Pre-sealing element with a rotation axis for a dynamic shaft seal arrangement, a shaft seal arrangement with a rotation axis for a dynamic seal, and a shaft assembly

Abstract

Shaft sealing arrangement (3) with a pre-sealing element (1) with an axis of rotation (2) for a dynamic shaft sealing arrangement (3), comprising at least the following components: - a radial shield (4) for covering a radial gap (5) between a first component (6) and a second component (7) rotatable relative to the first component (6); - a static support seat (8) by means of which, in operation, the pre-sealing element (1) is radially supported on the first component (6) in a statically sealing manner against an external environment (9); and - an axial sash (10) which, in use, is arranged axially overlapping with the second component (7) to form a sealing labyrinth (11), characterized in that the pre-sealing element (1) further comprises a pressure spoiler (12), wherein the pressure spoiler (12) is connected to the axial sash (10) in such a way that a pressure (13) transverse to the axial extension of the axial sash (10) on the pressure spoiler (12) tilts the axial sash (10) in the opposite direction.

Description

[0001] The invention relates to a pre-sealing element with an axis of rotation for a dynamic shaft seal arrangement, a shaft seal arrangement with an axis of rotation for a dynamic seal, and a shaft assembly.

[0002] Dynamic shaft seal assemblies with a pre-sealing element are known in various forms from the prior art, for example in the automotive sector. These assemblies consist of a radial gap between two components rotating relative to each other, and their primary function is to protect an interior space from dirt and water from the external environment. A bearing seat, for example comprising at least one rolling bearing, is formed in this radial gap or in its axial extension (on the inside of the shaft seal assembly).

[0003] JP 2015-137 754 A discloses a wheel bearing assembly with a body mounting flange that can be mounted on a steering knuckle and is an integral part of an outer ring with double-row raceways formed on its inner circumference. A wheel mounting flange is an integral part of a cylindrical wheel hub projecting axially outwards at the end face of the hub. At least one inner ring is pressed into the wheel hub and has double-row raceways on its outer circumference, opposite the raceways of the outer ring. Rolling elements are mounted in two rows between the respective raceways of the inner and outer rings. A seal is arranged at each of the lateral openings of the annular gap formed between the inner and outer rings. The outer circumferential part of the bearing is fitted into a receiving bore formed in the steering knuckle.A metal cover ring is pressed into the opening between the inner and outer rings at one end face of the inner ring, closing the opening and forming a labyrinth seal. The cover ring is positioned close to the receiving bore of the steering knuckle. The cover ring has a cylindrical mating area for pressing into the inner ring and a circular segment projecting radially outwards from this area. A sealing lip is integrated on the inside of the seal, angled outwards towards the inner side of the wheel and opposite the end face of the circular segment of the cover ring.

[0004] DE 103 58 876 A1 discloses a seal with deflector rings arranged concentrically around an axis of rotation and without contact with each other, wherein a first deflector ring has at least two axially adjacent radial ribs which are arranged without contact with a second deflector ring. An annular first cavity is formed between at least two axially adjacent radial ribs and the second deflector ring, which separates the radial ribs axially from each other so that they are freely opposite each other; the cavity is bounded in one radial direction by the second deflector ring and in the opposite direction by the first deflector ring.

[0005] With the increasing electrification of vehicle powertrains, reducing losses is becoming ever more crucial. It has been found that the shaft seal assembly also generates a significant friction loss. The aim is to reduce this friction loss while adhering to strict cost constraints.

[0006] Based on this, the present invention aims to overcome, at least partially, the disadvantages known from the prior art. The features of the invention are defined in the independent claims, for which advantageous embodiments are shown in the dependent claims. The features of the claims can be combined in any technically meaningful way, whereby the explanations in the following description and features from the figures, which comprise supplementary embodiments of the invention, can also be used.

[0007] The invention relates to a shaft seal arrangement and a pre-sealing element with an axis of rotation for a dynamic shaft seal arrangement, comprising at least the following components: - a radial shield for covering a radial gap between a first component and a second component that can rotate relative to the first component; - a static support seat by means of which, in operation, the pre-sealing element is radially supported on the first component in a statically sealing manner against an external environment; and - an axial sash which, in use, is arranged axially overlapping with the second component, forming a sealing labyrinth.

[0008] The pre-sealing element is characterized primarily by the fact that the pre-sealing element further comprises a pressure spoiler, wherein the pressure spoiler is connected to the axial sash in such a way that a pressure transverse to the axial extension of the axial sash on the pressure spoiler tilts the axial sash in the opposite direction.

[0009] The following text refers to the aforementioned axis of rotation whenever the axial direction, radial direction, or direction of rotation and corresponding terms are used, unless explicitly stated otherwise. Ordinal numbers used in the preceding and subsequent descriptions serve solely for unambiguous identification and do not indicate any order or ranking of the components referred to. An ordinal number greater than one does not necessarily imply the presence of another such component.

[0010] The pre-sealing element proposed here offers the advantage, compared to previously known pre-sealing elements, that it can be used with a dynamic shaft seal assembly with low friction or even frictionless (i.e., contactless). Simultaneously, excellent sealing is achieved by means of this pre-sealing element even under external pressure, for example, from dirty water or a high-pressure cleaner. In a preferred embodiment, the associated dynamic shaft seal assembly is completely shielded in such a state, where the pressure spoiler moves the axial tab.

[0011] The pre-sealing element is formed circumferentially around an axis of rotation and has as its main element a radial shield, by means of which the radial gap between a first component and a second component is covered, i.e., bridged and shielded. For example, such a radial shield is a disc portion (or a separate disc) of the pre-sealing element.

