DE7110633U - Sealing ring for reciprocating machine parts - Google Patents

Description

Copper asbestos co.

Gustav Bach, ^

71 Heilbronn-Sontheia

Rosenbergstrasse 22 A 32 151-du

'Aug. 4, 1972

Sealing ring for reciprocating machine parts

The invention relates to a sealing ring for .in the axial direction back and related machine parts, in particular for rods or pistons, the one made of elastic material, the Has sealing body comprising machine part, the opposite of which

preferably ■

Effective sealing surface above / above a working pressure medium divided by ribs arranged one behind the other in the axial direction and running transversely to the axial direction clear diameter in the non-tensioned state is smaller than the outer diameter of the machine part and in the built-in Btand is elastically expanded.

There are already seals for piston rods and the like. Known, which consists of a soft elastic material, annular sealing body of substantially rectangular cross-section baben. These seals are located one behind the other in the axial direction on their inner surface resting on the piston rod Liegeade and grooves extending in the circumferential direction are provided. The thickness of the annular sealing body is radial Direction dimensioned so that the sealing body during installation between the hole provided for receiving the seal in a

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fixed Maauulüeuteil and the SölbsüGtangc pressed together will. Usually such seals are also braced axially in order to fix them in their position. Such an axial tension increases the pressure acting on the sliding surface. However, such mechanical tension can only be limited to a limited extent Degree to be increased. Under the influence of temperature changes and By swelling the material used to manufacture the sealing body, Bich can determine the physical values of the elastic Deteriorate the material so far that no longer with a high. Service life can be expected. In general, at These known seals can only be created with considerable structural effort, which it would allow to compensate for the slackening pressure of the sealing body on the moving machine part during use and in this way a sufficient sealing behavior to ensure.

In a known sealing arrangement, the naoh lies outside tapered seal with one side on an outer wall, while on the inside a pressure ring under the force of a Spring is effective, which is supported on the housing. The sealing body is axially compressed by the spring and also in deformed in the radial direction, the contact pressure on the piston rod increased and at the same time a direct effect on the the housing receiving the sealing body is obtained. With this arrangement, a plurality of components are required. aside from that the spring acting on the pressure ring must be made strong so that it deforms the diaphragm sufficiently can. A tiling of this seal is only possible within very narrow limits. Lift the necessary for this known arrangement

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agile considerable installation space falls in particular the further disadvantage important that the sealing elements listed require very good guidance of the piston rod. With larger lead clearance only an insufficient sealing effect can be achieved, as the piston rod can then give way to the side and the inner contour of the sealing body deformed on one side, so that the radial compressive force decisive for the sealing effect on / the deformed

Zones / can be greatly reduced or even canceled gana, opposite area

There is also a device for sealing the piston rod of a shock absorber is known that a piston rod Comprising comprehensive sealing block, which is in a concentric to the piston rod axis recess of the shock absorber ^ ehäuses is inserted and braced radially and axially here and on its opposite to the shock absorber fluid effective on the Piston rod adjacent sealing surface by several arranged one behind the other in the axial direction and transversely to the axial direction running ribs is divided. In this known sealing arrangement, the sealing ribs have in an unstressed, i. E. When not installed, it has a clear inside diameter that is larger than the piston rod diameter. Also is the outer diameter of the sealing cap is larger than the diameter the housing recess selected so that by isdiale bias when pressing the sealing body into the housing recess a radial preload; arises and the sealing Installation of the sealing rib on the piston rod generated by a booking of the sealing body created in the direction of £ rÄdialfci will. Compared to the seals described above, in which the radial contact pressure of the sealing body is moved to and fro Machine part also by axial on the sealing

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body is generated compressive acting compressive forces in its axial length, these known devices have the peculiarity o.uf that the / \ xialrichtung arranged one behind the other Sealing ribs in their cross-sections running in the axial direction are triangular, with each of the dioh ribs belonging sealing edge has the smallest clear diameter

r -i n ° ", but at an angle to the DichVachse or to the axis of the Piston rod at an angle of 45 and inclined up to 60 ° Boundary surfaces are generated. The invention is based on the Knowledge from that with this known cross-sectional design of the sealing ribs the medium to be sealed in continuous operation a is exposed to high leakage.

