DE7318583U - Sealing arrangement for hydraulic pistons or piston rods - Google Patents

Description

H /. ZILKEN f Stuttgarts ^

_. Stlltsnburgilr. 1 (Hoehhaut)

Patent-Ing. τ.ι.ι _Ο η 240922

Bank account: Glrokeise Stuttgart N>. 2,983,228 Postal check: Stuttgart 4331 33

May 16, 1973

Applicant company

Buealc + Luyken KG 7 Stuttgart 80 Breitwiesenstrasse 27

Seal for hydraulic pistons or piston rods

The invention relates to a sifting for hydraulic Pistons or piston rods with a .Sealing ring made of plastic, essentially on the polytetrafluoroethylene basls as a contact seal between stationary and moving upper surface part and a radially tensioning ring and sealing, rubber-elastic clamping ring.

With such piston rod or piston seals

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let ee required because £ a slight leakage and ongoing movement is maintained. For the friction-saracn sealing piston and reciprocating

It is used, consisting of · a »plastic ring with an essentially rectangular« cross-section »or sealing of the · relatively moving gap ·· together with the swirling moving machine parts and a rubber-load layer on the secondary seal and gate tensioning of the · plastic ring ··· For the purpose of clear separation, la following the Kunatrtoffrlng causing the moving seal al · Diohtrlng _f the radial as a result of druokbedlngtor transverse pressing and ttberaÄ & bÄdinster Tcrspeaauag dsa Kuaststeffslag anpreestmde, gumlelastleche Sing al · Spannring rewarded · I

The sealing ring and the clamping ring are generally arranged together in a groove or recess for the housing (as a rod cover) or the piston (as a piston cover). ItBT clamping ring generally consists of a rubber-elastic Sing with a krelsfdxmigem (O-Blng) or Reohteek-shaped cross-section, and its radial axis of symmetry is arranged as an extension of the radial axis of symmetry of the right-octagonal slope ring. As a result of the radial door tension of the clamping ring between the groove gnmd and the outer (in the case of rod soldering) I bsw, inner (in the case of the piston seal) lateral surface of the

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Slehtrings becomes the secondary look way swisohen Slohtring and Vutgrund and Slohtrlng rose-closed

Sie jsftktisÄÄ * r * a * üfSKi · h & t »---- &> ^ aS * i * Heibungswerte eoloher vision combinations ror everything at» start-up and at low lifting speeds are much lower, all with conventional sightings old gumlelaetisohen Bertthr faces aa moving Maeehinentell ·

You but praktiiohe experience selgte AUOH, AeS the XoBbination from Siohtring "it in weeentllehen reehteokigem Quereohnitt and clamping ring about the same Leelcverhalten as the herkSasslishen ggssdelastischsn Beruhrttngsdichtungen has _f AUOH here forms when ^ - reciprocating motion infeige the toughness of absuAiehtenden 7IuIdS in the moving Siohtspalt a bottom current that su a «? Sohmierfilmbildung with lateral separation of the sealing contact surfaces leads. As a result of asjrmmetrlsehen Fressungs- ▼ ertel development in the Bertihrfläch · is formed at the gate and Silokhub generally a different thickness Sohmierfilm ge "ψ what Awfawwiiiytg sur yon absudlohtendem fluid at niederdrückeeitige" aide of Bishtspalts and danlt leads "for Leokage.

Abandonment of the lying Srfinduni; Is it _t through a suitable shape for the viewing ring that the leakage occurs

Back and forth movement of the piston rod or the piston clean rerringexn without increasing the friction values.

The "^ ird" ash dsr SrflndunÄ d * 4ttreh, achieves that the diaphragm ring together with the moving machine part forms a gap opening at a small angle towards the lower pressure side, whereby the hollow side sole of the circumferential surface of the sealing ring forming the gap into a narrow contact surface merges with the moving machine part and that this is also followed by an extension on the high-pressure side.

