DE2206771A1 - HIGH PRESSURE SEAL WITH THE O-RING ADAPTED SUPPORTING SURFACE AND EDGE-LOADED SEALING RING - Google Patents

Description

FICHTEL & SACHS AG - S C H W E I U ϊ ϋ B I

99ΠΚ771 ΡΑΚΘΠΕ- UHD GEBRAUCHSMUSÜiEEHILFSAimSLIUHa

High pressure seal with the O-Bing adapted abutment surface and

edge-loaded Diehtriag

The invention relates to a hydraulic lift a preferably made of elastic plastic, view " element, which is arranged in a sealing chamber let imd of a pretensioned elastomer body against the surface to be sealed is pressed, whereby the center of the area of the ElastomerkSr » pers above the Kent β facing the high pressure of the sealing element it lies and this edge is exposed to the highest contact pressure.

Such seals allow the removal of containers which are under high pressure and filled with hydraulic medium oscillating movable components and prevent a transition point between movable and stationary component Leakage of the hydraulic medium. In the case of such, commonly used seals, their tightness is proportional Relation to the force with which they are pressed against the surface to be sealed, the higher the contact pressure, the greater the tightness. The disadvantage here, however, is that high contact forces also cause high heat forces, which, for example, can result in the piston rod sealing of a hydraulic shock absorber as an uncomfortable delay in response.

The object of the present invention is therefore to provide a sealing arrangement to create, which can be communicated with a high contact pressure with relatively low friction.

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This object is achieved according to the invention in that the flat center of gravity of the pretensioned elastomer body is in all operating positions at an essentially constant axial distance from the edge of the sealing element facing the high-pressure chamber pressed more strongly than the rest of the seal. The sealing area is thus reduced, whereby the specific surface pressure increases. The Dichtungateil remote from the high-pressure chamber is thereby primarily a FiLhrungsaufgäbe _to% which prevent retraction of the sealing edge is to "The sealing edge is pressed by a pre-stressed by means of radial deformation of the elastomer body to a further feature of the invention in one of its contour in the biased according en State corresponding molding groove is arranged and the molding groove according to the invention is located on the side of the elastomer body facing away from the high-pressure chamber. As a result, the pressed surface is kept almost constant in an advantageous manner and the elastomer body represented by an O-bing is prevented from escaping even at very high internal pressure.

According to a further feature of the invention, the molding groove of the elastomeric body in a separate, provided in the sealing chamber seal carrier is mounted and dev separate Pichtungsträger opposite the Bückwand the Dichtungskamner with a game exposed · In this way, inexpensive to produce piston rod guides are used in large series, in which The high-pressure seal can be installed as a supplement, the piston rod guide is therefore universally usable, and the seal carrier can also be used as a securing component, which can yield to any small lateral deflections of the piston rod without reducing the contact pressure of the elastomer body.

According to a further feature of the invention, the sealing chamber is covered with a cover plate opposite the high-pressure chamber.

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borders. In this way, the entire piston rod guide seal unit can be calibrated preassembled in a ready-to-install manner and thus manufacture at low cost. The invention also provides that the direction chamber is connected to the high pressure chamber, the elastic force of the elastomer body is thus advantageous W ^ i .. · * »increased by the high pressure building up on it. One A further development of the invention provides that the connection between the sealing chamber and the high-pressure chamber is by means of in the cover arranged holes happens.

A further embodiment of the invention provides that the elastomer body is biased by a spring · This is achieved in an advantageous manner independent of exercise tolerance of the forming groove, during operation constant bias of the elastomer body. According to a further feature of the invention, the preload spring is represented by a plate spring which is held in its position by a spring carrier.

According to a further feature of the invention, the disc spring biased by the spring carrier. The preload of the disc spring can be adjusted and selected in an advantageous manner through the application of axial force during assembly. It is also provided that the deformation of the elastomer body by the door tension and the internal pressure of the sealed high-pressure chamber in the same direction runs, whereby a low hysteresis is achieved in an advantageous manner.

The disc spring is according to the invention by a spring carrier held in their position, which is provided with a vertically extending web and a horizontally extending angle. After a Another feature of the invention is the length of the web adjustable, which in an advantageous manner and with very simple means, the preload of the disc spring during the assembly can be varied and adjusted. According to a further feature, the plate spring is positively locked in the angle of the spring carrier stored and forms together with the lower edge of the piston «

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etansenführung, the elastomer body and the spring carrier one oil room. As a result, a counterpressure can build up in an advantageous manner at very high internal pressure, that of the load peak counteracts and thus limits the pressure load on the elastomer body.

