DE7141855U - Counter arrangement for axial mechanical seal - Google Patents

Description

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PATENT LAWYERS ζ

dipping. H. LEINWEBER dipl-inc. H. ZIMMERMANN

YM.-Adr.

IMII) IMMM

5th November 1971

DEUTSCHE PERROT-BREMSE GmbH, Mannheim-Friedrichsfeld Counter ring arrangement for axial mechanical seal

The innovation relates to a mating ring arrangement for axial mechanical seals with a sealing ring, in particular a carbon ring, rotating on a mating ring relative to a flat mating surface, which is spring-loaded in the direction of the mating surface.

Axial mechanical seals are used as seals between stationary and rotating components. Such a seal is required, for example, in hydrodynamic brakes. A "mechanical seal" is generally understood to mean a carbon ring which, while sealing, rotates around a corresponding mating surface in a sliding manner or vice versa. A particular problem is that the seal must work properly at both low and high speeds. Further, there is the requirement that the seal can withstand a liquid pressure of about 6 to 7 atu, and temperatures up to about 20O ⁰ C.

The temperature resistance can be achieved by choosing suitable materials. Also are measures known to control liquid pressure. Size However, the problem is the proper functioning of the seal at high speeds.

The prerequisite for this is first of all that the two surfaces that slide on each other are perfectly flat and smooth. The carbon ring is pressed against the opposing surface by a corresponding spring pressure and can, for example, stand still while the part having the opposing surface rotates. Of course, conversely, the carbon ring can also revolve and the opposing surface can be set. Due to the inevitable installation and manufacturing tolerances _t due to different thermal expansions, etc., it is now not possible, despite the highest precision in manufacturing, to keep the circumferential surface completely free of impact in the axial direction. The resilient and resiliently arranged carbon ring does indeed have an effect that compensates for the social impact. But this can only be done in the lower part _; Speed range can be regarded as sufficient. It has | namely shown that the two mutually sliding surfaces; at higher speeds, even with the slightest axial run-out, they tend to lift off and become leaky. This tangle adheres more or less to all known mechanical seals in which the circumferential surface or the part having it is more or less firmly connected to the circumferential shaft.

The task of innovation is to be one in every respect to achieve perfect sealing.

This object is achieved according to the invention in that the counter ring is floating in the axial and radial direction, that is, it is supported resiliently. The counter ring is useful for this purpose in a housing with the interposition of displacements of the counter ring in the axial and radial directions permitting elastic Hitige kept. The elastic rings can be Act o-rings. The friction between the relative to the sealing; ring circumferential mating ring is smaller than the friction between the mating ring and the elastic holding it Wrestling. This ensures that the elastic rings, which also function as a seal, are not caused by sliding friction wear SG has a decisive influence on the service life the hydrodynamic brake equipped with the mechanical seal. The floating bearing of the sliding ring With the help of the elastic hinge, the otherwise unavoidable axial run-out from the housing connected to the shaft does not affect the mating ring of the sealing ring will wear, so that even at high speeds a flawless Sealing is ensured. ;

A particularly simple embodiment consists in providing the housing with a surface that is parallel to the mating surface of the sealing ring and to provide an offset that extends over the counter ring at its circumference and is perpendicular to its counter surface. Of the Counter ring is inserted into the housing formed in this way with a particularly voluminous one inserted without pretension in between elastic ring between the mating surface of the sealing ring on the mating ring and the parallel bend of the housing

used, whereby this sealing ring achieves good sealing properties. A further one is expediently elastic Hung in a se circumference of the Ge counter ring provided annular groove inserted. This elastic ring is with its outer circumference protruding beyond the circumference of the counter ring in contact with the the circumference of the counter ring overlapping bend. This is expediently formed in such a conical manner with a small angle from that it opens towards the sealing ring. If the sealing ring is now more or more according to the hydraulic pressure

: less pressed against the mating ring, the drag torque that is transmitted from the housing to the mating ring via the two elastic rings also changes at the same time. With increasing pressure so the friction between \ grows the singing unddea counter ring. This happens once through ^! stronger compression of the bulky without bias \ loaded elastic ring and on the other straight ^DA: by that in the annular groove on the circumference of the counter ring fitting elastic ring j stronger in the narrow portion of the!

.>. conical housing is pushed in. i

; In the drawing, the renewal is for example shown, namely show:

1 shows, in section, an axial slide ring seal designed according to the invention and

FIG. 2 shows, on an enlarged scale, a detail of the Axia! Sliding ring seal from FIG. 1.

Fig. 1 shows a rotating shaft 1 on which a housing 2 is attached. One further recognizes the find piece a seated on the shaft 1 hub 5. The hub 3 has

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on its end face facing the housing 2 an annular groove j into which a static sealing ring 4 is inserted. That _; The housing 2 is braced against the sealing ring 4 with the aid of a spacer ring 5, which is also firmly attached to the shaft 1.