This combination ensures that _f 'ine mSgliohst short Berühraogexläcbe arises and as * high-pressure side of the touchpad to-fang a possible prime ■ increase in surface pressure between the seal and be sealed Stiinge accessible, while the low-pressure side. At the end of the contact surface there is as flat a drop in the plane pressure as possible, through which, behind the end of the contact surface, the sealing ring becomes

j widening wedge gap · Furthermore, the contact surface

partially toa radial contact pressure of this fluid and the clamping ring relieved «

If, for example, the

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Inner surface (in the case of a piston seal, the outer surface) of the die ring is conical and at the same time the radial thickness of the sealing ring is designed in such a way that, in connection with the modulus of elasticity of the sealing ring material, the sealing ring has a sufficient area against the radial load by the clamping ring, se created during installation of the sealing ring both the desired narrow Berühr zone, | and the weschrisbsne favorable Prsssungs = distribution in connection with the down print eitig to "approaching wedge-shaped gap opening · as with increasing sealing pressure a further elastic Umetülpbewegung of the sealing ring the angle of the If the wedge gap is reduced, the hydrodynamic huoctraneport is favored by the pluid adhering to the glaitilach, especially at the first pressure.

The desired point increase in the surface pressure at the start of the contact surface on the high pressure side is generated by settling as sharp as possible at this point. The point at which this paragraph is attached can also be removed from the high pressure face of the sealing ring and pushed further into the density gap. This creates a zone with a larger gap on the high pressure side in front of the contact surface, into which the pressure to be sealed penetrates and thus causes the contact surface to be deflated by radial contact pressure, the tone of the self-tensioning of the sealing ring, from the excessive pre-pressing

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Tension ring xuid from the rom tension ring in the radial direction transmitted Dichtdruok generated

The sealing ring is relatively sn of its (day sealing surface dimensioned so that the Solbenstange (the cylinder bore) compared to the diameter at the high pressure side end of the the conical inner surface (outer surface) extending towards the low pressure side, the eight rings have such an oversize (Undersize) shows "that when installed a contact surface which is very narrow in relation to the axial width of the die ring" arises "

In Yersuohen, where an O-ring was used as a clamping ring, it was found to be a particularly favorable ratio of the length between the rear face of the Diehtrings and the beginning of the contact surface but total length of the Diohtrings the value 2i5. The favorable opening angle of the Niederdzuokseite trowel gap was swisohen 5 ° and 10 °, if a common hydraulic oil was sealed for other fluids resultBioh other optimal values of the parameters mentioned

Another favorable design of a diaphragm ring results in ₉ if the contact surface on the hechdruok side instead of a sharp-edged shoulder is delimited by a conical gap opening towards the top, which on average has a significantly larger opening angle than that

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Ieilepalt aaf the low pressure side. The Mamtellinle of the den high-pressure-side gap-forming rotational surface of the eye * the ring can be straight, concave or convex. Because of this shape of the heehdruckseitlge Pressure gradient can be influenced in the contact area can, this shape represents a means with which a certain sealing ring can be optimized with regard to the desired Sehmler film dioke «Also with this design, the pressure penetrating into the high-pressure side rope gap results in a partial relief of the operating surface from the radial contact force *

With all models are then obtained very favorable conditions, ie small leakage and low friction forces _t when the actual Seiührsess äwisnhes Disätriag "ad Ve * ·

in relation to the axial width of the

Diohtrings “rather small” In the unpressurized state, this ratio is favorable in the range 5 % to 20 %.

The length of the column on the high pressure side for radial pressure equalization is varied depending on the desired ratio between heat and leakage and is swisväsa and about 70 % of the axial length de | Diehtrings »

How the invention can be carried out in lathering the flg. 1 to 5 in the drawings in section on one ttangcnabdlohtung

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In all figures, ρ means the light pressure to be sealed, p _n the generally lower pressure on the other side of the seal i ^ m moving machine part along a common contact surface 4

If the axis is 1 * 1 THE Ho tat ions axis of symmetry, it is seen vw a piston seal, the axis II-II, on the other hand, indicates a rod seal _c

The axial length B of the contact surface 3 is preferably very small compared to the entire axial length of the sealing ring,

In Fig. 1 the sealing ring has a sharp-edged radial shoulder 5 and on the high pressure ei te is on the length D a (in relation to the Sehmierfilmdicke zwinchen the contact surfaces during movement) relatively large gap between the cylindrical surface 6 of the Dielrtlring 1 and the Surface 3 of the machine part to be sealed is formed.

