Filter element of a liquid filter and a liquid filter

A filter element for a liquid filter is arranged in the liquid filter housing that has at least two housing parts such that an inlet of the housing for liquid to be filtered is separated from an outlet of the housing for filtered liquid. The filter element has a filter medium provided with a terminal disk. The terminal disk has a seal support for an outer radial annular seal that is to be clamped in a clamping area between the housing parts that are separable from each other. The seal support of the filter element has axially at least a base member and a cover member. The base member is fixedly connected to the terminal disk. The cover member is attached to the terminal disk, to the base member, or to terminal disk and base member. The annular seal is positioned between base member and cover member.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit under 35 USC 119 of foreign application DE 102011010076.8 filed in Germany on Feb. 1, 2011, and which is hereby incorporated by reference in its entirety.

TECHNICAL FIELD

The invention concerns a filter element for a liquid filter, in particular for fuel, oil or water, in particular of an internal combustion engine and especially of a motor vehicle.

BACKGROUND OF THE INVENTION

A liquid filter, in particular for fuel, oil or water, in particular of an internal combustion engine and especially of a motor vehicle, may be arranged in a filter housing. The housing may have at least two parts and the filter element is positioned therein in such a way that it separates at least one inlet of the housing for the liquid to be filtered from an outlet of the housing for the filtered liquid. The filter element includes a filter medium and may include at least one terminal disk that is connected to the filter medium with a seal support for an outer radial annular seal that can be clamped in a clamping area between the two housing parts of the housing that can be separated from each other.

In a certain known liquid filters, a zigzag-folded filter medium is arranged between two terminal disks. One of the two terminal disks has at the outer radial rim a seal support that is provided with a groove open outwardly in radial direction for receiving an annular seal made of an elastomer. The annular seal is clamped between two housing parts of the filter housing and seals thus the areas between the filter housing and the filter system. For mounting, the annular seal must be inserted into the securing groove in radial direction from the exterior. For this purpose, the annular seal must be stretched somewhat.

It is therefore an object of the present invention to design a filter element and a liquid filter of the aforementioned kind in such a way that the annular seal can be mounted as easily as possible on the seal support. Moreover, the annular seal should be embodied with a minimal material expenditure.

SUMMARY OF THE INVENTION

In accordance with the present invention, this is achieved in that the seal support in axial direction is at least of a two-part configuration and comprises a base member that is connected fixedly to the terminal disk and further comprises a cover member that is attached to the terminal disk and/or to the base member, wherein the annular seal is inserted or positioned between the base member and the cover member.

In the inventive disclosure herein, the terms axial and radial relate to an imaginary rotation and/or insertion axis of the liquid filter: in the direction of the axis in which the filter element is inserted into the housing and removed from the housing.

According to the invention, a base member of the seal support is fixedly connected to the terminal disk. Onto this base member, the annular seal is simply placed in axial direction without this requiring stretching or threading of the annular seal as is the case in known liquid filters. The cover member is placed in axial direction onto the base member and is secured on the terminal disk and/or the base member such that the annular seal is held in place between the base member and the cover member. The axial installation of the annular seal in the axial direction makes it possible to be flexible with respect to shape variants of the annular seal. In particular, a securing section of the annular seal that is secured between the cover member and the base member can have a minimal extension in the axial direction so that less material is needed for the annular seal.

In an advantageous embodiment, the base member can have a base member securing ring profile with a base member securing section that faces the cover member. The cover member can have a cover member securing ring profile with a cover member securing section that is facing the base member. The base member securing section and the cover member securing section can engage the securing section of the annular seal like pliers. With the pliers engagement the annular seal is optimally secured and fixed within the base member and the cover member. Advantageously, the securing section can be designed such that it is reduced in cross section at the location where the base member securing section and the cover member securing section engage it. In this way, it is prevented that the securing section can slide in radial direction or can even slip out of the pliers engagement outwardly in the radial direction. Since the annular seal is placed in axial direction onto the base member, the extension of the securing section of the annular seal in the radial direction can be selected to be greater than in case of the liquid filters of the prior art in which the annular seal must be stretched in order to be able to insert it radially from the exterior into the securing groove. An overlap of the securing section with the seal support in the radial direction can be selected to be correspondingly larger so that, in turn, the securing section, while provided with the same loadability, can be correspondingly thinner in axial direction; in this way, less material must be used. Advantageously, the spacing between the base member securing section and the cover member securing section and the axial extension of the securing section can be matched to each other such that the annular seal in the circumferential direction can move within certain limits. In this way, movements of the filter element, in particular as a result of pressure fluctuations in the housing, can be compensated. Moreover, with the positional tolerances of the annular seal achieved in this way the installation of the filter element in the housing is simplified.

