Patent Description:
The function of the axial seal consists in particular in bridging the spacing between the sealing surface and the opposite surface on the mating piece and feeding the fluid flow, sealed from the fluid duct, into the duct in the mating piece, and vice versa.

The object of the invention consists in providing a fluid line component which ensures with minimal effort a reliable seal even in the case of relatively high tolerances in terms of the spacing between the sealing surface and the opposite surface.

In order to achieve this object, in the case of a fluid line component of the type mentioned at the beginning, it is provided according to the invention that the axial seal has a support and a sealing element which is assembled on the support, wherein the support can be displaced relative to the sealing surface. The sealing element has the deformability required in order to be deformed in the axial direction to such an extent that the sealing element is clamped between the sealing surface and the mating surface at all times with sufficient pretension irrespective of the actual tolerances. The support ensures here that the sealing element cannot deform to an excessive extent and is held in the desired position for every tolerance situation.

According to one embodiment, it is provided that the sealing surface is arranged recessed in an end side of the fluid line component. The support is here held inside a peripheral shoulder into which the axial seal is inserted. In order to provide the desired elastic deformation of the axial seal, the support has a height which is less than the height of the axial seal in the undeformed state.

According to an alternative embodiment, it is provided that the sealing surface is arranged at a projecting connection piece of the fluid line component. In this case, the support can overlap the connection piece externally and guide the seal as a result. Accordingly, the support is configured to be higher in the axial direction than the seal in the undeformed state.

The sealing element is preferably pre-assembled on the sealing surface such that, when the fluid line component is mounted, it does not need to be fixed separately on the mating piece.

For this purpose, it can be provided that the sealing element is engaged behind a holding element which is provided on the fluid line component. The mechanical engaged connection formed in this way enables the axial seal to be pre-assembled with minimal effort, namely by it being pressed simply against the sealing surface provided to receive it.

According to a preferred embodiment, it is provided that the support is annular. The annular shape ensures the highest possible degree of stability when an elevated or reduced pressure acts on the support.

At least one outer edge of the support is preferably configured so that it is bevelled or rounded on a side facing the sealing element such that there are no sharp edges present which could damage the sealing element.

According to an embodiment of the invention, the fluid duct is an intake duct, wherein the support is arranged inside the sealing element. The reduced pressures which exist inside the axial seal during the operation of the fluid line component ensure that the sealing element is pressed firmly against the support and is supported by the latter. There is therefore no risk of the sealing element becoming detached from the support.

According to an alternative embodiment, it is provided that the fluid duct is a pressure duct, wherein the support is arranged outside the sealing element. In this embodiment too, the pressures acting during operation ensure that the sealing element is pressed firmly against the support which mechanically stabilizes the sealing element as a result. Here too, there is no risk of the sealing element becoming detached from the support.

The sealing element is preferably designed as annular and has two sealing lips which protrude radially at radially opposite ends of the sealing element. The sealing lips ensure the desired local surface pressure by which the sealing element reliably forms a seal at the sealing surface or the mating element.

The sealing lips preferably project axially from the support such that the axially required contact pressure is achieved.

The fluid line component according to the invention can in particular be a hydraulic pump, wherein the mating piece is a receptacle in a housing of a fluid storage tank. During mounting, the pump can be inserted into the receptacle with pre-assembled axial seals such that during the mounting the desired pretensioning of the axial seals is achieved there. At the same time, the axial seals are configured such that any mounting tolerances can be absorbed. This ensures that, irrespective of the tolerance situation, the axial contact pressure prevailing in each case does exceed or fall below the limits within which the axial seal reliably forms a seal.

The invention will be described below on the basis of various embodiments, which are illustrated in the appended drawings. In the drawings:.

A fluid line component <NUM> is shown in <FIG> which is a hydraulic pump in the exemplary embodiment shown.

The fluid line component <NUM> is assembled in a receptacle <NUM> of a mating piece <NUM>. The mating piece <NUM> is in this case a housing of a fluid storage tank. The fluid storage tank can be part of a gearbox housing, etc..

The fluid line component <NUM> has two fluid ducts <NUM>, <NUM>, the fluid duct <NUM> of which is an intake duct and the fluid duct <NUM> a pressure duct.

The mating piece <NUM> has a duct <NUM> which is associated with the intake duct <NUM>, and a duct <NUM> which is associated with the pressure duct <NUM>.

The fluid line component <NUM> is screwed to the mating piece <NUM> (see the schematically illustrated screw connections <NUM>), wherein that side of the fluid line component <NUM> which is arranged inside the receptacle <NUM> is situated opposite the base of the receptacle <NUM>. Axial seals <NUM>, which connect the fluid ducts <NUM>, <NUM> leaktightly to the ducts <NUM>, <NUM> assigned to them, are provided there.