[0012] The pre-sealing element further comprises a static support seat by means of which the pre-sealing element is radially supported on the first component and forms a static seal with this first component. In one embodiment, the static support seat is designed for a metallic pairing. In another embodiment, the static support seat of the pre-sealing element comprises a plastic, preferably a rubber-elastic plastic, on the component side (i.e., for contact or the sealing effect). In a preferred embodiment, the static support seat has an axial extension, with, for example, an L-shape being formed in cross-section by means of the radial shield and the static support seat. It should be noted that, depending on the application, the static support seat is arranged radially outward, radially inward, or at a mean radial height relative to the radial shield.Preferably, the support seat is supported on the rotating component during use.

[0013] The pre-sealing element proposed here also features an axial flange, which, due to axial overlap with the other (i.e., second) component, forms a sealing labyrinth in operation. A sealing labyrinth is a channel with at least one bend, preferably a 90° bend [ninety degrees of 360°], such that incoming fluid does not experience a deflection sufficient to generate significant back pressure.

[0014] Here, the second component has an axial outer surface with which the axial flange of the pre-sealing element axially overlaps during use. Alternatively, the second component has a recess with axial extension into which the axial flange is arranged to be axially inserted during use. In an advantageous embodiment, the axial flange is arranged radially outside the axially overlapping (corresponding) outer surface of the second component. Alternatively, the axial flange is arranged radially inside the corresponding outer surface of the second component.

[0015] It is proposed here that the pre-sealing element further comprises a pressure spoiler, by means of which a mechanical connection to the axial sleeve is formed such that, depending on a pressure applied transversely to this pressure spoiler, the axial sleeve can be tilted with a radial component of movement. In one embodiment, pressure, for example from a water jet of a high-pressure cleaner, is directed radially inwards onto the pressure spoiler, and the axial sleeve is moved radially inwards as a result of the reaction of the pressure spoiler (a radially outwards movement). Thus, in the area of ​​overlap with the second component, the axial sleeve is pressed towards the corresponding outer surface of the second component, for example against the second component, thereby narrowing or even closing the sealing labyrinth.

[0016] In an advantageous embodiment, the pressure spoiler extends axially away from the axial plate towards the external environment and is connected to the axial plate via a joint at the radial plate, thus transmitting force. In one embodiment, the pressure spoiler and the axial plate are arranged in a T-shape relative to the radial plate in cross-section, i.e., this arrangement is T-shaped in cross-section. For example, the joint is made of a rubber-elastic material; preferably, the entire pressure spoiler and / or the entire axial plate is made of a rubber-elastic material. In one embodiment, the radial plate is made significantly stiffer than the joint and / or the pressure spoiler or the axial plate.

[0017] A shaft seal assembly with a rotation axis for a dynamic seal can have at least the following components: - a radial shaft seal with at least one dynamic sealing lip for contact with a first component rotatable relative to the radial shaft seal and with a static sealing seat for contact with a second component fixed to the radial shaft seal; and - a pre-sealing element with a static support seat, by means of which, in operation, the pre-sealing element is radially supported on the first component in a statically sealing manner against an external environment, and with a radial shield, by means of which, in operation, a radial gap between the first component and the second component is projected, wherein, in operation, the pre-sealing element is arranged axially outside with respect to the radial shaft seal.

[0018] The shaft seal arrangement is designed so that the radial shaft seal ring and the pre-sealing element are arranged without contact with each other.

[0019] To protect an interior space with a shaft extending to the outside environment from external environmental influences during operation, a shaft seal assembly is proposed here. Furthermore, it is a function of the shaft seal assembly to prevent lubricant (e.g., grease or oil) from leaking out. This function is usually fulfilled solely by the radial shaft seal. The shaft seal assembly comprises a radial shaft seal and a pre-sealing element. The radial shaft seal is, for example, of conventional design and includes a dynamic sealing lip. The dynamic sealing lip is designed to bear against a (first) component that rotates relative to the radial shaft seal. This bearing against the sealing lip, and thus the sealing effect, is usually ensured by a separate energy storage element (e.g., a coil spring or worm spring).In one embodiment, the radial shaft seal ring comprises a plurality of dynamic sealing lips and / or at least one non-contacting pre-lip.

[0020] Furthermore, the radial shaft seal comprises a static sealing seat which, in operation, is positioned in contact with a (second) component fixed to the radial shaft seal. The radial shaft seal covers a radial gap, leaving only one (statically sealed) gap at the static sealing seat and one (dynamically sealed) gap at the at least one dynamic sealing lip. It should be noted that it is irrelevant whether the first or the second component is rotatable. Preferably, the static sealing seat is formed with the stationary (fixed) component, so that the radial shaft seal is also mounted vertically.

