Shaft sealing rings and shaft assemblies for high speeds

Abstract

The invention relates to a shaft sealing ring (18) for sealing the media side (H) of a shaft assembly (10) relative to an outer side (N), comprising a sealing section (24) which, in the operating state, extends along a sealing axis (D) and has a running surface (32) for dynamically sealing against a sealing surface (26) of a mechanical component (14) of the shaft assembly (10). The sealing section (24) is provided with a plurality of profile grooves (34), each of which is laterally delimited by a first flank (36) arranged on the media side during operation of the shaft sealing ring (18) and by a second flank (38) arranged on the ambient side during operation. The profile grooves (34) have a flow cross section (S) for the lubricating medium, which has a maximum value and a minimum value. Each minimum value (42) of the flow cross section (S) of the profile groove (34) is arranged aligned or substantially aligned with a maximum value (40) of the flow cross section (S) of the corresponding nearest profile groove (34).

Description

Technical Field

[0001] The invention relates to a shaft sealing ring and a shaft assembly for high rotational speeds according to the preamble of claim 1 . Background Art

[0002] For example, DE 70 16 392 U discloses a shaft sealing ring of this type.

[0003] In practice, shaft assemblies are frequently used in vehicle drives, power tools, machine tools, and the like. One or more shaft sealing rings are typically used to seal the sealing gaps (bearing gaps) between mechanical components that can move relative to each other. The maximum permissible speed of each mechanical component sealed by the shaft sealing ring depends primarily on the material of the shaft sealing ring, the operating pressure to be sealed, and the type and range of lubrication in the dynamic sealing section of the shaft sealing ring. It is well known that shaft sealing rings made of FKM (fluororubber) generally operate at higher speeds than shaft sealing rings made of NBR (nitrile rubber).

[0004] In practice, efforts are underway to optimize lubrication in the contact area between the dynamic sealing section and the sealing or counter surface in order to minimize thermal and mechanical loads on the shaft sealing ring. One approach involves providing the sealing section of the shaft sealing ring or adjacent structures with a tribological microstructure or macrostructure.

[0005] The shaft sealing ring disclosed in DE7016392U includes a circumferential sealing lip with a sealing band extending circumferentially between inner and outer truncated cone surfaces, the sealing band facing or facing away from the liquid being sealed during operation of the sealing device. The outer truncated cone surface is provided with guide surface portions, each forming a rib or groove surface, the latter obliquely intersecting the sealing band. At least two of the guide surface portions intersect the sealing band in opposite circumferential directions at an angle of no more than 20° relative to the plane of the sealing band. The guide surface portions have two intersecting, oppositely directed, helical rib groups formed on the outer truncated cone surface of the sealing device. Each group of ribs extends parallel to one another, and the helix angles (i.e., the angles at which the ribs intersect the sealing band) in the two groups of ribs are equal in magnitude and opposite in direction.

[0006] For example, US Pat. No. 4,118,856 A discloses a friction structure providing a bidirectional effect on the sealing section in the form of intersecting ribs or web-like material projections. However, due to its design, this friction structure is generally subject to considerable mechanical wear, particularly in high-speed applications, which is detrimental to the service life of the shaft sealing ring.

[0007] US20070187904A1 discloses a profile design for the sealing section of a shaft sealing ring that is also quite unsuitable for high-speed applications. Here, the sealing section is provided with channels with uniform flow cross-sections. These channels extend parallel to one another or at an angle relative to one another and intersect one another, thus being fluidically connected and, in some cases, forming blind ends. DE10109320A1 discloses a similar profile design for the running surface of the sealing section.

[0008] EP0798498 discloses a radial shaft sealing ring whose sealing section is provided with an annular groove for media return flow. At the bottom of the groove is a radially inwardly projecting hydrodynamic return means formed by circumferentially extending corrugations. The corrugations have an inner profile that tapers in a wedge shape toward the media to be sealed. This radial shaft sealing ring can be used in high-speed applications, but its return flow capacity is very limited, for example when the shaft sealing ring has a high contact pressure on the associated sealing surface.

[0009] DE10154789A1 discloses another shaft sealing ring with a sealing lip, which has a sealing section for dynamically sealing contact with the sealing surface of a mechanical component. The sealing section includes a running surface with a plurality of profile grooves. Each profile groove is implemented in an annular closed manner in the circumferential direction of the shaft sealing ring and is defined by a first flank arranged on the low-pressure side and a flank arranged on the high-pressure side or the medium side in the axial direction relative to the center plate of the shaft sealing ring. The flank arranged on the low-pressure side of each profile groove is wavy in the circumferential direction, while the flank on the high-pressure side of each profile groove can be straight, i.e. circular or wavy in the circumferential direction. In high-speed applications, the profile groove can ensure reliable return flow capacity for the lubricating medium entering the profile groove. However, the return flow capacity of the shaft sealing ring is also limited here, especially when the working pressure required to be sealed inside the sealing gap or on the medium side is high. Summary of the Invention

[0010] The object of the present invention is to provide a shaft sealing ring and a shaft assembly having a shaft sealing ring, which have further improved lubrication and return flow properties and further improved service life at high speeds, i.e. in high-speed applications, and even at higher operating pressures to be sealed.

[0011] The object associated with the shaft sealing ring is achieved by a shaft sealing ring having the features of claim 1. The shaft assembly according to the invention has the features of claim 17. Preferred developments of the invention are specified in the dependent claims.

