DE102016008502A1 - Filter element and method for producing the same - Google Patents

Abstract

A filter element (1) for filtering a fluid comprises a filter medium (2), which is arranged around a longitudinal axis (L) of the filter element (1), and at least one material integral end plate (4), which frontally attached to the filter medium (2) is. The end plate (4) is made of a Endscheibenmaterial which has a in the radial direction (R) changing stiffness, hardness and / or elasticity.

Description

Technical area

The present invention relates to a filter element and a method for producing such a filter element, for example for filtering oil for engines in motor vehicles.

State of the art

Filter elements, such as oil filter elements, usually have a star-shaped folded endless bellows, which is arranged between two end plates. To form such a continuous bellows, a first end portion of a filter medium and a second end portion of the filter medium are connected to each other.

The DE 10 2005 010 437 A1 discloses a filter element having an end disk for a filter medium folded annularly about a cylinder axis, the end disk being plasticized over a region in an end face of the filter medium and having a rubber ring on its radial inner side. The rubber ring is vulcanized and forms a tight and releasable connection to a centrally arranged connection element. Other filter elements of the prior art often require additional seals on the endplate.

Disclosure of the invention

Against this background, the present invention has for its object to provide an improved filter element.

Accordingly, a filter element for filtering a fluid with a filter medium disposed about a longitudinal axis of the filter element and having at least one integral material end plate is proposed. The material integral end plate is attached to the end face of the filter medium, and the end plate is made of a Endscheibenmaterial which has a changing in the radial direction of mechanical property, in particular a changing stiffness, hardness and / or elasticity.

For example, the mechanical property of the end plate material changes from the outer edge to an inner region of the end plate. It can be said that the end disk has a gradient from the inside to the outside in terms of its hardness, rigidity or elasticity. This has the advantage that, for example, due to be coupled to the filter element nozzle, tubes or connecting elements matched to this coupling strength. For example, in the presence of a passage opening in the end plate, further seals, for example with respect to a central tube, are dispensed with.

The material property which changes in the radial direction may depend, for example, on a degree of crosslinking of a polymer end plate material.

Preferably, a stiffness, hardness and / or elasticity of the Endscheibenmaterials increases in the radial direction to the outside. In particular, a hardness increases from the inside to the outside. In this respect, a sufficient flexibility or elasticity of the end plate can be achieved in an inner region, for example, to perform sealing functions.

In embodiments of the filter element, the end plate is at least partially made of a Endscheibenmaterial, which is curable by means of an energy input, in particular by a heating effect. For example, the endplate material may comprise a crosslinkable polymer, such as a PUR material. Upon exposure to heat, the polymers of the starting end-plate material crosslink and solidify. As a result, with increasing hardening, for example due to the effect of heat, the end disk material experiences a variable hardness.

With regard to the determination of a changing elasticity of the end disk from an inner to an outer region, a modulus of elasticity can be used. One speaks also of a Young module. The material hardness of the end plate can be determined by means of known hardness test methods. The determination of a Brinell hardness is conceivable DIN ISO 6506-1-4 , a Vickers hardness after DIN EN ISO 6507-1-4 , a Rockwell hardness after DIN EN ISO 6508-1 or others. Particularly suitable, however, is a Shore hardness test after DIN EN ISO 868 and DIN IN ISO 7619-1 , For example, the end plate material may comprise an elastomer so that Shore A Shore hardness may serve as a unit of hardness. In principle, other measuring methods are also conceivable.

In principle, it is desired that the material property, ie stiffness, hardness and / or elasticity changes relatively along the radial direction. That is, the end plate, for example, in a cylindrical geometry of the filter element, in the region of the longitudinal or symmetry axis, a different stiffness, hardness and / or elasticity compared to a Endscheibenbereich, which adjoins the lateral surface of the cylinder.

Preferably, the hardness with a suitable unit, such as the Shore A hardness, is at least 2% lower inside, preferably 5%, and more preferably 10% lower than the outside.

In embodiments, the end plate and the filter medium are firmly connected. In particular, the end plate and the filter medium are connected to one another in a fluid-tight manner and can not be removed from one another in a non-destructive way.

