HK1251283B - The sealing ring and its use - Google Patents

Description

Sealing rings and their applications

Technical Field

The present invention relates to a sealing ring and its application, wherein the sealing ring is constructed in a 7-shaped manner when viewed in cross section, comprises a first axial leg and a sealing leg having a sealing lip and comprises a tensioning element for stabilizing the sealing leg in a radial direction, wherein the sealing leg is connected to the first end side of the axial leg by means of a joint, the tensioning element is constructed in an annular manner and is formed by a spring constructed in a 7-shaped manner when viewed in cross section, and the tensioning element has a second axial leg and a stabilizing leg, the second axial leg is connected to the first axial leg and the stabilizing leg is connected to the sealing leg.

Background Art

Such sealing rings are known from FR1132266A, US2630343A and US3901517A.

FR 1 132 266 A discloses a sealing ring whose sealing lip is arranged radially on the outside of the sealing ring. Consequently, an axial leg is arranged radially on the inside of the sealing ring and has a side radially facing the sealing leg, the diameter of which increases continuously in the axial direction from the open end side of the known sealing ring toward the first end side and the joint. The sealing leg has an undercut, designed as a groove, on a side axially facing away from the open end side and on an inner side radially facing the first axial leg, so that the position of the joint, viewed in the radial direction, is offset toward the sealing lip.

The sealing ring known from US Pat. No. 2,630,343 A comprises an axial leg which is cylindrical on its side radially facing the sealing leg and extends from the open end face of the sealing ring to a joint which connects the axial leg and the sealing leg to one another in an articulated manner.

The tensioning element 7 is designed in the form of a truncated plate and is arranged in a construction space which is delimited by the mutually facing sides of the axial legs and the sealing leg.

The sealing ring known from US Pat. No. 3,901,517 A is designed as a grooved sealing ring for sealing a machine element that can reciprocate translationally. The sealing ring is C-shaped in cross section and has radially inner and outer sealing legs, one of which is designed to provide a dynamic seal and one of which is designed to provide a static seal. The tensioning element is also C-shaped in cross section and serves to separate the sealing legs relative to each other in the radial direction.

Another sealing ring is known from EP 2988035 A1. This known sealing ring is used to seal grease and includes a tensioning element disposed in a mounting groove of the sealing ring. The mounting groove is disposed on the side of the sealing leg radially remote from the sealing lip. The mounting groove has a mounting opening for the tensioning element on the side radially remote from the sealing lip. The mounting opening is defined by two guide strips disposed adjacent to each other at a distance in the axial direction. When viewed radially and in the manufacturing state of the sealing ring, the joint is disposed in the center of the sealing ring. Similarly, a substantially C-shaped joint space is disposed radially in the center of the sealing ring, in the region of the joint, and is open on one side in the axial direction. This joint space is designed to allow the medium to be sealed, which is present in the joint space, to be discharged from the joint space. Since the joint space is free of the medium to be sealed, undesirable hardening of the sealing ring is prevented, and the sealing leg can follow the highly dynamic deflection movements of the machine element to be sealed without significantly changing the contact force with which the sealing lip seals against the machine element.

DE 102009053558 A1 discloses a sealing ring that is shaped like a figure seven and comprises a first axial leg that is relatively thick in the radial direction and a sealing leg having a sealing lip. The sealing leg is connected to the first end face of the axial leg by a joint. However, no separately manufactured tensioning element is provided for stabilizing the sealing leg in the radial direction. When viewed in the radial direction and in the state of the sealing ring determined by its manufacture, the joint is arranged in the center of the sealing ring. Both end faces of the axial leg are formed with projections and are supported by these projections in the installation space of the sealing assembly. The projections prevent the sealing ring from rotating or tilting in the installation space during its intended use. The projections can be formed as self-sealing ridges that extend around the circumference, which provide a particularly good clamping effect on the axial leg in the installation space.

Summary of the Invention

The invention is based on the object of further developing a sealing ring of the type mentioned at the outset so that it has improved operating properties over a longer service life, which are essentially independent of the diameter to be sealed. In particular, the sealing lip, independently of the installation situation of the sealing ring and therefore independently of whether the sealing lip is arranged radially inside or outside the sealing ring, contacts the surface to be sealed of the machine element to be sealed in a sealing manner with a constant radial preload over a long service life.