[0012] The shaft sealing ring of the present invention allows for sealing the inner side or media side of a sealing gap of a shaft assembly (to which operating pressure may be applied, if necessary) from the ambient side or outer side. The shaft sealing ring comprises a sealing section that, when the shaft sealing ring is installed or in operation, extends along the sealing axis of the shaft sealing ring and has a running surface for dynamic sealing contact with a mating running surface of a mechanical part of the shaft assembly. The sealing section includes a running surface with a plurality of tribological macrostructures in the form of profiled grooves. The profiled grooves are each spaced apart on the sealing section in the axial direction relative to the sealing axis of the shaft sealing ring and are open to the dynamic running surface (contact surface) of the sealing section. Each profiled groove is laterally bounded by a first channel wall or flank, which is disposed on the media side during operation of the shaft sealing ring, and by a second channel wall or flank, which is disposed on the ambient side (outer side or low-pressure side) during operation. The first flank is linear or substantially linear in the circumferential direction, i.e., circular with respect to the sealing axis. The second flank extends bidirectionally in the circumferential direction of the shaft sealing ring, axially in the direction of the first flank, from each maximum value of the flow cross-section S of the profile groove to a minimum value of the flow cross-section. In other words, the design of the second flank results in a section-wise reduction and increase of the flow cross-section in the circumferential direction. According to the invention, each minimum value of the flow cross-section of the profile groove is arranged axially aligned or substantially aligned with the maximum value of the flow cross-section of the nearest profile groove, in particular the nearest one on the media side.

[0013] In an alternative embodiment of the invention, the groove depth of the profile groove or the flank profile of the profile groove directed toward the high-pressure side or toward the groove flank on the low-pressure side varies in the circumferential direction of the profile groove, in particular periodically, so that maxima and minima of the flow cross section are alternately formed in the profile groove. For example, the groove flank on the low-pressure side can extend obliquely or circularly.

[0014] Because the minimum flow cross section of the profile groove is axially aligned with the maximum of the nearest profile groove on the medium side, a narrow running surface segment can be arranged between these two segments. Consequently, a wide running surface segment (toward the sealing axis) can be formed between the maximum flow cross section of the profile groove and the minimum flow cross section of the nearest profile groove on the medium side. This results in particularly low and efficient axial return flow resistance of the lubricating medium toward the medium side, or high-pressure side H, during operation of the shaft sealing ring. This ensures particularly effective lubrication and cooling of the running surfaces of the sealing segment. In other words, the return drag capability of the shaft sealing ring is further improved. Consequently, this shaft sealing ring is particularly suitable for the high-speed applications mentioned at the outset.

[0015] It should also be noted that along the circumference of the shaft sealing ring, each partial cross section of the sealing segment can be provided with a uniform or substantially uniform large running surface segment for dynamically sealing the sealing segment against the sealing surface or mating running surface of the shaft assembly. This helps to improve the static and dynamic sealing capabilities of the shaft sealing ring and, in particular, helps to extend the service life of the shaft sealing ring even when the media-side operating pressure of the lubricating medium to be sealed is high.

[0016] Particularly preferably, the profile groove is annularly closed in the circumferential direction of the shaft sealing ring. This ensures lubrication and cooling of the running surface over the entire circumference. This makes it possible to particularly reliably compensate for local mechanical / thermal overstressing of the shaft sealing ring.

[0017] According to a further development of the present invention, at least some or all of the profile grooves can be completely interrupted in the circumferential direction, which can further increase the effective running surface of the shaft sealing ring and is particularly beneficial for improving the sealing ability of the shaft sealing ring.

[0018] It is highly preferred that each maximum flow cross section of the profile groove is at least twice, preferably at least three times, and very preferably at least four times, the maximum flow cross section of each minimum flow cross section. This is particularly advantageous for the lubricant absorption capacity of the respective profile groove and the retraction capacity (=return flow capacity) of the shaft sealing ring during operation. It is understood that if the profile groove terminates completely in the circumferential direction, the minimum flow cross section at both ends of the profile groove is always zero.

[0019] According to a preferred embodiment of the shaft sealing ring, the second flanks of at least some or all of the profile grooves extend helically on either side of the maximum flow cross section S of the respective profile groove, i.e., have a constant slope or pitch from the first flank to the minimum flow cross section of the respective profile groove. Thus, when unfolded, the second flanks are straight on both sides of the maximum value up to the minimum value of the respective profile groove.

[0020] According to an alternative embodiment, the second wing extends convexly or concavely in the direction of the first wing on both sides of each maximum value of the profile groove flow cross section (relative to the first wing) until the corresponding minimum value of the profile groove flow cross section. In this regard, the second wing has a non-constant slope or pitch on both sides of the maximum value and the respective minimum value. The second wing is also curved when deployed.

[0021] Through this embodiment, the flow cross-section of the profile groove can be designed according to the flow characteristics of the lubricating medium and the relative rotational speed of the mechanical parts to be sealed, so as to achieve an axial acceleration of the lubricating medium / the desired dynamic pressure head that is beneficial for the return flow effect in the minimum area of ​​the profile groove.

[0022] According to the invention, the cross-sectional shape of each profile groove can be circular or polygonal, or a mixture of these cross-sectional shapes. In this way, the profile groove can be optimally matched to the thickness of the sealing section or the thickness of the sealing lip forming the sealing section.