One of the axial seals <NUM>, namely the one on the pressure side of the hydraulic pump, is shown in <FIG> in a state in which the spacing between the end side of the fluid line component <NUM> and the base of the receptacle <NUM> corresponds to a nominal value. The gap is designated here as sn. In this state, the axial seal <NUM> bears with the desired pretension both against the fluid line component <NUM> and against the mating piece <NUM> such that a seal is reliably formed in the region of the transition from the pressure duct <NUM> in the fluid line component <NUM> to the duct <NUM> in the mating piece <NUM>.

The seal from <FIG> is shown in <FIG> in a state in which the spacing corresponds to a maximum value smax. Because of the dimensioning of the axial seal <NUM>, in this state too there is still a sufficient contact pressure such that the axial seal <NUM> reliably seals off the transition from the pressure duct <NUM> to the duct <NUM>.

A state is shown in <FIG> in which the spacing between the fluid line component <NUM> and the mating piece <NUM> corresponds to a minimum value smin. The axial seal <NUM> is here pressed together further axially, wherein it has sufficient space to expand such that it is not excessively compressed.

The axial seal <NUM> will be described below with the aid of <FIG> for the use case on the pressure side of the fluid line component, i.e. for the side on which an elevated pressure prevails in the fluid line component.

The axial seal <NUM> has an overall annular structure, wherein it has a support <NUM> and a sealing element <NUM>. The support <NUM> has an
L-shaped cross-section with a leg which forms a cylindrical surface concentric with the centre axis of the seal, and a leg which forms an annular surface extending radially with respect to the centre axis.

Metal or a sufficiently rigid plastic can be used as the material for the support <NUM>.

The sealing element <NUM> preferably consists of an elastomer and has a central section which is held on the support <NUM>, and two sealing lips <NUM> which project both radially and axially from the support <NUM> on sides of the sealing element which face away from each other.

The sealing element <NUM> is attached to the support <NUM> such that the sealing element <NUM> cannot be detached from the support <NUM> during transport and handling. For example, the dimensions of the sealing element <NUM> relative to the dimensions of the support <NUM> can be selected such that the sealing element <NUM> is fastened on the support <NUM> solely by virtue of the frictional forces which exist in the assembled state. The sealing element <NUM> can, however, also be firmly bonded, vulcanized, etc. to the support <NUM>.

A sealing surface <NUM>, which is provided concentrically with the centre axis M of the fluid duct <NUM>, is provided in the fluid line component <NUM> in order to hold the axial seal <NUM>. The sealing surface <NUM> is configured to be recessed in the fluid line component <NUM> such that a step <NUM> is provided in which the support <NUM> is guided. One of the sealing lips <NUM> bears against the sealing surface <NUM> as a result.

On the radially inner situated side, a holding element <NUM>, in the form of a peripheral collar which is provided with an undercut at its axial end, projects from the sealing surface <NUM>. The sealing lip <NUM> assigned to the sealing surface <NUM> engages behind it such that the axial seal <NUM> can be pre-assembled on the fluid line component <NUM>.

It is also possible to fasten the axial seal <NUM> only by means of an oversized fit between the sealing element and the holding element <NUM>, i.e. by a clamping effect. This has the advantage that it is possible to dispense with the undercut which is challenging from a manufacturing point of view.

Two cross-hatched regions are shown in <FIG> into which the sealing element <NUM> can deform in the case of different stresses.

The sealing element <NUM> is deformed into the region situated radially outside the sealing element <NUM> when high pressures exist inside the fluid duct. The sealing element is deformed into the region situated radially inside the sealing element <NUM> when the spacing between the fluid line component <NUM> and the mating piece <NUM> is very small.

The two legs of the support <NUM> are in each case configured as bevelled or rounded at their free ends such that the sealing element <NUM> can bear lightly there and, when it is deformed, can bear, uniformly supported, against the step <NUM> and the corresponding surface of the mating piece <NUM>.

The sealing lips have a self-reinforcing effect because the pressure acting inside the sealing element presses it against the sealing surface <NUM> and the mating surface on the mating piece <NUM>. As the pressure increases, the contact force of the sealing lips <NUM> on the fluid line component <NUM> and on the mating piece <NUM> also increases such that a reliable seal is ensured.

The force exerted as a whole on the support by the sealing lips <NUM> and the sealing element <NUM> also causes the support <NUM> to be pressed more strongly against the step <NUM> and the mating piece <NUM> as the pressures increase. As a result, it is ensured that no extrusion gap, into which the sealing element <NUM> could be pressed, can be formed between the support <NUM> and the surfaces on the fluid line component <NUM> and the mating piece <NUM> on which the support <NUM> is supported. As a result, the possibility that the sealing element <NUM> might be damaged by repeated deformation into an extrusion gap is prevented.