[0021] Furthermore, the shaft seal assembly includes a pre-sealing element. This pre-sealing element is designed as described above. However, it is not necessary to include an axial shim and / or a pressure spoiler. The pre-sealing element is formed circumferentially around an axis of rotation and has a radial shield as its main element. This shield covers, i.e., bridges and seals, the radial gap between a first component and a second component. The radial shield extends beyond the radial dimension of the radial gap, thus already forming an axial and / or radial gap to the second component. For example, such a radial shield is a disc portion (or a separate disc) of the pre-sealing element. In operation, the pre-sealing element is radially supported against the external environment by means of a static bearing seat on the first component, providing a static seal.The first component is the one against which the dynamic sealing lip of the radial shaft seal rests during operation. It should be noted that the first component can also be designed as an assembly, in which separate parts (for example, axially or as a sleeve) are connected to one another. The bearing seat is designed such that a static seal is formed with the first component. In one embodiment, the static bearing seat is designed for a metallic pairing and is, for example, joined to the first component by press fit. In another embodiment, the static bearing seat of the pre-sealing element comprises a plastic, preferably a rubber-elastic plastic, on the component side (i.e., for the contact or sealing effect).In a preferred embodiment, the static support seat has an axial extension, with the radial shield and the static support seat forming an L-shape in cross-section. It should be noted that, depending on the application, the static support seat is arranged radially outward, radially inward, or at a mean radial height relative to the radial shield. Preferably, the support seat is supported on the rotating component during use.

[0022] For example, the radial shield is made of plastic and / or sheet metal, and a combination of both materials is also possible. It should be noted that the pre-sealing element is positioned axially and externally relative to the radial shaft seal. This means the pre-sealing element is positioned to provide effective shielding from the external environment and to block any direct path to the radial shaft seal.

[0023] It is further proposed here that the radial shaft seal and the pre-sealing element within the shaft seal assembly be arranged relative to each other in such a way that they are free from contact with one another. Thus, they are arranged without contact with each other within the shaft seal assembly during operation. Due to the contactless arrangement of the two components, (at least during normal operation) fewer, and in a preferred embodiment no, friction losses are caused by the shaft seal assembly.

[0024] In an advantageous embodiment, an axial shim is provided at the end of the radial shield radially opposite the support seat, for example, of the type and function described above. Under normal operating conditions, the axial shim is preferably also arranged without contact, i.e., a radially extending (ring-shaped) gap is formed between the axial shim and the second component.

[0025] It should be noted that a gap as part of a sealing labyrinth is preferably between 0.5 mm [half a millimeter] and 3 mm, particularly preferably equal to or less than 1.5 mm. A gap length in a sealing labyrinth is preferably several millimeters, for example more than 4 mm [four millimeters]. The selection is to be made according to the available installation space as well as the permissible manufacturing and assembly tolerances (for example, concentricity and runout).

[0026] In a further advantageous embodiment of the shaft sealing arrangement, it is proposed that a first trapping chamber is formed axially outside the dynamic sealing lip by the pre-sealing element.

[0027] The first collection chamber is located on the side of the pre-sealing element facing away from the outside environment, i.e., axially within the shaft seal assembly. This first collection chamber also has a radially outward opening and is, for example, U-shaped. The opening of the first collection chamber is designed such that water penetrating from the outside collects within it. Here, too, the rotation of one of the components induces an expulsion movement, so that a large portion of the water that has penetrated and been collected by the first chamber is transported out of the shaft seal assembly.

[0028] In a further advantageous embodiment of the shaft seal arrangement, it is proposed that a second trapping chamber is formed axially outside the dynamic sealing lip of the radial shaft seal ring.

[0029] As described above, the circumferential radial shield of the pre-sealing element creates a barrier to the direct path to the radial shaft seal. Access is therefore only possible via a coiled channel (sealing labyrinth). However, because this results in a reduced sealing effect, preferably an open gap, water can still penetrate the shaft seal assembly between the pre-sealing element and the radial shaft seal. Therefore, it is proposed here that a second collection chamber be formed by the radial shaft seal. Preferably, the second collection chamber is arranged radially centrally with respect to the radial gap on the radial shaft seal. The second collection chamber is formed axially further out than the at least one dynamic sealing lip. In one embodiment, the dynamic sealing lip is directed radially inwards.The second collection chamber is then, for example, arranged on the radial wall of the radial shaft seal between the static sealing seat and the dynamic sealing lip. In one embodiment, the dynamic sealing lip is oriented axially and outwards. The second collection chamber is then arranged radially further outwards, preferably also on the radial wall of the radial shaft seal.

[0030] The second collection chamber is designed with a radially outward opening, for example, in a U-shape. This opening is configured so that water entering from the outside collects within the second chamber. It has been shown that rotating one of the components (preferably the first component) within the shaft seal assembly induces an expulsion movement, thereby transporting a large portion of the water that has entered and been collected in the second chamber out of the shaft seal assembly.

[0031] In an advantageous embodiment of the shaft seal arrangement, it is further proposed that the first trapping chamber is arranged further outwards in a channel between the outside and the dynamic sealing lip of the radial shaft seal than the second trapping chamber of the radial shaft seal according to an embodiment as described above.

[0032] In one embodiment, the first collection chamber is arranged radially closer to the axis of rotation than the second collection chamber. In a preferred embodiment, the first collection chamber is arranged radially further outward than the second collection chamber, so that only an overflow or (less frequently) splash can penetrate into the second collection chamber. The first collection chamber is located within a channel that connects the external environment to the radial shaft seal at the radial end of the shaft sealing assembly. The first collection chamber is, for example, formed integrally with the radial shield of the pre-sealing element. It should be noted that the second collection chamber of the radial shaft seal is functionally designed according to at least one of the above embodiments.

[0033] The channel between the external environment and the at least one dynamic sealing lip is formed by the sealing labyrinth of the shaft seal assembly. Preferably, the channel is designed to discharge any water that has penetrated the channel. The flow obstructions formed by the at least one collection chamber are designed such that water can be discharged from the channel more easily than water can penetrate it.

[0034] In a further advantageous embodiment of the shaft sealing arrangement, it is proposed that a sealing labyrinth is formed by the pre-sealing element in axial overlap with the first component and the second component.