[0023] According to another embodiment of the invention, the first and / or second flank can have at least partially different flank slopes relative to the sealing axis of the shaft sealing ring. This minimizes local material weakening of the sealing section due to the profile groove and, in the case of the second flank, achieves a stronger flow return effect for the shaft sealing ring.

[0024] At least some or all of the first flanks of the profile grooves, arranged on the medium or high-pressure side, and the second flanks arranged on the ambient side, preferably converge in the radial direction toward the sealing axis. In other words, the profile grooves can taper in the direction of their radial depth. On the one hand, this simplifies the axial return flow of lubricating medium from one profile groove to the next. On the other hand, if the radial sealing ring is designed as an injection-molded part, this offers manufacturing advantages, in particular simplifying demolding of the radial sealing ring and avoiding defective parts. This also minimizes material weakening of the shaft sealing ring in the area of ​​the profile groove.

[0025] The radial depth of the profile groove relative to the sealing axis varies in the circumferential direction of the shaft sealing ring. In particular, the depth at the maximum flow cross section of the respective profile groove is greater than the depth at the minimum flow cross section. This allows the flow cross section of the profile groove to be adjusted particularly effectively, even for relatively small shaft sealing rings.

[0026] According to a further development of the invention, the axial backflow capacity of the shaft sealing ring can be further increased by the fact that the running surface section arranged between the profile groove minimum and the respectively nearest profile groove maximum (under medium manipulation) can be deformed in the radial and / or axial direction relative to the rest of the shaft sealing ring. This minimizes the mechanical flow resistance during the axial transfer of lubricating medium from one profile groove to the nearest profile groove on the media side.

[0027] According to a particularly preferred embodiment of the invention, the sealing section is formed by a sealing lip of the shaft sealing ring. The sealing lip preferably extends away from the retaining section of the shaft sealing ring and is parallel or substantially parallel to the sealing axis in the installed state of the shaft sealing ring.

[0028] Depending on the intended scope of use, the shaft sealing ring can comprise or consist of a viscoelastic or rubber-elastically deformable material. It is understood that the shaft sealing ring can have a reinforcing insert (=armor insert), which is preferably embedded / arranged in or on the above-mentioned retaining section of the shaft sealing ring.

[0029] According to the present invention, the shaft sealing ring can be designed as a radial shaft sealing ring or an axial shaft sealing ring. In the case of a radial shaft sealing ring, the sealing axis coincides with the central axis of the radial shaft sealing ring and, in the installed state, coincides with the axis of motion of the machine component to be sealed. In the case of an axial shaft sealing ring, the sealing surface / sealing axis is arranged to extend orthogonally to the central axis of the axial shaft sealing ring.

[0030] Preferably, the essentially rectilinear course of the first limb according to the invention in the circumferential direction comprises an axial modulation, the maximum amplitude of which is less than half, in particular less than a quarter, of the maximum amplitude of the second limb.

[0031] Preferably, the substantially aligned arrangement according to the invention of the minimum of the profile groove and the maximum of the respectively nearest profile groove includes a circumferential offset of at most half the angular distance between a minimum of the profile groove and the adjacent maximum. This offset allows the characteristics of the recirculation effect to be influenced. Particularly preferably, the circumferential offset is approximately ¼ of the angular distance between a minimum of the profile groove and the adjacent maximum.

[0032] In the case where the groove depth of the profile groove according to the invention or the groove depth of the low-pressure side groove flank of the profile groove pointing toward the high-pressure side or toward the high-pressure side groove flank varies periodically in the circumferential direction of the profile groove to alternately form maximum and minimum values ​​of the flow cross section in the profile groove, the profile grooves can be straight and extend parallel to each other or can be wavy and extend parallel to each other.

[0033] The shaft assembly of the present invention comprises a first mechanical component in the form of a shaft and a second mechanical component surrounding the shaft. In particular, the second mechanical component can be a shaft housing. The shaft and the second mechanical component are arranged so as to be spaced apart from each other with a sealing gap (bearing gap) formed therebetween and are adjustable relative to each other about the axis of rotation.

[0034] A shaft sealing ring is used to seal the media side / inner side or high-pressure side H against the sealing gap or the outer side or low-pressure side N of a shaft assembly. The shaft sealing ring is designed as described above and rests with its sealing section in a dynamically sealing manner against a sealing surface or mating surface of one of the two machine components. In the case of an internally sealing shaft sealing ring, the sealing surface or mating surface is formed by the shaft, while in the case of an externally sealing shaft sealing ring, the sealing surface or mating surface is formed by the machine component surrounding the shaft (i.e., radially arranged on the outside). Relative movement of the shaft and the machine component about the axis of rotation facilitates the shaft sealing ring's return flow of lubricating medium that reaches the low-pressure side N or between the sealing section and the sealing surface. Due to the relative rotational movement of the shaft and the machine component in the circumferential direction of the profile groove, lubricating medium is forced into the constrictions of the respective profile groove and conveyed axially toward the media side H via the low-pressure side flanks of the profile groove, which are curved toward the low-pressure side or media side. Here, the lubricating medium reaches the widening of the flow cross section closest to the profile groove arranged on the high-pressure side. This facilitates the axial retraction function of the shaft sealing ring toward the inner side or the medium side. It should be noted that due to the design of the profile groove, the shaft sealing ring has a return function for the lubricating medium arranged in / reaching the profile groove regardless of the direction of rotation.

