阅读说明：本技术 过滤装置、过滤元件和适配件 (Filter device, filter element and adapter ) 是由 H·贾内克 A·克林泽 A·韦尔 A·克拉万雅 于 2019-08-16 设计创作，主要内容包括：过滤装置具有空心圆筒形的过滤元件以及旁通阀,所述旁通阀的阀体布置在适配件上,所述适配件布置在所述过滤元件的端侧上。至少一个旁通孔被引入到所述适配件中。(The filter device has a hollow-cylindrical filter element and a bypass valve, the valve body of which is arranged on an adapter piece, which is arranged on the end face of the filter element. At least one bypass hole is introduced into the adapter.)

1. A filter device, in particular a liquid filter device, having a hollow-cylindrical filter element (3) received in a filter housing, which can be traversed radially by a fluid to be purified, surrounds a purification-side cavity (4) and has axial end disks (5, 6), wherein an adapter piece, which is formed separately from the end disks (5, 6) and has an adapter body (14), which can be connected in a sealing manner to the end disks (5) when the filter element (3) is installed in the filter housing and in operation is connected in a sealing manner to the end disks (5) and into which at least one bypass opening (16), which can be closed by a valve body (11) and which is used for bypassing the filter element (3), is introduced, wherein the valve body (11) closes the bypass opening (16) and opens against a spring force when a predetermined pressure difference exists And releasing the bypass opening (16), wherein the adapter comprises a bypass valve (10) with the valve body (11).

2. The filter device according to claim 1, the adapter piece further having a check valve (40) which is arranged in the adapter body (14) downstream of the bypass valve (10), in particular in or at the pipe connection (15), and in particular preferably projects from the pipe connection (15) into an outlet (101) of a housing upper part (202).

3. The filter device as claimed in claim 1, characterized in that a check valve (40) is arranged downstream of the bypass valve (10), wherein a check valve seat (44) is arranged in the valve body (11) of the bypass valve (10).

4. The filter device according to claim 1 or 2, wherein the adapter body (14) overlaps a cavity (4) in the filter element (3) with the bypass valve (10) in a flow-tight manner and has a flow connection section (15).

5. The filter device according to one of the preceding claims, characterized in that the adapter, in particular the adapter body (14), is connected, in particular welded or glued, in a sealing manner releasably or non-releasably to the upper end disk (5) of the filter element (3).

6. The filter device according to any one of the preceding claims, characterized in that the adapter, in particular the adapter body (14), at least partially covers the end side of the filter element (3).

7. The filter device according to one of claims 3 to 6, characterized in that the flow connection section of the adapter, in particular of the adapter body (14), is configured as a pipe connection (15) extending in the axial direction, in particular from the filter element (3).

8. A filter device as claimed in claim 7, characterised in that a sealing ring (20) is fitted onto or a sealing geometry is formed onto the pipe connection (15).

9. The filter device according to one of claims 1 to 8, characterized in that an intermediate tube (9), which is preferably designed separately from the filter element (3) and serves for radial support of the filter element (3), projects into the filter element (3).

10. The filter device according to the preceding claim, characterized in that the intermediate tube (9) has at least one clamping element (18) which projects into the cavity (4) of the filter element (3) and has a radially outwardly directed clamping force for clamping the lower end disc (6).

11. The filter device according to the preceding claim, characterized in that the clamping element (18) overlaps the end disc (6) in the axial direction and projects in particular in the radial direction into the filter medium body of the filter element (3).

12. The filter device according to one of the preceding claims, characterized in that the valve body (11) is fixed in a form-fitting manner in the axial direction on the adapter, in particular on the adapter body (14).

13. The filtering device according to the preceding claim, characterized in that a spring element (12) is loaded to the valve body (11), the spring element being supported on the adapter, preferably by a lower part (21) fixed on the adapter or surrounded by the adapter body (14).

14. The filter device according to one of the preceding claims, characterized in that a sealing element or a nonwoven ring (19) is arranged or formed between the end disc (5, 6) and the adapter, in particular on the upper end disc (5).

15. The filter device according to one of the preceding claims, characterized in that an end disc (5) is connected in a sealed and damage-free releasable or non-damage-free manner to the adapter, in particular to the adapter body (14).

