lip 9 extends substantially radially towards the mounting section 4 of the running plate 2 and is in sealing contact with it. The second radial sealing lip 10 also extends substantially radially towards the mounting section 4 of the running plate 2, but does not touch the mounting section 4. This means that a radial gap 11 is formed between the second radial sealing lip 10 and the mounting section 4, which has a width of approximately 0 mm to approximately 1 mm, and more specifically, approximately 0.1 mm to approximately 0.5 mm. In the operating state of the seal 1, the second radial sealing lip 10 faces a bearing chamber of the wheel bearing (not shown) and is designed to reduce, and in particular prevent, the escape of lubricating grease from the bearing chamber. Therefore, the second radial sealing lip 10 can also be referred to as a grease lip 10.

[0038] The first radial sealing lip 9 is in sealing contact with the mounting section 4 of the guide plate 2. In the exemplary embodiment shown here, the first radial sealing lip 9 has a circumferential spring element 12 that biases the first radial sealing lip 9 towards the mounting section 4. The spring element 12 ensures a sealing contact even as wear of the first radial sealing lip 9 begins, particularly in the contact area with the mounting section 4. Furthermore, the first radial sealing lip 9 has an inlay 13 made of a friction-reducing material, such as PTFE. The inlay 13 is received in the first radial sealing lip 9 in such a way that it forms the sealing contact with the mounting section 4.This reduces friction generated during the operating state of seal 1 by rotation of the sealing assembly 3 relative to the guide plate 2. Alternatively, the first radial sealing lip 9 can be coated with a friction-reducing material, e.g., a PTFE coating, instead of the inlay 13. Additionally, or alternatively, the mounting section can be coated with a friction-reducing material, e.g., a PTFE coating.

[0039] The first radial sealing lip 9 serves to separate a grease region 14 of the seal 1 from a water region 15 of the seal 1. The grease region 14 is located facing the wheel bearing (not shown) when the seal 1 is in operation. Its purpose is twofold: firstly, to prevent the lubricating grease within the wheel bearing from escaping, and secondly, to contain a sealing grease designed to extend the service life of the seal. In other words, the grease region 14, bounded axially A on one side by the first radial sealing lip 9 and axially A on the other side by the second radial seal 10, essentially serves to contain the sealing grease.The water area 15 is located in an area which, in the operating state of the seal 1, is positioned away from the wheel bearing (not shown) and is designed to capture water and other foreign substances, such as dirt, that penetrate the seal 1 and transport them back outwards, as will be explained in more detail below.

[0040] The axial sealing lip 8 is arranged substantially outside the first radial sealing lip 9 in the radial direction and extends substantially axially towards the running plate 2, in particular towards the sealing section 5 of the running plate 2, without contacting the sealing section 5. Thus, an axial gap 16 is formed between the axial sealing lip 8 and the running plate 2. The running plate 2 further comprises a diversion section 17 and a radially outer end section 18. The diversion section 17 is arranged radially outside the sealing section 5 and extends substantially obliquely or at an angle to the sealing section 5 and, viewed radially, outwards from the sealing arrangement 3 in the direction R, and transitions into the radially outer end section 18, which extends substantially outwards in the radial direction R.

[0041] The sealing assembly 3 and the running plate 2 form a space 19, which can also be referred to as a collection chamber 19. More precisely, the collection chamber 19 is formed by a guide section 20 of the sealing assembly 3, the axial sealing lip 8, and the diverting section 17. Furthermore, the collection chamber 19 is connected to an opening gap 21, which is formed by an axial distance 22 between the radially outer end section 18 of the running plate 2 and a radially outer end section 23 of the sealing assembly 3.

[0042] The collection chamber 19 is designed to collect foreign matter, such as water, dirt, etc., which penetrates the seal 1 through the opening gap 21, and to transport it back out through the opening gap 21. For this purpose, the diversion section 17 is arranged essentially opposite the opening gap 21, so that foreign matter penetrating the seal 1 through the opening gap 21 encounters the diversion section 17. The diversion section 17 is designed to be inclined or curved in such a way that the foreign matter is lifted by the diversion section 17 along an imaginary extension 25 over the gap 16 and transported into the collection chamber 19. Thus, the diversion section 17 prevents foreign matter from penetrating further into the seal 1 via the axial gap 16 between the axial sealing lip 8 and the sealing section 5, and enables friction-reduced operation of the seal 1.Furthermore, a diameter ratio can be defined between a first diameter of the axial sealing lip 8 and a second diameter of the axial sealing lip 8, wherein the second diameter is located closer to the sealing section 5 and is larger than the first diameter. In particular, the diameter ratio can be 1:1.06, more specifically 1:1.04, and further, more specifically 1:1.02.

