Patent Application
20150152754
This application claims the benefit and priority of German Application No. 10 2013 018 108.9, filed Dec. 3, 2013. The entire disclosure of the above application is incorporated herein by reference.
The present disclosure relates to a seal, comprising a sealing ring made from an elastomeric material, an intermediate ring made from a polymeric material and a supporting ring, the sealing ring, the intermediate ring and the supporting ring being arranged concentrically with respect to one another, and the sealing ring and the supporting ring being arranged in each case on the sides of the intermediate ring which face away axially from one another.
A seal of this type is known generally, the sealing ring, the intermediate ring and the supporting ring being manufactured in each case separately and being completed to form a seal assembly during mounting on a machine element to be sealed.
Here, all the rings of the seal assembly are supported without adhesion on the respectively axially adjacent rings.
The mounting of the above-described seal is complicated and relatively unreliable in terms of process, because the individual rings have to be completed to form the seal during the mounting on the machine element to be sealed. In particular, the sealing ring can be damaged easily during mounting. On account of relatively inexact positioning of the respective rings relative to one another and on account of a possible gap extrusion of the sealing ring, the seal achieves merely a relatively unsatisfactory sealing result.
The present disclosure is based on the object of developing a seal of the type mentioned at the outset, in such a way that said seal can be mounted more simply on the machine element to be sealed, that the risk of damage to the individual rings, of which the seal consists, is reduced to a minimum, and that the seal has constantly satisfactory use properties during a long service life.
According to the present disclosure, this object is achieved by way of a seal including a sealing ring made from an elastomeric material, an intermediate ring made from a polymeric material, and a supporting ring; the sealing ring, the intermediate ring, and the supporting ring being arranged in each case on the sides of the intermediate ring which face away axially from one another, characterized in that the sealing ring, the intermediate ring, and the supporting ring form a preassembled unit.
It is further provided that the sealing ring, the intermediate ring and the supporting ring form a pre-assembled unit.
Here, it is advantageous that the mounting of the seal on the machine element to be sealed is simplified substantially as a result. The sealing ring, the intermediate ring and the supporting ring are first of all completed to form the pre-assembled unit. The pre-assembled unit is then mounted as a single-piece entirety on the machine element to be sealed.
As a result, the mounting of the seal on the machine element to be sealed is simplified as far as possible and the risk of damage to the rings is also reduced to a minimum as a result of the rings being combined to form the pre-assembled unit.
By virtue of the fact that a relative displacement, in particular an eccentric movement of the rings relative to one another, is ruled out by way of the combination to form the pre-assembled unit, the rings, of which the seal consists, always have an exact and ideal position relative to one another. This great dimensional accuracy of the pre-assembled unit aids a satisfactory sealing result of the seal during a long service life.
It can be provided according to one advantageous refinement that the intermediate ring is connected in each case in a material-to-material manner to the sealing ring and the supporting ring. As a result of the material-to-material connection, leaks in the region of the joints between the rings which adjoin one another in each case in a contiguous manner are ruled out. Moreover, it is advantageous that the rings are positioned particularly exactly with respect to one another permanently as a result of the material-to-material connection, and the seal overall is particularly dimensionally accurate. In particular, on account of the material-to-material connection, there are no eccentricities of the individual rings relative to one another which impair the use properties. Overall, the seal has only very low mounting and sealing gaps, and the gap extrusion, in particular of the sealing ring, is reduced to a minimum.
The sealing ring can be composed of an FKM material. Fluororubbers have satisfactory resistance to most media to be sealed and satisfactory resistance to high and low temperatures. A material of this type is therefore satisfactorily suitable for a sealing ring.
Moreover, fluororubbers with different specifications which are adapted to the respective application are available inexpensively.
For many applications, it has proven advantageous if the FKM material which is used has a Shore A hardness of from 60 to 90. A Shore A hardness of this type has been proven, in particular, when the seal is used as a high-pressure seal. High-pressure applications prevail, for example, if injection valves of an internal combustion engine are sealed. In cases of this type, pressures of up to approximately 450 bar have to be sealed. Even when they are used as high pressure seals, sealing rings having the stated Shore A hardness have constantly satisfactory use properties during a long service life.
According to a further advantageous refinement, the intermediate ring can be composed of a PA6.6 material. The use of a material of this type is advantageous because it has very satisfactory strength and durability, and satisfactory resistance to most of the materials to be sealed.
The supporting ring can be composed of a metallic or a sintered material. Supporting rings made from metallic materials can be manufactured particularly simply and inexpensively; in contrast, supporting rings made from sintered material have particularly high strength and particularly low wear during the use as intended of the seal.
The sealing ring can have at least one axial sealing lip on the side which faces axially away from the intermediate ring.
Depending on the respective conditions of the application, it can be provided as an alternative that, on the side which faces axially away from the intermediate ring, the sealing ring has a radially inner and a radially outer axial sealing lip which are assigned to one another adjacently at a radial spacing.
The refinement with the radially inner and the radially outer axial sealing lip brings about a self-reinforcing sealing lip geometry which spreads the intermediate ring open as a result of the hydrostatic pressure and therefore prevents a gap extrusion of the sealing ring.
