Filter device, in particular for gas filtration

A filter device with filter housing and housing cover has a filter element disposed therein. A first holding part on the filter element projects past an outer wall surface of the filter element. A second holding part in the form of a counter holding part on the housing cover interacts with the first holding part. The first and second holding parts engage each other in a mounted state of the filter element. A first form-fit part is arranged on the filter element axially spaced from the first holding part and is associated with a second form-fit part in the form of a counter form-fit part. The first form-fit part and the first holding part, by rotational movement of the filter element about a longitudinal axis of the filter element, are each transferable into a form-fit engaged state with the counter holding part and the counter form-fit part, respectively.

BACKGROUND OF THE INVENTION

The invention concerns a filter device, in particular for gas filtration, for example, an air filter for internal combustion engines, comprising a filter element that is received in a filter housing which is closable by a housing cover, wherein on the filter element a holding part is arranged that projects past the outer wall surface and has correlated therewith a counter holding part on the housing cover and the holding parts engage each other in the mounted state. The invention concerns also a filter element receivable in the filter device.

Air filters for motor vehicles for filtration of the combustion air to be supplied to an internal combustion engine of a vehicle are known. Such an air filter as described, for example, in DE 20 2005 020 099 U1, comprises a hollow-cylindrical filter element which is flowed through radially from the exterior to the interior by the combustion air to be purified, wherein the clean air is discharged axially. The filter element is received in a filter housing and, according to DE 20 2005 020 099 U1, is secured by a clamping and locking action on a counter holder on the inner side of the housing cover by means of a holding part, which is formed monolithically with an end-face end disk of the filter element and is projecting radially past the wall surface of the filter element. In this context, the holding part during the insertion movement of the filter element is axially locked with the counter holder.

SUMMARY OF THE INVENTION

The invention has the object to configure a filter device with simple constructive measures such that the filter element is securely held and can be exchanged in a simple way.

This object is solved according to the invention in that on the filter element, at an axial spacing to the holding part, a form-fit part is arranged that has correlated therewith a counter form-fit part, wherein the form-fit part and holding part by means of a rotational movement about the longitudinal axis of the filter element are transferable into a form-fit engaged state. The dependent claims provide expedient further embodiments.

The filter device according to the invention is used for filtration of a fluid, in particular a gas, wherein optionally also liquid media can be filtered. Preferably, the filter device according to the invention is used as an air filter for motor vehicles, in particular for an internal combustion engine or for the fresh air to be supplied to the interior of the motor vehicle.

In the mounted state, the filter element received in the filter device is secured on at least one location on the filter housing cover. A second location is provided either on the filter housing or also on the filter housing cover.

In one embodiment with a fixation of the filter element exclusively in the housing cover, tolerances and relative movements between housing and cover can be disregarded when designing the element fixation so that a narrower tolerance configuration of the connecting devices and the sealing device between filter element and housing cover is possible. In a service situation, the filter element, held within the cover, can be removed from the housing in a simple way. Removal of the filter element from the cover is possible in a simple way outside of the installation environment of the air filter device.

The filter device comprises a filter element that can be flowed through by the fluid to be purified and is received in a filter housing which can be closed off by a housing cover. On the filter element, a holding part is arranged that projects past the outer wall surface of the filter element and has correlated therewith a counter holding part on the housing cover. In the mounted state, the holding parts on the filter element and on the housing cover engage each other so that a first holding or fixation point for holding the filter element on the housing cover is provided.

Moreover, the filter element comprises a further connecting location relative to the housing or the housing cover. This is realized by means of a form-fit part that is arranged with axial spacing relative to the holding part on the filter element and has correlated therewith a counter form-fit part. The counter form-fit part is located preferably on the housing cover wherein optionally also an arrangement of the counter form-fit part on the filter housing is conceivable. As a result of the axial spacing between the holding part and the form-fit part that are both arranged on the filter element, the filter element is secured by two different axially spaced apart connecting locations on the housing or on the housing cover.

For holding and locking the filter element on the housing cover or filter housing, a rotational movement about its longitudinal axis is imparted onto the filter element. The rotational movement of the filter element transfers the holding part as well as the form-fit part on the filter element into the locking position in which both parts are form-fittingly engaging the correlated counter holding part or counter form-fit part provided on the housing or on the cover. The form fit on the holding part as well as on the form-fit part is thus produced by the same rotational movement about the longitudinal axis of the filter element. In a corresponding way, form fit for removal of the filter element from the housing cover or filter housing can be canceled again by a rotational movement in the opposite direction.