Advantageously, the cover member securing ring profile can be connected by connecting sections, arranged like spokes of a wheel, with an inner radial fastening ring section that, for fastening the cover member, is attached to the terminal disk and/or the base member. With the fastening ring section, the cover member can be fixedly connected in a simple way with the terminal disk and/or the base member. The spoke arrangement of the connecting sections is stable but still elastic so that in particular movements of the filter element caused by pressure fluctuations in the liquid filter can be compensated in a simple way in the housing. Moreover, liquid can pass without pressure loss through the connecting sections. Incidentally, the spoke arrangement can be optimized with respect to material and weight.

Advantageously, the cover member can be provided between the cover member securing ring profile and the fastening ring section with at least one, in particular annular, support section for supporting the connecting sections with respect to the terminal disk. With the support section the cover member is supported in axial direction and is stabilized with respect to shape and position. The support section can be secured advantageously on the terminal disk so that the stability of the connection of the cover member with the terminal disk is improved. Such an additional fixation of the cover member on the terminal disk has moreover the advantage that the pliers-type engagement of the annular seal by the base member securing section and the cover member securing section is improved. The pressing force that acts upon the pliers-type engagement on the securing section of the annular seal can thus be defined in a better way. The spacing of the base member securing section and of the cover member securing section can be kept constant more easily so that the securing section for an optimally predetermined pressing force cannot slip out of said engagement.

In a further advantageous embodiment, the cover member, in particular the fastening ring section, can form at least partially a receptacle for an inner radial annular seal. Advantageously, the fastening ring section can have a cover section that delimits a receptacle for the inner radial annular seal in a corresponding socket of the terminal disk or the base member in axial direction. This has the advantage that even the inner radial annular seal can be inserted, without being deformed, into the receptacle in axial direction so as to be secured therein after attachment of the cover member.

Advantageously, the cover member can be attached by means of a snap connection, a rotation and/or insertion connection, in particular a screw connection or bayonet connection, an adhesive connection or a weld connection to the terminal disk and/or the base member. A snap connection and a rotation and/or insertion connection can be effected in a simple way without requiring tools. A snap connection can moreover be designed such that, when assembling the components, no attention must be paid with respect to their orientation relative to each other. Rotation and/or insertion connections are stable and can be easily released. Adhesive connections or weld connections are robust for long periods of time. The requirements with respect to shape of the connecting surfaces are lower for adhesive connections or weld connections as compared to snap connection and rotation and/or insertion connections.

The object is solved further with the liquid filter according to the invention in that the seal support in axial direction is at least of a two-part configuration and comprises a base member that is connected fixedly to the terminal disk and further comprises a cover member that is attached to the terminal disk and/or to the base member, wherein the annular seal is inserted or positioned between the base member and the cover member. The features and advantages disclosed above in connection with the filter element according to the invention apply also to the liquid filter.

In the Figures, same components are identified with same reference characters.

DETAILED DESCRIPTION

InFIG. 1, a detail of a fuel filter10of an internal combustion engine12, shown only schematically, of a motor vehicle is illustrated. The fuel filter10comprises a two-part filter housing14that is assembled of a cup-shaped housing pot or housing cup16and a housing cover18. The rim of the housing cup16that is facing the housing cover18is provided with several steps and forms a connecting flange area20that extends in radial direction outwardly. In this context and in the following description, the terms radial and axial refer to a virtual mounting axis21in which direction a filter element42is inserted into the filter housing14and removed from the housing14. On the connecting flange area20, the housing cover18is attached by means of screws22that are distributed uniformly in circumferential direction.

In radial direction, within the connecting flange area20the stepped rim of the housing cup16delimits a clamping area24for an outer radial annular seal26. Coaxial to the mounting axis21, an outlet tube28for filtered fuel passes through the housing cover18into an interior30of the filter housing14that constitutes the clean side of the filter. The outlet tube28is connected with the internal combustion engine12by means of a first fuel conduit32.