Furthermore, a particularly suitable application of the sealing ring according to the invention is to be achieved.

According to the invention, this object is achieved with advantageous features.

To achieve this object, it is provided that the first axial leg has an undercut on its side radially facing the sealing leg, which extends in the axial direction from the second end face of the first axial leg toward the first end face and the connection.

A tensioning element having a shape corresponding to the shape of the entire sealing ring, ie a 7-shaped configuration, results in advantageous operating properties of the sealing ring, independently of whether the sealing leg with its sealing lip is arranged radially inside or outside the sealing ring.

The tensioning element can be designed to be essentially equilateral.

The sealing ring in EP2988035A1 mentioned at the beginning is mainly provided for a radially inner sealing system. The sealing leg and the sealing lip are arranged radially inwardly of the sealing ring, wherein the sealing lip seals around the surface of the machine element to be sealed, such as a shaft, under radial preload.

For systems with radially external seals, annular coil springs designed as tensioning elements are disadvantageous when the axial leg is arranged radially inward and the sealing leg, with its sealing lip, extends radially outward from the axial leg. Annular coil springs are currently used as tension springs for internally sealed systems. In systems with external seals, such springs must be designed as compression springs. While this is feasible in principle, it often complicates assembly and secure positioning of the spring in the installation space. The risk of ejection from the installation space is significantly greater than with tension springs.

In contrast, the sealing ring according to the present invention uses a spring configured in the shape of a figure 7 as a tensioning element, the outer shape of which is adapted to the outer shape of the sealing ring. This sealing ring has the advantage that it can also be used effectively in externally sealed systems, i.e., in these externally sealed systems, the sealing legs extend radially outward with a sealing lip and, for example, contact sealingly a wall that delimits a housing opening.

The sealing ring according to the present invention maintains consistently good performance regardless of whether the sealing lip is arranged radially inside or outside the sealing ring. Due to the aforementioned shape of the spring, a radial spring force is generated by the radial movement of the spring. Whether the system is externally sealed or internally sealed is irrelevant for practical purposes. The sealing lip is pressed against the surface to be sealed due to the bending of the spring, so this pressing can be achieved independently of the diameter.

The spring designed in the shape of a figure of seven can well compensate for relatively large radial deflection movements of the machine element to be sealed, without significantly changing the contact force with which the sealing lip contacts the surface to be sealed in a sealing manner.

It is also advantageous that a spring configured in the shape of a figure 7 can be manufactured simply and cost-effectively. It is also easy to integrate such a spring into the sealing ring.

The first axial leg, on its side radially facing the sealing leg, has an undercut that extends axially from the second end side of the first axial leg toward the first end side and the joint. In general, it has proven advantageous in terms of operational characteristics, particularly in systems with radially externally sealed sealing rings, for the joint to be positioned as far radially as possible from the sealing lip between the first axial leg and the sealing leg. This allows the sealing leg to follow relatively large radial deflection movements of the machine element to be sealed particularly well. The magnitude of the radial deflection movement depends on the diameter to be sealed. For example, the diameter to be sealed may be 4 meters in a wind turbine or 18 meters in a tunnel boring machine. Due to the joint being positioned as far radially as possible from the sealing lip and the resulting good elastic flexibility of the sealing leg, the sealing lip, even in these conditions, contacts the surface to be sealed with a consistently good contact pressure and, therefore, a sealing effect over its entire circumference.

The aforementioned advantageous operating characteristics of the sealing ring are enhanced by the fact that, viewed in the radial direction and in the state of the sealing ring as determined by its production, the connection is arranged in the third of the sealing ring furthest from the sealing lip. The compensating capacity in the case of high eccentricity and large diameters to be sealed is significantly lower in sealing rings in which the connection is arranged approximately in the center of the sealing ring as viewed in the radial direction and in the state of the sealing ring as determined by its production, compared to the aforementioned embodiments.