16. Filter element (3), in particular a liquid filter element, for receiving in a filter device according to one of the preceding claims, which can be traversed radially by a fluid to be purified and has axial end disks (5, 6), wherein on the end side of the filter element (3) an adapter having an adapter body (14) can be arranged.

17. Adapter for arrangement on a filter element (3) in a filter device according to one of claims 1 to 15, having a bypass valve (10) with a valve body (11) and an adapter body (14) with at least one bypass opening (16) which can be closed by the valve body (11), wherein the adapter, in particular the adapter body (14), is designed for sealingly connecting to an end disk (5) of the filter element (3), wherein the valve body (11) closes the bypass opening (16) and opens and releases the bypass opening (16) against a spring force in the presence of a predetermined pressure difference.

Technical Field

The invention relates to a filter device, in particular a liquid filter device, a filter element for receiving in the filter device, and an adapter for arranging on the filter element, according to the preamble of claim 1.

Background

DE 102009033263 a1 describes a fuel filter having a hollow-cylindrical filter element which is traversed radially from the outside to the inside by the fuel and which is covered on the end face by an end disk. For stabilization, a grid-like support body is inserted into the interior of the filter element, in which support body a bypass valve with a spring-loaded valve body is accommodated, which closes off the outflow opening of the cylindrical interior in one of the end discs during normal filter operation. In this state, the unfiltered fluid flows through the filter element in the radial direction from the outside to the inside and is discharged from the cavity in the axial direction via the side axially opposite the bypass valve. If the flow resistance is too high due to the filter element being contaminated, the bypass valve opens so that the unfiltered fluid can reach the clean side directly bypassing the filter element.

A similar liquid filter is also described in EP 1199093 a1, which likewise shows a bypass valve in the interior of a hollow-cylindrical filter element, the valve body of which is subjected to a force by the force of a spring element toward the opening in the end disk of the filter element.

Disclosure of Invention

The object of the invention is to provide a filter device having a hollow-cylindrical filter element and an integrated bypass valve, which can be used in a versatile manner in a simple manner.

This object is achieved according to the invention by the features of claim 1 and the dependent claims. The dependent claims indicate suitable developments.

In a preferred embodiment, therefore, a filter device is proposed, which has a hollow-cylindrical filter element received in a filter housing, the filter element can be traversed in the radial direction by the fluid to be purified, surrounds the purification-side cavity and has an axial end disk, wherein an adapter piece which is preferably designed separately from the end disk is arranged on the end face of the filter element, the adapter is preferably further capable of being sealingly connected to the end disk when the filter element is installed in the filter housing and is sealingly connected to the end disk during operation and has at least one bypass opening that can be closed by the valve body for bypassing the filter element, wherein the adapter comprises a bypass valve with a valve body, wherein the valve body closes off the bypass opening and opens and releases the bypass opening against a spring force in the presence of a predetermined pressure difference. The bypass opening is preferably arranged in an adapter body which forms the main component of the adapter and supports the other functional components and can provide a sealing surface or seal which seals against the filter element and/or the housing.

The filter device according to the invention is used for filtering a fluid, preferably a liquid such as lubricating oil or fuel. If necessary, the filter device can also be used for filtering gaseous fluids. The filter device has a hollow-cylindrical filter element which is received in a filter housing and through which a fluid to be purified flows in the radial direction. The flow direction preferably occurs radially from the outside to the inside.

The inner cavity in the filter element forms a flow chamber which, when flowing through from the outside to the inside in the radial direction, represents the clean side from which the cleaned fluid flows out in the axial direction. The two opposite end sides of the filter element are each covered by an end disk, wherein a flow opening for axially transferring the purified fluid to an outlet opening from the filter device is introduced into at least one of the end disks. The filter medium body of the filter element is designed, for example, as a pleated filter and consists of paper or nonwoven.

Preferably, a bypass valve or a bypass valve is integrated into the filter system at the adapter piece, the valve body of which is loaded by a spring element with a force in the closed position. In a normal operating mode, the bypass valve is closed: the valve body closes a bypass opening between an inner cavity in the filter element and a space surrounding the filter element for unfiltered fluid, the so-called unfiltered fluid. If the pressure in the unfiltered fluid rises above a threshold value relative to the pressure on the clean side, for example if the filter element is blocked, the valve body is adjusted from the closed position into the open position against the force of the spring element acting thereon, as a result of which the bypass is released and unfiltered fluid can flow off directly from the unfiltered side to the clean side bypassing the filter medium body. In a normal mode, during normal filtering operation at a pressure in the unfiltered fluid below the threshold value, the bypass valve is closed so that the unfiltered fluid flows through the filter media body of the filter element.