The filter element is preferably embodied to be hollow-cylindrical and is flowed through radially from the exterior to the interior by the fluid to be purified. The externally positioned wall surface forms the raw side, the interior the clean side from which the purified fluid is discharged axially. For insertion and mounting, the filter element is moved axially into its mounting position and subsequently rotated about its longitudinal axis so far that the holding part and the form-fit part on the filter element move into form-fit position with the correlated counter holding part or counter form-fit part on the housing cover or filter housing. In this connection, it may be expedient to embody at least one of the locking devices like a bayonet closure in which, during the rotational movement, parts on the filter element and on the housing cover or filter housing lock form-fittingly with each other in such a way that form fit is provided in axial direction. For example, the form-fit part on the filter element can be designed as a bayonet closure. It is however also possible, additionally or alternatively, to lock the holding part like a bayonet closure on the housing cover or filter housing.

According to a further expedient embodiment, the filter element on at least one axial end face, optionally on both axial end faces, is provided with an end disk, respectively, that is comprised, for example, of plastic material and is connected fixedly with the filter medium of the filter element. The end disks can be supports of the holding part and/or of the form-fit part on the filter element; optionally, the holding part and/or form-fit part is formed monolithically with the respective end disk. In this context, the holding part projects radially past the wall surface of the filter element while the form-pit part does not mandatorily project radially past the wall surface of the filter element but optionally is positioned within the wall surface and projects only in axial direction past the surface of the end disk. The form-fit part is, for example, designed as a pocket which optionally is arranged at the axial end face of the end disk wherein the counter form-fit part on the housing or the cover is provided with a locking element that upon rotational movement of the filter element moves into the pocket. The counter form-fit part has for this purpose a contour that is complementarily embodied to the pocket on the filter element and that moves circumferentially into the pocket that is open at one end, wherein the rotational movement is limited in that the counter form-fit part impacts on the inner wall at the other end of the pocket.

Alternatively, the form-fit part can be embodied on an end disk as a contour, for example, in the form of hooks, which complementarily engages counter form-fit parts that are designed as pockets.

The holding part on the filter element can be formed as a locking hook which is projecting radially past the filter element and in the mounted position projects into a locking tab which forms the counter holding element on the housing cover. In this context, it can be expedient that, on the locking hook, at least one elastic springy contact part is formed that in the mounted state loads the locking tab on the housing cover with a clamping force so that the locking hook is held securely at the locking tab. The elastic springy contact part is in particular formed monolithic with the locking hook. In an alternative embodiment, the holding part on the filter element can be designed as a locking tab while a locking hook is embodied on the housing or housing cover.

In order to prevent accidental release of the filter element by return rotation about the longitudinal axis of the filter element, according to a further advantageous embodiment an elastic snap lever is provided at the housing or the cover which is resting in the mounted state on a locking projection at the circumferential side of the filter element. The snap lever can be arranged on the inner side of the housing cover or optionally also immediately on the filter housing. The snap lever which is advantageously formed monolithic with the housing cover or the filter housing acts elastically in radial direction and projects with a clamping force radially into the locking projection on the circumferential side of the filter element. In the mounted state a release of the filter element is precluded in this way. The latter can be removed only once the snap lever has been manually bent open elastically so that the snap lever is disengaged from the locking projection on the circumferential side of the filter element and the filter element can be rotated back so far about its longitudinal axis that the form fit between holding part and counter holding part as well as between form-fit part and counter form-fit part is canceled; subsequently, the filter element can be removed axially.

In an alternative embodiment, an elastic snap lever is provided on the end disk which in the mounted state locks at a locking projection on the inner side of the housing cover or of the housing. The snap lever which is advantageously formed monolithic with the end disk acts elastically in radial direction and projects with a clamping force radially into the locking projection on the housing wall or the housing cover wall.

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

DESCRIPTION OF PREFERRED EMBODIMENTS

In the Figures, an air filter for the internal combustion engine of a motor vehicle is illustrated as an embodiment. The filter device1embodied as an air filter comprises a hollow-cylindrical filter element4in a filter housing2(FIG. 1a) which is flowed through by the fluid to be purified radially from the exterior to the interior. The air to be purified flows through a lateral inlet E into the air filter housing2. The discharge of the purified fluid is realized axially via the inwardly positioned clean chamber through the outlet A of the housing cover3(FIG. 1b). The filter element4is secured by axially spaced apart holding and form-fit elements on a housing cover3which is attachable to the filter housing2.