According to a further embodiment of the invention and its use it is provided on a piston rod guide and seal unit, to assign a tension stop to the preload spring and to represent this tension stop by means of a stop ring arranged in the cylinder. This avoids in an advantageous manner that the piston rod extending too far and the piston attached to it the preload spring or its spring carrier damaged or the Spring characteristics changed.

A drawing of the invention is shown in the accompanying drawings Figures shown and explained in more detail below. The figures show in detail:

1 shows a high-pressure seal arrangement according to the invention with a shaped groove incorporated into the piston rod guide;

2 shows a high-pressure seal arrangement according to the invention with a shaped groove and cover disk incorporated in the seal carrier}

Fip ;. _i ^ a high-pressure sealing arrangement according to the invention with a shaped groove incorporated into a seal carrier and a cover plate with a connecting hole)

4 shows a high-pressure seal arrangement according to the invention with a shaped groove machined into the piston rod guide and an elastomer body pretensioned by a plate spring.

In Fig. 1, a piston rod guide arranged in a cylinder 2 is shown 1 shown, which has a high pressure chamber 8 to the outside

3098 * 31 / "Ö7 3 2

and through which a piston rod 3 is guided - The piston rod 3 is sealed against the piston rod guide 1 by a sealing element 5, which is in operative connection on the high pressure side with a support ring 6 and is pressed against the piston rod 3 by an elastomer body 4 »The seal 5 »A support ring 6 and the elastomer body 4 are arranged in a sealing chamber 14 which is delimited on the high pressure side by a cover plate 7, the cover plate 7 being arranged in a piston rod guide 1 so that the pressure medium can pass through. On the side facing away from the high pressure, the sealing chamber 14 has a shaped groove 20 into which the blastomer body 4 fits in a prestressed state so that its center of area 17 WTI ^ '^ eP''llltr9 ^^ t ^ e ^ F ^^ »

always and in every operating position in the axial distance 19 to the sealing edge 18 of the sealing element 5 is located.

FIG. 2 shows an embodiment of the invention in which the shaped groove 20 is introduced into a seal carrier 9. Of the The seal carrier 9 is exposed with a play 15 with respect to the rear wall 16 of the sealing chamber 14 and allows the piston rod 3 a slight deflection without the sealing element 5 or the elastomer body 4- are damaged. In the case of the in Fig. illustrated embodiment is the Dichtungskaiömer 14 by means of through the cover plate 7 extending holes 10 with the high pressure chamber 8 connected so that the high inside * kink can build up unhindered on the elastomer body 4 «

In the embodiment shown in FIG. 4, the elastomer body 4 preloaded by a plate spring 11. The shaped groove 20 is in the piston rod guide; 1 introduced and has a tolerance that is independent of the preload of the elastomer body 4 on. The plate spring 11 is held in its position by a spring carrier 12, which has a vertically extending web and a horizontally extending angle 23 is provided. Below the lower edge 24 of the piston rod guide 1 and the elastomer

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Marked body 4 there is an oil space 13, which is delimited laterally by de-web 22 and downward by the Vcrspeimfeder 11. The sealing edge 18 of the sealing element 5 is pressed by the axially pretensioned elastomer body 4 against the surface of the piston rod 3 to be sealed. A stop safety device in the form of a stop ring 21 upstream of the high pressure chamber 8 is embedded in the inner wall of the cylinder 2 and prevents the guide-sealing line from being damaged if the piston rod 3 or the piston, not shown, is extended too far.

On the basis of the figures described above, the function of the invention High pressure seal described in more detail below;