On the end face of the filter element, an adapter piece is preferably arranged, which is preferably designed separately from the end disk and has an adapter body as a main or supporting component, wherein the adapter body of the adapter piece supports the bypass valve, so that the adapter body and the bypass valve together form at least one structural unit (i.e., an adapter piece), wherein the bypass valve or the valve body of the bypass valve is arranged on the adapter body. Preferably, the adapter body forms a valve seat against which the valve body of the bypass valve or bypass valve seals in the closed state. The adapter can limit the adjustment travel of the valve body in the closed position of the valve. Furthermore, the adapter body has a flow connection section, by means of which the interior space in the hollow cylindrical filter element can be connected to a connection line or a connection tube for a fluid. The adapter thus has a dual function: on the one hand, the adapter part is connected to the valve body of the bypass valve as a structural unit, wherein the valve body is subjected to a force by the force of the spring element in the direction of the bypass opening in the adapter part, and on the other hand, a flow is guided between the interior space in the filter element and the connecting line by the flow connection section of the adapter part. The bypass opening in the adapter body is preferably radially outside the flow connection section.

Due to this configuration of the adapter, in the normal mode, when the bypass valve is closed, flow guidance can be carried out and through the bypass valve on the same end face of the filter element. The filter device can thus be used, for example, as an oil filter in a suspended position, with its end projecting, for example, into an oil sump in an oil sump, when the longitudinal filter axis extends vertically, without the risk that: the heavily contaminated oil passes directly from the unfiltered side to the clean side from the bottom of the oil sump when the bypass valve arranged at the upper end of the oil filter is open. The bypass valve is adjacent to the overlying end disc of the filter element. When passing through the filter element from the outside to the inside in the radial direction, the interior space in the hollow-cylindrical filter element forms a clean side from which the cleaned fluid is discharged in normal operation via the flow connection section of the adapter.

The adapter is arranged on the end face of the filter element and overlaps the inner cavity. The flow connection section preferably extends as a pipe connection in the axial direction and can be used for connecting a further line, through which the purified fluid can be discharged. The pipe connection advantageously receives a circumferential sealing element for a flow-tight connection to another pipe or a mating part. The sealing element can be configured as an O-ring, a rectangular seal or a sealing lug. As the material, for example, an elastomer or a nonwoven fabric can be used. Alternatively, the sealing element can also be formed directly on the pipe connection, for example by two-component injection molding, or be formed integrally with the adapter material.

At least one, advantageously several bypass openings in the end adapter body or adapter piece are preferably located radially inside the diameter of the inner cavity in the filter element, so that upon opening of the valve body a direct flow connection exists between the space surrounding the end of the filter element and the inner cavity. The bypass opening is at the same time located radially in the region of the outer diameter of the outlet pipe connection or completely outside the pipe connection. In a preferred arrangement, the plurality of openings are arranged annularly at radial intervals around the pipe connection. With the valve body open, unfiltered fluid flows through the bypass opening into the cavity, from which unpurified fluid can be discharged in the axial direction via the pipe connection on the adapter.

The valve body is clamped, for example, positively on the adapter body or on a lower part of the bypass valve connected to the adapter body, for example, on the adapter body or the lower part, wherein an axial relative movement of the valve body is possible for the opening and closing movement to be able to be performed.

The adapter is placed onto the end face of the filter element and overlaps the cavity in the filter element in a flow-tight and fluid-tight manner. According to an advantageous embodiment, the adapter or adapter body simultaneously forms one of the end disks; in this case, the adapter body can be bonded or glued to the end face of the filter element. In an alternative embodiment, the adapter can be connected to the end disk of the filter element in a non-releasable manner, in particular by welding, for example by means of mirror welding, to the end face of the filter element.

However, an embodiment of the adapter part and the end disk is also possible in which the separate adapter part or the adapter body overlaps the end disk completely or partially in the radial direction. Between the end disk on the end side of the filter element and the inserted adapter or adapter body, a sealing element or nonwoven ring can be arranged, which is arranged directly adjacent to the flow opening in the end disk and thus to the cavity in the filter element. The sealing element or the nonwoven loop can optionally have an L-shaped cross section and project axially into the cavity. The sealing element or the nonwoven loop prevents that a fault flow between the end disc and the adapter can occur between the environment and the cavity in the normal mode. The sealing element or the nonwoven loop can also be designed as an adhesive layer, with which the adapter is glued to the end face of the filter element.