[0043] During operation of the seal 1, centrifugal forces are generated by the rotation of the sealing assembly 3 relative to the guide plate 2. These forces transport the foreign matter in the collection chamber 19 along the boundary walls formed by the sealing assembly 3 towards the guide section 20. The guide section 20 is designed as an inclined plane 24, which is inclined towards the opening gap 21. Thus, under the influence of the centrifugal forces, the foreign matter is transported along the guide section 20 towards the opening gap 21, through which it is conveyed outwards, also due to the centrifugal forces. Reference symbol list

[0044] 1 Seal 2 Running plate 3 Sealing arrangement 4 Mounting section (running plate) 5 Sealing section (running plate) 6 Sealing plate 7 Sealing element 8 Axial sealing lip 9 First radial sealing lip 10 Second radial sealing lip 11 Radial gap 12 Spring element 13 Inlay 14 Grease area 15 Water area 16 Axial gap 17 Diverter section 18 Radial outer end section (running plate) 19 Gap 20 Guide section 21 Opening gap 22 Axial distance 23 Radial outer end section (sealing plate) 24 Incline 25 Imaginary extension Aaxial direction Radial direction

Claims

1. A seal (1) for sealing a wheel bearing for a wheel mounting, having: a running plate (2) designed to be connected in a non-rotatable manner to a radially inner component of the wheel mounting, and a seal arrangement (3) designed to be connected in a non-rotatable manner to a radially outer component of the wheel mounting, wherein the seal arrangement (3) has a sealing plate (6) and a radially circumferential sealing element (7) with at least one axial sealing lip (8), wherein the sealing element (7) is secured to the sealing plate (6), and the axial sealing lip (8) extends substantially axially in the direction of the running plate (2), wherein a radially outer end section (23) of the sealing plate (6) and a radially outer end section (18) of the running plate (2) form an axial opening gap (21) that opens into a catch chamber (19), wherein the catch chamber (19) is designed as an intermediate space between the running plate (2) and the seal arrangement (3), wherein a gap (16) is formed in the axial direction (A) between the axial sealing lip (8) and the running plate (2), the running plate (2) has a diverting section (17) designed to guide penetrating foreign substances into the catch chamber (19) via the gap (16) between the axial sealing lip (8) and the running plate (2), and the seal arrangement (3) has a guide section (20) designed to guide the foreign substances out of the catch chamber (19) by means of a rotary movement of the seal (1), characterised in that the diverting section (17) is formed at an angle such that an imaginary extension (25) of the diverting section (17) at the transition to the substantially vertically extending sealing section (5) does not intersect an outer diameter of the axially extending sealing lip (8), in particular extends radially outside of the outer diameter of the axially extending sealing lip (8).

2. The seal (1) according to claim 1, wherein the diverting section (17) has a straight-line contour or a curved contour formed by at least one radius as viewed in a longitudinal section.

3. The seal (1) according to either one of claims 1 to 2, wherein the guide section (20) is designed as a slope (24) that is inclined radially outwards towards the opening gap (21) and is designed to guide the foreign substances to the opening gap (21).

4. The seal (1) according to claim 3, wherein the slope (24) is formed as substantially non-parallel to the diverting section (17).

5. The seal (1) according to claim 3 or 4, wherein the slope (24) has an inclination of about 10° to 40°, in particular of about 12° to 25°, further in particular of about 15° to 20°, with respect to the rotational axis of the seal (1).

6. The seal (1) according to any one of claims 1 to 5, wherein the radially outer end section (23) of the sealing plate (6) is arranged in a radially extending and in a substantially parallel manner with respect to the radially outer end section (18) of the running plate (2).

7. The seal (1) according to any one of the claims 1 to 6, wherein the gap (16) between the axial sealing lip (8) and the running plate (2) is up to 1 mm, in particular about 0.1 mm to 0.5 mm.

8. The seal (1) according to any one of claims 3 to 7, wherein the slope (24) extends substantially to the radially outer end section (23) of the sealing plate (6), or wherein the seal arrangement (3) further has a cylindrical seat at a radially outer inner diameter and the slope (24) extends substantially to the cylindrical seat.

9. A wheel mounting for a vehicle, such as a car and / or a truck, having: an axle journal, a wheel hub, a wheel bearing, wherein the wheel hub is rotatably arranged on the axle journal via the wheel bearing, and a seal (1) according to any one of the preceding claims, which is arranged for sealing the wheel bearing, in particular on an inside of the wheel.