The pressure p ^ penetrates unthrottled xn this gap and relieves the counteracting pressure and the surface pressure in the contact surface up to paragraph 5 in the radial direction

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determining radial forces of the sealing ring · 1 and the clamping ring 2. Through. Variation of the length «D can be used G-ϊΉ, ά der ^ itlaLStvui ^ to be set. This fixing There is a compromise between leakage on the one hand and wear and friction of the Siohtung on the other hand and it thus depends on the conditions of use of the Seal abο Between the contact surface and the low-pressure side End face 7 is a conical surface β attached to the sealing ring 1 in such a way that between the surface 8 and the surface 3 an ei oh widening towards the Stirrfläohe 7 Forms wedge gap. The angle of the wedge gap is on the Kiederdruakseits because of the desired gentle pressure drop in the contact area, which increases with higher "bridges as a result of £ ippbevsgu" s d * · binlitrings, and amounts to Sealing rings made of plastic, preferably 5 ° to 10 °.

In Pig, 2 the contour 9a between the high-pressure end wall 10 and the common contact surface 4 on the sealing ring is convexly curved. The relief effect also occurs here. The high pressure-side end of the sealing ring here has a greater rigidity _{e than in the embodiment shown in FIG. 1}

In Pig. 3, the contour 9b is formed by a conical surface with a straight cantilever line, the Wiskel being essential is made larger than the outer angle.

- 10 -

Xn Fig. 4 let the Kontor $ o konrex and it gives see thereby again in relation to a small lubricating film dioke when moving the surface 5 in direction T ('Forhub) cheaper »sharp-edged paragraph 5a on the hoehdruokseitiges Side of the Bertlhrfläohe

Finally, for reasons of profitability, for example Manufacturability, the contour on the Hoohdruok side as in Flg. 5 shown, from swoi syllndrisohen Absätsen bsw · Turnings 9d and 9e or generally consist of several fur · · stttoken with continuous or discontinuous transitions «

Patent claims s

- 11

Claims (1)

Patent Ug. - 11 - 'J Stattgart J? AJ »·« Baeak ♦ Luyken 3 a claims 1. sealing door hydraulisch® pistons or piston rods with Onea Sicthtriag sub Sttarfcstöi * In wsseatlichen ssf the Pe tetrafluoräthylenbasis as BerUhrunfradiohtung between rohendea «nd moving Maeehinenteil and a, the sealing * ring radially exciting \ and sealing» gunmielastlaohen clamping ring, dadaroh in that " The Bioh ^ ring together with Aea moving Masohlnentell (cylinder bore or on the low pressure side a small one. Angle opening gap forms, with the high-pressure edge of the circumferential surface of the gap forming the gap Sielitxl & gs in sins sohsude JBerührfläohe old to the moving Casino part passes over and you look at it on the hoohdraekside also aneoliliess a spring weather song. 2 «Poetry nftoh Claim 1, characterized in that the Hechdruelsseltige bath of the contact area in a sharp-edged, radial sap of the diehtring merges. diir claims 1 and ₉ daduroh gek: "miiseiohAst, 7318583 24.87.75 that the sealing ring between the radial shoulder vc \ d its hoohdruokseitenea end face has a cylindrically turned circumferential surface in the manner of a step _t whereby the gap between this surface of the sealing ring and the surface of the moving machine part is at least 0.3 aim (Fig. 1). 4. Seal according to claim _1, characterized in that the sealing ring is shaped in such a way that between the contact surface and the high-pressure end face of the sealing ring a gap which is steadily widening towards the high-pressure side forms (Jig, 2-4). 5β seal ^^ iaeh claim l, _t gekeimzaiohnet characterized in that the Diohtring so shaped that between the 1st ,, Beruhrflache and hochiiruckeeitigen face log to Hochdruckeeite forms out in one or more stages widening gap (71g x 5). 731IS83