FR2740194A1 - RADIAL SEALING RING - Google Patents

Abstract

Radial sealing ring comprising a support ring (1) and a flat seal (2) in the form of a circle ring, extending essentially in the radial direction, of an elastically deformable raw material, the ring support (1) and the flat seal (2) being connected together, the flat seal (2) being able to be radially pre-bent on the inside in the direction of a space (3) to be sealed and being provided in the axial direction, d firstly, a first surface profiling (6, 8) on the side opposite the space (3) to be sealed for the delivery of leakage liquid into the space (3) to be sealed during the rotation of the shaft (4) to be sealed in a first direction of rotation (5, 7), the latter surface profiling being able to be placed under radial prestress against the shaft (4) in a sealed manner. The flat seal (2) is provided in the axial direction, on the other hand, with a second surface profiling (8, 6), on the side opposite to the first surface profiling (6, 8) for the delivery of liquid. in space (3) to be sealed when the shaft (4) is rotated in a second direction of rotation in the opposite direction to the first direction of rotation (5, 7).

Description

RADIAL SEALING RING

  The invention relates to a radial sealing ring comprising a support ring and a flat seal in the form of a circle ring, extending essentially in the radial direction, of an elastically deformable raw material, the ring d the support and the flat seal being connected together, the flat seal being able to be radially pre-bent on the inside in the direction of a space to be sealed and being provided in the axial direction, on the one hand, with a first surface profiling on the side opposite the space to be sealed for the delivery of leaking liquid into the space to be sealed during the rotation of the shaft to be sealed in a first direction of rotation, the latter profiling being able to be placed under radial prestress against the shaft of

waterproof way.

  This radial sealing ring is known from document DE 36 07 662 A1. The radial sealing ring is provided with a cylindrical packing,

  which is designed in the shape of a disc and which consists of polytetrafluoroethylene.

  The surfaces of the flat seal are provided on both sides with notches annularly concentrically, eccentrically or spirally around the axis of the shaft to be sealed, the notches of a flat seal surface being disposed between the notches of the opposite flat gasket surface. The objective, which must be achieved by means of the already known radial sealing ring, is that the flexibility of the material of the flat seal must be increased. The radial sealing ring must be able to be used reliably with a long service life. The notches on both sides on the surfaces of the flat seal may extend at a right angle or at an acute angle to

2 2740194

  the surface of the flat seal. Polytetrafluoroethylene has good resistance to media and thermal constancy, as well as good sliding behavior. Because the notches in the axial direction are provided on both sides of the flat gasket, the disadvantage of the weakly elastic properties of polytetrafluoroethylene is partially compensated, so that, for example, shafts which do not turn absolutely in circles, for example having a low impact in height, can be made waterproof in an improved manner. If the notches formed on the side facing the shaft to be sealed are arranged in the form of a spiral, a delivery torsion known per se of the medium to be sealed is established in the direction of the space to be sealed when the rotation of the shaft to be sealed in a direction of rotation. In order to increase the pressure force of the flat seal on the shaft and to compensate, at least partially, for the clean radial force, reduced by the notches, of the sealing lip, an annular return spring can be placed on the opposite side of the shaft to seal the sealing lip. If a twisting of the medium to be sealed is envisaged in the direction of the space to be sealed, two lip rings with spring designed differently are necessary to seal the axial ends of the shaft of a shaft pivoting around of its axis, in order to take into account the senses of

  different rotation regarding the front sides of the shaft ends.

  The objective of the present invention is to improve a radial sealing ring of the type mentioned at the start so that two lip rings with spring designed in an identical manner can seal the ends of a shaft opposite one to the other. 'the other in the axial direction, each of the lip rings with spring having to effect a delivery action of the medium to be sealed in the direction of the space to be sealed. The radial sealing ring according to the invention must permanently allow a discharge action of the medium to be sealed in the direction of the space to be sealed regardless of its mounting position of the support ring relative to the housing and in the sense of rotation of

the tree to be sealed.