In embodiments, the end plate includes an opening for axially inserting a center tube. The central tube is used for example for fluid supply or removal. The fact that, for example, in the region of the opening, the end plate has a higher elasticity or lower stiffness or hardness than in the outer region, the center tube can then easily insert and seal radially secure. Furthermore, an improved robustness against vibrations is given as with consistently rigid end plates. In embodiments, the filter element comprises a central tube, and the end plate directly surrounds or encompasses the central tube with a softer and / or more flexible material section which is more elastic than an outer edge region. As a result, a particularly favorable sealing effect is achieved with respect to the central tube.

There is also proposed a method of manufacturing a filter element having a longitudinal axis in which a filter medium and at least one end plate made of a Endscheibenmaterial are axially assembled, and wherein the Endscheibenmaterial is selected and / or treated so that the end plate in the radial direction has changing stiffness, hardness and / or elasticity.

In a variant of the method, an output end disk material attached to an end face of the filter medium is hardened differently from an outer edge to an inner region to the end disk material. Curing takes place for example by an energy input, which is generated differently from the inside out. This results in a Aushärtegradienten, for example, from the inside out to the periphery of the end plate. The Ausgangsendscheibenmaterial is so far preferably an elastomer which is foamable and / or curable. PUR materials and PUR foams have proven suitable for the end disk material which can be cured.

In embodiments of the method, the end plate is further provided with an opening. For example, the mechanical property of the Endscheibenmaterials changed from the outer edge to the opening.

In further embodiments, the filter medium is folded. In embodiments, the filter medium is designed as a bellows made of a zigzag folded filter media web. The filter medium is in particular arranged so that the bellows is formed star-shaped. In particular, the filter medium forms a closed ring. Alternatively, the filter medium may also be unfolded and thus smooth.

The filter element is preferably used in motor vehicles, trucks, construction vehicles, watercraft, rail vehicles, agricultural machinery or vehicles or aircraft application. The filter element may be configured to filter water, air, urea solution, oil or fuels, such as diesel fuel, kerosene or gasoline. The filter element may be, for example, an oil filter, a fuel filter or the like.

Further possible implementations of the invention also include not explicitly mentioned combinations of features or method steps described above or below with regard to the exemplary embodiments. The person skilled in the art will also add individual aspects as improvements or additions to the respective basic form of the invention.

Further embodiments of the invention are the subject of the dependent claims and the embodiments of the invention described below. Furthermore, the invention will be explained in more detail by means of embodiments with reference to the accompanying figures.

Brief description of the drawings

It shows:

1 a schematic perspective view and a schematic sectional view of an embodiment of a filter element;

2 a schematic perspective view and a sectional view of another embodiment of a filter element;

3 - 6 : schematic partial representations of elements of the filter element for explaining a manufacturing method for a filter element;

7 : Curve for energy inputs for curing end disc material;

8th : Hardness curve for end disks in the radial direction; and

9 : Investigation results on hardness properties of Endscheibenmaterialien.

In the figures, identical or functionally identical elements, unless otherwise indicated, have been given the same reference numerals.

Embodiments of the invention

The 1 shows a schematic perspective view of an embodiment of a filter element 1 (left) and a schematic sectional view of the filter element (right). The filter element 1 For example, it is suitable to filter water, air, urea solution, oil or fuels such as diesel fuel, kerosene or gasoline. In particular, the filter element finds 1 in motor vehicles, lorries, construction vehicles, watercraft, rail vehicles or aircraft application. Furthermore, the filter element 1 also find application in buildings. For example, the filter element 1 an air filter, an oil filter, a fuel filter or the like.

The filter element 1 includes a bellows 3 with a longitudinal axis L, in particular an endless bellows. The bellows 3 is from a filter medium 2 manufactured. Here is the filter medium 2 as a fold pack 3 formed of pleated filter material. The filter element 1 has a cylindrical geometry with a longitudinal axis L and a radial extent R perpendicular to the longitudinal axis L. The bellows 3 forms along the axial direction A an outer circumferential surface around the interior 6 of the filter element 1 out.