The invention is based on the object of creating a sealing ring which ensures a long service life and which Avoids Kachteile of the above mentioned designs. The invention is based on the knowledge that the production of the sealing body used material for the production of the /.uflagezonon of the sealing body on the reciprocated Machine part to tensile stresses acting in the primary direction stressed and therefore in its untensioned state in his clear diameter must be kept smaller than the outer diameter of the reciprocating machine part. Of this On the basis of the invention it is proposed that the common axis facing boundary surfaces in the axial direction one behind the other arranged ribs of the sealing body in the untensioned state with the common axis an angle include, which is smaller than 30 °, preferably smaller than 20 and with ooiner tip to be sealed against the day "shows medium and that, furthermore, these surface areas form a

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Intersect the sealing edge with a second boundary surface, which are at least approximately perpendicular to the common axis stands. In this embodiment of the sealing ribs according to the invention, it is ensured that the opposite to the perpendicular to the axis standing boundary surfaces directed movement of the machine part to be sealed on the sealing edge that on the Medium adhering to the machine part can be stripped off and only in a very thin film on the reciprocating The machine part remains stuck and therefore the inevitable lubrication with respect to the seal ensures in the opposite direction of movement to the only very pointed Boundary surfaces not to a significant extent can be repressed, but largely unaffected returned to the working area of the medium to be sealed. This return effect, which does not indicate any significant loss Lets the medium to be sealed arise, can be particularly promoted that in a further embodiment of the invention the ribs lying one behind the other in the axial direction with increasing distance from the medium to be sealed at their the Axis facing boundary surfaces include increasing angles with the common axis. This means that "at of the rib next to the medium to be sealed, the boundary surface facing the axis with the common axis encloses an angle of, for example, only 1G ° at the sealing edge, where, on the other hand, the next rib has such an angle of about 20 and the third, even further from the one to be sealed The rib facing the axis is remote from the medium Boundary surface can have an angle of inclination of about 30 °. However, the mentioned limitation areas do not need necessarily designed as conical surfaces The boundary lines of the cross-sections of the ribs can

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be designed more than curves that increase with distance of the medium to be sealed have increasing radii of curvature, these boundary lines for example on the the sealing rib immediately adjacent to the medium to be sealed can have a constant radius of curvature and in the case of the subsequent one Rib have a smaller, also constant radius. But it is without further ado within the scope of the invention In principle, if these radii for one and the same sealing rib, for example the first sealing rib of a for the edge of reconciliation applicable, relatively large Radius is due to the smaller Y.'ert with increasing distance from the medium to be sealed.

Further details and expedient embodiments of the invention emerge from those described below and in the drawing; jev. ^! Ausit / hrungsbeisr '^ len shown in an axial longitudinal section and in detail in connection with the subclaims.

The sealing ring according to FIG. 1 has a sealing body made of rubber 1, which extends in the radial direction along a transverse uur not shown, extends on the longitudinal axis of the metallic support ring 2 using the sealing and into a centrally arranged one Hub part 3 passes over, which is part of the Dlchtkörpera Lüdet and on its one reciprocating machine part, for example a piston rod facing inner surface in the axial direction offset from each other three sealing ribs 4a, 4b and 4c. In the representation shown in FIG. 1 assumes that the left end face 11 of the sealing hub 3 dera medium to be sealed, which iu the gas · -, Ι · αικρί '~ or riüasigkeits-

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pbase can be present and can also be under working pressure, facing. Each of these running in the circumferential direction Sealing ribs have a delimitation surface 5 facing the axis, which is connected to the axis of the sealing ring (not shown) or of the sealing ring to this parallel reference line AA includes an acute angle <x, which for the embodiment shown in FIG has the same value of about 10 ° for all three sealing ribs 4a, 4b and 4c. The tip of this angle or the tips of these angles are directed towards the medium to be sealed. The inclined in this way to the axis Boundary surfaces 5 intersect with those facing the medium to be sealed, at least towards the sealing ring axis approximately perpendicular end faces 6 and thereby form a sealing edge 12. These sealing edges 12 get a built-in State of the sealing ring in which the sealing ribs 4a, 4b and 4c are expanded radially from the inserted machine part, such an effective stripping process for the medium adhering to the machine part to be sealed, that this medium only as a very thin film under the sealing edges during the working movement directed from left to right of the machine part can get through. On the other hand, causes the extremely flat inclination of the boundary edges. 5, that with the reverse movement running in the opposite direction of the machine part this thin film, which produces an extremely good braking effect, practically without any significant displacement can return to the starting position through under the sealing edges 12.

This asymmetrical, only opposite the medium to be sealed The wix 'effective Abotreifffekt is in the embodiment according to Fig. 1 still supported by the fact that the clear inner

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diameter of the sealing ribs 4a and 4b and 4c on their sealing canton 12 is chosen to be larger by bo, the further the sealing ribs are in the axial direction from the medium to be sealed. This clear diameter is for the medium to be sealed directly opposite sealing edge 12 of the first sealing rib 4a denoted by D »

On the rear end face of the sealing body vulcanized onto the support ring 2, facing away from the medium to be sealed stands a wiper lip 9 directed outwards and obliquely against the axis, which prevents dirt from penetrating into the sealing surfaces prevented and with the third sealing rib 4c, which is furthest away from the medium to be sealed, a lubrication pocket 7 forms, which can be used to hold a lubricant or which in excess during the backward movement of the Kashhi / nteilp despite the favorable design of the boundary surfaces 5 accruing medium absorbs.