In an advantageous embodiment, the adapter has means for a form-locking connection, in particular a releasable and non-releasable snap connection, with the housing. For this purpose, projections such as lugs or webs on the housing in the region of the outlet interact in such a way with latching hooks on the adapter in order to prevent or prevent the adapter from being pulled out of the outlet. The connection means may be designed such that the adapter is received either without axial play or alternatively with a predefined axial play in the housing, so that the adapter is allowed to move in the housing in the axial direction within a defined range of travel.

In an advantageous embodiment, the filter device has a check valve which, in normal operation, is opened by the applied pressure difference and allows an unobstructed fluid flow. In the event of no pressure difference acting on the filter device, for example in the case of an oil filter of an internal combustion engine in the motor-off state, the check valve and the bypass valve are closed. The filtered fluid cannot flow back to the unfiltered side.

If the filter element has too great a flow resistance, for example due to contamination, the bypass valve opens.

In the maintenance situation, the filter element is moved downwards after opening the cover. By virtue of the connection of the filter element and the adapter, the adapter is also pulled downward until the connection of the housing and the adapter does not allow further movement. The check valve remains closed.

In the case of a positive-locking connection with axial play, the sealing point between the housing and the adapter can be released, so that the fluid can flow downstream of the check valve.

In a preferred embodiment, the adapter furthermore has a check valve which is arranged downstream of the bypass valve in or on the pipe connection and particularly preferably projects from the pipe connection into the outlet of the housing upper part.

In an alternative embodiment, a check valve is arranged downstream of the bypass valve, wherein a check valve seat is formed in the valve body of the bypass valve, so that the unit consisting of bypass valve and check valve can be formed in a particularly space-saving manner, in particular in the axial direction, so that the filter device can be arranged compactly. The check valve seat and the valve body here preferably form a structural unit, in particular the check valve seat and the valve body can be formed in one piece.

In this embodiment, the check valve body is supported by a check valve spring which is received on the opposite side in a check valve cover which is connected to the pipe connection, preferably formed in one piece with the pipe connection. The check valve is designed such that it opens in the operating direction during the through-flow through the filter element and closes, for example, when the oil flow is stopped, in order to prevent a backflow in the opposite direction.

In a further advantageous embodiment of the filter device, the check valve spring is supported on the valve body of the bypass valve on the opposite side of the check valve body, so that possible changes in the position of the valve body of the bypass valve received in the adapter have no effect on the switching behavior of the check valve, since the distance between the check valve body and the spring receptacle for the check valve spring on the valve body and the spring prestress of the check valve spring remain unchanged.

In the filter element, a support tube or an intermediate tube can be arranged, the wall of which has sufficiently large through-flow openings for the radial through-flow of the filter element not to be impeded. The intermediate tube imparts additional stability to the filter element. At the same time, the intermediate tube can be used to fix and axially support the adapter.

In a further advantageous embodiment, the intermediate tube has at least one clamping element which projects into the cavity of the filter element and connects the intermediate tube to the filter element in a form-fitting or force-fitting manner and is fixed axially to the filter element. For example, a plurality of clamping elements can be formed on the intermediate tube in a distributed manner over the circumference in order to clamp the intermediate tube to the filter element with a uniform force distribution. The clamping element advantageously overlaps the end disk in the axial direction and projects radially into the filter medium body of the filter element or the filter element.

The clamping elements on the adapter apply a radially outwardly directed force to the filter medium body or to the material of the end disk, which extends in the axial direction slightly into the material of the filter medium body.

The filter device can be constructed in a two-part construction by: the housing component forms a first structural unit with the intermediate pipe and the filter element and the adapter forms a second structural unit with the bypass valve, wherein the two structural units can be assembled during the first installation and then the filter device can be assembled by connection to the housing upper part.

The unit pre-assembled with the present invention can be pre-fabricated prior to assembly of the filtration device. It is thus possible to provide a unit consisting of an adapter part with a bypass valve and, if appropriate, a check valve and a filter element, which is first connected to the cover and then screwed into the housing part together with the cover.