The piston rod guide 1 is sealed with a sealing element 5 against the surface of the piston rod J to be sealed. The side of the seal facing away from the high pressure chamber 8 serves to guide it, while the sealing edge 18 facing the high pressure chamber 8 has the actual sealing function. The sealing edge 18 is pressed against the surface to be sealed by the radially pretensioned elastomer body 4. The elastomer body 4 is radially biased from its originally circular to an oval shape, namely at its outer diameter depending on the outer diameter of the sealing chamber 14 and at its inner diameter depending on the outer diameter of the sealing element it 5 · The dem The radius of the elastomer body 4 facing away from the high-pressure chamber 8 is determined by the shaped groove 20 into which the O-input, which is pretensioned to form an oval, fits smoothly. When the pressure rises in the high-pressure chamber 8, hydraulic medium passes through between the cover plate 7 and. the piston rod 3 existing play in the sealing chamber 14 and presses the elastomer body 4 firmly into the shaped groove 20. Since the elastomer body 4 can no longer escape in the shaped groove 20, it is compressed and transmits a radially directed contact pressure to the sealing element 5. The sealing edge 18 of the sealing element 5 is in the direction of the high pressure chamber from the outer? a relatively stiff material existing support ring 6 supported and so prevented from under the

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A ^ tearing pressure of the elastomer body 4 to evade downwards. At the same time, the support ring 6 is also exposed to the pressure ^ hydraulic medium complained of an ejection force facing away from the high pressure chamber 8, which is transferred via the sealing edge 18 to the sealing element 5 and here a kind of compression; "causes that - there a radial deflection facing away from the sealing surface is prevented by the elastomer body 4 - as a radial contact pressure the sealing surface of the piston rod 3 has an effect. By mainly on the sealing edge 18 of the sealing element 5 directed contact pressure A relatively high surface pressure is created here, which means the overall contact pressure can be kept smaller than if the sealing element 5 over its entire length against the Sealing surface would have to be pressed. This will reduce the friction between Sealing element 5 and piston rod 5 significantly reduced with optimum sealing effect at the same time. Due to the mold groove 20 according to the invention, even with the highest pressure loads the elastomer body 4 does not give way and thus maintains the axial distance 19 between its centroid 17 »the than Starting point for the directed contact force can, and the sealing edge 18 in each operating position essentially at. The sealing element 5 always experiences what is known as its sealing edge 18 an optimal pressure corresponding to the internal pressure and you · » activity means, at the same time, comparatively less comfort for example a shock absorber reducing friction.

In the embodiment according to FIG. 2, the molding groove 20 is in a Seal carrier 9 incorporated, which is exposed with a game 15 opposite the rear wall 16 of the sealing chamber 14 in the Piston rod guide 1 is installed. The seal carrier 9 can be equipped with different radii of the shaped groove 20, which depend on the required contact pressure by the elastomer body 4 and nevertheless in a standardized sealing chamber 14 can be installed. One and the same piston rod guide 1 can thus be used for different shock absorbers and so launched and manufactured in larger and more rational series will. At the same time, the clearance 15 of the piston

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When driving, there is a slight radial evasion caused by MUgIiehe transverse ventilation without the risk of damage to the seal and thus a leak in the high-pressure chamber 8 the hydraulic medium of the high-pressure chamber 8 can suit the cover disk 7 with its play in relation to the piston rod 3 be provided with holes 10, as shown in Figure 3 * The function of the sealing arrangement according to the invention is the same as described below in Figure 1 »

In a further embodiment of the invention, as shown in FIG 4 is shown, the elastomer body 4 experiences its preload by a preloaded spring 11. The elastomer body 4 is preloaded axially rather than rsdial, i.e. in in the same direction as it is later in operation, the pressing force through the compressed hydraulic medium of the high-pressure chamber β experiences · Here, however, the prestressing force by the hydraulic medium does not act directly on the elastomer body 4, but rather on it the plate spring 11 which it transfers to the elastomer body 4. Pie mode of operation of the pressing of the sealing element 5 by the Elastomer body 4 with a substantially constant distance 19 is the same as written below in FIG Undergoes preload The plate spring 11 can thus deviate on the side facing away from the high pressure chamber 8 and on its inner diameter facing the solenoid rod 3, thereby relieving it Internal pressure in the high-pressure chamber 8 thus relaxes the plate spring 11 in parallel. When the plate spring 11 is completely relaxed, it lifts from the angle 23 of the spring support 12 and releases the path into the oil chamber 13 for the hydraulic medium. As a result, the pressed surface of the plate spring 11 is enlarged

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on the other hand, there is a certain one that supports the elastomer body 4 Generated back pressure and thus avoided an absolute voltage peak. The elastomer body 4- is not so strongly pressurized that it loses its elastic properties and the sealing element 5 * a with too little contact pressure presses against the surface of the piston rod 3 to be sealed. This makes the seal particularly durable and virtually regardless of the internal pressure of the high pressure chamber 8. The biasing of the plate spring 11 is done in a very simple way by shortening or lengthening the web 22 of the spring carrier 12 during the pre-assembly of the piston rod guide seal unit. The radius of the shaped groove 20 is largely independent of the tolerance since the bias of the elastomer body 4- at this embodiment no longer happens through a radial deformation and can so in a very simple way in a right rough work process are introduced.