[0035] It is understood that the shaft sealing ring can be tensioned with its dynamic sealing section, ie with its sealing lip (if present), against the sealing surface by means of a rubber-elastically deformable prestressing element.

[0036] Furthermore, the shaft sealing ring can be arranged in a (mounting) cartridge, by means of which the shaft sealing ring can be provided in a simplified manner and optionally with more sealing elements known per se, and mounted in a retaining structure of a machine component or a shaft.

[0037] The sealing lip of the shaft sealing ring bears against the sealing surface with its running surface, ie with the contour groove open toward the sealing surface, in a dynamic and static sealing manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The invention will be explained in more detail below with reference to the exemplary embodiments shown in the drawings. The embodiments shown and described are not to be understood as exhaustive, but rather have exemplary character for describing the invention.

[0039] In the attached figure:

[0040] Figure 1 A shaft assembly is shown having a shaft and a mechanical component surrounding the shaft, and a shaft sealing ring for sealing a bearing gap or a sealing gap formed between the shaft and the mechanical component;

[0041] Figure 2 Show the basis Figure 1 Detailed detail of the sealing section of the shaft sealing ring, showing the contour groove on the running surface side;

[0042] Figure 3 A detailed partial view of another shaft sealing ring is shown;

[0043] Figure 4 A detailed partial view of another shaft sealing ring is shown;

[0044] Figure 5 A detailed partial view of another shaft sealing ring is shown;

[0045] Figure 6 A detailed partial view of another shaft sealing ring is shown;

[0046] Figures 7A-7J Showing the profile grooves of shaft sealing rings with different geometric flow cross sections;

[0047] Figure 8A 、 8B Shows the profile grooves of shaft sealing rings with different groove depths or different flow cross-section flank profiles;

[0048] Figure 9 A detailed partial view of another shaft sealing ring is shown;

[0049] Figures 10A-10H Different modulation variants of the flanks of the profile groove of a shaft sealing ring are shown;

[0050] Figure 11 A detailed fragmentary view showing another shaft sealing ring; and

[0051] Figure 12A 、 12B A detailed detail of another shaft sealing ring is shown. DETAILED DESCRIPTION

[0052] Figure 1 A shaft assembly 10 is shown, which can be used in many technical fields, such as drives for vehicles, machine tools, power tools, and even pump and compressor drives. Shaft assembly 10 comprises a first mechanical component in the form of a shaft 12 and a second mechanical component 14 surrounding shaft 12, which can be designed, for example, as a shaft housing, a mounting sleeve, or the like. Shaft 12 and mechanical component 14 are arranged spaced apart from one another, forming a bearing gap or sealing gap 16, and are adjustable relative to one another about an axis of rotation designated L.

[0053] The shaft sealing ring, generally designated 18, is used to seal the inner side or media side (or high-pressure side) H of the sealing gap 16 from the outer side N of the sealing gap 16. The shaft sealing ring 18 includes a retaining section 20, a sealing lip 22 fastened to or molded onto the retaining section 20, and a sealing section 24 formed by the sealing lip 22. The sealing lip 22 can extend away from the retaining section 20 in an axial direction relative to the central axis Z of the shaft sealing ring 18. In the assembled state shown, the central axis Z of the shaft sealing ring coincides with the rotational axis L of the shaft assembly 10. The shaft sealing ring 18 rests with its sealing section 24 on a mating or sealing surface 26 of the shaft 12 in a dynamically sealing manner. The retaining section 20 is disposed in a retaining groove 28 of the machine component 14. The retaining section 20 of the shaft sealing ring 18 can be made of a different material than the sealing lip 22. The material of the retaining section 20 preferably has a greater modulus of elasticity than the material of the sealing lip 22. For example, the retaining section 20 can include metal, plastic (especially viscoelastically deformable plastic) or a composite material or consist of one of these materials. Of course, the shaft sealing ring can also be formed in one piece, for example made of viscoelastic plastic or elastomer.

[0054] Shaft sealing ring 18 can be used Figure 1 An elastically deformable prestressing element 30 , indicated by a dashed line and embodied as a worm spring or an elastomer ring, prestresses the sealing surface 26 .

[0055] In the assembled state shown, the sealing section 24 extends along the sealing axis D of the shaft sealing ring 18. In the case of the shaft sealing ring, which is designed here as a radial shaft sealing ring, the sealing axis D coincides with the center axis Z of the shaft sealing ring 18. If the shaft sealing ring 18 is designed as an axial shaft sealing ring, the sealing surface or the sealing axis D is arranged in the assembled state so as to extend orthogonally to the center axis Z of the shaft sealing ring and to the axis of motion L of the two machine components 12, 14.

[0056] according to Figure 1 The sealing segment 24 includes a running surface 32 and a plurality of profile grooves 34 arranged in the running surface 32. The profile grooves 34 serve as friction structures and are arranged spaced apart from one another in the assembled state in the axial direction relative to the sealing axis D. It should be noted that each profile groove 34 is open toward the dynamic running surface 32 of the sealing segment 24 and, therefore, is open in the radial direction toward the sealing surface 26 of the shaft 12 in the assembled state.

[0057] exist Figure 2 According to Figure 1 Detailed perspective view of the sealing section 24 of the shaft sealing ring 18 .