[0035] It should be noted that in the embodiments described above, a sealing labyrinth is formed, for example, exclusively by means of radial overlap (e.g., by means of a radial overhang of the radial shield) and / or by means of at least one of the trap chambers. In one embodiment, alternatively or additionally, a sealing labyrinth is formed by means of the aforementioned axial flange, i.e., solely by axial overlap with a shoulder of the second component and thus on the inlet side of the sealing labyrinth, preferably radially outside the second component. In an alternative or additional embodiment, an axial overlap with the first component and the second component is formed by means of a (first) trap chamber (as described above).The axial overlap and the resulting radial gap of small radial extent not only reduce the probability of dirt and water entering from the external environment, but also create a flow obstruction or increased flow resistance for any water that may enter.

[0036] In an advantageous embodiment, a sharp kink is formed in the channel following the axial overlap, for example with a radial or even opposing axial extension. This results in a flow pattern that generates dynamic pressure and thus further increases flow resistance. Furthermore, a radial component preferably creates an opposing outflow during rotating operation.

[0037] In an advantageous embodiment of the shaft seal arrangement, it is further proposed that the pre-sealing element is made at least partially of a plastic, preferably a fiber-reinforced plastic.

[0038] In one embodiment, the bearing seat of the pre-sealing element is made of a sheet metal part, preferably a metal sheet. This has the advantage that the pre-sealing element can be connected to the first component in a rotationally fixed manner, for example by means of a press fit, and can be sealed either on its own or together with an intermediate (preferably rubber-elastic) plastic component. Plastic, on the other hand, has the advantage of usually being corrosion-free and / or lighter than a conventional pre-sealing sheet and potentially more cost-effective to manufacture (for example, by injection molding).

[0039] In one embodiment, the radial shield and / or the optional first collection chamber of the pre-sealing element is made of plastic. In a preferred embodiment, the plastic components of the pre-sealing element are at least partially formed from a fiber-reinforced plastic, for example, using glass fibers, carbon fibers, and / or aramid fibers. Preferably, the axial plate, the radial shield, and / or the first collection chamber are formed from the fiber-reinforced plastic.

[0040] In an advantageous embodiment, a metal sheet core is at least partially (preferably completely) encased by one or more plastics, for example by (preferably multi-component) injection molding.

[0041] In an advantageous embodiment of the shaft seal arrangement, it is further proposed that the pre-sealing element is formed according to an embodiment as described above, wherein preferably the radial shield has a rigid core and the pressure spoiler and the axial ash are formed in a rubber-elastic manner.

[0042] The pre-sealing element is designed according to an embodiment as described above. In a preferred embodiment, the radial shield is alternatively or additionally designed with a stiffening core. For example, the core is made of a metal sheet or a fiber-reinforced plastic. The pressure spoiler and the axial sleeve, on the other hand, are made of a rubber-elastic plastic or material. The rubber-elastic plastic of the pressure spoiler and the axial sleeve is shaped such that the axial sleeve can tilt with a radial component of movement. In one embodiment, by means of external pressure (for example, from a water jet of a high-pressure cleaner), which is directed radially inward onto the pressure spoiler, the axial sleeve is moved radially inward as a result of the reaction of the pressure spoiler (a radially outward movement).This reduces or closes the gap present in the overlap area of ​​the axial ash during use.

[0043] A shaft assembly can therefore have at least the following components: - a first component, - a second component, wherein the first component is rotatable relative to the second component and between which a radial gap is formed; - a radial shaft seal with at least one dynamic sealing lip, which rests against the first component, which is rotatable relative to the radial shaft seal, and with a static sealing seat against the second component, which is fixed to the radial shaft seal; and - a pre-sealing element with a static support seat, by means of which the pre-sealing element is radially supported on the first component in a statically sealing manner against an external environment, and with a radial shield, by means of which the radial gap between the first component and the second component is covered up to an axial channel with a radial extension, wherein the pre-sealing element is arranged axially outside with respect to the radial shaft seal.

[0044] The shaft assembly can be designed such that the axial channel has an inlet and the radial gap has an axially outer outer edge, wherein an axial distance between the inlet of the axial channel and the outer edge of the radial gap is greater in magnitude than the radial extent of the axial channel, and that the radial shaft seal and the pre-sealing element are arranged without contact with each other.

[0045] A shaft assembly comprises a shaft and a bearing seat for the shaft, wherein the shaft is rotatable about an (imaginary) axis of rotation. The shaft assembly comprises a first component, for example, the shaft, and a second component, for example, a housing with a bearing seat. The first component and the second component are rotatable relative to each other, with preferably only one of the two components (generally the shaft) rotating in space. The shaft comprises (assembled in one piece or detachably) for example, a plurality of different other components, such as gear teeth, a shaft connection, or a belt receptacle. In one embodiment, the shaft assembly is part of a gear stage.

[0046] It should be noted that the components along the axis of rotation may have different radial distances, meaning that a radial gap does not necessarily have to be parallel to the axis of rotation and / or have the same radial extent.

[0047] To prevent the ingress of dirt particles and / or water and thus ensure the desired service life of the shaft assembly, a pre-sealing element and a radial shaft seal (shaft sealing arrangement) are provided. The radial shaft seal is designed, for example, as in one of the aforementioned embodiments and / or conventionally. In this embodiment, the pre-sealing element can be designed particularly simply and cost-effectively, and can also be arranged without contact with the radial shaft seal. The pre-sealing element is sealedly connected to the first component by means of a bearing seat, for example, as in the embodiments described above.Reference is also made here to the embodiments of the preceding description with regard to the materials, wherein the pre-sealing element is preferably formed entirely from a sheet of metal, particularly preferably metal sheet without plastic coating.