The sealing lip can be arranged radially inside or outside the sealing ring. Surprisingly, the sealing ring has consistently good performance characteristics, independent of whether the sealing lip is arranged radially inside or outside the sealing ring. A surface to be sealed arranged radially outside can be sealed with the same reliability by the sealing ring as a surface to be sealed arranged radially inside.

According to an advantageous embodiment, the second axial leg can be embedded in the first axial leg, and the stabilizing leg can be embedded in the sealing leg. Advantageously, the spring forms an integral component of the sealing ring. This reliably prevents undesirable wear of the spring both when storing the sealing ring before use and during its intended use in the installed state.

The second axial leg can be at least substantially surrounded by the first axial leg, and the stabilizing leg can be at least substantially surrounded by the sealing leg. Advantageously, this allows for particularly reliable and durable positioning of the spring in the sealing ring. Despite the use of the spring, the sealing ring appears to be virtually one-piece, and the assembly effort required is therefore minimal. The risk of assembly errors is also minimized.

According to an advantageous embodiment, the spring is completely surrounded by the sealing material of the first axial leg and the sealing leg, thereby effectively protecting the spring from external influences.

The spring is preferably arranged within the sealing ring on the mutually facing sides of the first axial leg and the sealing leg. Advantageously, the spring substantially directly delimits the substantially C-shaped joint space of the sealing ring. The operating characteristics of the sealing ring, in particular the pivotability of the sealing leg with the sealing lip around the joint, depend substantially on the operating characteristics of the spring. Even with large radial pivoting movements of the machine element to be sealed and corresponding pivoting movements of the sealing leg with the sealing lip around the joint, the sealing ring does not undesirably harden due to the sealing material being arranged within the acute angle of the spring and being undesirably compacted during the pivoting movement of the sealing leg around the joint, which could adversely alter the operating characteristics of the sealing ring.

The spring can be made of spring steel. Advantageously, the spring does not relax even over the long service life of the sealing ring, and the sealing ring thus exhibits consistently good performance characteristics over the long service life. Other materials that can be used for the spring include, for example, polymer materials that have sufficiently good elastic performance characteristics.

The first axial leg and the sealing leg, more preferably the first axial leg, the sealing leg, and the joint, can merge into one another in one piece and be made of a uniform material and made of a sealing material. The simple, component-free design allows for simple and cost-effective production of the sealing ring. The sealing material can be an elastomer or polyurethane, preferably having a Shore A hardness of 60 to 80. Such a material ensures a good sealing effect over a long service life.

The aforementioned sealing ring may be used in tunnel boring machines, wind power plants or other radial applications.

BRIEF DESCRIPTION OF THE DRAWINGS

An exemplary embodiment of the sealing ring according to the invention is explained in more detail below with reference to FIG. 1 .

FIG1 shows a schematic diagram of an exemplary embodiment of a sealing ring according to the invention.

DETAILED DESCRIPTION

The sealing ring shown in FIG. 1 is designed in the shape of a 7 and has a spring 8 , also designed in the shape of a 7 , as a tensioning element 6 , which forms an integral component of the sealing ring and is completely surrounded by the sealing material of the sealing ring.

The sealing ring comprises a first axial leg 1 and a sealing leg 2 with a sealing lip 3. Depending on the application, the sealing leg 2 and the sealing lip 3 are arranged radially inside or outside the sealing ring. Two symmetry axes are schematically shown, radially adjacent to the sealing lip 3 or radially adjacent to the first axial leg 1. The sealing leg 2 is articulated to a first end face 5 of the axial leg 1 by means of an articulated joint 4. The joint 4 is arranged as far as possible from the sealing lip 3 in a radial direction 7 in order to compensate for large eccentricities of machine elements (not shown here). Such large eccentricities primarily occur when the diameter to be sealed is large, for example, approximately 2 meters or more.

The joint 4 transitions integrally with the axial leg 1 and the sealing leg 2 and is constructed from the same material as the axial leg and the sealing leg. When viewed in the radial direction 7 and in the state of the sealing ring determined by its manufacture, the joint 4 is arranged in the third 16 of the sealing ring furthest from the sealing lip 3. To further improve the pivotability of the sealing leg 2 relative to the first axial leg 1 about the joint 4, the first axial leg 1 has an undercut 13 on its side 11 radially facing the sealing leg 2. The undercut extends in a radial direction 14 from the second end face 15 of the first axial leg 1 to the first end face 5 and to the joint 4.