3 2740194

  This objective is achieved according to the invention by a radial sealing ring comprising a support ring and a flat seal in the form of a circular ring, extending essentially in the radial direction, made of an elastically deformable raw material, the support ring and the flat seal being connected together, the flat seal being able to be radially pre-bent on the inside in the direction of a space to be sealed and being provided in the axial direction, on the one hand, with a first surface profiling on the side opposite the space to be sealed for the delivery of leakage liquid into the space to be sealed during the rotation of the shaft to be sealed in a first direction of rotation, the latter profiling surface that can be placed under radial prestress against the shaft in a sealed manner. The flat seal is provided in the axial direction, on the other hand, with a second surface profiling, on the side opposite to the first surface profiling for the delivery of leakage liquid into the space to be sealed during rotation of the shaft in a second direction of rotation opposite to the first direction of rotation, in that the flat seal can be pre-bent radially on the inner side of both sides in the axial direction and in that the second surface profiling can be put under

  radial prestress against the shaft in a leaktight manner.

  It is therefore advantageous that, by virtue of the arrangement of the surface profiling on the two sides of the flat seal of the rotary shafts, they are to be sealed with one and the same ring, regardless of their direction of rotation, a discharge action of the medium to be sealed in the sense of space to be sealed that can be permanently obtained. Economically, the configuration of the radial sealing ring is particularly advantageous since the two directions of rotation of the shafts can be sealed by an identical radial sealing ring, in which case only one tool is necessary for the manufacture of the radial sealing ring and storage is simplified thanks to the use of a radial sealing ring only and the risk of assembly errors when replacing the

  lip rings with spring is minimized.

4 2740194

  The flat seal of the radial seal ring is preferably made of PTFE (polytetrafluoroethylene). The radial sealing ring is therefore resistant to most environments to be sealed. The PFTE also has good thermal constancy, as well as good sliding behavior. A flat PFTE seal is almost free from wear, since after some initial wear the surface is varnished and therefore very resistant. The flat seal is preferably placed against the shaft with first and second coincident surface profiling. It is therefore advantageous that two lip rings with identical spring designed in each case can be applied each time to the opposite ends of one another of a shaft to be sealed, one of the lip rings with spring surrounding the shaft sealingly with the first surface profiling and the other radial sealing ring surrounding it with the second surface profiling and the delivery properties of the medium to be sealed being coincident in

  the sense of space to be sealed thanks to the same surface profiling -

  concerning the surface of the tree. For applications, in which in the area of the two ends of the shaft a variable delivery effect, of different strength is desired, then for example, when the medium to be sealed has along the shaft to be sealed a variable viscosity due to a drop in temperature, it may on the other hand be advantageous for the two surface profilings to be able to be formed by differentiating one from the other,

  in order to achieve repression effects different from each other.

  The surface profiling can be formed in each case by circular recesses in the form of a groove, in which case the recesses and the cavities of the shaft limit a section essentially in the shape of a triangle and the axial limitations of the recesses opposite to the space at sealing are arranged essentially perpendicular to the axis of the tree. In order to obtain a discharge effect in the direction of the space to be sealed, the recesses of the respective surface profilings are formed by passing one inside the other in a helical manner, in which case during the use es 2740194 according to the radial sealing ring preferably at least two complete turns of the flat seal touch the shaft in a sealed manner. A configuration of this type has proved to be advantageous with regard to a good action of

  delivery even with a small number of turns of the rotary shaft.

  The recesses which form the first and second surface profiling are preferably limited by bars which, seen in section, have an essentially corresponding thickness of material. The recesses are preferably created by avoiding the use of machining processes by removal, for example by stamping or because the recesses are already formed in the flat seal during shaping. It is then advantageous for the flat seal to withstand, without deterioration, a very large number of force cycles, since the effects of notching in the region of the recesses are reduced in comparison with the machining by removal processes. The manufacture of the flat seal is simplified by the essentially corresponding material thickness of the bars. A configuration of this type reliably avoids an undesired accumulation of material, which is disadvantageous from the point of view of manufacturing technique and in consideration of good properties of use. The support ring can be formed in one piece by interlocking, be made of a hard raw material and have an axial and radial projecting part. The support ring preferably consists of a metallic raw material and is formed by a sheet metal ring. The entire radial sealing ring can therefore be produced

  comparatively simple and inexpensive.