[0048] Furthermore, the pre-sealing element forms an axial channel in the second component, wherein the axial channel has an axial extent that corresponds at least to the radial extent (gap width or ring width) of the axial channel, and is preferably many times greater. The axial channel significantly reduces the potential angle of entry for water from the external environment.

[0049] It is proposed here that the (outer) inlet, i.e., the inlet facing away from the radial shaft seal, of the axial channel is offset inwards within the radial gap. Thus, there is an axial distance between the inlet of the axial channel and the (outer) outer edge of the radial gap, preferably of the second component, where this axial distance is greater in magnitude than the radial extent of the axial channel. In one embodiment, the axial distance is at least half the axial extent of the axial channel. In another embodiment, the axial distance is exactly or greater than twice the radial extent of the axial channel. It should be noted that the radial extent is not necessarily constant over the axial extent of the axial channel. In that case, the reference value considered here is the maximum radial extent of the axial channel.In one embodiment, a back pressure of up to approximately 20 MPa [twenty megapascals] can be achieved using the axial channel.

[0050] The outer edge of the radial gap is, for example, a circumferential edge between the cylindrical receptacle of the second component, which encompasses the bearing seat for the first component, and an outer surface of the second component, which extends radially. The outer edge thus borders, or forms the boundary with, the beginning of the radial gap and / or the wall of the second component, which is also present in the axial channel.

[0051] Due to the axial offset of the axial channel inwards, i.e., away from the external environment or the outer edge and towards the radial shaft seal, the potential entry angle for water from the external environment is further reduced. This interaction already achieves a very good pre-seal. In many applications, due to the surrounding structure, water ingress along a line congruent with the axial channel is therefore impossible.

[0052] In an advantageous embodiment, the pre-sealing element is formed from a sheet metal part, preferably by cold forming, for example deep drawing, and has a P-shape in cross-section extending from the bearing seat, with the P being open at the rear towards the external environment. A U-shape is thus formed adjacent to the axial channel, which is held radially spaced from the bearing seat by a disc. The U-shape is suitable for collecting water impacting the radial shield and preventing it from flowing into the axial channel, preferably facilitating its discharge into the external environment.

[0053] In a preferred embodiment, the radial shaft seal ring is designed with a (second) trapping chamber, wherein the axial channel is arranged to overlap axially with the second trapping chamber.

[0054] Preferably, a radial gap is formed between the second trap chamber and the pre-sealing element, which has approximately the same radial extent as the axial channel.

[0055] In one embodiment, the radial shaft seal is provided to be replaceable. For this purpose, installation space is provided so that a new radial shaft seal can be inserted axially displaced by preferably 1 mm to 4 mm, and particularly preferably by 2 mm or 2.5 mm. This is often necessary due to the formation of wear grooves and axial corrosion on the outer surface of the first component. To keep the axial distance between the radial shaft seal and the pre-sealing element constant or similar for optimal operation of the sealing labyrinth, the pre-sealing element must also be displaced axially inwards by the aforementioned amount. In this embodiment, it is advantageous that the pre-sealing element does not protrude beyond the radial gap and can therefore be inserted into it.In an embodiment where the radial shield of the pre-sealing element projects beyond the radial gap, one solution is to design an axial distance that is, for example, 0.5 mm to 1 mm larger than the necessary displacement of the replaced radial shaft seal. Alternatively, the pre-sealing element is replaced accordingly.

[0056] According to another aspect, a shaft assembly is proposed, comprising at least the following components: - a first component, - a second component, wherein the first component is rotatable relative to the second component and between which a radial gap is formed; and - a shaft sealing arrangement according to an embodiment as described above, by means of which the radial gap between the first component and the second component is dynamically sealed against an external environment, wherein preferably the first component is designed as a shaft and the second component comprises a bearing seat for the first component designed as a shaft. The shaft assembly further comprises a shaft seal arrangement according to one of the above embodiments. The shaft seal arrangement is designed such that the radial gap is dynamically sealed against the external environment. This prevents the ingress of dirt particles into the radial gap and ensures the desired service life of the shaft assembly. Furthermore, it is a function of the shaft seal arrangement to prevent a lubricant (e.g., grease or oil) from escaping. This function is usually fulfilled solely by the radial shaft seal ring.

[0057] In a preferred embodiment, the first component is designed as a shaft and arranged for rotation about the axis of rotation. The second component is fixed relative to the first component and includes at least one bearing seat for the shaft. A friction-reducing bearing element, for example a rolling bearing or a rolling bearing assembly, is preferably arranged between the shaft and the bearing seat.

[0058] In an advantageous embodiment of the shaft assembly, it is further proposed that the pre-sealing element is designed according to an embodiment as described above and that the axial shim comprises a contact lip. wherein preferably the second component comprises a running groove complementary to the contact lip, the contact lip is dipped radially into the running groove of the second component as a result of corresponding pressure transverse to the axial extension of the axial plate on the pressure spoiler.

[0059] If water under high pressure impacts the shaft assembly (for example, using a high-pressure cleaner), water ingress into a conventional shaft assembly cannot be ruled out. Therefore, it is proposed here that the pre-sealing element, according to one embodiment, be designed as described above and additionally include a contact lip on the axial sleeve. The contact lip is, for example, formed integrally with the axial sleeve and, in one embodiment, represents a thickening of the axial sleeve at one axial end.

