DK179957B1

DK179957B1 - Sealing system and protective mounting sleeve with integrated seal cover

Info

Publication number: DK179957B1
Application number: DKPA201870308A
Authority: DK
Inventors: Heldmann Martin; Colineau François; Hintenlang Günter
Original assignee: Carl Freudenberg Kg
Priority date: 2017-05-22
Filing date: 2018-05-18
Publication date: 2019-10-30
Also published as: DE102017004871B3; DK201870308A1

Abstract

Sealing system, comprising a sealing ring (1) with at least one sealing lip (2) and a protective assembly sleeve (3) with integrated sealing cover (4), wherein the sealing lip (2) encloses the protective assembly sleeve (3) on the outer circumference side, without contact and with radial spacing.

Description

Sealing system and Protective Assembly Sleeve with Integrated Sealing Cover

Description

Technical Field

The invention concerns a sealing system, comprising a sealing ring with at least one sealing lip and a protective assembly sleeve with integrated sealing cover.

Prior art

A sealing system and a protective assembly sleeve with integrated sealing cover of this kind are known from DE 103 25 254 A 1.

The sealing ring is designed as a radial shaft seal with a dynamically-stressed sealing lip. The protective assembly sleeve has a protective surface, extending in the axial direction, for the sealing lip, wherein the protective surface is enclosed, under radial pre-stress, by the sealing lip.

The sealing cover is provided with a holding device designed like a handle that is non-destructively detachable from the sealing cover. The holding device is bound to the protective assembly sleeve with a joint and is pivoted around the joint.

On the one hand, the protective assembly sleeves serve for bearing and transport of sealing rings. On the other hand, protective assembly sleeves are used for the assembly of sealing rings on a shaft, to prevent the sealing lip of the sealing ring from being damaged thereby. During the assembly of the sealing ring on a shaft, the protective assembly sleeve protects the sealing lip of the sealing ring from damage through sharp-edged transitions or sharp-edged profiles of the shaft, e.g., when the shaft has multi-tooth or spline profiles. After the assembly, the protective assembly sleeve is separated from the sealing ring, and then the sealing lip encloses the sealed surface of the sealed shaft under radial pre-stress.

If the sealing system and a machine element housing, in which the sealing ring is to be used, form a pre-assembled unity, then the sealing cover ensures that the opening of the protective assembly sleeve, and thereby the housing, are sealed. Contaminations from the environment are thereby hindered from intruding into the housing. For example, lubricants, with which the housing is already filled, are thereby also prevented from entering and contaminating the environment from the interior of the housing during the transport of the housing.

However, it should be noted that the fabrication of the previously mentioned sealing system requires great diligence, and, thereby, generally speaking, the danger exists that the sealing lip of the sealing ring will be damaged by the assembly of the protective assembly sleeve. This is mainly attributable to the fact that the sealing lip has an overlap with respect to the protective surface of the protective assembly sleeve, and a sharp-edged (e.g., not diligently deburred) protective assembly sleeve can thus damage the sealing lip. Apart from that, it should be noted that the assembly power required for the completion of the sealing system is so great that the sealing system is not mountable by hand. That, too, is because the sealing lip of the sealing ring in the previouslymentioned sealing system securely encloses the protective assembly sleeve under radial pre-stress. For the assembly of the protective assembly sleeve in the sealing ring, an assembly tool - especially, a pressing tool - is necessary.

This makes the fabrication of the sealing system laborious and expensive.

US 2013/0256995 and GB 2226091 each disclose a sealing system as defined in the preamble of claim 1.

Disclosure of the invention

The invention has the aim of further developing a sealing system and a protective assembly sleeve with integrated sealing cover of the kind previously described that results in a simplified manufacturing process - especially, in that the sealing lip of the sealing ring is even more securely protected from deformation and/or damage by the assembly of the protective assembly sleeve in the sealing ring, where the joining force for the fabrication of the sealing system is reduced - especially, for the assembly of the protective assembly sleeve in the sealing ring, and where a highly convenient releasable connection is provided between the sealing ring and the assembly sleeve.