  The support ring is preferably wrapped essentially completely in elastomeric raw material, the elastomeric raw material, which surrounds the axially projecting part radially on the outside,

  being designed as a static acting casing seal.

  The axial projecting part and the elastomeric raw material surrounding on the outer circumference the axial projecting part are compressed in the bore of a housing surrounding the shaft, in which case the support ring and the elastomeric raw material are arranged under radial prestress at

6 2740194

  inside the housing. The integral coating of the support ring with an elastomeric raw material provides perfect anticorrosive protection of the support ring, so that for the manufacture of the support ring it is possible to use, for example, raw materials inexpensive metal. The elastomeric raw material, which surrounds on its circumference the part projecting axially in the radial direction, also achieves an additional perfect insulation against impact, which benefits a long service life of the radial sealing ring. Movements of a rotating shaft and /

  or a vibrating housing are therefore not directly transmitted to the flat seal.

  io This is then particularly significant, when it is made of PTFE, since a flat seal consisting of raw material of this type has in principle weaker elastic properties than those of a flat seal made of configured elastomeric material. correspondingly. The deformations present on the flat PTFE seal are kept to a minimum thanks to the casing, which is arranged in the radial direction between the axial projecting part and the housing limiting the bore, perfect properties of use.

  for a long period of use due to this.

  In order to complete the aforementioned advantageous effects of the elastomeric raw material on the flat seal, it is preferably provided that the radial projecting part of the flat seal is disposed contiguously with an axial spacing and that the axial slot formed by the spacing is completely filled with elastomeric raw material and the flat seal and the elastomeric raw material are bonded in an adhesive manner. An adhesive bond can for example take place by vulcanizing the two parts together or by bonding them. The radial sealing ring is disposed both axially and radially, being isolated from vibrations within its mounting space, the vibration isolation being due to the inherent elasticity of the flat seal. and the elastomeric raw material, which surrounds the support ring. In order to obtain a reliable adhesive connection of the flat seal to the support ring or to its casing of elastomeric raw material, the profiling of

7 2740194

  surface of the flat seal preferably extend each time radially outward only to the inner radial limit of the support ring. The part of the flat seal extending essentially in the radial direction

  during mounting does not therefore exhibit surface profiling.

  Two lip rings with identical spring, of the technique described above, are preferably used for sealing a shaft passing through a space to be sealed in the area of its two shaft ends. Two identically designed spring lip rings can be used for sealing a camshaft of an internal combustion machine, in which one of the spring lip rings surrounds the ends in each case of the camshaft opposite to each other in the axial direction. For applications in which a shaft is to be sealed in the area of its axial ends, in which case the space to be sealed is located in the axial direction between the shaft ends, a radial seal ring is required to sealing, which ring sealingly surrounds the shaft ends on the circumference. Thanks to the configuration according to the invention of the radial sealing ring, two identical sealing rings can enter into application although the shaft to be sealed, which pivots about its axis, pivots in opposite directions, seen each time from the space to be sealed in the direction of the shaft end. Despite the identical structure of the lip rings with spring used, designed in an identical manner, reliable sealing and a backflow of the medium to be sealed in the direction of the space to be sealed are guaranteed. In addition, the flat seals are pre-bent in the zone of their internal limitation each time in the direction of the space to be sealed, in which case the first surface profiling of the first radial sealing ring and the second surface profiling of the second identically designed radial sealing ring surround each time sealingly on the circumference of the pivoting shaft around its axis. In this exemplary embodiment, the surface profiling has a configuration

8 2740194

  when they touch the tree adjacent to each other. This results in a corresponding discharge effect from each of the lip rings with spring in the direction of the space to be sealed. Because the delivery capacity of the two lip rings with spring coincides, there is no danger that the medium to be sealed overflows into the spaces

  surrounding at the level of the flat seal with comparatively lower discharge.