<FIG> shows a second embodiment. The same reference signs are used for the first embodiment shown in <FIG>, and, in this respect, reference is made to the explanations above.

The difference between the embodiment in <FIG> and that in <FIG> consists in that fact that, in the case of the embodiment in <FIG>, the sealing surface <NUM> is not configured as recessed in the fluid line component <NUM> and instead represents an end surface of a protruding connection piece.

The difference between the first and the second embodiment consists in particular in the configuration of the leg of the support <NUM> which forms the cylindrical surface configured concentrically with respect to the centre axis M. Whilst in the embodiment in <FIG>, this leg is shorter than the axial height of the sealing element <NUM>, in the embodiment in <FIG>, this leg projects axially from the corresponding sealing lip <NUM> of the sealing element <NUM>. The leg here overlaps the connection piece such that the axial seal <NUM> is guided radially on the connection piece by means of the support <NUM>. A sliding guide is formed here which can absorb the axial tolerances.

The sliding guide is dimensioned with regard to the existing gap such that the sealing element <NUM> cannot be pressed into the gap in the case of the pressures which occur.

<FIG> shows a third embodiment. The same reference signs are used for the components known from the preceding embodiments, and, in this respect, reference is made to the explanations above.

The embodiment in <FIG> is a combination of the embodiments in <FIG>. The sealing surface <NUM> is configured, similarly to the embodiment in <FIG>, so that it is recessed in the fluid line component <NUM>, whilst the support <NUM> projects with one leg from the end of the sealing element <NUM> and forms a sliding guide with the neighbouring surfaces of the fluid line component <NUM>, in this case with the inner surface of the fluid duct <NUM>. In contrast to the first and second embodiment, the axial seal <NUM> in the third embodiment serves to seal the intake duct <NUM> (i.e. in the case of a reduced pressure) such that the support <NUM> is arranged radially inside the sealing element <NUM>.

Also in the third embodiment, a radial undercut can be used with which the sealing lip <NUM> associated with the sealing surface <NUM> engages inside the receptacle in the fluid line component <NUM>.

<FIG> shows a fourth embodiment. The same reference signs are used for the features known from the preceding embodiments, and, in this respect, reference is made to the explanations above.

The difference between the third and the fourth embodiment consists in the sealing surface <NUM> in the fluid line component <NUM> being provided not on the base of a receptacle or recess for the axial seal <NUM> and instead forms an end side of a connection piece. The axial seal <NUM> is assembled on the latter such that the leg of the support <NUM> situated on the inside projects into the fluid duct <NUM> and in this way ensures radial guidance of the axial seal <NUM>.

Here too, a holding element <NUM> is provided which forms a radial undercut behind which one of the sealing lips <NUM> of the sealing element <NUM> engages mechanically. The axial seal <NUM> is pre-assembled on the fluid line component <NUM> as a result.

According to a development which is not illustrated, an additional elastic element, which stresses the sealing lips in opposite directions in order to increase the contact force and hence the sealing effect, is provided on the axial seal <NUM>. The elastic element can consist, for example, of spring steel and be formed in a similar fashion to those which are known from radial shaft sealing rings.

Shown in <FIG> is a variant of the axial seal <NUM> which differs from the preceding embodiments in that the support <NUM> is provided with a local deformation <NUM>, for example a rib or bead. As a result, in the starting state the support <NUM> bears against the sealing element <NUM> with a smaller surface. The advantage is better deformability of the sealing element <NUM>, specifically when effecting a large tolerance compensation.

Alternatively, a mating contour, corresponding to the contour of the support, can be provided in the sealing element such that the rib or bead of the support engages here mechanically.

As a further option, a mechanical undercut could here create more flexibility because the sealing element <NUM>, when compressed, can easily adapt to / fit snugly against the undercut contour of the support <NUM>.

Claim 1:
Fluid line component (<NUM>) with a fluid duct (<NUM>, <NUM>), a sealing surface (<NUM>) which surrounds the outlet of the fluid duct (<NUM>, <NUM>) on an outer side of the fluid line component (<NUM>), and an axial seal (<NUM>) which bears against the sealing surface (<NUM>) and can be brought to bear against an opposite surface of a mating piece (<NUM>) in order to connect the fluid duct (<NUM>, <NUM>) leaktightly to a duct (<NUM>, <NUM>) in the mating piece (<NUM>), wherein the axial seal (<NUM>) has a support (<NUM>) and a sealing element (<NUM>) which is assembled on the support (<NUM>), wherein the support (<NUM>) can be displaced relative to the sealing surface (<NUM>), characterized in that the support (<NUM>) has an L-shaped cross-section with a leg which forms a cylindrical surface concentric with the centre axis of the seal, and a leg which forms an annular surface extending radially with respect to the centre axis.