If there is sufficient axial play between the adapter and the housing in the region of the connecting mechanism, the unit consisting of the housing cover, the filter element, the adapter with the bypass valve and, if appropriate, the check valve can be clamped into the housing in a first step and secured against falling out before the cover is screwed rotationally onto the housing in a second step and the filter device is closed.

Drawings

Further advantages and suitable embodiments can be gathered from the further claims, the description of the figures and the drawings. Wherein:

fig. 1 shows a section of the individual components of a filter device designed as an oil filter after assembly, with a hollow-cylindrical filter element and with a receiving housing component and an intermediate pipe, wherein an adapter with a bypass valve and a check valve is slipped onto the filter element at the end;

FIG. 2 shows a cross-section of a slightly modified embodiment of the filter device of FIG. 1;

fig. 3 shows an alternative embodiment in which a non-return valve is arranged in the adapter part of the filter device.

In the drawings, like components are provided with like reference numerals.

Detailed Description

Fig. 1 and 2 show a filter device 1 embodied as an oil filter, which has a housing component 2 embodied as a cover, which is part of a filter housing and is screwed into a housing upper part 200 from below. Furthermore, a filter element 3 is provided which can be inserted into the housing component 2 and which is of hollow cylindrical design and is traversed in the radial direction from the outside to the inside by the fluid to be purified. The filter element 3 has a cavity 4 in the interior, which forms the clean side of the filter element. End discs 5, 6 are located on both end sides of the filter element 3, which end discs close the filter medium body of the filter element 3 in an axially flow-tight manner. The filter medium body is preferably designed as a star-folded bellows made of paper or nonwoven.

The housing component 2 is designed as a screw-in unit which forms a cover and has teeth on the outside which allow the housing component 2 to be screwed into the housing upper part 200 from below. In the bottom region of the housing component 2, there is preferably an overflow screw 7, which is preferably also in flow connection with the cavity 4 in the filter element 3 in the installed state. With unscrewing of the overflow hole screw 7, the oil that has accumulated in the housing member 2 and in the cavity 4 can be drained. In the installed state, the filter device 1 assumes the position shown in the figures, in which the filter longitudinal axis 8 extends at least almost vertically.

Furthermore, the filter device 1 comprises an intermediate tube 9 which, in the installed state, projects into the cavity 4 of the filter element 3 and additionally stabilizes the filter element. The intermediate tube 9 rests against the inner wall of the cavity 4 and has large flow openings through which the fluid can pass when passing through the filter element. The intermediate tube 9 is clamped to the bottom of the housing component 2, for example by means of a latching mechanism.

An adapter piece having an adapter body 14 is placed on the upper end face of the filter element 3, which adapter piece is preferably connected in a sealing manner to the upper end disk of the filter element 3 in the ready-to-operate state. As shown in the figures, the upper end disk 5 preferably has a radial sealing surface (no reference numeral) radially inward, which furthermore preferably rests in a sealing manner as shown on a cylindrical sealing contact surface (no reference numeral) of the adapter body 14. The adapter is equipped with a bypass valve 10 which, in the open state, connects the unfiltered side directly to the clean side, so that the fluid enters the cavity 4 directly, bypassing the filter medium body. The bypass valve 10 comprises a valve body 11, which is clamped in an axially adjustable manner on the intermediate pipe 9, and a spring element 12, which is, for example, a valve spring, is preferably and, as shown in the figures, supported on a lower part 21 of the bypass valve 10 and axially loads the valve body 11 in the direction of the closed position. Alternatively, the spring element can be formed integrally with the valve body from an elastic material. The lower part 21 is preferably also latched to the adapter body 14 by means of the hook-shaped section 13 with radially outwardly directed hook lugs, as shown in the drawings, by: the hook-shaped section 13 engages behind a support 35 extending in the circumferential direction on the adapter body 14. This allows the valve body 11 to perform an axial adjustment movement relative to the adapter body 14 between its closed position and its open position, while the valve body 11 is clamped in a loss-proof manner on the adapter body 14 in the axial direction. In the installed state, the valve body 11 and the spring element 12 are preferably located in the cavity 4 of the filter element 3, thereby minimizing the installation space requirement.

