GB2337798A

GB2337798A - Rotary sliding ring seal

Info

Publication number: GB2337798A
Application number: GB9912176A
Authority: GB
Inventors: Hans-Henning Zutz
Original assignee: Federal Mogul Burscheid GmbH
Current assignee: Federal Mogul Burscheid GmbH
Priority date: 1998-05-26
Filing date: 1999-05-25
Publication date: 1999-12-01
Also published as: ITMI991031A1; DE19823410C2; DE19823410A1; GB9912176D0; IT1312484B1

Abstract

The invention relates to a sliding ring seal 1 with a sliding-ring 2 and a counter-ring 3. The counter-ring 3 is held in a machine part 8 by means of a trapezoidal sealing ring 6. The sealing ring 6 has an axial extension member 7, on the end region of which there is arranged a secondary seal 9. In this manner, a closed space 12 is formed which can be filled with lubricant.

Description

2337798 ROTARY SLIDING RING SFAL is The invention relates to a sliding

ring seal with a sliding ring and a counter-ring which are axially loaded towards each other by a resilient sealing ring and are sealed directly or indirectly relative to a machine part, at least the sliding ring having a sealing ring which has a roughly trapezoidal cross-section.

The sealing of tractor axles has been effected up till now by means of radial shaft seals. The demand for longer service lives in the sealing of the driving axle can no longer be satisfied by radial shaft seals because of the high dirt load to which tractors can be subjected.

For this reason, sliding ring seals have already been used with the driving shafts of building machinery which are subjected to a high level of wear and tear because of dust, sand, mud or stones.

These sliding ring seals comprise metallic sliding rings and/or counterrings which are fixed by means of resilient sealing rings in the machine part to be sealed.

with an extreme accumulation of dirt it so happens that the dirt impedes the freedom of movement of the sliding rings which can lead to- failure of the sealing rings. In order to stop dirt from getting into the slide gap, it has been proposed already, according to US 4 256 315, to seal the sealing gap by means of additional sealing bodies arranged on the outer circumferential face of the sliding rings.

The disadvantage of these very thin-walled sealing bodies resides in the fact that, when dirt has built up and subsequently dried out and hardened in said sealing bodies, the sealing bodies can be destroyed during rotation of the sliding rings.

The object underlying the invention is to improve a sliding ring seal of the known type in such a manner that, for one thing, the sealing function is improved and, for another, usage is possible in machines where normally radial shaft seals are used.

This object is achieved according to the invention by the characterising features of patent claim 1. Advantageous developments of the invention are set out in the sub-claims.

The secondary seal is configured as a radial shaft seal and prevents dirt from proceeding into the region of the rotating mechanical seal. Since a closed space is formed between the axial extension member or the secondary seal and the sliding ring and counter-ring, and can be filled with a lubricant, e.g. grease, dirt which has overcome the secondary seal is prevented from being able to harden in front of the sliding- or counter-ring.

The rotating mechanical seal does not require a new receiving bore: instead, the bores provided for the rotary shaft seals can be used.

An embodiment of the invention, given by way of example, is illustrated in the drawing and will now be described in more detail.

Fig. 1 illustrates a sliding ring seal 1 comprising a rotating sliding ring 2 and a stationary counter-ring 3. The sliding- and counter-rings 2, 3 are not designed symmetrically. While the sliding ring 2 is supported in a sealed manner via a sealing ring 4, which is designed as an 0-ring, on a rotating machine part 5, the counter-ring 3 extends into a trapezoidal sealing ring 6. The counter-ring 3 can be joined to the sealing ring 6, moulded in or connected to the latter in any manner.

According to the invention, the trapezoidal sealing ring 6 has an axial extension member 7 which is fixed in the housing 8 by means of a ring 13 pressing outwardly. In the end region of the axial extension member 7, there is arranged a secondary seal 9. The secondary seal is designed as a radial shaft seal and is provided with sealing lips 10, 10' which are pressed onto the surface of the rotating machine part 5 by means of a helical tension garter spring 11.

A closed space 12 is formed in this way between the sliding- and counterrings 2, 3 and the axial extension member 7, this space being able to be used as a reservoir for a lubricant.

AS soon as any dirt penetrating through the sealing lips 10, 10' from outside, gets into this space 12, it mingles with the lubricant, as a result of which hardening of the dirt is effectively prevented.

The sliding ring seal 1 according to the invention thus presents a combination of a radial shaft seal and a conventional sliding ring seal, having the advantage that the lifespan of the seal is substantially improved.

Claims

1. A sliding ring seal with a rotary sliding ring and a stationary counter-ring which are axially loaded towards each other by a resilient sealing ring and are in use sealed directly or indirectly relative to a machine part, at least the counter-ring having a sealing ring which has an approximately trapezoidal cross-section, characterised in that the trapezoidal sealing ring (6) has an axial extension member (7) which spans the sliding-ring (2), and counter-ring (3) and on the end region of which there is arranged a secondary seal (9) which in use abuts against- the machine part (5) to be sealed forming a seal, so that a closed space (12) is formed radially between the sliding- and counter-rings (2, 3) and the extension member (7).

2. A sliding ring seal according to claim 1, characterised in that the secondary seal (9) is joined integrally to the sealing ring (6).

3. A sliding ring seal according to claim 1 or 2, characterised in that the secondary seal (9) has at least one sealing lip (10, 10').

4. A sliding ring seal according to any of claims 1 to 3, characterised in that the secondary seal (9) is designed as a radial shaft seal and is pressed on to the machine part (5) by means of a radially resilient element (11).

5. A sliding ring seal according to claim 4, characterised in that the resilient element (11) is a helical tension spring.

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6. A sliding ring seal according to any of claims 1 to 5, characterised in that the closed space (12) is filled with a lubricant.