Frequently, nonwoven plastic materials are folded in a zigzag fashion as filter materials. The filter medium 2 includes, for example, a filter fabric, a Filtergelege or a filter fleece. In particular, the filter medium 2 be prepared in a spunbond or meltblown process. Furthermore, the filter medium 2 felted or needled. The filter medium 2 may comprise natural fibers, such as cellulose or cotton, or synthetic fibers, for example of polyester, polyvinyl sulfite or polytetrafluoroethylene. Fibers of the filter medium 2 may be oriented in, skewed and / or transversely to the machine direction during processing.

At the frontal fold profiles of the folded filter medium 2 which is the bellows 3 is in the orientation of the 1 each at a front or end side of the filter medium 2 on the upper side and underside an end plate 4 . 5 intended. The filter element 1 has at least one end plate 4 . 5 but prefers two endplates 4 . 5 , on. In particular, the end plates 4 . 5 fluid-tight with the filter medium 2 connected. It may be a bonding of the end plates 5 . 6 by means of, for example, an adhesive film which is the filter medium 2 facing, with the filter medium 2 respectively. The end discs 4 . 5 can also be made of one piece by foaming and curing of a plastic material initially present in sheet form as Ausgangsendscheibenmaterial, such as PUR. Through the end discs 4 . 5 experiences the filter element 1 a certain stability and can be used in a corresponding fluid circuit. The filter medium 2 can also during production in partially molten or foamed Endscheibenmaterial the end plates 4 . 5 be impressed.

A connection opening 7 is for example part of the upper end disk 4 , Similarly, the lower end plate 5 also have a connection opening, which like the connection opening 7 the upper end disc 5 can be connected to a resource port or a central tube.

During operation, for example as an oil filter, the fluid to be filtered, such as oil, flows through the pleated filter medium 2 in the direction of the longitudinal axis L. As a rule, the filter materials and geometries of the filter medium 2 or the filter element 1 adapted to a given flow direction. For example, in the 1 from the side of the raw fluid RO and up the filtered pure fluid RE shown. In that sense, the orientation of the 1 an interior 6 of the filter element 1 facing surface of the bellows 2 the downstream side, and the outer circumferential surface of the cylindrical bellows 3 forms the inflow side of the filter element 1 , Inside the bellows 3 is an optional support element, in particular a support tube, is provided which between the end plates 4 . 5 is present. The support element 10 can through an opening 7 introduced and with the end discs 4 . 5 be connected.

The material properties of in the 1 illustrated end plate 4 and in embodiments also the end plate 5 change in the radial direction R. By a suitable treatment of Endscheibenmaterials the end plate 4 results in a different hardness or elasticity from the longitudinal axis L to the radial direction R outer region of the end plate 4 , This can be done in the area of the opening 7 a favorable sealing effect by the example softer or more flexible design of Endscheibenmaterials in the region of the opening 7 available. It can be argued that the end plate has a radial gradient in terms of hardness.

In the 2 is another embodiment for a filter element 10 indicated. The embodiment of the 2 has essentially the same Elements like her in terms of 1 are indicated and described. In the filter element 10 is also the upper side of the end plate 4 with a cap 8th Mistake. On the left side you can see that in the manner of a plastic cap, the end plate formed for example of PUR elastomer 4 is sheathed. This cap 8th has in the orientation of 2 top Handling or fastening elements 9 For example, for connection to a pipe or a nozzle.

In the cross-sectional view of 2 you realize that a center tube 11 through the opening 7 in the end disk 4 passes through and through a projection 12 at the end push 4 is secured. The cap 8th and the end disc 4 can be glued together, but often it is sufficient by the projection 12 a kind of locking with the bottom of the end plate 4 in the area of the opening 7 to achieve.