In accordance with the invention, this aim is achieved by the features of claims 1 and

21. The sub-claims refer to advantageous embodiments of the present invention.

In order to achieve this aim, the sealing lip and the protective assembly sleeve are connected in a positive fit to each other through a non-destructive, latchable connection that is detachable, and wherein the latchable connection is formed through an undercut in the sealing ring or in the protective assembly sleeve, in which a projection of the protective assembly sleeve or of the sealing ring is latchable.. The advantage here is that the sealing lip never touches the protective assembly sleeve at any point during the fabrication of the sealing system. Burrs and/or increased roughness of the protective assembly sleeve have no detrimental influence on the sealing lip. There is also the advantage, through the contact-free assignment of the sealing lip to the protective assembly sleeve, that the joining force for the assembly of the protective assembly sleeve in the sealing ring for the fabrication of the sealing system is reduced. A relative movement with friction between the protective assembly sleeve and the sealing lip, which would increase the joining force, does not take place. Thereby arises the possibility that the sealing system is mountable by hand (without tools).

A sealed machine element that is sealed by the sealing ring from the sealing system can be formed through a shaft shoulder, wherein the sealing diameter of the sealing shaft shoulder corresponds approximately to the sealing diameter of the sealing lip of the sealing ring in such a way that the sealing lip encloses and seals the sealing surface with less overlap under radial pre-stress.

In the assembly direction of the sealing shaft shoulder, a further shaft shoulder can be arranged with a comparably small sealing diameter that has a multi-tooth or spline profile. This, mostly sharp-edged, profile is inserted through the protective assembly sleeve (e.g., into a sealed housing). Subsequently, the protective assembly sleeve is removed, and the shaft further inserted in the assembly direction up until the sealed shaft shoulder is tightly sealed by the sealing lip of the sealing ring.

In contrast to the other shaft shoulder that is designed as a multi-tooth or spline profile, the sealing surface of the sealing shaft shoulder has a usual surface finish that has no undesired detrimental influence on the performance characteristics and/or service life of the sealing lip.

The sealing lip can consist of an elastomeric material. Sealing lips from elastomeric material are especially sensitive to touch with sharp-edged and/or rough objects. The contact of a sealing lip from elastomeric material with a sharp-edged protective assembly sleeve can lead to the sealing lip being damaged and its function thereby no longer being fulfilled. Such damage is often not readily apparent, such that the damage to the sealing lip first becomes apparent during its intended use through a leakage, and the damaged sealing ring must be replaced at great cost and expenditure of time. It is therefore especially important that particularly sensitive sealing lips of the protective assembly sleeve be formed without contact and with radial spacing.

The sealing lip, which is formed without contact and with radial spacing on the outer circumference side of the protective assembly sleeve, can be formed as a dynamicallystressed sealing lip. It is especially important for dynamically-stressed sealing lips that, before their intended use, they not be elastically deformed or damaged at all - for example, in such a way that the sealing ring is bound to the protective assembly sleeve and completed for the sealing system. Even slight damage to a dynamically-stressed sealing lip can easily lead to a total failure of the sealing ring during its intended use particularly, for example, when they have a delicate geometry for the enhancement of the performance characteristics - as with a return feed.

The sealing lip can at least be assigned an adjacent dirt sealing lip with axial spacing. Such dirt sealing lips serve, for example, the function of keeping environmental contaminations away from the sealing lip.

According to an initial design, it can be stipulated that the dirt sealing lip consist of elastomeric material, and the protective assembly sleeve be enclosed on the outer circumference side, without contact and with radial spacing. Such a design is therefore advantageous when the sealing lips and at least one dirt sealing lip merge into one piece and are formed with uniform materials. The dirt sealing lip is usually just as sensitive as the sealing lip, and must likewise be protected from an elastic deformation or any damage by means of the protective assembly sleeve during the fabrication of the sealing system.

According to a different design, it can be stipulated that the dirt sealing lip consist of elastomeric material, and the protective assembly sleeve be enclosed on the outer circumference side, without contact and with radial spacing. Such a dirt sealing lip can, for example, consist of PTFE. Dirt sealing lips are - especially, if they consist of a polymer material - often less sensitive than sealing lips made from elastomeric material. Such a dirt sealing lip can thereby securely enclose the protective assembly sleeve on the outer circumference side under elastic pre-stress, without problems. Abutting contact of the dirt sealing lips with the protective assembly sleeve has the further advantage that the protective assembly sleeve is pre-centred, in relation to the sealing lip, during assembly in the sealing ring by the dirt sealing lip, and, to a great extent, concentrically inserted into the sealing ring. As a result, there is no risk of touching and/or damaging the sealing lip during the assembly of the protective assembly sleeve in the sealing ring.