  An exemplary embodiment of a radial seal according to the invention is also

  explained later in the document using the accompanying drawings.

  Figure 1 shows an embodiment of the ring

  sealing according to the invention in its inherent form in manufacturing.

  2 shows the radial sealing ring of Figure 1 in the assembled state, the shaft to be sealed pivoting about its axis in a first

relative direction of rotation.

  3 shows the radial seal ring of Figure 1 in the assembled state, the shaft, relative to the mounting of the radial seal ring, pivoting in a second direction of rotation about its axis, which is opposite

  in the first direction of rotation of figure 2.

  FIG. 4 represents the sealing of a shaft pivoting around its axis in the area of its shaft ends, the lip rings with spring designed in an identical manner limiting in the axial direction the space to be sealed. In FIG. 1 is shown an embodiment of a radial sealing ring, which essentially consists of a support ring 1, of an elastomeric raw material essentially completely surrounding the support ring 1 and d '' a flat seal 2 made of PTFE. The flat seal 2 is designed to be essentially smooth and has on both sides, from the radially inner limitation 22 of the support ring 1 in the radial direction inwards in the axial direction, each time a surface profiling 6, 8 The flat seal 2 can be bent on both sides in the area of the surface profiling 6, 8 in the axial direction, so as to be able to surround a shaft 4 to be sealed on the circumference. The two surface profiles 6, 8 are designed in such a way

9 2740194

  so that they guarantee a backflow of the medium to be sealed in the direction of the space 3 to be sealed, when they are in sealed engagement with a shaft 4 pivoting about its axis 13. The surface profilings 6, 8 are

  each designed in the shape of a propeller.

  The support ring 1 is - seen in section - designed essentially in the shape of a T and has an axial projecting part 18 and a radial projecting part 19. The two projecting parts 18, 19 are, in this embodiment, essentially completely surrounded by elastomeric raw material, which induces perfect anticorrosive protection. The elastomeric raw material 20, which surrounds the axial projecting part 18 on the outside radially, is profiled in the form of a groove on the side opposite to the axial projecting part 18. Thanks to a configuration of this type, the tolerances diameter of the bore of the housing 23, on the one hand, and / or the diameter tolerances of the support ring 1, on the other hand, are compensated. The elastic raw material 20 provides a vibration-absorbing arrangement of the radial sealing ring between the housing 23 and a shaft 4 to be sealed, the vibration-absorbing properties positively influencing the duration of use of the flat gasket 2 composed of PTFE. The deformations of the flat seal 2 are thereby reduced, as well as the symptoms of fatigue, so that improved properties of use for a longer period of use

are inherent.

  In Figure 2, the radial seal ring of Figure 1 is pressed into the bore of a housing 23 and surrounds the shaft 4 pivoting about its axis 13 on the circumference. The space to be sealed is characterized by the number of

  reference 3, while the downstream side is provided with the reference number 24.

  The shaft 4 rotates to the right in this exemplary embodiment, so that this results in a discharge action from the medium to be sealed in the direction of

space 3 to be sealed.

  The radial seal ring of Figure 1 is shown in Figure 3, the radial seal ring corresponding to the embodiment of Figure 2 being also disposed in the bore of a housing 23 and surrounding so

2740194

  tight the shaft 4 pivoting about the axis 13 with the second surface profiling 8 of the flat seal 2. Unlike the embodiment of Figure 2, the shaft 4 rotates in a second direction of rotation 7 in the direction reverse of the first direction of rotation 5, so to the left. The advantageous vibration absorption arrangement of the radial sealing ring also exists here. In Figure 4 is shown a shaft 4, which is sealed in the region of its axially opposite ends each time through an identically designed radial sealing ring. The space 3 to be sealed is limited in the axial direction by the spring-loaded lip rings. The flat seals 2 of the spring-loaded lip rings entered into application are each time pre-bent in the direction of the space 3 to be sealed and bring the shaft 4 into contact with the first and the second surface profiling 6, 8. The arrangement of the lip rings with spring carries out each time a repressing action of the medium to be sealed in the direction of the space 3 to be rendered

  waterproof, so that leakage is reliably avoided in all cases.

