RING FILTER ELEMENT AND LIQUID FILTER UNIT

Description

[0001] The present invention relates to a ring filter element with an upper end disk, a lower end disk and a filter material arranged between them, according to the preamble of claim 1. The invention further relates to a liquid filter device with a filter housing having an idle channel and such a ring filter element arranged in the filter housing.

[0002] From EP 1 229 985 B1 a generic ring filter element is known with an upper end disk, a lower end disk and a pleated star arranged between them, as well as with a pin arranged eccentrically on the lower end disk and projecting in the axial direction.

[0003] From DE 11 2018 000 382 T5, a filter system with a corrugated, interlocking housing-end-plate interface geometry is known, in which a filter element end plate and a filter housing component meet at an interface. The filter housing component comprises a corrugated or repeating pattern that interlocks with a matching corrugated or repeating pattern on the end plate of the filter element. The corrugated or repeating pattern is intended to prevent the filter element from rotating freely relative to the filter housing component of the filter system.

[0004] From DE 11 2007 001 880 T5 a rapid drain filter device is known, comprising a filter housing, a clean liquid channel which runs axially in the housing, a maintenance drain channel which is located at an axial end of the housing and which is led radially away from the clean liquid channel.

[0005] From WO 2018 / 087 294 A1, a filter system for a liquid medium to be filtered is known, comprising a filter housing with a housing pot and with a housing cover which can be screwed onto the housing pot or screwed into the housing pot by means of a screw movement in order to close the housing pot, wherein the housing pot has a drain channel with a bottom drain opening for the liquid medium.

[0006] From US 2018 / 257 011 A1, a filter insert for removable arrangement in a filter housing is known, comprising a first actuating means positioned at a first end of the filter insert, wherein the first actuating means comprises an outer contact surface defining a projection or recess, and wherein the projection or recess forms part of a structure with varying extent in an axial direction of the filter insert along a circumferential direction of the filter insert, such that the first actuating means is configured to be actuated by a corresponding second actuating means of a filter housing cover.

[0007] In ring filter elements of this type, continuous stress can cause a pin sealing an idle channel to break or tear off. This results from pressure on an end plate due to pulsations occurring during operation. The broken pin causes problems, at least when replacing the ring filter element, as the pin can no longer be removed along with the element. Furthermore, there is a risk that a broken pin will no longer reliably seal the idle channel during operation, thus compromising the proper functioning of a liquid filtration system equipped with such a ring filter element.

[0008] The present invention therefore deals with the problem of providing an improved or at least an alternative embodiment for a ring filter element of the generic type, which in particular overcomes the disadvantages known from the prior art.

[0009] This problem is solved according to the invention by the subject matter of independent claim 1. Advantageous embodiments are the subject matter of the dependent claims.

[0010] The present invention is based on the general concept of providing a ring filter element with a direct or indirect support option against a filter housing of a liquid filter device via its lower end disk, thereby significantly reducing the loads acting on the pin during operation of the liquid filter device, particularly those caused by pulsations. The ring filter element according to the invention has an upper end disk, a lower end disk, and a filter material arranged between them, which can, for example, be designed as a zigzag-shaped pleated star. An eccentrically arranged pin, projecting axially from the lower end disk, is provided on the lower end disk for closing an idle channel in a filter housing of a liquid filter device.According to the invention, at least one support contour projecting axially from the lower end disc, separate from the pin, is provided for direct or indirect support against a filter housing. This support contour makes it possible to support the lower end disc and, above it, the ring filter element directly or indirectly against the filter housing. This offers a significant advantage, particularly in the case of pulsations occurring during operation, as the load no longer acts on the interface between the pin and the lower end disc, where a comparatively large notch effect can occur, but can be transferred via the support contour from the end disc or the pin directly into the filter housing.The pressure pulsations exert pressure on the lower end plate and force the pin into the idle channel. During these pressure pulsations, the pin moves piston-like within the idle channel, subjecting it to a high notch load at its connection point to the lower end plate. This stress eventually leads to the pin breaking off. The support of the lower end plate on the filter housing also includes indirect support via the pin and the support contours on the filter housing. This design ensures that, particularly during pressure pulsations, the pin is directly supported by these contours on the filter housing, preventing it from being forced into the idle channel.This prevents the pin from breaking off the lower end plate, caused by pressure pulsations occurring during operation of the liquid filter unit, as well as the associated disadvantages, such as difficulties in replacing the ring filter element and potential leaks due to the broken pin. With the solution according to the invention, i.e., the at least one support contour according to the invention, a significantly increased functional reliability can thus be achieved with virtually no additional design effort. It is, of course, conceivable that the at least one support contour could be formed integrally with the lower end plate and, for example, manufactured together with it in a single plastic injection molding process.To realize the invention, only a one-time changeover of a plastic injection molding tool is required, whereby, purely theoretically, it is of course also conceivable that at least one support contour is subsequently arranged on a conventional lower end disc, for example glued on, which offers the great advantage that conventional ring filter elements can also be retrofitted according to the invention.