In the 3 is a detail of an end plate 4 shown schematically in cross section. The in the 3 illustrated end plate 4 For example, in the embodiment according to the 1 or 2 as upper end disc 4 be used. The end disc 4 has a circular geometry and a central opening 7 , This results in an inner opening 7 circumferential edge 44 and one the circumference of the end plate 4 circumferential outer edge 43 , In this respect one can also speak of an inner area 41 the end plate 4 and an outer area 42 the end plate 4 speak. A radial direction is with R starting from the opening 7 specified. Preferably, the area is now 41 softer or more flexible or less hard than the outer area 42 the end plate 4 , This will allow, for example, a center tube 11 as it is in the 2 is indicated, slightly through the opening 7 is insertable and a good radial sealing fit due to the flexibility and the contact pressure in the radial direction of the inserted center tube 11 arises. In the outer area 42 however, the end plate is harder, so that a sufficient and good stability of the entire filter element is created.

In the 4 is for explaining a manufacturing method for a filter element, as for example in the 1 or 2 shown as a filter medium 2 and a corresponding end plate 4 be added axially to each other. The axial direction is designated by A. In addition, the shows 5 for example, a plan view of a filter element or an end plate 4 with an opening 7 and a filter medium designed as an endless bellows. The filter medium is folded in a zigzag shape and forms a star-shaped fold. In the 5 are for explanation outer fold edges 31 and inner fold edges 32 indicated by folding sections 33 are connected. The outer folds 31 Run substantially on the circumference or form a lateral surface of the cylindrical filter element, as shown in the 1 is indicated.

For example, in a manufacturing process, an initial end-plate material such as a non-crosslinked PUR foam or other elastomeric foam is first used. The Ausgangsendscheibenmaterial can also be present as a flat film or as a circular strip and then be expanded. For this a shape can be used. In the 6 this is indicated by way of example, as with the Endscheibenmaterial 4 assembled filter medium 2 in a mold 13 is used.

In order now to achieve a radially changing material property, in particular a changing hardness, of the end plate, after the Ausgangsendscheibenmaterial in the mold 13 is inserted and with the bellows or filter medium 2 connected, a cross-linking or curing of Endscheibenmaterials performed. This is done, for example, with the shape designed as a heating mold 13 Heat introduced into the Ausgangsendscheibenmaterial. In this case, for example, outside a higher temperature than inside irradiated. It is also conceivable, the outer edge of the end plate 4 (see. 3 , Area 42 ) to apply heat for a longer time, so that a stronger hardening of the Ausgangsendscheibenmaterials takes place.

In the 7 is a possible curve for an energy input for curing a corresponding Endscheibenmaterials depending on the radius R indicated. It can be seen that the energy input is increased from the center at radius 0 to the outer region of the end plate, or outer edge at d / 2. In the 7 the energy input is indicated in arbitrary units. For example, this may be due to a certain temperature profile in the heating mold 13 be achieved, in which the temperature increases from the inside out. However, it is also conceivable for a uniform temperature radiation, with a longer temperature radiation takes place with increasing radius. This results in a stronger curing in the outer region and a lower in the inner region and in particular in the region of the opening 7 ,

For example, a hardness curve can result in units of Shore-A, as in the 8th is indicated. On the x-axis you can see the radius from a mid-point of an end-plate to the outer edge at d / 2. For example, a Shore hardness Shore-A at the midpoint or an inner edge 44 (see. 3 ) of the end plate 4 at about 80, while towards the outer perimeter, So the area 42 the end plate, up to 95 Shore-A increases. In this case, graded gradients, but also linear gradients are conceivable. Further, other measurement units may be used to determine a hardness.

The Applicant has now carried out investigations on possible Endscheibenmaterialien. In the 9 corresponding test results on hardness properties of end disk materials are shown as a function of degrees of cure. On the x-axis you can see a degree of cure in units of percent. For this purpose, a known PUR material was considered as foam in the manner of a film or plate, which foams and is crosslinked under heat. The tests assumed a complete cure of 100% after 58 seconds at a temperature of 150 ° C. In this respect, the results in the 9 indicated scale with 60% cure after 35 seconds and 300% cure after 174 seconds. On the left scale, the resulting Shore A hardness of Endscheibenmaterials is indicated and on the right scale, the proportion of polymerized Endscheibenmaterial.

