Abstract
A sealing ring for a sealing system in the form of a pneumatic or hydraulic system includes a peripherally arranged sealing edge for dynamically contacting a sealing surface of a machine part. The sealing edge is closed in a ring shape relative to the central axis of the sealing ring. The sealing ring in its unloaded state has, in a section comprising the central axis, a transverse axis which, with the central axis, encloses an angle ? with 7????90?. The sealing ring may be produced from a longitudinal profile.
Claims
1. A method for producing a sealing ring from a longitudinal profile, comprising the following steps: providing the longitudinal profile in the form of a tube or a rod; three-dimensionally defining the sealing ring to be separated from the longitudinal profile in the material of the longitudinal profile with a transverse axis of the sealing ring (10) that extends at an angle ? to the mid-axis of the longitudinal profile with 7????90?; and separating the sealing ring from the longitudinal profile by removing material; wherein a multicomponent longitudinal profile which has layers that differ from one another in their material characteristics is provided as the longitudinal profile.
2. The method as claimed in claim 1, wherein the angle ? is chosen between 10? und 45?.
3. The method as claimed in claim 1, wherein the angle ? is chosen between 13? und 30?.
4. The method as claimed in claim 1, wherein the layers are arranged extending coaxially to the mid-axis of the multicomponent longitudinal profile.
5. The sealing ring for a pneumatic or a hydraulic system, having a sealing edge configured for dynamically contacting a sealing surface of a machine part, which sealing edge is closed in a ring shape relative to a central axis of the sealing ring, wherein the sealing ring in its unloaded state has, in a section comprising the central axis, a transverse axis which forms with the central axis the angle ? with 7????90?, wherein the sealing ring is produced according to the method of claim 1.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] In the drawings:
[0026] FIG. 1 shows a longitudinal profile in a detail of a longitudinal section, with exemplary contours of sealing rings to be produced from the longitudinal profile, wherein their contours in the longitudinal profile are defined in the conventional way (prior art);
[0027] FIG. 2 shows a longitudinal profile in a detail of a longitudinal section, with exemplary contours of sealing rings to be produced from the longitudinal profile, wherein their contours in the longitudinal profile are defined in the way according to the invention;
[0028] FIG. 3 shows a block diagram with individual method steps of the method according to the invention for producing the sealing ring according to FIGS. 1 to 5;
[0029] FIGS. 4A-E shows a sealing system comprising a sealing ring in a chronological sequence of individual mounting steps of the sealing system, namely when introducing a first machine part into the second machine part, in the seal retaining structure of which the sealing ring is partly pre-installed (FIG. 4A); during first-time contact of the first machine part with the partly installed sealing ring (FIG. 4B); as the sealing ring is pivoted radially counter to the elastic restoring forces inherent to the seal, and during the first-time contacting of the sealing edge (FIG. 4C); as the sealing ring is pivoted further into the seal retaining structure (FIG. 4D); and when the sealing surface is contacted by the sealing edge in the non-pressure-loaded mounting state;
[0030] FIG. 5 shows the sealing system according to FIG. 4 when the high-pressure side is loaded with an operating pressure P below the maximum operating pressure P.sub.max;
[0031] FIG. 6 shows the sealing system according to FIG. 4 when the high-pressure side is loaded with a maximum operating pressure P.sub.max;
[0032] FIGS. 7A-B show a sealing ring of two-component design in a cropped sectional view (FIG. 7A) and in the operationally ready installed state (FIG. 7B);
[0033] FIGS. 8A-B shows a sealing ring of two-component design in a cropped sectional view (FIG. 8A) and in the operationally ready installed state (FIG. 8B); and
[0034] FIGS. 9A-B show a radial sealing ring in the form of a scraper of three-component design in a cropped sectional view (FIG. 9A) and in the operationally ready installed state (FIG. 9B).
DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION
[0035] In the prior art, sealing rings and, specifically, also so-called scrapers, which are assigned to the radial sealing rings, are usually produced in the injection molding process or from a longitudinal profile in the course of a material-removing fabrication process. According to the illustration, as a rule cylindrical tubes and less frequently rods (solid profiles) are used as the longitudinal profile. According to the conventional fabrication method of the sealing rings, the sealing ring to be fabricated is defined in the material of the longitudinal profile. In the sectional illustration according to FIG. 1, the exemplary contours of different sealing rings 10, radial sealing rings here merely by way of example, are shown in the material of such a tubular longitudinal profile 12. The mid-axis 14 of the longitudinal profile 12 coincides with the central axis 16 of the sealing rings 10 respectively to be fabricated therefrom. The respective transverse axis 18 of the sealing rings 10 to be fabricated are all aligned so as to run strictly parallel or substantially parallel to the central axis 16 and to the mid-axis 14 of the longitudinal profile 12.