An inlet tube34for the fuel to be filtered extends eccentrically and radially within clamping area24through the housing cover18into an annular inlet space36of the filter housing14; this space36constitutes the raw (unfiltered) side. The inlet tube34is connected by means of a second fuel conduit38with a fuel tank40. In the second fuel conduit38a fuel pump is arranged that is not illustrated and is of no interest with respect to the instant invention.

In the filter housing14, the filter element42is arranged in such a way that it separates an opening of the inlet tube34from an opening of the outlet tube28, i.e., the clean-side interior30from the raw-side inlet space36.

The filter element42comprises, as shown inFIGS. 2 to 3, a first terminal disk44that is facing the housing cover18, a second terminal disk that is not illustrated and that is facing the bottom, not illustrated, of the filter housing10. A skeleton-like or grid-like central tube46extends between the first terminal disk44and the second terminal disk. The central tube46is surrounded by a filter medium48in the form of a filter bellows of zigzag-folded nonwoven. The central tube46delimits the interior30of the filter medium48at the clean side.

The terminal disk44has an outlet opening50that is concentric to the central tube46. The outlet opening50is surrounded at the side that is facing the housing cover18with a hollow cylindrical connecting socket52. The coaxial outlet tube28is inserted in the connecting socket52.

On its inner radial circumferential side, the connecting socket52has a sealing step54extending inwardly in the radial direction. An O-ring seal56is resting on the sealing step54and is seal-tightly supported against the inner wall of the connecting socket52and against the outer wall of the outlet tube28.

The filter medium48is surrounded by an annular inlet space58which is in communication with the inlet tube34by means of the raw-side inlet space36. The filter medium48can be flowed through by the fuel to be filtered in radial direction from the exterior to the interior from the annular inlet space58to the interior30.

The terminal disk44and also the filter element42are secured by the seal support60and the annular seal26in the filter housing14.

The seal support60is of a two-part configuration and comprises a base member62and a cover member64.

The base member62has a plurality of supports66by means of which a base member securing ring profile68is connected monolithically with the terminal disk44. Connecting passages69are realized between the supports66and connect the inlet space36with the annular inlet space58.

The base member securing ring profile68has an L-shaped profile. A base leg section16of the base member securing ring profile68extends approximately parallel to the terminal disk44and passes at its inner radial side into the supports66. On the outer radial side of the base leg section70a base member securing section72adjoins. The base member securing section72extends axially relative to the mounting axis21and faces away from the terminal disk44.

The cover member64has a cover member securing ring profile74that has also an L-shaped profile. A cover leg section76of the cover member securing ring74extends parallel to the base leg section70of the base member securing ring profile68. In radial outward direction, the cover leg section76passes into a cover member securing section78that extends in axial direction toward the base member securing ring profile68. Viewed In axial direction, the cover member securing section78is aligned with the base member securing section72.

The free edges of the cover member securing section78and of the base member securing section72delimit a gap80. In the gap80, there is a securing section82of the annular seal26. The base member securing section72and the cover member securing section78engage the securing section82like a pair of pliers in a pliers engagement.

The securing section82is located on the side of the annular seal26that is positioned in radial direction inwardly. It passes in radial direction outwardly into a sealing section84that is approximately of a half moon shape when viewed in profile. The extension of the sealing section84in axial direction is greater than the extension of the securing section82in radial direction. The sealing section84is located in radial direction outside of the base member securing section72and the cover member securing section78. With its inner radial side, the sealing section84is positioned on both sides of the gap80against the base member securing section72and the cover member securing section78. In radial direction inwardly of the pliers-type engagement of the base member securing section72and of the cover member securing section78, the securing section82has a thicker portion86viewed in axial direction. The pliers-type engagement is located radially between the thicker portion86and the sealing section84. The extension of the thicker section86in axial direction is significantly larger than the axial extension of the gap80and prevents that the annular seal26can slide in radial direction out of the pliers-type engagement.