The sealing ring shown in FIG. 2 as a second exemplary embodiment in axial section has one on the circumferential surface 2o otherwise not shown, reciprocating machine parts facing inner surface also three sealing ribs 24a, 24b and 24c and a wiper lip 29. In the lower rope; ed to the previously described embodiment Here the sealing ring is received in a hat 23 and has the special feature that is extremely important for its effect, that the sealing ring on his your to be sealed, also from the end face 22 facing the left side facing the medium has a plurality of recesses 25 running in the radial direction,

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those remaining between the groove base 27 and the die body 21 Connect the cavity with the annular space 28 located in front of the first sealing edge 26a facing the medium to be sealed. The medium stripped from the foremost sealing edge 26a of the first sealing rib 24a can thus initially settle in the Collect annular space 28, as the sealing edge 26a as well as before described Ausführungsbß <3play behind the face or 11 of the sealing body is reset, and then from the Annular space 28 get into a return bore Jo. Here However, if it is essential that the stripped medium is in the

than a cavity / a remaining between the sealing body and the groove additional pressing force acting in the radial direction against the reciprocating machine part acts on the sealing body j / As a result of the radial recesses 25, an additional contact pressure can be obtained for the sealing ring.

In the Pig. 2, in order to increase the radial contact pressure in the sealing body 21, a helical spring 37 which is central with respect to its cross section and which is tensioned in its circumferential direction is provided. This helical spring is also used; to press a sealing lip 38 formed on the sealing body 21 against the groove base 27 under elastic tension, \

While in the embodiment of FIG. 1, the reconciliation angle ex. has a constant value well below 30 ° between the boundary surfaces 5 and the sealing axis for all sealing ribs, it is provided in the exemplary embodiment according to FIG. 2 that this boundary angle is all the greater

+) as soon as the medium side is pressurized.

- 1o

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- 1ο -

the further away the associated sealing rib is from the medium to be sealed. This angle of inclination (K is the embodiment according to Fig. 2 for the medium to be sealed adjacent sealing rib 24a as in the embodiment of Fig. 1 about 30 °, and then rises up to the third sealing rib 24c to a value of OC = maximum of 25 °, at which of the middle sealing rib 24b, the angle <X is approximately 15 °. This results in a considerable improvement in the return movement of the machine part to be sealed compared to the drawing to the left, since the film of medium adhering to the machine part, which has not been stripped off, is all the easier to get into the 24c lying portions can be distributed can reach the working space back ■ _f the better its volume or to the sealing between two edges 24a, 24 "b respectively.

The technical aspects described in the embodiment according to Fig. 2 result in a life of at least 50 $ increased life for the seal and its functionality, because on the one hand a sufficiently high wiping effect against the medium to be sealed is achieved and on the other hand due to the small incline division of the in Fig. 1 With 5 indicated boundary surfaces of the sealing ribs arranged one behind the other, a sufficiently high level of lubrication is ensured without the risk of significant leakage loss for the medium to be sealed.

The construction principles described above are also applicable to the Embodiment according to FIG. 3 realized. There is the radial contact pressure directed against the machine part to be sealed except through the elastic expansion of the sealing body

- 11 -

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η,

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41 achieved exclusively by the ring spring indicated at 42. The peculiarity lies in the one shown there Embodiment in that, when there is pressure in the system, on the one hand, the radial recesses 45 opposite the groove base 47 occurring overpressure of the stripped medium supporting the axially directed one exerted by the annular spring 42 Contact pressure acts. In this embodiment is the opposite! for the embodiment according to FIG. 2 no drainage hole 30 is provided for the stripped medium.