[0058] When the shaft sealing ring 18 is in operation, the profile groove 34 is laterally delimited in the axial direction by a first channel wall / flank 36 arranged on the medium side or high-pressure side H (i.e., the high-pressure side) and by a second channel wall / flank 38 arranged on the outer side N (i.e., the low-pressure side). The profile groove 34 is annularly closed on both sides in the axial direction. In other words, there are no fluid connections or the like between the profile grooves 34.

[0059] The high-pressure-side first flanks 36 of the profile grooves 34 each have a straight or substantially straight course in the circumferential direction. In contrast, the low-pressure-side flanks 38 of each profile groove 34 each have a wave-shaped course in the circumferential direction of the shaft sealing ring 18. Consequently, the free flow cross section (=net flow cross section) of each profile groove 34 in the circumferential direction for the lubricating medium for lubricating the contact area between the sealing section 24 and the sealing surface 26 alternates between maximum values ​​40 and minimum values ​​42.

[0060] Each maximum value 40 of the flow cross section of the profile groove 34 can be at least three times, in particular at least four times, the minimum value 42 of this flow cross section S.

[0061] The low-pressure-side second flank 38 extends axially from each maximum 40 in a concavely curved manner on both sides relative to the first flank 36 in the direction of the nearest minimum 42. The (low-pressure-side) second flank 38 is designed to be wavy overall in the circumferential direction.

[0062] The maximum values ​​40 and minimum values ​​42 of the flow cross-sections S of two profile grooves 34 that are directly adjacent to one another in the axial direction are arranged offset relative to one another in the circumferential direction, so that each constriction 42 of the profile groove 34 is aligned or substantially aligned axially in the direction of the media side or high-pressure side H with the maximum value 40 of the respectively nearest profile groove 34. Accordingly, each maximum value 40 of the maximum flow cross-section S of the profile groove 34 is aligned or substantially aligned axially in the direction of the media side or high-pressure side H with the minimum value 42 of the respectively nearest profile groove 34. Thus, axially in the direction of the media side or high-pressure side H, the maximum value 40 of the profile groove 34 is respectively adjacent to the wide running surface section 32 a, and the constriction 42 of the profile groove 34 is correspondingly adjacent to the narrow running surface section 32 b of the running surface 32 of the sealing section 24.

[0063] It should be noted that, on the circumference of the shaft sealing ring 18, in each partial cross section of the sealing segment, a uniform or substantially uniform large running surface segment is ensured for the sealing segment to dynamically seal in contact with the sealing surface or mating running surface of the shaft 12 or the mechanical component 14 of the shaft assembly 10. This is beneficial to the sealing capability of the shaft sealing ring 18.

[0064] If the shaft 12 and the machine component 14 move relative to each other about the rotational axis L, the return flow effect of the shaft sealing ring 18 is favored for the lubricating medium reaching the low-pressure side N or between the sealing section 24 and the sealing surface 26. Due to the relative rotational movement of the shaft 12 and the machine component 14 and regardless of the direction of rotation, the lubricating medium is displaced in the circumferential direction of the profile grooves 34 in the direction of the minimum 42 of the flow cross section S of each profile groove 34. As the lubricating medium flows over the second flank 38 (which is curved / bent axially inwardly toward the media side H), the lubricating medium is accelerated / conveyed axially toward the sealing surface and, as indicated by arrow A, toward the high-pressure region H. Thus, the lubricating medium reaches the profile groove 34 closest to the media side in the region of the maximum 40 of its flow cross section S. This facilitates the axial recirculation (or pumping) function of the shaft sealing ring 18 toward the media side or high-pressure side H. It should be noted that, due to the shape of the profile groove 34, the shaft sealing ring 18 can achieve a return flow function for the lubricating medium disposed therein, regardless of the direction of rotation.

[0065] The shaft sealing ring 18 or the sealing lip 22 of the shaft sealing ring 18 can, in particular, include or be formed from a rubber-elastic or visco-elastically deformable elastomeric material, for example PTFE (polytetrafluoroethylene).

[0066] Figure 3 Another embodiment of a radial shaft sealing ring 18 is shown. Here, the profile groove 34 is also annularly shaped and has no interruptions on the sealing section 24. Figure 2 The illustrated embodiment differs in that the second flank 38 of the profile groove 34 is not wavy. Instead, the second flank 38 extends straightly from each maximum 40 of the flow cross section of the profile groove 34 on both sides relative to two minima 42 of the flow cross section S of the respective profile groove 34, which are arranged closest. In the region of each minimum 42 and each maximum 40, the second flank 38 forms an obtuse angle α1, α2, respectively.

[0067] The second flanks 38 of the profiled grooves 34 can also be formed in a curved manner from each maximum 40 of the flow cross section of the respective profiled groove 34 to the two nearest minimum values ​​42 of the flow cross section of the profiled groove 34 .

[0068] exist Figure 4 In the embodiment shown, the second flanks 38 are each concave relative to the first flanks 36, and according to Figure 5 In the embodiment shown, the second flank is convex relative to the first flank 36 of the profile groove 34. The second flank 38 is curved in the region of the minimum 42 of the flow cross section of the respective profile groove 34. In operation, depending on the direction of rotation ( Figure 1), the acceleration of the lubricating medium in the direction of the respective minimum / medium side H can be increased by the curved course. This makes it possible to further increase the return flow capacity of the shaft sealing ring 18.