[0036] The fabrication of sealing rings 10 according to the invention, including radial sealing rings and scrapers, is explained below in conjunction with FIGS. 2 and 3. FIG. 2 shows, in a manner corresponding to FIG. 1, a longitudinal profile 12 in a sectional illustration with the contours of individual sealing rings 10 to be fabricated from the longitudinal profile 12 according to the method of the invention. FIG. 3 shows a block diagram with individual method steps of the method 100 according to the invention.
[0037] According to the method 100 according to the invention, a longitudinal profile 12 is provided in a first step 102. The longitudinal profile 12 can be designed as a cylindrical tube or as a cylindrical rod (in particular, made of solid material). In a further step 104, the respective sealing ring 10 to be fabricated is defined in the material of the longitudinal profile 12, as is shown in FIG. 2 by using the exemplary contours of different sealing rings 10, here radial sealing rings merely by way of example. The sealing rings 10 to be fabricated are arranged and defined with their transverse axes illustrated in FIG. 2 arranged to be tilted at an angle ? to the mid-axis 14 of the longitudinal profile 12 and to the central axis 16 of the respective sealing ring 10 to be produced. The magnitude of the angle ? is in principle greater than 7?. The magnitude of the angle ? can, in particular, be between 11? and 90?.
[0038] In a further step 106, the sealing ring 10 or the sealing rings 10 is/are cropped (separated) or machined out of the longitudinal profile 12 in the course of a material-removing process. For this purpose, the material-removing fabrication methods and machine tools established in seal production in the prior art can be used. To this extent, in practice costly new investment is rendered superfluous.
[0039] According to FIG. 2, the sealing rings 10 produced according to the method 100 of the invention, as compared with the sealing rings 10 known from the prior art (FIG. 1), have a different internal diameter d.sub.1, d.sub.2 in the region of their respective axial end 20 on the high-pressure side and their axial end 22 on the low-pressure side. If the sealing ring 10 is installed in a seal retaining structure, in particular a (rectangular) groove in a machine part, then this is intrinsically possible only with torsion of the sealing ring 10. In other words, during its installation, a moment must be exerted on the sealing ring.
[0040] It should be noted that a multicomponent, for example a two-component, longitudinal profile 12, can be used as a longitudinal profile 12. Such a longitudinal profile 12 has a multi-layered structure. Thus, sealing rings having radial or axial segments 24, 26 which differ from one another in their material characteristics can be produced from the multicomponent longitudinal profile 12. Here, the individual components or (material) layers 28, 30 of the longitudinal profile 12 shown are arranged coaxially to the mid-axis 14 of the longitudinal profile 12 and permanently connected to one another. Consequently, these cannot be separated from one another without destroying the longitudinal profile 12; it is obvious that the longitudinal profile 12 can also have more than the two (material) layers shown.
[0041] FIGS. 4 show the installation of a sealing system 200 having a sealing ring 10, here with an internally sealing radial sealing ring by way of example, at successive points in time. The sealing system 200 can, for example, be a pneumatic or hydraulic system.
[0042] The sealing system 200 comprises a first machine part 32 and a second machine part 34 which, in the mounting state, are spaced apart from each other, forming a sealing gap 36, and are arranged so as to be movable relative to each other along and/or around a movement axis 38.
[0043] The first machine part 32 can be, for example, a piston rod. The second machine part can be, for example, a cylinder. The first machine part 32 has a sealing surface 40, and the other machine part 34 has a seal retaining structure 42. To seal off a high-pressure side H of the system 200 or the sealing gap 36, a sealing ring 10 is used. The sealing ring 10 in the mounting state of the system 200 is arranged to be retained in the seal retaining structure 42, here in the form of an annular groove of rectangular cross section (=rectangular groove). The sealing ring 10 has a high-pressure first and a low-pressure second end face 44, 46. The inner peripheral side of the sealing ring 10 is designated by 48 and the outer peripheral side by 50. The two end faces 44, 46 of the sealing ring 10 can be designed to extend parallel to each other.
[0044] In the mounting state, the sealing edge 52 of the sealing ring 10 bears in a dynamically sealing manner on the sealing surface 40 of the first machine part 32. For an adequate contact pressure of the sealing edge 52 and the sealing surface 40, a rubber-elastically deformable preloading element 54 is used. The preloading element 54 bears peripherally on the periphery of the sealing ring 10 and loads the latter against the sealing surface 40. The preloading element 54 can be designed, for example, as a rubber ring or as a garter spring.
[0045] The first machine part 32 here has a run-on chamfer 56 at one end as a mounting aid. During the mounting of the system 200, the first machine part 32 is introduced into the second machine part 34 from the high-pressure side H longitudinally and coaxially to the movement axis 38, FIG. 4A. In chronological sequence, firstly a supporting structure 58 of the sealing ring 10 is contacted by the first machine part 32 before the latter contacts the sealing edge 52, FIG. 4B.