[0011] At least one support contour can be positioned in a transition area between the pin and the lower end plate, thereby significantly relieving stress on the pin in its previously notch-prone area and at least reducing the risk of pin breakage. The support contours are arranged radially offset (adjacent) to the axis of the pin.

[0012] In a further development not covered by the invention, two support contours are provided, each extending tangentially or circumferentially from a shaft of the pin and integrally connected to both the shaft of the pin and the lower end plate. Such an embodiment offers the significant advantage that the support contours can be formed integrally with the lower end plate and thus manufactured together with it, as well as with the shaft of the pin. Therefore, in this embodiment, the lower end plate, together with the pin and the at least one support contour, can preferably be manufactured as a single-piece injection-molded plastic part, thus simplifying the design and reducing costs.Furthermore, the integral connection of at least one support contour to the pin shaft stiffens the pin, making it more robust and thus less susceptible to damage during handling. This integral connection significantly reduces the notch stress previously present at the angular transition from the pin shaft to the lower end plate, which contributed to pin breakage due to pressure pulsations. The pin shaft, particularly in the area near the end plate, can still be considered part of the lower end plate.

[0013] In an embodiment not covered by the invention, the pin shaft has a cruciform cross-section with two intersecting webs, wherein at least two support contours are connected to at least one of the webs. The preferably two support contours thus extend the respective web in the radial direction of the pin shaft, whereby, in this case, only the injection mold needs to be adapted accordingly in the area of ​​this web to produce the two support contours.

[0014] In an embodiment not covered by the invention, the at least one support contour has a support surface parallel to a surface of the lower end disc. If two support contours are provided, each has a support surface parallel to a surface of the lower end disc. With such a parallel support surface and a complementary counter-support surface on the filter housing, a planar contact of the ring filter element can be achieved via its lower end disc and the at least one support contour on the filter housing. This prevents highly concentrated point load transfer and allows the load to be distributed over a surface.

[0015] In an embodiment not covered by the invention, at least one support contour has a support surface inclined towards a surface of the lower end disk. If two support contours are provided, each has a support surface inclined towards a surface of the lower end disk and, for example, has an arrow-like shape. Such an inclined support surface can, for example, provide axial support for the lower end disk and thus for the ring filter element at a funnel-shaped inlet of the idle channel. In this case, the inclined support surface can be either flat or convex, thereby creating a planar or linear contact with a conical inner surface of a funnel-shaped inlet of the idle channel. A convex support surface offers the significant advantage of being able to compensate for any dimensional inaccuracies and installation tolerances.Here too, the end disc is supported by the pin and the support contours on the filter housing.

[0016] In another embodiment not covered by the invention, two support contours are arranged separately and directly adjacent to the pin or its shaft on the lower end plate and are designed in the form of knobs or protrusions. Such knobs can be formed integrally with the lower end plate, making them both simple and cost-effective to manufacture. In theory, however, it is also conceivable to manufacture such support contours separately and thus retrofit conventional ring filter elements by, for example, welding or bonding the support contours to the lower end plate. In this case, it is only necessary to check whether a filter housing in which the ring filter element is installed has corresponding counter-support surfaces on which the support contours of the ring filter element can rest.