The sealing ring may be formed as a radial shaft seal. Radial shaft seals are successfully used in various sizes for various inserting applications, e.g., for the sealing of gear-housing in motor vehicles.

It is advantageous if the sealing system is developed altogether as a pre-assembled unit. The sealing ring and the protective assembly sleeve are then securely connected to each other and can be mounted together in a sealed machine element.

For the assembly of the sealing system, the protective assembly sleeve is (e.g., by hand) inserted axially into the sealing ring without touching the sealing lip. In the end position of the protective assembly sleeve, the latchable connection is closed with respect to the sealing ring, and the sealing ring and the protective assembly sleeve are securely set together.

To detach the latchable connection, when a sealed shaft, with its surface critical for the sealing lip, is passed on the sealing lip in the axial direction, the protective assembly sleeve is (e.g., by hand) pulled out under the sealing lip of the sealing ring. Subsequently, the sealing shaft is brought into its end position, and the sealing lip and, if necessary, the dirt sealing lip enclose the sealing surface of the shaft under radial elastic pre-stress.

The undercut and the projection are detachable from one another by an initial pull. The initial pull is thereby measured in such a way that the latchable connection can be detached by hand by the sealing system technician without any problem, and that an unintended detachment of the latchable connection is nevertheless avoided.

The sealing ring can have an initial lead-in chamfer for the protective assembly sleeve on the axial side facing away from the sealing lip. The assembly of the protective assembly sleeve in the sealing ring is thereby simplified. The initial lead-in chamfer ensures centring of the protective assembly sleeve obtained from the sensitive sealing lip of the sealing ring.

The undercut can be arranged in the initial lead-in chamfer. Here, the advantage is that the insertion force of the protective assembly sleeve in the sealing ring is minimal, up until the last moment before the locking in of the latchable connection. Only in the last moment before the projection is latched into the undercut and the latchable connection is closed is the necessary insertion force for latching greater.

The protective assembly sleeve may have a second lead-in chamfer narrowing in a funnel shape axially in the direction of the sealing lip, wherein both lead-in chamfers are arranged concentrically to and extended essentially in parallel with one another. The second lead-in chamfer forms a centring aide for a sealing shaft, which, in the assembly direction, is first led through the second lead-in chamfer and then under the sealing lip of the sealing ring.

Preferably, it can be provided that the projection be arranged on the second lead-in chamfer. The sealing system has thereby, altogether, compact dimensions especially, in the axial direction.

The protective assembly sleeve can consist of a polymer material. Such protective assembly sleeves are simple and cost-effective to manufacture, as well as resistant to moisture and the usual, sealed media. The protective assembly sleeve need not be particularly tolerant and/or have a high surface finish, because the sealing lip encloses the protective assembly sleeve on the outer circumference side, without contact and with radial spacing.

The protective assembly sleeve can have an initial break-off clip for removing the protective assembly sleeve from the sealing ring after successful assembly of the sealing system in a sealed machine element. Such a break-off clip is preferably merged in one piece with the protective assembly sleeve and formed of uniform material. The break-off clip can be single-stream recycled together with the protective assembly sleeve, if necessary.

According to an advantageous embodiment of the present invention, the protective assembly sleeve and the sealing cover are designed so that they merge into one another and are formed of uniform material. Protective assembly sleeve and sealing cover can be manufactured together in only one procedural step. Thereby, the sealing system is, altogether, simple and inexpensive to manufacture.

The protective assembly sleeve can have a centrally-arranged through hole that is closed by the sealing cover due to manufacturing conditions. The sealing cover can be detachable from the through hole side wall of the protective assembly sleeve. For that, the sealing cover can have a second break-off clip, wherein the sealing cover is detachable from the protective assembly sleeve by a second pull. The opening of the central through hole of the protective assembly sleeve for the assemblage of a sealing shaft is thereby especially simple, and self-explanatory for the user of a sealing system.

The first pull is greater than the second pull. That is advantageous for preventing the latchable connection between the sealing ring and the protective assembly sleeve from being unintentionally released early, before the sealing cover of the protective assembly sleeve is torn off.