[0060] To ensure an increased sealing effect, in a preferred embodiment the second component is designed such that it includes a running groove complementary to the contact lip. The running groove is designed as a circumferential recess of the second component. In one embodiment, the contact lip is arranged with a radial overlap, i.e., immersed in the running groove. In a preferred embodiment, during normal operation (without increased pressure on the pressure spoiler), the contact lip is spaced from the running groove to such an extent that there is no radial overlap with the running groove, i.e., the contact lip is radially spaced axially laterally to the running groove relative to the imaginary extension of the remaining surface.

[0061] The pre-sealing element, together with the integrated pressure spoiler, is designed such that, by means of a hinge, the axial sleeve can be immersed in the complementary running groove with its contact lip when the corresponding pressure occurs. The hinge is designed and arranged such that only a predefined portion of the axial sleeve immerses radially. In one embodiment, the annular gap, i.e., the distance between the axial sleeve and the axial extension of the second component, can thus be reduced, with the contact lip and the running groove being arranged without contact. Due to the narrowing of the annular gap, a further or extended sealing labyrinth is created.

[0062] In an alternative embodiment, the joint of the pre-sealing element is designed such that, under appropriate pressure, a defined (thin) contact line can be established between the contact lip and the running groove. This results in an additional seal with a minimally increased friction loss. It should be noted that the use of high-pressure cleaners, which generate sufficient water pressure, is only possible at very low rotational speeds of the shaft assembly. Therefore, the friction loss in the considered application is very low or negligible, and damage to the contact lip is prevented.

[0063] The invention described above is explained in detail below against the relevant technical background with reference to the accompanying drawings, which show preferred embodiments. The invention is in no way limited by the purely schematic drawings, although it should be noted that the drawings are not dimensionally accurate and are not suitable for defining size relationships. It is illustrated in Fig. 1: a gear stage with a shaft assembly and a conventional shaft seal arrangement; Fig. 2: a cross-sectional view of a shaft seal arrangement in a first embodiment; Fig. 3: a cross-sectional view of a shaft seal arrangement according to Fig. 2 in a second embodiment; Fig. 4: in a cross-sectional view a shaft seal arrangement in a third embodiment; Fig. 5: in a cross-sectional view a shaft seal arrangement in a fourth embodiment; Fig. 6: a cross-sectional view of a shaft seal arrangement in a fifth embodiment; and Fig. 7: in a cross-sectional view a shaft seal arrangement in a sixth embodiment.

[0064] In Fig. Figure 1 shows a gear stage 33 with a shaft assembly 23 and a conventional shaft seal arrangement 49 in a sectional view. As shown, an axis of rotation 2 runs approximately in the center of the image from left to right, with the gear stage 33 arranged around this axis of rotation in the plane of the image. In this embodiment, the gear stage 33 is a planetary gear unit in a gear housing 34 and is connected to a shaft connection 35 by means of a shaft 29, which is arranged coaxially to the axis of rotation 2. A conventional shaft seal arrangement 49 is arranged axially overlapping the shaft connection 35.

[0065] The shaft assembly 23 comprises a first component 6, which here is configured as the shaft 29 and is designed for rotation about the axis of rotation 2, a second component 7, which is fixedly mounted relative to the first component 6, and a conventional shaft seal assembly 49. As shown, to the right of the conventional shaft seal assembly 49, the second component 7 is designed such that a bearing seat 30 is formed there, the bearing seat 30 being designed to receive an (outer) shaft bearing 36. Radially inside the outer shaft bearing 36, an inner shaft bearing 37 (for the sun gear of the planetary gear) is arranged. The conventional shaft seal assembly 49 comprises a conventional pre-sealing plate 50 and a conventional radial shaft seal 52.It is clearly evident here that in this conventional embodiment, the conventional pre-sealing plate 50 separates the axially inner area of ​​the conventional shaft seal assembly 49 from an external environment 9. The conventional pre-sealing plate 50 is torque-resistantly connected to the shaft connection 35, or rather via its outer surface 38, for example by crimping. A frictional contact is formed between the conventional pre-sealing plate 50 and the conventional radial shaft seal 52, namely a conventional axial lip 51, which rubs against the conventional pre-sealing plate 50.

[0066] In Fig. Figure 2 shows a cross-sectional view of a shaft seal arrangement 3 in a first embodiment. The shaft seal arrangement 3 comprises a pre-sealing element 1 and a radial shaft seal 15, wherein the radial shaft seal 15 is arranged between the first component 6 and the second component 7, i.e., in the radial gap 5, and the pre-sealing element 1 is positioned outside the radial gap 5. For example, in use replacing the conventional shaft seal arrangement 49 according to Fig. The first component 6 is designed as a shaft 29. Radially outside the first component 6, the second component 7 is arranged with a radial gap 5. The second component 7 is designed according to its use in the construction situation as shown. Fig. 1 the gearbox housing 34 with the bearing seat 30.