It can be assumed that all polymers are crosslinked with 100% fraction of polymerized film end-face. It can now be seen that as the degree of cure increases, the Shore A hardness of the endplate material also increases. That is, in the production of a corresponding end plate 4 , as in the filter elements after the 1 or 2 can be used by a suitable temperature profile, for example, the heating shell 13 (see. 6 ) a different hardness in the inner region relative to the outer region of the end plate 4 be achieved.

In this respect, the proposed manufacturing method and the filter elements allow on the one hand can be dispensed with additional sealing elements in the region of the opening, and on the other hand, that adapted to the respective operating or application situation Endscheibenhärte can be achieved. By virtue of the fact that, for example, the end disk becomes softer or more elastic or less hard inwardly, it is also possible to compensate better for vibrations which are caused by connection elements, such as center pipes or connecting pieces, which extend into an opening in the end disk. The mechanical stress of the entire filter element is thus reduced. It is thus possible to achieve an adjustable degree of stiffness, hardness or elasticity of the end disk material in the end disk.

Although the invention has been described in terms of preferred embodiments, it is also modifiable. For example, mechanisms other than degrees of cure can create varying stiffness in the radial direction. It is conceivable irradiation or a gradual change in the composition of the Endscheibenmaterials from the inside out. Under material einstückig is to be understood that the respective end plate does not consist of multi-part or assembled elements. At least one contiguous material region of the inserted end plate has a material property changing in the radial direction, such as rigidity, hardness or elasticity.

LIST OF REFERENCE NUMBERS

1, 10

filter element

2

filter media

3

bellow

4

end disk

5

end disk

6

inner space

7

port opening

8th

cap

9

retaining element

11

center tube

12

projection

13

heating form

31

outer fold

32

Innenfaltental

33

folding section

41

inner area

42

outer area

43

outer edge

44

inner edge

A

axial direction

d

Endscheibendurchmesser

e

energy input

L

longitudinal axis

R

radial direction

RE

clean fluid

RO

unfiltered

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102005010437 A1 [0003]

Cited non-patent literature

• DIN ISO 6506-1-4 [0010]
• DIN EN ISO 6507-1-4 [0010]
• DIN EN ISO 6508-1 [0010]
• DIN EN ISO 868 [0010]
• DIN IN ISO 7619-1 [0010]

Claims (10)

Filter element ( 1 ) for filtering a fluid with a filter medium ( 2 ), which about a longitudinal axis ( 1 ) of the filter element ( 1 ) is arranged around, and with at least one material integral end plate ( 4 ), which frontally to the filter medium ( 2 ), wherein the end plate ( 4 ) is made of a Endscheibenmaterial which has a in the radial direction (R) changing stiffness, hardness and / or elasticity. Filter element according to claim 1, wherein a rigidity and / or hardness of the Endscheibenmaterials increases in the radial direction (R) to the outside. Filter element according to claim 1 or 2, wherein the end plate ( 4 ) is at least partially made of a Endscheibenmaterial, which by means of an energy input, in particular by a heat, is curable. Filter element according to one of claims 1-3, wherein the end plate ( 4 ) and the filter medium ( 2 ) are firmly connected. Filter element according to one of claims 1-4, wherein the filter medium ( 2 ) as a bellows ( 3 ) is configured. Filter element according to one of claims 1-5, wherein the end plate ( 4 ) an opening ( 7 ) for axial insertion of a central tube ( 11 ). Filter element according to claim 6, with the central tube ( 11 ), whereby the end disc ( 4 ) the central tube ( 11 ) directly with respect to an outer edge region ( 42 ) comprises a more elastic, softer and / or more flexible material section. Method for producing a filter element ( 1 ) with a longitudinal axis (L), in which a filter medium ( 2 ) and at least one end plate made of a Endscheibenmaterial ( 4 ), and wherein the end plate material is selected and / or treated such that the end plate has a radially varying stiffness, hardness and / or elasticity. The method of claim 8, wherein a Ausgangsendscheibenmaterial attached to an end face of the filter medium is hardened differently from an outer edge to an inner region in the Endscheibenmaterial. The method of claim 8 or 9, wherein the end plate is provided with an opening.

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