As can be seen inFIG. 1bin connection withFIG. 2, a holding part7is located on an end face of the filter element4and is provided in particular monolithic with an end disk6of plastic material that is attached to the end face of the filter medium of the filter element4. The holding part7is designed as a locking hook which is projecting radially past the wall surface of the filter element4. The holding part7has correlated therewith a counter holding part8which is designed as a locking tab and is arranged on the inner side of the housing cover3. On the holding part7elastic springy contact parts10are integrally formed which in the mounted state press against the counter holding part8and in this way provide for an increased frictional connection between holding part7and counter holding part8. As can be seen inFIG. 2together withFIGS. 3 and 4, on the holding part7on the filter element4two elastic springy contact parts10are formed between which the counter holding part8is received. Upon placement of the housing cover3onto the filter housing2, a securing rib16on the filter housing2secures the connection against release.

InFIGS. 3 to 5, the filter element4is illustrated in different perspective views. The filter element4is hollow-cylindrical and has a longitudinal axis5. At the end faces, the filter element4is framed by an end disk6or9, respectively.

The holding part7is embodied monolithic with a first end disk6on the filter element4and projects, in particular in radial direction, past the outer wall surface of the filter element. In the area of the oppositely positioned end disk9, there are a total of three form-fit parts11uniformly distributed about the circumference which are formed monolithic with this end disk and, as can be seen in the enlarged illustration according toFIG. 6, are designed pocket-shaped. Each pocket-shaped form-fit part11on the filter element4is limited in circumferential direction by a wall while the side of the pocket11which is positioned opposite the circumferential wall is embodied to be open. This makes it possible that a complementarily formed counter form-fit part13(FIGS. 7, 8) at the inner side of the housing cover3can move via the open side of the pocket11into the latter until it hits the circumferential wall12.

Accordingly, in the area of both axially oppositely positioned end faces of the filter element4, holding or form-fit parts7,11are provided which, upon rotational movement of the filter element4about its longitudinal axis5, move into a form-fit connection with the correlated counter holding part8or counter form-fit part13on the housing cover3. In the area of the end disk6there is only a single holding part7while in the area of the oppositely positioned end disk9a total of three form-fit parts11uniformly distributed about the circumference are provided. Accordingly, as shown inFIG. 7, on the inner side of the housing part3a total of three counter form-fit parts13uniformly distributed about the circumference are provided also.

The counter form-fit part13on the inner side of the housing cover3, as can be seen in the enlarged illustration according toFIG. 8, is embodied as an axially projecting and circumferentially extending projection which is inserted into the pocket11with the rotational movement upon mounting of the filter element.

As can be seen inFIG. 7together withFIGS. 9 through 12, on the inner side of the housing cover3an elastic springy snap lever14is formed which in radial direction of the filter element4is springy and secures the mounted filter element4in its locked rotational position. On the circumferential side of the end disk6on the filter element4, there is a locking projection15(FIGS. 10, 12) on which the snap lever14is resting lockingly when the filter element4is closed or locked. Accordingly, in the closed position of the filter element4(FIGS. 9, 10), the rotational position of the filter element is secured and an accidental release of the filter element is precluded.

For removal of the filter element4from the housing cover3, the snap lever14must be manually moved out of its locked position radially outwardly so that the snap lever14is disengaged from the locking projection15and the locking form fit in circumferential direction is canceled. Subsequently, the filter element4can then be rotated back about its longitudinal axis until the form-fit part11disengages the counter form-fit part12and the holding part7also disengages the counter holding part8. Subsequently, the filter element4can be removed axially.

The insertion of the filter element4into the housing cover3is realized in the reverse sequence wherein the snap lever14will locked automatically. Accordingly, the filter housing cover3and filter element4form a unit that is easy to handle and can be simply joined with the filter housing2to a filter device1. Upon installation of the unit of filter housing cover/filter element in the filter housing2, the housing-fast securing rib16additionally secures the connection of holding part7and counter holding part8because, due to the interaction of holding part7and securing rib16, a rotational movement of the filter element4about its longitudinal axis is prevented.

The fixation of the filter element4in the air filter is realized in the illustrated embodiment exclusively in the filter housing cover3. Accordingly, component tolerances and component movements in operation and component changes due to heat and moisture between filter housing2and filter housing cover3must not be taken into consideration in designing the attachment and sealing action of the filter element4.