[0067] The pre-sealing element 1 is arranged on the left (i.e., further out) as shown and is torque-resistant to the first component 6 by means of a support seat 8. The support seat 8 is formed, for example, from a (here L-shaped) sheet metal part. A radial shield 4, for example, injection-molded from a plastic 21, is integrally connected to the support seat 8. The radial shield 4 extends radially so that the radial gap 5 is completely covered, thus preventing the ingress of dirt particles and / or water on a direct path to the radial shaft seal 15. An axial shim 10 is also integrally formed with the radial shield 4 and is arranged here with axial overlap with the second component 7. A (narrow) axial annular gap 40 is thus formed between the second component 7 and the axial shim 10, which effectively reduces the ingress of water.As shown, a first collection chamber 19 is connected to the radial shield 4 on the inside below the axial plate 10. In this embodiment, it is also formed in one piece, for example, injection-molded from a plastic 21. The first collection chamber 19 is (purely optionally) designed here such that it is also arranged axially overlapping with the second component 7 (but radially inside it). The first collection chamber 19 is designed to collect incoming water and is (purely optionally) L-shaped. The radial shield 4, the axial plate 10, and the first collection chamber 19 are preferably made of a fiber-reinforced plastic 21.

[0068] Within the radial gap 5, the radial shaft seal 15 is arranged, comprising a plurality of dynamic sealing lips 16 and fixed to the second component 7 by means of a static sealing seat 17. These functions are, for example, conventional. Additionally, the radial shaft seal 15 includes a (second) collection chamber 18, which, as shown, is arranged inwards towards the channel, i.e., radially inside, the first collection chamber 19 of the pre-sealing element 1. The sealing lips 16 (here three) are in contact with the shaft 29 and are clamped to the shaft 29 by means of an energy storage element 39 (for example, a worm spring). It should be noted that a dynamic sealing lip 16 can also be implemented without a separate energy storage element 39, for example, as a diaphragm shaft seal or as a PTFE sealing lip (lower coefficient of friction).The radial shaft seal 15 is reinforced here (purely optionally) by means of a (preferably metallic) sheet (here, purely optionally, L-shaped). It should be noted that in this embodiment, the two collection chambers 18, 19 are U-shaped, with the opening directed radially outwards.

[0069] The shaft seal assembly 3 is designed by means of the axial shroud 10 and the two collection chambers 18, 19 such that these form a channel 20 in the radial direction, creating a sufficiently complex sealing labyrinth 11. Any water that may penetrate the channel 20 cannot, or can only penetrate to a very small extent, enter the radial gap 5. Due to their mass and inertia, dirt particles can only penetrate to the dynamic sealing lips 16 if they are very small. These particles are easily removed and / or, even if they do penetrate, are of little to no harm to the dynamic sealing lips 16 and / or the components (e.g., rolling bearings, gears) inside (in or behind the sealed radial gap 5). At the same time, any water and dirt that do penetrate is easily removed by gravity when stationary, or at least by centripetal force during operation of the shaft assembly 23.

[0070] In Fig. Figure 3 shows a shaft seal arrangement 3 in a cross-sectional view. Fig. 2 in a second embodiment. The shaft seal arrangement 3 is, without exclusion of the general principles, shown for the sake of clarity only, largely analogous to that shown in Fig. The embodiment shown in 2 is identical, so reference is made to the description there.

[0071] In contrast to the embodiment in Fig. In this embodiment, the pre-sealing element 1 is designed such that the radial shield 4 and the axial shim 10 are integrally manufactured with the bearing seat 8 from a single sheet metal part. Axially within the shaft seal assembly 3, the first collection chamber 19 is formed from a plastic 21 and is firmly connected to the radial shield 4, for example by injection molding. The second collection chamber 18 is, in comparison to the embodiment in Fig. 2 cantilever-like structures. Furthermore, an outwardly shaped projection is formed from the first trapping chamber 19.

[0072] In Fig. Figure 4 shows a shaft seal arrangement 3 in a cross-sectional view. Fig. 2 in a third embodiment. The shaft seal arrangement 3 is, without exclusion of the generalities, shown for the sake of clarity only, largely analogous to the one described in Fig. 2 and Fig. The embodiments shown in the 3 are identical, so reference is made to the description therein.

[0073] In contrast to the embodiment in Fig. In this embodiment, the pre-sealing element 1 is designed such that the axial sleeve 10 is formed from plastic 21 and a pressure spoiler 12 is additionally formed axially outwards from the axial sleeve 10. The pressure spoiler 12 enables a load-dependent narrowing of the axial annular gap 40. For this purpose, the pre-sealing element 1 is designed such that a joint 14 (formed at the transition to the radial shield 4) causes a slight tilting movement with a radial component when a corresponding pressure 13 (shown from below) acts on the pressure spoiler 12. In one embodiment, the axial sleeve 10 is then pressed against the corresponding gap surface 45 of the second component 7, thus closing the axial annular gap 40. This is particularly advantageous if the sufficiently large pressure 13 required for this can only occur briefly according to a load assumption or is only applied when stationary.

[0074] In Fig. Figure 5 shows a shaft seal arrangement 3 in a cross-sectional view. Fig. 2 in a fourth embodiment. The shaft seal arrangement 3 is, without exclusion of the generalities, shown for the sake of clarity only, largely analogous to that shown in Fig. The embodiment shown in section 4 is identical, so reference is made to the description therein.

[0075] In contrast to the embodiment in Fig. In this embodiment, the pre-sealing element 1 is designed such that the metal sheet 42, which forms the bearing seat 8, is overmolded with a plastic 21. The sheet thus serves as a stiffening core 22 for the radial shield 4. For example, the axial shroud 10, the pressure spoiler 12, and the first collection chamber 19 of the pre-sealing element 1 are formed by means of a plastic overmolding.