Brief Description of the Drawings

Two design examples of the inventive sealing system and protective assembly sleeve with integrated sealing cover are explained in more detail in the following figures 1 through 3.

Shown are, each in schematic representation:

Figure 1 an initial exemplary embodiment of a sealing system, in which the sealing lips and dirt sealing lips of the sealing ring consist of an elastomeric material, and the protective assembly sleeve in each case is enclosed on the outer circumference side, without contact and with radial spacing,

Figure 2 a second exemplary embodiment of a sealing system, similar to the exemplary embodiment from Figure 1, wherein, however, only the sealing lip encloses the protective assembly sleeve on the outer circumference side, without contact and with radial spacing, and

Figure 3 a view of the sealing systems from Figures 1 and 2.

Detailed Description of the Invention

Figures 1 and 2 each schematically show an exemplary embodiment of an inventive sealing system.

Each sealing system comprises the sealing ring 1, which is formed as a radial shaft seal. The sealing ring 1 has a dynamically-stressed sealing lip 2, which consists of an elastomeric material and which encloses the protective assembly sleeve 3 on the outer circumference side, without contact and with radial spacing.

In the design examples shown here, the sealing ring 1 and the protective assembly sleeve 3 are detachably and non-destructively connected in a positive fit through a latchable connection 7. The latchable connection 7 is formed by an undercut 8 in the initial lead-in chamfer 11 of the sealing ring 1, wherein, in the undercut 8 of the projection 9, the protective assembly sleeve 3 is latchable. The projection 9 is arranged on the side, radially facing undercut 8, of the second lead-in chamfer 12 of the protective assembly sleeve 3.

The protective assembly sleeve 3 is, in both sealing systems according to Figures 1 and 2, removed from the sealing ring 1 by the first break-off clip 13, when a sealing shaft (not shown here), with its surface critical for the sealing lip 2, is introduced past the sealing lip 2 in a housing (also not shown here).

In order to release the centrally-arranged through hole 14 of the protective assembly sleeve 3 for the assembly of a sealed shaft, the sealing cover 4 is separated, by the second break-off clip 15, from the wall, adjoining the through hole 14, of the protective assembly sleeve 3.

The first pull 10, which is used for the release of the latchable connection 7, in order to non-destructively separate undercut 8 and projection 9 from one another, must be greater than the second pull 16, by which the sealing cover 4 is detachable from the protective assembly sleeve 3. It is prevented thereby that the latchable connection 7 is detached unintentionally before the sealing cover 4 is torn off of the protective assembly sleeve 3.

In figure 1, an initial exemplary embodiment is shown.

The sealing lip 2 of the sealing ring 1 encloses the protective assembly sleeve 3 on the outer circumference side, without contact and with radial spacing, like the two dirt sealing lips 5 to which the sealing ring 2 on the side facing the environment 17 with axial spacing is adjacently assigned.

In this design example, sealing lip 2 and the dirt sealing lips consist of a coordinated elastomeric material. The first lead-in chamfer 11, also, is designed with materials coordinated with the sealing lip 2 and the dirt sealing lips 5.

Through the radial spacing and the contactless assignment of the protective assembly sleeve 3, deformations of sealing lip 2 and dirt sealing lips 5 are securely precluded by the protective assembly sleeve 3, as is, by the assembly of the protective assembly sleeve 3, damage to sealing lip 2 and dirt sealing lips 5.

In figure 2, a second design example of the inventive sealing system is shown, similar to the design example from Figure 1. The way in which the sealing system from Figure 2 is differentiable from the sealing system from Figure 1 is that only one dirt sealing lip 5 is provided and this dirt sealing lip 5 consists of a polymer material, and the protective assembly sleeve 3 on the outer circumference side is securely enclosed under elastic pre-stress.

When the protective assembly sleeve 3 is inserted in assembly direction 18 into the sealing ring 1 for the manufacturing of the sealing system, the first, circularly-designed dirt sealing lip 5 becomes deformed in the area of its axial inner circumference in the direction of sealing lip 2 and causes thereby a pre-centring of the protective assembly sleeve 3 with respect to sealing lip 2. The protective assembly sleeve 3 can be inserted with particular ease into the sealing ring 1, without touching the sealing lip 2 of the sealing ring 1.

The sealing system according to the invention has a simple construction and can be manufactured in a simple and cost-effective manner.