[0017] According to the invention, the support contour has ring-segment-like support elements that are arranged at least partially around the pin or its shaft. The ring-segment-like support contour, with circumferentially arranged interruptions, ensures reliable drainage of any liquid present in the filter housing when the ring filter element is replaced. Furthermore, the ring-segment-like support elements provide uniform support for the lower end disc against the filter housing around the pin or its shaft, thereby reducing the risk of damage to the pin. Alternatively, according to the invention, it is also conceivable that the support contour is arranged in a closed ring around the pin.In this case, the support contour could be used as an additional sealing contour, which provides additional sealing for a ring filter element installed in a filter housing and a pin immersed in an idle channel of the filter housing, provided that the support contour is located close to an inlet of the idle channel.

[0018] In another embodiment not covered by the invention, the pin could also be supported at its tip if, for example, a transverse bolt is inserted in the idle channel.

[0019] The present invention is further based on the general concept of designing a liquid filter device, for example a fuel filter or an oil filter, with a filter housing having an idle channel and a ring filter element according to the invention arranged in the filter housing, wherein the ring filter element, in its installed state, is supported directly on the filter housing via at least one support contour projecting axially from the lower end disk. This significantly reduces, in particular, the load on the pin or a shaft of the pin, caused, for example, by pressure pulsations during operation of the liquid filter device, and thereby considerably increases the service life of the liquid filter device.

[0020] Advantageously, a partially circumferential rim is arranged around the idle channel, against which the ring filter element rests with its lower end disc and its two support contours, each with support surfaces parallel to a surface of the lower end disc. This makes it possible to support the lower end disc near the idle channel relative to the filter housing, thereby relieving stress on the pin.

[0021] Alternatively, the idle channel could have a funnel-shaped inlet with a conical inner surface. The ring filter element rests on this surface with its lower end plate and support contours, each with its support surfaces inclined towards a surface of the lower end plate. If the support surfaces are flat, a similarly flat counter-support surface on the inner surface of the funnel-shaped inlet can achieve a flat contact area and thus broad support. However, a convex design of the support surfaces of the support contours is also conceivable. In this case, they would only contact the counter-support surfaces on the filter housing at points or along lines, thereby compensating for, for example, dimensional or manufacturing tolerances.The support contours can be arranged on the shaft of the pin, whereby the area of ​​the shaft near the end disk with the support contours can also be seen as part of the lower end disk.

[0022] Further important features and advantages of the invention will become apparent from the dependent claims, the drawings and the associated description of the figures based on the drawings.

[0023] It is understood that the features mentioned above and those to be explained below can be used not only in the combination specified, but also in other combinations or on their own, without leaving the scope of the present invention.

[0024] Preferred embodiments of the invention are shown in the drawings and are explained in more detail in the following description, wherein identical reference numerals refer to identical or similar or functionally identical components.

[0025] Each of these shows, schematically: Fig. 1 shows a sectional view through an embodiment of the liquid filter device not covered by the invention; Fig. 2 shows a detailed view A from Fig. 1in the area of ​​an inlet of an idle channel and a lower end disk supported against a filter housing via support contours, Fig. 3 another view of a lower end disk of a ring filter element not covered by the invention, Fig. 4 a sectional view through a filter housing in the area of ​​an idle channel with a lower end disk of an embodiment of the ring filter element not covered by the invention, which is supported against the filter housing via support contours, Fig. 5 a view from above of counter-support contours on the filter housing in the area of ​​an idle channel with a cut-out pin, Fig. 6 a partially cut-out view of an idle channel to illustrate inclined support surfaces with an embodiment of the ring filter element not covered by the invention, Fig.7. A view from below of a lower end disk of a ring filter element not covered by the invention, with support contours arranged separately from the pin.