In radial direction inward, the cover member securing ring profile74is formed monolithically with a plurality of connecting sections88that are arranged like spokes of a wheel. The connecting sections88extend to an inner radial fastening ring section90of the cover member64and are monolithically connected thereto. The fastening ring section90has approximately the shape of a cup whose open side is facing the terminal disk44. At its bottom, the fastening ring section90has a through opening92through which the outlet tube28is extending. The fastening ring section90is pushed with its open side onto the connecting socket52. An annular disk section93of the bottom of the fastening section90that surrounds the through opening92in radial direction outwardly projects past the connecting socket52in radial inward direction and forms in this way a boundary of a receptacle, in particular of a seal receptacle94, for the O-ring seal56. The seal receptacle94is moreover delimited by the seal ring step54and an inner radial circumferential wall of the connecting socket52that is extending between the seal ring step54and the annular disk section93.

The cover member64has a hollow cylindrical support section96arranged in radial direction between the cover member securing ring profile74and the fastening ring section90; this support section96is connected monolithically with the connecting sections88. In circumferential direction between two of the connecting sections88, respectively, a connecting intermediate section98extends from the support section96to the cover member securing ring profile74. The support section96is resting with its rim against the exterior side of the terminal disk44.

In radial direction inside of the support section96, on the exterior side of the terminal disk44a hollow cylindrical looking hook ring100is formed. On the free edge of the looking hook ring100a circumferentially extending looking hook102is formed in radial outward direction. In the mounted state, the looking hook102engages the inner radial circumferential wall of the support section96so that a snap connection104between the cover member64and the terminal disk44is realized.

For assembly of the fuel filter10, the terminal disk44together with the base member62is produced separate from the cover member64.

The upper terminal disk44and the lower terminal disk are connected to the folded filter medium48and the central tube46.

The annular seal26and the O-ring seal56are also produced separately. The O-ring seal56is inserted in axial direction from the exterior into the seal receptacle94.

The annular seal26is inserted in axial direction into the base member securing ring profile68in such a way that the thicker portion86of the securing section82is located radially inside the base member securing section72and the sealing section84is positioned radially outside thereof.

Subsequently, the cover member64is mounted in axial direction on the base member62such that the open side of the fastening ring section90is leading. In this connection, the fastening ring section90is pushed onto the connecting socket52and the support section96onto the looking hook ring100. The looking hook102engages the inner radial wall of the support section96so that the cover member64is attached to the terminal disk44. The cover member securing section78of the cover member securing ring profile74engages in the axial direction the securing section82of the annular seal26so that the annular seal26is secured fixedly in the seal support60between the base member securing section72and the cover member securing section78. The bottom of the fastening ring section90closes off the seal receptacle94so that the O-ring seal46is secured therein.

The filter element42is now inserted in axial direction into the housing cup16of the filter housing14until the side of the base member securing ring profile68and the side of the sealing section84of the annular seal26that are facing the terminal disk44are resting against the step of the clamping area24of the housing cup16.

Now the housing cover18is mounted in axial direction on the housing cup16wherein the outlet tube28is inserted through the through opening92and the outlet opening50. The O-ring seal56seals the outlet opening50relative to the outlet tube28. The sealing section84of the annular seal26is clamped seal-tightly between the housing cover18and the step of the camping area24of the housing cup16whereby the sealing section84is elastically deformed.

The housing cover18is secured with screws22on the housing cup16.

In the above described embodiment of a fuel filter10and of a filter element42, the following modifications are possible inter alia.

The invention is not limited to fuel filters of internal combustion engines of motor vehicles. Instead, they can be used also in other types of liquid filters, for example, oil filters or water filters, also outside of automotive technology. The invention can also be used in connection with industrial motors.

Instead of the connecting sockets88, other types of connection between the cover member securing ring profile74and the fastening ring section90can be provided also.

The seal support60can also be designed such that it supports only the outer radial annular seal26. The inner O-ring seal56can be secured separately.

In addition to, or as alternative to, the snap connection104of the cover member64to the terminal disk4, the cover member64can also have a corresponding fixation on the base member62. The support section96can be comprised of separate segments instead of being of a circumferentially closed (continuous) structure.

Instead of the snap connection104, it is also possible to employ a different kind of detachable or non-detachable connection to the terminal disk44, for example, a rotation and/or insertion connection, in particular a screw connection or a bayonet-type connection, an adhesive connection or a weld connection.

The annular seal26can also have a different profile, for example, the thicker portion86can be eliminated.