The housing 2 is bent several times. It has at least one bend perpendicular to the axis of the shaft 1 and one bend parallel to the axis of the housing on the circumference of the housing. As a result, | In the housing 2 there is a pocket in which a counter ring f> of a sealing ring 7 is inserted with the interposition of two elastic rings 8 i and 9 in a floating manner. Of these, the elastic ring 8 is a voluminous O-ring, which is without pretension; on a shoulder 10 of the housing is centered, which runs parallel to the ^[axis of the shaft. 1 This bulky elastic ring 8, which consists for example of a temperature-resistant η elastomers is pressed a corresponding bend on the housing 2 between an opposing surface of the sealing ring on the counter ring, and a direction parallel to this surface, and thereby its cross section so slightly formed de- ^j from the circular shape, as indicated in FIG. 2. The deformation i takes place under the action of a spring 11 acting on the sealing ring 7 in the direction of the counter ring 6 or by the forces exerted by the pressure medium. For this purpose, by appropriately dimensioning the parts, it is ensured that the pressurized ring surface / on the sealing ring side of the counter ring 6 is at least equal to or preferably larger than the pressurized ring surface Y on that side of the counter ring 6 which faces the elastic ring 8 . In this way, a secure seal against pressure medium 12 is achieved and the counter ring 6

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lifts off the elastic King 9 and too much leakage oil after can seep inside. The preload of the springs 11 on the sealing ring 7 is then sufficient to prevent leakage losses at the elastic Ring 8 safe to prevent.

In the radial direction, the counter ring 6 is the stationary one, designed for example as a carbon ring Sealing ring 7 centered by the elastic ring 9, which is used with very little bias and only one

has reduced sealing effect with respect to the pressure medium 12. The caused by the elastic rings 8 and 9 Sliding friction with respect to the counter ring 6 or the housing 2 has to be greater than the friction between the counter ring

6 and sealing ring 7. In addition, the the the The centering elastic ring 9 receiving part of the housing 2 with the small angle indicated in FIG. 2 ÖC be slightly conical. This becomes one possible different bias of the sealing ring 7 taken into account. With increased preload of the sealing ring i

7 namely increases the friction between the sealing ' ring 7 and counter ring 6. But since the counter ring 6 is held against movement by the elastic bings 8 and 9 and; must be stopped, must be between | see sealing ring 7 and counter ring 6 and the friction between the elastic ring 9 and the counter ring 6 overlapping bend of the housing 2 are increased. This happens automatically due to the conical design of the housing 2, because the elastic ring 9 is pushed further inward by the increased contact pressure of the sealing ring 7 with the counter ring 6, in whose circumferential groove it sits, and is thus more compressed.

-7-

Thus the counter ring assembly for axial face seals described ensures an easily displaceable for all calibration DEVICES storage of the counter ring also relatively large swash strokes of the housing 2 does not thereby result in corresponding Axialschlägen the counter-ring 6. In this manner, even at high speeds for a perfect seal and thus for perfect sealing ensured in every operating situation.

71A185520 r 72

Claims (8)

- 8 protection claims: 1. Counter-ring arrangement for axial mechanical seal with a sealing ring, in particular carbon ring, rotating relative to a flat counter-surface on a counter-ring, which is spring-loaded in the sighting of the counter-surface, characterized in that the counter-ring (6) is floatingly mounted in the axial and radial directions * 2. Device according to claim 1, characterized gekennzeiehnei ^ -that the counter ring (6) is held in a housing (2) with interlayer displacements of the counter ring in the axial and radial direction allowing elastic rings (8 ₃ 9). 3. Apparatus according to claim 2, characterized in that the elastic Eine (8,9) are Ü-rings. 4. Apparatus according to claim 2 or 3, characterized in that the elastic rings (8,9) from consist of temperature-resistant elastomers. 5. Device according to one of claims 2 to 4, characterized in that the housing (2) has a for Opposite surface of the sealing ring (7) parallel and one of the counter ring (6) overlapping on its circumference, to its Opposite surface has a vertical bend. 6. Apparatus according to claim 5, characterized in that that between the mating surface of the sealing ring (7) on the mating ring (6) and the offset of the housing (2) parallel to this a particularly voluminous elastic ring (8) is inserted without pretension. 7. Device according to one of claims 1 to 6, characterized in that the GegenriSig (6) has a fiingnut on its circumference, into which an elastic ring (9) is inserted. * 8. Apparatus according to claim 7, characterized in that the counter-ring (6) on its circumference overlapping bend with the bing axis is in fiichtung of the sealing ring (7) forming a small angle opening;