In the exemplary embodiment shown in FIG. 4, too, the sealing body 51 lies under axial pretension on the wall 39 and has several radially extending on its end face facing the medium to be sealed Recesses 55 on. It is opposite to the pressure of the stripped medium prevailing in front of the groove base 57 sealed in that its rear sealing lip 58 under the radial pressure of two tension springs 67 and 68 stands in a in the peripheral surface of the sealing body introduced groove 65 are arranged supported both in the radial and in the axial direction. As in the previously described exemplary embodiments are several rearward in the axial direction: - sealing ribs arranged one inside the other 54a, 54b, 54c and 54d are provided, the one to be sealed Machine part or their common sealing ring axis facing limiting surfaces in contrast to Fig. 1 not a constant, but one

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the greater the distance of the sealing ribs Have an angle of inclination ex with respect to the axis of the sealing ring, the further away the sealing ribs are from the medium to be sealed. To better distribute the from the Ringfeöern and 68 on the sealing body 51 exerted radial compressive forces is in the embodiment shown in Fig. 4 · at The base of the recess receiving the annular springs is a circumferential direction extending portion of a thin tape 7o provided, which is rolled with a smaller inner diameter and is inserted at the bottom of the recess. This band has the effect that the circumferentially biased Annular springs 67 and 68 cannot dig into the material of the sealing body even if it is only relatively small elastic recovery elasticity. having. This is particularly advantageous when the sealing arrangement according to the invention should also be effective if the media to be sealed have strongly changing pressure values.

The embodiments Fig. 3, 4 have the advantage that the seals due to their free mobility in the radial direction, namely also larger within the groove can easily adjust radial play dor piston rod in the storage.

The formation according to the invention of the sealing edges 12 of the ribs 4a, 4b, 4c, according to which they can have different clear diameters in the unrestrained state, can be used in any way realize, e.g. in such a way that the middle sealing lips are larger Diameter than the outer sensors or vice versa.

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The springs 8, 37, 42, 67, 68 also cause at Change in the physical values of the elastic material due to swelling and temperature, the radial force remains in a determinable order of magnitude.

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Claims (1)

A 32 151-you Expectations 1. Sealing ring for machine parts moving back and forth in the axial direction, in particular for rods or pistons that encompass a machine part made of elastic material Has sealing body, its - effective medium with respect to a preferably under working pressure Sealing surface is subdivided by ribs arranged one behind the other in the axial direction and running transversely to the axial direction, their clear diameter in the unstressed state of the sealing ring smaller than the outer diameter of the machine part is and is elastically expanded in the installed state, characterized in that the Begreozun ^ surface facing the axis (5) of the ribs (4a, 4b, 4 "or 24a, 24b and 24c or 54a, 54b, 54c and 54d) in the unstressed state the axis encloses an angle (öO that is smaller than 30, preferably smaller than a3s 20 ° and with his Point against the medium to be sealed shows and that this delimitation surface is also used to form a sealing edge (12) intersects with a second delimitation area (6), which is at least approximately perpendicular to the axis. Sealing ring according to claim 1, characterized in that the ribs (4 $, 4b, 4c) with increasing distance from the to be sealed Medium on their boundary surfaces facing the axis (5) Include larger angles with the curved axis. - 2 - 3. Seal according to claim 1 or 2, characterized in that the sealing edges (12) of the ribs (4a, 4b, 4c) have a clear diameter in the unrestrained state, which increases with the Distance from the medium to be sealed to the individually. Ribs is chosen larger. 4. Sealing ring according to one of claims 1 to 3, characterized in that that the sealing body (21) is arranged in the groove (23) of a stationary machine part and with a Leg (38) rests sealingly on the groove base (27). 5. Dichtriug according to one of claims 1 to 4 nit one in one Sealing body arranged in the groove of a stationary machine part, characterized in that the sealing body on one end face, preferably on that end face which the facing the medium to be sealed, several radially extending recesses (25, 45, 55), which between deja hat base (27 or 57) and your sealing body (21, 41, 51) remaining Koulrauia with the before the first, dam to be sealed Medium facing sealing edge (12, 26a) lying Rin ^ rauia (28) connect. 6. Sealing ring according to one of claims 1 to 5 »characterized in that that a scraper (29) is arranged on the end face of the sealing body (21) facing away from the medium. 7. Sealing ring according to claim 1 to 6 with iu a groove of a fixed Sealing body arranged on the machine part, characterized in that the sealing body has an integrated sealing lip which, under elastic deformation, is removed from the medium ^ / "N ίΤ \ Λ reversed, preferably abutting the boundary wall of the groove perpendicular to the axis with elastic deformation. Sealing ring according to claim 7 »with an attached in the sealing body, in the circumferential direction of the groove and with a sealing spring arranged in this, characterized in that that the sealing lip (38, 46, 58) is tensioned by the spring with elastic deformation against its contact surface is held. Sealing ring according to one of Claims 1 to 8 with one in the sealing body attached, running in the circumferential direction of the groove and with / siher arranged in this sealing spring, thereby characterized in that between the sealing spring (67 »68) and the base (65) of the groove receiving the sealing spring circumferentially extending, rolled portion of a thin strip (7o) is provided. 71 ^ 063326.10.72