[0069] Figure 6 A detailed detail of another embodiment of a shaft sealing ring 18 is shown. Here, the profile groove 34 is completely interrupted or divided in the circumferential direction of the shaft sealing ring 18. Here, too, the second flank 38 extends on both sides from the maximum value 40 of the flow cross section of the respective profile groove 34 to the nearest minimum value 42 of this flow cross section. The minimum value 42 of the profile groove 34 is located in the direction of rotation ( Figure 1 ) in the axial direction and the maximum value 40 of the flow cross section of the contour groove 34 closest to the medium side. At each minimum 42, the flow cross section is zero. The second flank 38 of the contour groove 34 can also be aligned with the maximum value 40 of the flow cross section of the contour groove 34 closest to the medium side. Figure 3 In a corresponding manner, it extends straight or in a convex curve to two respectively nearest minima 42 of the flow cross section S of the respective profile groove 34 .

[0070] It should be noted that the flow cross section S of the profile groove 34 of the shaft sealing ring 18 may have different geometries, as will be discussed in more detail below with reference to FIG. 7 .

[0071] Different from Figure 2-6 While extending in a plane at a right angle to the central axis Z, the contour groove 34 can also extend obliquely or tilted relative to the central axis Z.

[0072] Figure 7A A detailed fragment of the rectangular profile groove 34 of the sealing section 22 of the shaft sealing ring 18 is shown. The first and second flanks 36, 38 are parallel to one another and, in the installed state of the shaft sealing ring 18, are arranged orthogonally to the sealing axis D. The profile groove 34 has a bottom section 44 that is arranged parallel to the sealing axis D. The depth of the profile groove 34 is denoted by T. The width of the profile groove is denoted by B.

[0073] according to Figure 7B and 7C , the contour groove 34 can taper in the direction of its depth extension. In addition, the two flanks 36, 38 can also form different angles β, γ with the running surface 32 of the sealing section 24. Figure 7B , the angle γ of the second wing 38 is smaller than the angle β of the first wing 36. Figure 7C , the angle γ is greater than the angle β.

[0074] like Figure 7D As shown, other polygonal (e.g. pentagonal) cross-sectional geometries of the profile groove 34 are also possible. Figure 7DOne flank 36 , 38 or both flanks 36 , 38 of the contour groove 34 can be segmented, ie angled, as shown for the second flank 38 .

[0075] For example, according to Figure 7D and Figure 7E , the bottom section 44 of the contour groove 34 can be arranged obliquely relative to the running surface 32 .

[0076] according to Figure 7F , the profile groove 34 can also have a triangular cross-sectional geometry. In this case, the bottom section 44 that can be separated from the flanks 36, 38 is omitted.

[0077] according to Figure 7G One or both flanks 36, 38 can also be designed to be curved at least in sections and, if necessary, to form a phase 46 with the running surface, which facilitates the entry of the lubricating medium into the profile groove 34. Figure 7H The bottom section 44 can be designed to be curved and transition seamlessly into one of the two flanks 36 , 38 .

[0078] according to Figure 7I The flow cross section of the profile groove 34 may be generally of circular symmetrical geometry, or, according to Figure 7J , the flow cross section of the contour groove 34 is a circular asymmetric cross-sectional geometry.

[0079] like Figure 8A China-Israel Figure 7C As shown in the embodiment of FIG, the groove depth T of the bottom section 44 can vary periodically by an amount Δ, as viewed in the circumferential direction of the profile groove 34. Since the angle β of the high-pressure side groove flank 36 is flatter than the angle γ of the low-pressure side groove flank 38, the periodic variation Δ of the groove depth T of the bottom section 44 (particularly when the groove width of the profile groove 34 remains constant in the circumferential direction) leads to a backflow effect in the direction of the high-pressure side H.

[0080] like Figure 8B China-Israel Figure 7D As shown in the embodiment of the embodiment, when viewed in the circumferential direction of the profile groove 34, the flank direction of the groove flank 39 of the profile groove 34 pointing toward the high-pressure side H or the groove flank 36 pointing toward the high-pressure side, which is inclined here, on the low-pressure side, changes periodically by an amount Δ. Due to the inclined position of the low-pressure side groove flank 39 pointing toward the high-pressure side H, the periodic change Δ in the flank direction of the inclined low-pressure side groove flank 39 can lead to a backflow effect in the direction of the high-pressure side H (especially even when the groove width of the profile groove 34 remains unchanged in the circumferential direction). Instead Figure 8B The inclined slot flank 39 in the middle, the other toward the high pressure side H or toward the low pressure side slot flank 36 pointing to the high pressure side slot flank, such as Figures 7H to 7J The circular low-pressure-side flank 38 in FIG. 3 has a flank course which, viewed in the circumferential direction of the profile groove 34 , changes periodically by an amount Δ.

[0081] replace Figure 2-6 The first flank of the high-pressure side of the profile groove 34 can also be modulated axially as seen in the circumferential direction of the profile groove 34. For example, Figure 9 In the embodiment, the first wing 36 is wavy or sinusoidal, specifically, it has a periodic, uniform amplitude in the circumferential direction of the profile groove 34. Instead of a sinusoidal curve, the axial amplitude of the first wing 36 can also vary in any other manner. For example, there can be a small "overshoot" of the amplitude, which can specifically lead to the targeted generation of turbulence in the profile groove 34. The maximum amplitude of the first wing 36 is less than half the maximum amplitude of the second wing 38, preferably less than one-quarter of the maximum amplitude of the second wing 38.