[0026] According to the Fig. 1 , has an embodiment of the liquid filter device 1 not covered by the invention, for example an oil filter, a hydraulic filter or a fuel filter, a filter housing 2 and a ring filter element 3 arranged therein and not covered by the invention. The ring filter element 3 has, in a known manner, an upper end disk 4, a lower end disk 5 and a filter material 6 arranged between them, which is formed, for example, in the form of a zigzag-folded star-shaped pleat. On the lower end disk 5, an eccentrically arranged pin 8 is projecting from the lower end disk 5 in the axial direction 7 (see also the Figs. 2 to 7) for closing an idle channel 9. With the ring filter element 3 installed in the filter housing 2, the pin 8 thus dips into the idle channel 9 and closes it, for example by means of an O-ring seal 10 (see figure). Fig. 4 , 6 and 7According to the invention, at least one support contour 11, projecting axially 7 from the lower end disk 5, is provided separately from the pin 8 on the lower end disk 5. This support contour allows the lower end disk 5, and thus the ring filter element 3, to be directly supported against the filter housing 2. This offers the significant advantage that pressure pulsations generated, for example, by a pump during operation of the liquid filter device 1, can be transmitted from the ring filter element 3 directly to the filter housing 2 via the support contours 11, thereby significantly reducing the load on the pin 8. In particular, this reduces the risk of the pin 8 breaking off near the lower end disk 5 under constant pressure pulsation.

[0027] The following section discusses various embodiments of the support contours 11, which are not covered by the invention: According to the Figs. 1 to 4Two support contours 11 are provided, each extending tangentially from a shaft 12 of the pin 8 and formed integrally with both the shaft 12 of the pin 8 and the lower end plate 5. The shaft 12 of the pin 8 has a cruciform cross-section with two intersecting webs 13, 13', with the two support contours 11 being connected to, or integrally formed with, one of the webs 13, 13'. This allows for a particularly simple and cost-effective manufacturing process for the support contours 11, which are not covered by the invention, since they can be produced by a simple modification of a plastic injection mold together with the pin 8 or its shaft 12 and the entire lower end plate 5.

[0028] If one considers the support contours 11 according to the Figs. 1 to 4, it can be seen that the support contours 11 shown there each have a support surface 15 parallel to a surface 14 of the lower end disk 5. Alternatively, the two support contours 11 according to the Fig. 6 each a support surface 15' inclined to the surface 14 of the lower end disk 5.

[0029] By integrally connecting at least one support contour 11 to the shaft 12 of the pin 8, the notch stress previously present at the angular transition from the shaft 12 of the pin 8 to the lower end disk 5, which was a contributing factor to the pin 5 breaking off due to pressure pulsations, can be significantly reduced or even eliminated. The shaft 12 of the pin 5 can still be considered part of the lower end disk 5, particularly in the area near the end disk. The at least one support contour 11 can also be arranged in a transition area between the pin 8 or its shaft 12 and the lower end disk 5. "Adjacent to the pin 8" in this context means separate from it.

[0030] The support of the lower end disc 5 on the filter housing 2 also includes the indirect support of the lower end disc 5 via the pin 8 and the support contours 11 on the filter housing 2, whereby in particular the pin 8 is directly supported via the support contours 11 on the filter housing 2 in the event of pressure pulsations and can therefore no longer be pressed into the idle channel 9.

[0031] According to the Fig. 6The support surface 15' shown can be flat and inclined to the surface 14 of the lower end disk 5, or convex, in which case there is no planar contact with a counter-support surface 16 at an inlet 17 of the idle channel 9, but only a linear contact. In this case, the inlet 17 is funnel-shaped with a conical inner surface on which the ring filter element 3, with its lower end disk 5 and its two support contours 11, each with their support surfaces 15' inclined to the surface 14 of the lower end disk 5, rests. In this case, the support contours 11 can also serve to align the pin 8 relative to the idle channel 9 and thus at least facilitate the easy insertion of the pin 8 into the idle channel 9.