[! 1

Claims (12)

  1. Radial sealing ring comprising a support ring and a flat seal in the form of a circle ring, extending essentially in the radial direction, of an elastically deformable raw material, the support ring and the seal flat being connected together, the flat seal being able to be radially pre-bent on the inside in the direction of a space to be sealed and being provided in the axial direction, on the one hand, with a first surface profiling on the side opposite to the space to be sealed for the discharge of leaking liquid into the space to be sealed during the rotation of the shaft to be sealed in a first direction of rotation, the latter surface profiling being able to be placed under radial prestress against the shaft in a sealed manner, characterized in that the flat seal (2) is provided in the axial direction, on the other hand, with a second surface profiling (8, 6), on the side opposite to the first profiling of surface (6, 8) for refo only leakage liquid in the space (3) to be sealed when the shaft (4) is rotated in a second direction of rotation (7, 5) in the opposite direction to the first direction of rotation (5, 7) , in that the flat seal (2) can be pre-bent radially from the inside on both sides in the axial direction and in that the second surface profiling (8, 6) can   be placed under radial prestress against the shaft (4) in a leaktight manner.   2. Radial sealing ring according to claim 1, characterized in   that the flat seal (2) consists of PTFE.   3. radial sealing ring according to one of claims 1 to 2,   characterized in that the flat seal (2) can be placed against the shaft (4) with a   first and second coincident surface profiling (6, 8).   4. Radial sealing ring according to claim 3, characterized in that the surface profiling (6, 8) are formed each time by o .. circular recesses (9, 10), in the form of a groove, in that that the recesses (9, 10) and the shaft (4) limit cavities (11, 12) of cross section 12 2740194   essentially triangular and in that the axial limitations of the recesses (9, 10), opposite the space (3) to be sealed, are arranged   essentially perpendicular to the axis (13) of the shaft (4).   5. Radial sealing ring according to claim 4, characterized in that the recesses (9, 10) are designed so as to merge into each other helically and in that during the intended use of the ring radial sealing at least two complete turns (14, 15, 16, 17) of the   flat seal (2) touches the shaft (4) in a sealed manner.   6. Radial sealing ring according to one of claims 4 to 5,   characterized in that the recesses (9, 10), which form the first and second surface profiling (6, 8), are limited by bars (18) which, seen in section, have an essentially corresponding thickness of material.   7. radial sealing ring according to one of claims 1 to 6,   characterized in that the support ring (1) is designed as a single piece, consists of a hard raw material and has a part   axially projecting (18) and a radially projecting part (19).   8. Radial sealing ring according to claim 7, characterized in that the support ring (1) is enveloped essentially completely of raw material (20) elastomer and in that the raw material (20) elastomer, which surrounds the axially projecting part (18) on the outside so   radial, is designed as a housing gasket acting statically.   9. Radial sealing ring according to one of claims 7 to 8,   characterized in that the radial projecting part (19) is arranged adjacent to the flat seal (2) with an axial spacing, in that the axial slot (21) formed by the spacing is completely filled with raw material (20 ) elastomer and in that the flat seal (2) and the raw material (20)   elastomer are connected in an adhesive way.   10. Radial sealing ring according to one of claims 1 to 9   characterized in that the surface profiles (6, 8) extend each time 13 2740194   in the radial direction outwards only up to the radial limitation (22) internal of the support ring (1).   11. Use of two lip rings with spring designed so   identical according to one of claims 1 to 10, for sealing a   shaft (4) crossing a space (3) to be sealed in the area of its two shaft ends.   12. Use of two lip rings with spring identically designed according to claim 11 for sealing a camshaft of an internal combustion machine, one of the lip rings with spring o10 surrounding each time so seals the ends of the camshaft   opposite to each other in the axial direction.