Spring 8 defines a C-shaped joint space 17, which is delimited by the mutually facing sides 11, 12 of first axial leg 1 and sealing leg 2. Spring 8 is situated directly adjacent to this joint space 17, essentially directly beneath the surfaces of first axial leg 1 and sealing leg 2. The second axial leg 9 of spring 8 extends axially parallel to the first axial leg 1 of the sealing ring, and the stabilizing leg 10 of spring 8 extends essentially parallel to the sealing leg 2. Stabilizing leg 10 ensures that the sealing leg 2, and thus the sealing lip 3, are attached to the machine element to be sealed in the circumferential direction with a constant contact pressure over a long service life, with the sealing lip 3 sealingly contacting the surface of the machine element to be sealed.

The machine element to be sealed can be formed radially from the inside in a sealing manner by the shaft to be sealed or radially from the outside in a sealing manner by a wall to be sealed which delimits the housing opening.

The sealing ring according to the present invention always maintains consistently good performance regardless of whether the sealing lip 3 is arranged radially inside or outside the sealing ring. Due to the aforementioned 7-shaped shape of the spring 8, a radial spring force is generated by the radial movement of the spring 8. The bending of the spring 8 causes the sealing lip 3 to be pressed against the surface to be sealed, so this pressing is independent of the diameter.

Due to its good performance characteristics over a long service life, the sealing ring according to the invention is particularly well suited for use in tunnel boring machines or wind turbines, even if the sealing ring is radially externally sealed.

Claims (10)

1. A sealing ring, which is configured in a figure-7 shape when viewed in cross-section, the sealing ring comprising a first axial leg (1) and a sealing leg (2) including a sealing lip (3) and a tensioning element (6) for stabilizing the sealing leg (2) in the radial direction (7), wherein the sealing leg (2) is connected to a first end side (5) of the axial leg (1) by means of a joint (4), wherein the tensioning element (6) is annularly configured and formed by a spring (8) configured in a figure-7 shape when viewed in cross-section. The tensioning element has a second axial leg (9) and a stabilizing leg (10), the second axial leg (9) being connected to the first axial leg (1) and the stabilizing leg (10) being connected to the sealing leg (2), characterized in that the first axial leg (1) has a side recess (13) on its radially facing side (11) of the sealing leg (2), the side recess extending in the axial direction (14) from the second end side (15) of the first axial leg (1) toward the first end side (5) and the connector (4). 2. The sealing ring according to claim 1, characterized in that, when viewed in the radial direction (7) and in the manufacturing-determined state of the sealing ring, the joint (4) is located in the third (16) of the sealing ring furthest from the sealing lip (3). 3. The sealing ring according to claim 1 or 2, characterized in that the sealing lip (3) is disposed inside or outside the sealing ring in the radial direction (7). 4. The sealing ring according to claim 1 or 2, characterized in that the second axial leg (9) is embedded in the first axial leg (1) and the stabilizing leg (10) is embedded in the sealing leg (2). 5. The sealing ring according to claim 1 or 2, characterized in that the second axial leg (9) is at least substantially surrounded by the first axial leg (1) and the stabilizing leg (10) is at least substantially surrounded by the sealing leg (2). 6. The sealing ring according to claim 1 or 2, characterized in that the spring (8) is disposed on the sides (11, 12) of the first axial support leg (1) and the sealing support leg (2) facing each other. 7. The sealing ring according to claim 1 or 2, wherein the spring (8) is made of spring steel. 8. The sealing ring according to claim 1 or 2, characterized in that the first axial support leg (1) and the sealing support leg (2) are integrally transitioned into each other and are constructed of the same material and made of sealing material. 9. The sealing ring according to claim 1 or 2, characterized in that the first axial support leg (1), the sealing support leg (2) and the joint (4) are integrally transitioned into each other and are constructed of the same material and made of sealing material. 10. The application of the sealing ring according to any one of claims 1 to 9 in a tunnel boring machine or wind power equipment.