[0032] In the embodiment according to the Figs. 1 to 5, the support surfaces 15 are formed parallel to the surface 14 of the lower end disk 5, wherein at least one counter-support surface 16 (cf. Fig. 4 ) also runs parallel to the surface 14 of the lower end disk 5, so that the support contours 11 are supported over a flat area via their support surfaces 15 on the opposite counter-support surfaces 16.

[0033] According to the invention, the support contour 11 (not shown) has ring-segment-like support elements that are arranged at least partially around the pin 8. This enables particularly uniform support of the lower end disk 5 and thus of the ring filter element 3 in the axial direction 7 relative to the filter housing 2. In an alternative embodiment of the invention, it is of course also conceivable that the support contour 11 is designed as a closed ring around the shaft 12 of the pin 8, so that by contact of the support contour 11 via its support surface 15, a tight seal can be achieved against a counter-support surface 16, whereby the support contour 11 can perform not only a support function but also a sealing function.

[0034] Alternatively, in an embodiment not covered by the invention, it is also conceivable that the at least one support contour 11 is arranged separately and directly adjacent to the pin 8 on the lower end disk 5 and is designed in the form of knobs 18. Such an embodiment with two support contours 11 arranged separately and directly adjacent to the pin 8 on the lower end disk 5 is, for example, described in the Fig. 7 As shown. With such a support contour 11, it is possible to retrofit conventional ring filter elements and make them less sensitive to pressure pulsations. It is desirable to position the support contours 11 as close as possible to the shaft 12 of the pin 8 in order to support it directly against the filter housing 2.

[0035] With the ring filter element 3 and the liquid filter device 1 according to the invention, it is possible to significantly reduce the load on a pin 8 during operation of the liquid filter device 1, for example, caused by pressure pulsations triggered by a pump, and thereby also significantly reduce the risk of the pin 8 breaking off. According to the invention, this is achieved by directly supporting the ring filter element 3 via its lower end disk 5 and the support contours 11 arranged thereon on the filter housing 2. In the most favorable case, only a one-time modification of a plastic injection mold used for manufacturing the lower end disk 5 is required to implement the support contours 11 according to the invention.Retrofitting is also relatively easy via separately designed support contours 11, which can be arranged on the lower end disc 5 of conventional ring filter elements, for example by gluing or welding.

Claims

1. Ring filter element (3), - having an upper end plate (4), a lower end plate (5) and a filter material (6) arranged in between, in particular a folded star, - having a pin (8), arranged eccentrically at the lower end plate (5) and protruding in axial direction (7), for closing a no-load operation channel (9), characterized in that - at the lower end plate (5) separate from the pin (8) there is at least one supporting contour (11) protruding in axial direction (7) from the lower end plate (5) for supporting on a filter housing (2), - in that the supporting contour (11) has ring segment-like supporting elements which are arranged at least partially around the pin (8), or in that the supporting contour (11) is arranged in a closed ring shape around the pin (8).

2. Liquid filter apparatus (1) having a filter housing (2) having a no-load operation channel (9) and a ring filter element (3) according to claim 1 arranged in the filter housing (2), wherein the ring filter element (3) is supported on the filter housing (2) in the installed state by the at least one supporting contour (11) protruding in axial direction (7) from the lower end plate (5).

3. Liquid filter apparatus according to claim 2, characterized in that an at least partially peripheral edge (19) with a counter supporting surface (16) is arranged on the no-load operation channel (9), on which counter supporting surface the ring filter element (3) is supported with its lower end plate (5) and its at least one supporting contour (11) with its supporting surface (15) parallel in each case to a surface (14) of the lower end plate (5).

4. Liquid filter apparatus according to claim 2, characterized in that the no-load operation channel (9) has a funnel-shaped inlet (17) with a conical inner surface, which forms the counter supporting surface (16) on which the ring filter element (3) is supported with its lower end plate (5) and two supporting contours (11) with their supporting surfaces (15') inclined in each case relative to a surface (14) of the lower end plate (5).