The prevailing pressure from the fuel supply presses the elastomer onto the intermediate ring, and, as a result of its end side which faces the sealing ring being spread open radially, said intermediate ring closes the radial mounting gaps, with the result that a gap extrusion of the elastomer is largely avoided.
On the side which faces the intermediate ring axially, the sealing ring can have an annular positioning projection which is arranged in a congruently designed depression of the intermediate ring. It is advantageous here that the surfaces of the sealing ring and intermediate ring which make contact with one another are enlarged as a result of the positioning projection of the sealing ring and the depression in the intermediate ring. As a result, a particularly long-term connection of the two rings to one another can be brought about, for example by way of a material-to-material connection. Moreover, the positioning of the sealing ring and intermediate ring relative to one another during the manufacture of the seal is simplified. The manufacture of the seal is particularly reliable in terms of process as a result.
On its side which faces axially away from the sealing ring, the intermediate ring can have a holding claw which engages in a positively locking manner behind an undercut of the supporting ring. If the intermediate ring and the supporting ring are fixed on one another in an exclusively positively locking manner, the metal disk can be detached in a destruction-free manner from the intermediate ring and can be recycled in a correctly sorted manner following the use of the seal.
A particularly long-term connection between the intermediate ring and the supporting ring can be achieved by virtue of the fact that said rings are connected to one another not only in a positively locking manner but also, moreover, in a material-to-material manner. The joint between said two rings is absolutely tight as a result of the additional material-to-material connection.
The supporting ring can have an annular supporting face on the end side which faces axially away from the intermediate ring. If, for example, the seal is used to seal an injection valve of an internal combustion engine, the annular supporting face serves as a mounting stop for the injection valve to be mounted.
Those faces of the sealing ring, intermediate ring and supporting ring which adjoin one another in an adjacent manner can preferably be in bearing contact with one another in a gap-free manner. As a result, the seal has satisfactory dimensional stability, and a satisfactory sealing action is aided by way of said gap-free contact.
Moreover, the present disclosure relates to the use of an above-described seal for sealing an injection valve of an internal combustion engine.
Seals for sealing an injection valve of an internal combustion engine have up to now been of multiple-part construction. Here, a previously known seal comprises, for example, a sealing ring which is configured as an O-ring, and a PTFE ring which adjoins the former on the end side on one side, an intermediate ring made from a polymeric material being arranged on that side of the PTFE ring which faces axially away from the O-ring. A metal disk is arranged on that side of the intermediate ring which faces axially away from the PTFE ring.
The PTFE ring is provided to close the predefined mounting gaps radially by way of deformation upon pressure loading. In the invention which is claimed here, this is ensured with the aid of the intermediate ring or the self-reinforcing lip contour of the axial sealing lip.
One exemplary embodiment of the seal according to the present disclosure will be explained in greater detail in the following text using the FIGURE:
The FIGURE shows one exemplary embodiment of the seal according to the present disclosure in a diagrammatic illustration. The seal is formed by the pre-assembled unit 4, the pre-assembled unit 4 comprising the sealing ring 1, the intermediate ring 2 and the supporting ring 3.
In the exemplary embodiment which is shown here, the sealing ring 1 is composed of an elastomeric material, the intermediate ring 2 is composed of a polymeric material and the supporting ring 3 is composed of a metallic material.
The sealing ring 1, the intermediate ring 2 and the supporting ring 3 are arranged concentrically with respect to one another and are connected to one another in a material-to-material manner.
The seal which is shown is used to seal an injection valve of an internal combustion engine, the seal having the sealing ring 1 on the end side at one end and the supporting ring 3 on the end side at the other end. On its side which faces axially away from the intermediate ring 2, the sealing ring 1 has a radially inner axial sealing lip 5.1 and a radially outer axial sealing lip 5.2 which are assigned to one another adjacently at a radial spacing. The radially inner axial sealing lip 5.1 seals radially to the outside with respect to the rail connection opening, whereas the radially outer axial sealing lip 5.2 seals the fuel-conducting connection on the injection valve radially to the inside.
On that side of the seal which faces axially away from the axial sealing lips 5.1, 5.2, the annular supporting face 10 is provided as a constituent part of the supporting ring.
In the exemplary embodiment which is shown here, all the rings, of which the pre-assembled unit 4 consists, are connected to one another in a material-to-material manner. As a result, the joints between the individual rings are absolutely tight and the seal can be handled in a particularly simple manner because the installer charged with mounting merely has to mount the pre-assembled unit 4 in its entirety. The risk of mounting errors is reduced to a minimum as a result.
The annular positioning projection 6 of the sealing ring 1 bears tightly against the congruently designed depression 7 of the intermediate ring 2; the intermediate ring 2 has a holding claw 8 which engages into an undercut 9 of the supporting ring 3 in a positively locking manner.
The seal according to the present disclosure can be manufactured simply and inexpensively and can be handled without problems.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2013 018 108.9 | Dec 2013 | DE | national |