[0046] In a manner derived from the axial (insertion) movement of the first machine part 32, the sealing ring 10 is moved into the seal retaining structure 42 in a radial direction with deformation of the sealing ring 10 on the high-pressure side by the first machine part 32, so that a moment 60 acts on the sealing ring 10. In other words, the supporting structure 58 effects a moment acting in the radial direction, as a result of which the angle ? (cf. FIG. 4a) is reduced while deforming the radial sealing ring 10 and the preloading element 54 (cf. FIG. 4c). At the same time, the radial sealing ring 10 and the first machine part 32 are centered relative to the central axis 16 or movement axis 38. Overall, during the mounting of the system 200, excessive loading of the sealing edge 52 and damage thereto can be counteracted as a result.
[0047] It is only during a further axial movement of the first machine part 32 into the second machine part 34 that according to FIG. 4C the sealing edge 52 is also contacted by the run-on chamfer 56 of the first machine part 32 and the sealing ring 30 is moved further into the sealed retaining structure 42 by the further axial movement of the first machine part 32, until the sealing edge contacts the sealing surface 40 of the first machine part (FIG. 4D) and, finally, the mounting state of the sealing system 200, shown in FIG. 4E, in the non-pressure-loaded state is achieved. Even here, the angle ? reduced by the mounting still exists.
[0048] It should be noted that in the non-pressure-loaded mounting state of the system 200, the preloading element rests on the sealing ring 10 in such a way that an effective mid-plane 62 of the preloading element 54 is arranged to be offset relative to the sealing edge 52 of the sealing ring 10 in an axial direction toward the high-pressure side H of the sealing ring 10.
[0049] In FIG. 5, the sealing system 200 explained above in conjunction with FIGS. 4 is shown with an operating pressure P prevailing on the high-pressure side H, with [0050] P=1 MPa.
[0051] FIG. 6 shows the sealing system 200 with a maximum operating pressure Pmax of 30 MPa, by way of example here, prevailing on the high-pressure side H.
[0052] According to FIGS. 5 and 6, when an operating pressure P is applied to the high-pressure side of the sealing gap 36, the effect is a displacement of the effective mid-plane 62 of the preloading element 54, which displacement is pressure-proportional to the operating pressure P, in an axial direction toward the low-pressure side N. Here, the angle ? between the transverse axis 18 of the sealing ring 10 and the central axis 16 of the sealing ring 10 or the movement axis 38 is reduced further and can even experience a sign change. In other words, a parallel alignment of the transverse axis 18 relative to the central axis is achieved only in the installed operating state and when an operating pressure P is applied to the high-pressure side.
[0053] At the maximum operating pressure P.sup.max (FIG. 6), the preloading element can be isovolumetrically deformed substantially in an axial direction toward the low-pressure side N and radially in the direction onto and against the sealing surface 40. The sealing ring 10 then bears peripherally on the sealing surface 40 with its sealing edge 52 and with a longitudinal segment 64 immediately adjacent to the sealing edge 52 on the low-pressure side. As a result, large-area support of the sealing ring 10 is made possible, by means of which undesired damage to the sealing edge 52 of the sealing ring 10 is counteracted even at a high system pressure. At the same time, the sealing gap 36 is closed over a long distance in an axial direction, which means that an adequate sealing action of the sealing ring 10 is ensured even at a maximum operating pressure Pmax.
[0054] The sealing ring 10 can also have an end section 66 on the low-pressure side (FIG. 5) which tapers (in section) at least partly (e.g. conically) toward the end face 46 on the low-pressure side. As a result, as the operating pressure P rises as far as the maximum operating pressure P.sub.max, this benefits a radial deformation of the preloading element 54 radially in the direction of the sealing surface 40 and a tilting moment acting on the sealing ring 10.
[0055] In FIGS. 7 to 9, sealing rings 10 are each shown in a cropped sectional view (FIG. 7A, 8A and 9A) and in the mounting state/in operational use (FIGS. 7B, 8B and 9B). The sealing rings 10 are each designed as multicomponent parts and cropped out of a longitudinal profile in the manner explained above.
[0056] In the unloaded state of the sealing rings 10, the dividing line 68 (cf. also FIG. 2) between the material layers of the sealing rings 10in the longitudinal section of the radial seals 10is arranged to extend parallel to the central axis. When the sealing rings 10 are completely mounted, this is in each case arranged to extend obliquely with respect to the central axis 16. This makes it possible to position a first material, for example with a good sealing and frictional performance, on the sealing edge, and to position a further material with, for example, a high resistance to the extrusion of the sealing rings 10 on the low-pressure side. As an additional or alternative advantage, this can be used to identify the front and rear side of the sealing rings 10 with a color and thus to improve the installation and testing routines.
[0057] The sealing ring 10 designed as a scraper according to FIGS. 9 has a three-layer structure. Here the scratching and sealing edge 70 is formed from a hard and mechanically robust material, while the dynamically sealing sealing edge 52 is formed from another material, for example with a good frictional behavior. Those regions which are in contact only with the preloading element or the seal retaining structure can be formed from an inexpensive material.