The sensitive sealing lip of the sealing ring and, if necessary, the sensitive dirt sealing lips are first adjacently touched by a sealed surface of a sealed machine element and elastically deformed. During the manufacturing and subsequent placement of the sealing system, the sealing lip 2, at least, of the protective assembly sleeve 3 is not touched and can therefore not be deformed and/or damaged. By means of the contactless assignment, the joining force in the manufacturing of the sealing system is low enough that the sealing lip and the protective assembly sleeve can be joined by hand.

Claims

P a t e n t k r a v

A sealing system comprising a sealing ring (1) with at least one sealing lip (2) and a protective mounting sleeve (3) with integral sealing cover (4), wherein the sealing lip (2) encloses the protective mounting sleeve (3) on the outer perimeter side, without contact and with radial distance, characterized in that the sealing ring (1) and the protective mounting sleeve (3) are connected to each other in a positive form of fit through a non-destructive, fastening connection (7) which is removable and wherein the fastening connection (7) is formed through an undercut (8) in the sealing ring (1) or in the protective mounting sleeve (3), in which a protrusion (9) can be secured by the protective mounting sleeve (3) or by the sealing ring (1).

Sealing system according to claim 1, characterized in that the sealing lip (2) consists of an elastomeric material.

Sealing system according to any one of claims 1 or 2, characterized in that the sealing lip (2) is dynamically tensioned during the intended use of the sealing ring (1).

Sealing system according to any one of claims 1 to 3, characterized in that the sealing lip (2) is connected in an adjacent manner to at least one axial spacer sealing lip (5).

Sealing system according to claim 4, characterized in that the dirt seal lip (5) consists of an elastomeric material and the protective mounting sleeve (3) is enclosed on the outer circumferential side, without contact and at radial distance.

Sealing system according to claim 4, characterized in that the sealing lip (5) consists of an elastomeric material and the protective mounting sleeve (3) is securely enclosed on the outer circumferential side under elastic prestressing.

Sealing system according to any one of claims 1 to 6, characterized in that the sealing ring (1) is formed as a radial shaft seal (6).

Sealing system according to any one of the preceding claims, characterized in that the undercut (8) and the projection (9) can be detached from one another by a first pulling force (10).

Sealing system according to any one of claims 1 to 8, characterized in that the sealing ring (1) on the axial side facing away from the sealing lip (2) has a first insertion phase (11) for the protective mounting sleeve (3).

Sealing system according to any of the preceding claims, characterized in that the undercut (8) is arranged in the first insertion phase (11).

Sealing system according to any one of claims 1 to 10, characterized in that the protective mounting sleeve (3) has a second insertion phase (12) which narrows into a funnel shape axially in the direction of the sealing lip (2) and that both the insertion phase ( 11, 12) are arranged concentrically with and extending substantially parallel to each other.

Sealing system according to any one of the preceding claims, characterized in that the projection (9) is arranged in the second insertion phase (12).

Sealing system according to any one of claims 1 to 12, characterized in that the protective mounting sleeve (3) consists of a polymeric material.

Sealing system according to any one of claims 1 to 13, characterized in that the protective mounting sleeve (3) has a first breaking clip (13) for removing the protective mounting sleeve (3) from the sealing ring (1) after successful mounting of the sealing system.

Sealing system according to any one of claims 1 to 14, characterized in that the protective mounting sleeve (3) and the sealing cover (4) are configured in such a way that they are completely joined together and are made of a uniform material.

Sealing system according to any one of claims 1 to 15, characterized in that the protective mounting sleeve (3) has a centrally located through hole (14) which is closed by the sealing cover (4) due to manufacturing conditions.

Sealing system according to any one of claims 1 to 16, characterized in that the sealing cover (4) can be removed by the wall forming the border of the through-hole (14) of the protective mounting sleeve (3).

Sealing system according to any one of claims 1 to 17, characterized in that the sealing cover (4) has a second breaking clip (15).

Sealing system according to any one of claims 1 to 18, characterized in that the sealing cover (4) can be removed by the protective mounting sleeve (3) by another pulling force (16).

Sealing system according to any one of the preceding claims, characterized in that the first traction (10) is greater than the second traction (16).

Protective mounting sleeve (3) with integrated seal cover (4), characterized in that it is designed according to any one of claims 1 to 20.