[0082] exist Figures 10A-10H Different variants of the first and / or second flank 36, 38 are shown in FIG, wherein the amplitude is a function of the circumferential angle of the shaft 12. These variants are different functions that are n-periodic about the circumference of the axis 12, where n is a natural number.

[0083] Figure 10A A sinusoidal curve with a period length of 1 / 2 is shown (n=2).

[0084] Figure 10B A sinusoidal curve with a period length of 1 / 5 is shown (n=5).

[0085] Figure 10C shows a non-periodic curve, which is composed of Figure 10A and Figure 10B The sum of the curves shown forms .

[0086] Figure 10D shows a non-periodic curve, which is composed of Figure 10A and Figure 10B The difference between the curves shown is formed.

[0087] Figure 10E A periodic triangular curve is shown (n=6).

[0088] Figure 10F A periodic sawtooth curve is shown (n=6).

[0089] Figure 10G A periodic symmetrical arc-shaped curve is shown (n=3).

[0090] Figure 10H A periodic asymmetric arc-shaped curve is shown (n=4).

[0091] A particularly advantageous embodiment of the profile groove 34 is a combination of flanks 36, 38 having the same period or flanks 36, 38 in which the period of one flank 36, 38 is a multiple of the period of the other flank 36, 38. Preferably, over the circumference of the profile groove 34, as many minimum values ​​42 of the flow cross section of the profile groove 34 as possible are aligned with as many maximum values ​​40 of the corresponding nearest profile groove 34 as possible.

[0092] exist Figure 2-6 In contrast to the arrangement in which the maximum values ​​40 and the minimum values ​​42 of the flow cross-sections of two adjacent profile grooves 34 are arranged in axial alignment, the minimum value 42 of the flow cross-section of the profile groove 34 can also be arranged offset in the circumferential direction relative to the nearest maximum value 40 of the flow cross-section of the nearest profile groove 34, specifically by a maximum offset of half the angular distance between the minimum value and the adjacent maximum value of the profile groove 34 starting from the aligned arrangement. The offset makes it possible to influence the characteristics of the backflow effect. Particularly preferably, the offset is approximately 1 / 4 of the angular distance between the minimum value and the adjacent maximum value of the profile groove 34. The aligned arrangement of the minimum value 42 of the flow cross-section of the profile groove 34 with the nearest maximum value 40 of the profile groove 34 corresponds to an angular offset of 0° exist Figure 11 The angular offset of the minimum value 42 of the flow cross section of the profile groove 34 from the nearest maximum value 40 of the flow cross section of the nearest profile groove 34 is is 90°, which corresponds to half the angular distance between a minimum 42 and an adjacent maximum 40 of the profile groove 34 .

[0093] Figure 12A 、 12B The embodiment shown in Figure 2-6 The difference is that here the contour grooves 34 are straight and parallel ( Figure 12A ) and wavy and parallel ( Figure 12B ) extend side by side. When viewed from the circumferential direction of the profile groove 34, the groove depth of the profile groove 34 periodically alternates and respectively has valleys (i.e., the maximum value 40 of the flow cross section of the profile groove 34) and peaks (i.e., the minimum value 42 of the flow cross section of the profile groove 34). Since the groove flanks on the high pressure side are flatter (e.g., Figure 8A ) and / or due to the inclined position of the trough flanks on the low pressure side pointing towards the high pressure side (e.g. Figure 8B ), such a periodic or aperiodic variation of the groove depth T can lead to a backflow effect in the direction of the high-pressure side H (especially even if the groove width of the contour groove 34 remains unchanged in the circumferential direction).

Claims

1. A shaft sealing ring (18) for sealing the medium side (H) of a shaft assembly (10) relative to the outside (N), comprising a sealing section (24) which, in the operating state, extends along a sealing axis (D) and has a running surface (32) for bearing in a dynamic sealing manner against a sealing surface (26) of a mechanical part (12) of the shaft assembly (10), in, The sealing section (24) is provided with a plurality of profile grooves (34), which are arranged spaced apart from one another in the direction of the sealing axis and are designed to be open toward the running surface (32). Each profile groove (34) is laterally delimited by a first flank (36) arranged on the medium side during operation of the shaft sealing ring (18) and by a second flank (38) arranged on the outside during operation of the shaft sealing ring (18). It is characterized by: (a) the first flank (36) has a straight or substantially straight course in the circumferential direction of the shaft sealing ring (18), the second flank (38) extends bidirectionally in the circumferential direction of the shaft sealing ring (18) from each maximum value of the flow cross section (S) of the profile groove (34) axially in the direction of the first flank (36) to a minimum value (42) of the flow cross section (S), and each minimum value (42) of the flow cross section (S) of a profile groove (34) is arranged aligned or substantially aligned with the maximum value (40) of the flow cross section (S) of the corresponding nearest profile groove (34), or (b) the groove depth (T) of the profile groove (34) varies in the circumferential direction of the profile groove (34) so ​​that maximum values ​​(40) and minimum values ​​(42) of the flow cross section (S) are alternately formed in the profile groove (34), and each minimum value (42) of the flow cross section (S) of a profile groove (34) is arranged to be aligned or substantially aligned with the maximum value (40) of the flow cross section (S) of the corresponding nearest profile groove (34), or (c) at least some of the profile grooves (34) or each profile groove (34) are implemented in an annular closed manner, the flank direction of the groove flanks (39) of the profile groove (34) changes in the circumferential direction of the profile groove (34) so ​​that maximum values ​​(40) and minimum values ​​(42) of the flow cross section (S) are alternately formed in the profile groove (34), and each minimum value (42) of the flow cross section (S) of a profile groove (34) is arranged to be aligned or substantially aligned with the maximum value (40) of the flow cross section (S) of the corresponding nearest profile groove (34).