[0076] One (independent) further difference to the embodiment according to Fig. 4 is the running groove 32 in the gap surface 45 of the second component 7 corresponding to the axial bearing 10, and a contact lip 31 is located at the free end of the axial bearing 10. In this illustration, a pressure 13 is applied, and the axial bearing 10 is deflected from its rest position. Alternatively, the rest position is shown here. The joint 14 is configured such that when a pressure 13 occurs, for example, as with a high-pressure cleaner, the axial bearing 10 tilts radially inward on the pressure spoiler 12. In this process, the axial bearing 10, as shown (i.e., without contact), engages the running groove 32 of the second component 7 with its contact lip 31. Alternatively, the contact lip 31 engages to the bottom of the running groove 32, i.e., in contact.

[0077] In Fig. Figure 6 shows a shaft seal arrangement 3 in a cross-sectional view. Fig. 2 in a fifth embodiment. The radial shaft seal 15 of the shaft seal assembly 3 is, without exclusion of the generalities, but purely for the sake of clarity, largely analogous to the ones shown in Fig. 2 to Fig. The embodiments shown in section 5 are identical, so reference is made to the description therein.

[0078] In contrast to the previous embodiments, in this embodiment the pre-sealing element 1 is designed with a radial shield 4 having a smaller radial extent 25 than the radial gap 5 to be sealed. The radial shield 4 is P-shaped, with an axial web 43 connected to a radial web 47 on the sealing seat side (i.e., radially outward). This is followed by a bottom web 44, and then by an intermediate web 46 connected to a radial web 47. An axial channel 24 is formed between the axial web 43 and the second component 7. This channel has a small radial extent 25 compared to its axial extent. The (outer) inlet 26 of the axial channel 24 is offset inwards, towards the radial shaft seal 15, by an axial distance 28 from the outer edge 27 of the second component 7. The axial distance 28 is significantly larger than the radial extent 25 of the axial channel 24.

[0079] In Fig. Figure 7 shows a shaft seal arrangement 3 in a cross-sectional view. Fig. 2 in a sixth embodiment. The shaft seal arrangement 3 is, without exclusion of the generalities, shown for the sake of clarity only, largely analogous to that shown in Fig. The embodiment shown in 6 is identical, so reference is made to the description there.

[0080] In contrast to the embodiment in Fig. In this embodiment, the pre-sealing element 1 is designed such that the radial shield 4 has an end rib 48 following the axial web 43, which extends radially outside the radial gap 5, i.e., further out than the outer edge 27 of the second component 7, and extends so far that the radial gap 5 is completely radially covered because the radial shield 4 projects beyond the radial gap 5.

[0081] The shaft seal arrangement proposed here, with a pre-sealing element, provides an improved seal against dirt particles while simultaneously reducing friction losses. Reference symbol list 1 Pre-sealing element 2 Rotation axis 3 Shaft seal arrangement 4 radial shield 5 radial gap 6 first component 7 second component 8 support seat 9 Outdoor environment 10 Axial ash 11 Sealing Labyrinth 12 Print Spoilers 13 Print 14 joint 15 Radial shaft seal 16 dynamic sealing lips 17 static sealing seat 18 second trap chamber 19 first trap chamber 20 channels 21 Plastic 22 core 23 Shaft assembly 24 Axial canal 25 radial expansion 26 Entrance 27 outer edge 28 axial spacing 29th wave 30 bearing seat 31 Contact lip 32 running groove 33 gear stage 34 Gearbox housing 35 shaft connection 36 outer shaft bearing 37 inner shaft bearing 38 outdoor area 39 Energy storage element 40 axial annular gap 41 Radial wall 42 Metal 43 Axial web 44 Ground floor 45 Gap surface 46 Intermediate walkway 47 Radial web 48 End bridge 49 conventional shaft seal arrangement 50 conventional pre-sealing sheet 51 conventional axial lip 52 conventional radial shaft seal

Claims

[1] Shaft sealing arrangement (3) with a pre-sealing element (1) with an axis of rotation (2) for a dynamic shaft sealing arrangement (3), comprising at least the following components: - a radial shield (4) for covering a radial gap (5) between a first component (6) and a second component (7) rotatable relative to the first component (6); - a static support seat (8) by means of which, in operation, the pre-sealing element (1) is radially supported on the first component (6) in a statically sealing manner against an external environment (9); and - an axial plate (10) which, in use, is arranged axially overlapping with the second component (7) to form a sealing labyrinth (11), characterized by, that the pre-sealing element (1) further comprises a pressure spoiler (12), wherein the pressure spoiler (12) is connected to the axial ash (10) in such a way that a pressure (13) transverse to the axial extension of the axial ash (10) on the pressure spoiler (12) tilts the axial ash (10) in the opposite direction. [2] Shaft sealing arrangement (3) according to claim 1, wherein a first trapping chamber (19) is formed axially outside the dynamic sealing lip (16) by the pre-sealing element (1). [3] Shaft seal arrangement (3) according to one of the preceding claims, wherein a second trapping chamber (18) is formed axially outside the radial shaft seal ring (15) than the dynamic sealing lip (16). [4] Shaft sealing arrangement (3) according to one of the preceding claims, wherein the pre-sealing element (1) is axially overlapping with the first component (6) and the second component (7) to form a sealing labyrinth (11). [5] Shaft seal arrangement (3) according to one of the preceding claims, wherein the pre-sealing element (1) is made at least partially of a plastic (21), wherein the plastic (21) is preferably fiber-reinforced. [6] Shaft sealing arrangement (3) according to one of the preceding claims, wherein preferably the radial shield (4) has a rigid core (22) and the pressure spoiler (12) and the axial shroud (10) are formed in a rubber-elastic manner.

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