The adapter part, as shown, comprises the adapter body 14 and, on the one hand, the bypass valve 10 as a structural or assembly unit and, on the other hand, a pipe connection 15, preferably formed in one piece and made of a uniform material, on the adapter body 14, which establishes a flow connection between the cavity 4 in the filter element 3 and a discharge line or a discharge pipe to be connected to the pipe connection 15. The adapter body 14 rests, for example, on the upper end disk 5 of the filter element 3 and optionally covers the end disk 5 at least partially, if appropriate completely. The adapter piece which closes the cavity 4 upward has a bypass opening 16 in the region of the outer circumference or radially outside the pipe connection 15 extending in the axial direction, but radially within the diameter of the cavity 4. The cavity 4 can communicate with the surrounding space through a bypass hole 16 in the adapter body 14.

The bypass opening 16 in the adapter body 14 is closed in normal operation by the valve body 11, which has a central recess 17, through which the cavity 4 communicates with the pipe connection 15, but is formed on its end face in the manner of an annular gasket, which axially abuts against the inner side of the adapter body 14 and closes the bypass opening 16. The valve body 11 preferably has, as shown in the drawing, a likewise annular gasket-like valve sealing ring 22 for abutment against an adapter piece and for sealingly closing the bypass opening 16. The valve sealing ring 22 can be formed, for example, from an elastomer or a nonwoven fabric. If the pressure in the unfiltered fluid on the outer side of the filter element 3 exceeds a limit value or threshold value (for example if the filter element is blocked), the valve body 11 is axially displaced by the unfiltered fluid in the open position against the force of the spring element 12 acting thereon, whereupon the unfiltered fluid can flow through the opened bypass opening 16 into the cavity 4 in the filter element 3 and can be discharged therefrom through the pipe connection 15.

The intermediate tube 9, which can preferably be separated from the filter element 3 but can also be formed integrally as part of the filter element 3, has a cylindrical sealing contact surface (no reference numeral) on the side axially opposite the pipe connection 15 and, if it abuts against it, preferably a clamping element 18, which projects into the cavity 4 and directly abuts against the inner wall of the filter medium body of the filter element 3, which delimits the cavity 4. The clamping element 18 has, on its radially outer side, a clamping lug which projects beyond the material of the lower end disk 6 and hooks there. In this way, the filter element 3 is reliably clamped in its axial position on the intermediate tube 9. As shown in the figures, the lower end disk 6 preferably has a radially inner radial sealing surface (no reference numeral) which bears sealingly against a cylindrical sealing contact surface (no reference numeral) of the intermediate pipe 9.

If necessary, the central tube 9 can be connected to the filter element by means of adhesive bonding, wherein in this case the clamping element 18 can be dispensed with.

If necessary directly adjacent to the opening of the cavity 4, an annular sealing element or a nonwoven ring can be placed on the upper end disk 5 for supporting the radial sealing surface (the sealing element is not shown in the figures).

The intermediate pipe 9 has an end which sealingly closes the lower end disk 6 and which has a particularly central discharge pipe connection with a preferably outwardly directed radial seal 71. The outlet screw 7 sealingly closes the housing part 2 with a screw-side radial seal 72, which radially abuts against a cylindrical sealing abutment of the housing part 2 on the inside. The outlet screw preferably has a central cylindrical recess which is open towards the interior of the housing and which receives the outlet nipple of the intermediate pipe 9 and provides a hollow cylindrical sealing contact surface for the radial seal 71 on the intermediate pipe side. The screw-side radial seal 72 is preferably arranged axially at the level of the sealing contact surface for the intermediate tube-side radial seal 71.

An outer sealing ring 20 is fitted onto the pipe connection 15 of the adapter body 14, said sealing ring being inserted into a circumferential groove on the pipe connection 15. The pipe connection 15 is inserted in a sealing manner into the outlet 101 of the housing upper part 200, wherein a flow-tight or fluid-tight connection between the pipe connection 15 or the adapter body 14 and the housing upper part 200 is ensured by the sealing ring 20. Alternatively, the sealing ring situated on the housing part upper part 200 can seal against the pipe connection 15 or the adapter body 14.