The invention relates not only to those illustrated by way of example Embodiments, the spring support 12 can also be screwed on instead of pressed in, or the spring 11 can be replaced by a other than a Belleville washer, or the seal on applied to a piston.

EP33 - Scho
8.2.72

309833/0732

Claims (18)

PATENT CLAIMS 220677 / 1) j Hydraulic high pressure seal with a Torsugsweiee ^ - ■ bending element made of elastic plastic, which is arranged in a sealing chamber and is pressed by a prestressed elastomer body against the surface to be sealed, the center of the area of the elastomer body lies above the edge of the viewing element facing the high pressure and this edge of the Is exposed to maximum contact pressure, characterized in that that the center of gravity (1?) of the prestressed Elaeto ~ Merkörpers (4) in all operating positions in one in we ~ The constant axial distance (19) from the edge (13) of the optical element facing the high-pressure chamber (8) is borrowed (5) is located. 2) Hydraulic high-pressure seal according to claim 1), characterized in that the elastomer body (4) in a shape corresponding to its contour in the pretensioned state (20) is arranged. 3) Hydraulic high pressure seal according to claims 1) and 2), characterized in that the elastomer body (4) on its side facing away from the high pressure chamber (3) is arranged in a shaped groove (20) corresponding to its contour in the prestressed state. 4) Hydraulic high pressure seal according to claims 1) to 3), characterized in that the shaped groove (20) in one a separate seal carrier (9) provided in the seal chamber (14) is attached 5) Hydraulic high pressure seal according to claims 1) to 4), characterized in that the separate seals carrier (9) opposite the rear wall (16) of the sealing chamber ~ 2 -309833/0732 (14) with a game (15) is exposed. 6) Hydraulic high pressure seal according to claims 1) 5) j characterized in that the sealing chamber | (14) opposite the high pressure chamber (8) by a cover plate (7) is limited 7) Hydraulic high pressure seal according to claims 1) to 6), characterized in that the sealing chamber (14) is connected to the high pressure chamber (8) 8) Hydraulic high pressure seal according to claims 1) to 7) «characterized in that the: Dichtungskamaer (14) is connected to the high pressure chamber (8) through bores (10) 9) Hydraulic high-pressure seal according to claim 1), characterized in that the elastomer body (1) is a spring (11) is biased. 10) Hydraulic high pressure seal according to claim 1) and 9), characterized in that the ElaetomerkSrper (4) through a plate spring (11) is biased. 11) Hydraulic high pressure seal according to claims 1), 9) and 10), characterized in that the disc spring (11) is held in place by a spring support (12). 12) Hydraulic high pressure seal according to claims 1) and 9) to 11), characterized in that the cup spring (11) can be pretensioned by the spring carrier (12) 13) Hydraulic high pressure seal according to claims 1) and 9) to 12), characterized in that the spring support (12) has a vertically extending web (22) and this Web (22) is adjustable in length. 14) Hydraulic high pressure seal according to claims 1) and 9) to 13) * characterized in that the spring (11) shape » 309833/0732 coherently in the intn angle (23) of the spring carrier (12) stored lit. 15) Hydraulic high-pressure dicntung according to claims 1) and 9) to 1 #) _f characterized in that the spring (11) with an oil rough (13) opposite the lower edge (24-) of the piston rod guide (1) or the like is free lies. 16) Hydraulic high pressure seal according to dan claims 1) and 9) here 15) »characterized in that the fader (11) the Kolhanatanganführungunge-seal unit is assigned to a cable stop 17) Hydraulic high pressure seal according to claims 1) and 16), characterized in that the Zuganachlag through a stop ring (21) arranged in the cylinder (2) is shown 18) Hydrauli β before high pressure seal according to dan claims 1) and 9) to 15) «characterized in that the deformation is the ElastoaerkSrpers (4-) by pretension and internal pressure sealed high pressure chamber (8) runs in the same direction. EPBS - Scho
8.2.1972 309833/0732 Le e rs e r t e