2. The shaft sealing ring (18) according to claim 1, characterized in that In variants (a) or (b), at least some of the profile grooves (34) or each profile groove (34) is designed to be annularly closed.

3. The shaft sealing ring (18) according to claim 1, characterized in that In variants (a) or (b), at least some of the profile grooves (34) are completely interrupted in the circumferential direction.

4. The shaft sealing ring (18) according to claim 1 or 2, characterized in that The maximum value (40) of the flow cross section (S) is at least twice the minimum value (42) of the flow cross section (S).

5. The shaft sealing ring (18) according to claim 1 or 2, characterized in that The second flank (38) extends axially in the circumferential direction in the direction of the first flank (36) to a respective minimum (42) on both sides of each maximum (40) of the flow cross section (S) of each profile groove (34) or partial profile groove (34), either linearly or convexly or concavely curved.

6. The shaft sealing ring (18) according to claim 1 or 2, characterized in that The flow cross section (S) of at least some of the profile grooves (34) or each profile groove (34) has a circular or polygonal geometry.

7. The shaft sealing ring (18) according to claim 1 or 2, characterized in that The first or second flank (36, 38) has different flank slopes (β, γ) at least in sections relative to a sealing axis (D) of the shaft sealing ring (18).

8. The shaft sealing ring (18) according to claim 1 or 2, characterized in that The first media-side flanks (36) and the outer second flanks (38) of at least some of the profile grooves (34) or all of the profile grooves (34) converge in the radial direction toward the sealing axis (D).

9. The shaft sealing ring (18) according to claim 1 or 2, characterized in that At least some of the profile grooves (34) or all of the profile grooves (34) have a radial depth (T) which varies in the circumferential direction of the shaft sealing ring (18).

10. The shaft sealing ring (18) according to claim 1 or 2, characterized in that A running surface section (32b) arranged between a maximum value (40) of the flow cross section (S) of a profile groove (34) and a minimum value (42) of the flow cross section (S) of the corresponding nearest profile groove (34) can be deformed in radial or axial direction relative to the rest of the shaft sealing ring (18) under the influence of the medium, so as to simplify the axially directed return transport of the medium from one profile groove to the nearest profile groove (34) during operation of the shaft sealing ring (18).

11. The shaft sealing ring (18) according to claim 1 or 2, characterized in that The sealing section (24) is formed by the sealing lip (22) of the shaft sealing ring (18).

12. The shaft sealing ring (18) according to claim 1 or 2, characterized in that The shaft sealing ring (18) at least partially comprises or consists of a visco-elastically deformable or rubber-elastically deformable polymer material.

13. The shaft sealing ring (18) according to claim 1 or 2, characterized in that The shaft sealing ring (18) is designed as a radial shaft sealing ring.

14. The shaft sealing ring (18) according to claim 1 or 2, characterized in that The substantially rectilinear course of the first limb (36) comprises an axial modulation in the circumferential direction, the maximum amplitude of which is less than half the maximum amplitude of the second limb (38).

15. The shaft sealing ring (18) according to claim 1 or 2, characterized in that The arrangement of the minimum value (42) of the flow cross section (S) of one profile groove (34) and the maximum value (40) of the flow cross section (S) of the corresponding nearest profile groove (34) comprises an offset in the circumferential direction of at most half the angular distance between the minimum value of the flow cross section (S) of the profile groove (34) and the maximum value of the flow cross section (S) of the adjacent profile groove (34).

16. The shaft sealing ring (18) according to claim 1 or 2, characterized in that In the case where the groove depth (T) of the profile groove (34) or the flank direction of the groove flanks (39) of the profile groove (34) varies periodically in the circumferential direction of the profile groove (34) so ​​as to alternately form maximum values ​​(40) and minimum values ​​(42) of the flow cross section (S) in the profile groove (34), the profile grooves (34) extend straight and parallel next to each other or extend in a wavy manner and parallel next to each other.

17. The shaft sealing ring (18) according to claim 9, characterized in that The radial depth (T) is greater at each maximum (40) of the flow cross section (S) of the respective profile groove (34) than at a minimum (42) of the flow cross section (S).

18. The shaft sealing ring (18) according to claim 14, characterized in that The maximum amplitude of the axial modulation is less than one quarter of the maximum amplitude of the second wing (38).

19. A shaft assembly (10), comprising: A first machine part in the form of a shaft (12) and a second machine part (14) surrounding the shaft (12), which are arranged spaced apart from each other to form a sealing gap (16) and can be adjusted relative to each other about an axis of rotation (L); and a shaft sealing ring (18) for sealing the medium side (H) of the sealing gap (16) relative to the outside (N) of the sealing gap (16), wherein the shaft sealing ring (18) is designed as a shaft sealing ring according to claim 1 or 2 and rests with its sealing section (24) in a dynamically sealing manner on a sealing surface or a mating running surface of one of the first and second machine parts.

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