Furthermore, the adapter part preferably comprises, as shown in fig. 1 and 2, a check valve 40, which is arranged downstream of the bypass valve 10 on the clean side and in or at the pipe connection 15 and preferably projects from the pipe connection 15 into the outlet 101, as shown in fig. 1 and 2. For this purpose, the pipe connection 15 preferably has, at its axial end facing away from the filter element 3, a check valve seat 44 against which the check valve body 41 rests in a sealing manner by means of a check valve spring 42, which is supported on the opposite side by a check valve cover 43 connected to the pipe connection 15. The check valve 40 is designed such that it opens in the operating direction during the through-flow through the filter element 3 and closes, for example, when the oil flow is stopped, in order to prevent a backflow in the opposite direction.

In an alternative embodiment of the filter device 1 according to fig. 3, a check valve 40 is arranged downstream of the bypass valve 10 on the clean side, wherein the check valve seat 44 is arranged in the valve body 11 of the bypass valve 10. The check valve body 41 rests in a sealing manner against a check valve seat 44 by means of a check valve spring 42, which is supported on the opposite side by a check valve cover 43 connected to the pipe connection 15, preferably formed integrally with the pipe connection 15. In this embodiment, the non-return valve 40 is arranged in a space-saving manner inside the adapter and is designed such that it opens in the operating direction during the through-flow through the filter element 3 and closes, for example, when the oil flow is stopped, in order to prevent a return flow in the opposite direction.

In a further embodiment of the filter device 1, which is not shown here and is similar to the embodiment shown in fig. 3, the check valve spring 42 is supported on the valve body 11 of the bypass valve 10 on the opposite side of the check valve body 41, so that possible changes in the position of the valve body 11 of the bypass valve 10 received in the adapter have no effect on the switching behavior of the check valve 40, since the distance between the check valve body 41 and the spring receptacle for the check valve spring 42 on the valve body 11 and thus the prestress of the check valve spring 42 remain unchanged.

The adapter, in particular the adapter body 14, preferably has at least one latching hook 31 which can interact with a lug or a separating strip 30 in the outlet 101 in such a way that the adapter is prevented or prevented from being pulled out of the outlet 101.

In the embodiment of fig. 1, the latching hook 31 is designed such that it clamps the adapter part substantially without axial play in the outlet 101. "without axial play" means in this respect that the position of the adapter does not change so significantly that the sealing ring 20 can slip. The fluid in the outlet 101 therefore remains in the outlet when the filter element 3 is removed, since the adapter is also held in the outlet in a sealing manner by the latching hook 31. The separation between the unfiltered side and the clean side therefore also continues on the adapter during the replacement of the filter element. In this embodiment, the bypass valve 10 also seals when the filter element 3 is removed during a filter element replacement.

In the embodiment of fig. 2 and 3, the latching hook 31 is designed such that it clamps the adapter part with axial play in the outlet 101. By "with axial play" is meant in this respect that the position of the adapter can be varied in such a way that the sealing ring 20 is disengaged when the adapter is moved axially downwards. The fluid in the outlet 101 can thus flow out of the outlet 101 when the filter element 3 is removed, so that a small amount of fluid remains in the system when it is replaced. A snap-free embodiment can also be considered, in which case the adapter piece can be removed together when the filter element 3 is replaced, for example to replace the seal 20, if necessary. The selection between variants can be made application-specifically according to a function prioritization.

In the variant shown in fig. 1 to 3, the intermediate tube 9 is preferably connected to the lower housing component 2 by means of a snap connection 32, so that the intermediate tube 9 is pulled out together when the housing component 2 is released. The lower end disk 6 is furthermore preferably designed such that it has a higher holding force in the axial direction relative to the central tube 9 than the upper end disk 5 has relative to the adapter body 14. This can be done, for example, by: the fit of the radial seal against the cylindrical sealing abutment between the lower end disc 6 and the intermediate tube 9 is designed to be more secure than the fit of the radial seal against the cylindrical sealing abutment between the upper end disc 5 and the adapter body 14. As an alternative or in addition, it can be provided, as in the embodiment shown, that the lower end disk 6 is designed such that it engages behind the clamping element 18.

In the variant shown in fig. 2 and 3, the engagement of the radial seal with respect to the cylindrical sealing contact surface between the upper end disk 5 and the adapter body 14 is preferably designed such that the holding force in the axial direction, in particular caused by friction, is greater than the holding force, in particular caused by friction, between the outlet 101 and the seal 20. It can thus be ensured that, during disassembly, the seal 20 is disengaged and fluid can flow out of the outlet 101.