DE102017001540A1 - filter means - Google Patents

Abstract

A filter device comprising a filter element (3) and a bypass device (5) which has a spring-loaded valve body (43) which opens from a predefinable bypass opening pressure, and a fluid-carrying connection between an unfiltrate and a filtrate side of the filter element (3) under at least partially Bypassing of the filter material (21) of this filter element (3) provides, wherein a control device (79) is present, by means of which the bypass opening pressure is temperature controlled variable, characterized in that the control device (79) the bypass opening pressure from reaching a predetermined temperature threshold of a high Lowers pressure to a low pressure.

Description

The invention relates to a filter device with a filter element and a bypass device, which has a spring-loaded valve body which opens from a predetermined bypass opening pressure and creates a fluid-conducting connection between an unfiltrate and a filtrate side of the filter element with at least partial bypass of the filter material of this filter element, wherein a control device is present, by means of which the bypass opening pressure is temperature-controlled variable.

Filter devices, in particular when used for mobile applications, such as in motor vehicles or mobile work equipment, for example for the filtration of gear oils or hydraulic oils, it comes to operating phases, which run under different temperature conditions. The resulting changes in viscosity between low cold start temperatures and much higher operating temperatures, regardless of the operating state of the filter material of the filter element, so whether functional or blocked, to different differential pressures, so that the response of the bypass device is influenced to an undesirable extent by the viscosity. With regard to this problem is in the document WO 01/55563 A2 discloses a filter device of the type mentioned, which provides as a control device for temperature-controlled change of the bypass opening pressure a valve body loading closing spring whose spring hardness varies depending on the temperature in such a way that at low cold start conditions, the spring hardness low and at higher temperature, such as the operating temperature , is harder. In a closing spring, which provides the spring hardness for the desired bypass function with the usual bypass opening pressure of three bar only in normal operation at temperature, this means that in the low temperature range weak closing spring of the bypass in low temperature operation, as in cold start, due to the increased Viscosity of the fluid is open pending high differential pressure, regardless of the state of the filter material. The opened bypass thus leads to a contamination of the system despite the presence of a functional filter element.

Based on this prior art, the invention has the object to provide a filter device available, the bypass device is characterized by a particularly advantageous performance.

According to the invention this object is achieved by a filter device having the features of claim 1 in its entirety.

According to the characterizing part of claim 1, an essential feature of the invention consists in that the control device lowers the bypass opening pressure from a high pressure value to a low pressure value after reaching a predefinable temperature threshold value. This opposite to the above known solution control behavior of the control device allows a particularly advantageous performance of the filter device according to the invention. In the specification of the temperature threshold value on the transition temperature between cold operation with high fluid viscosity and the range in which the viscosity of the hot fluid is in the normal range, and when designing the bypass device to the usual opening pressure of, for example, three bar, the bypass device operates in the entire range Operating temperature optimally, with an opening of the bypass in the desired manner only in response to a malfunction (blocking) of the filter material. Since the control device prescribes a high pressure value in the invention at temperatures below the threshold for the opening of the bypass, the disadvantage of the known solution is avoided at the same time that the high viscosity at cold start operation opens the bypass unnoticed by the functional state of the filter element. Due to the provided in the invention high pressure value at high viscosity, the bypass remains closed at functional conditions, so permeable filter element even at cold start conditions, as long as there is no blocking of the filter material and thereby opens the bypass despite the raised opening pressure value. In the invention, therefore, also in the area of the cold operation, the bypass function is dependent on the condition of the filter element and thereby safe operation of the filter device under all operating conditions, i. without the risk of contamination of the system under cold start conditions.

In advantageous exemplary embodiments, the control device has a bimetallic element which produces a fluid-conducting connection between the non-filtrate side and a control chamber accommodated in the bypass device, which is connected to the filtrate side of the filter element below this temperature threshold value, starting from the predefinable temperature threshold value. Advantageously, therefore, the change of the bypass opening pressure is effected by a switching process controlled by the fluid pressure at a clearly predetermined switching temperature.

Advantageously, the arrangement may be such that the temperature threshold is 20 ° C. and / or that the control means lowers the bypass opening pressure from the high of five bars to the low pressure of three bars.

In particularly advantageous embodiments, in a closed state of the valve body, in which this rests on housing parts of the bypass device, the control chamber bounded by these housing parts, wherein in the control chamber each unfiltrate and a filtrate port open, depending on the fluid temperature alternately from the bimetallic element are closable. As a result, depending on the control position of the bimetallic element, the valve body is loaded with different opening force, which acts against the closing force of the spring and is generated by the fluid pressure.

The bimetallic element may advantageously be designed in the manner of a plate-like round control disk forming a snap element which, at its edge in the control chamber by means of a fixing device, releases a fluid path from the non-filtrate side into a subspace of the control chamber in its position blocking off the filtrate side otherwise the filtrate connection opens. Such a bimetallic disc may be formed such that it bulges depending on the temperature on one side or the other and depending on the curvature assumes a blocking position or release position.

The arrangement may furthermore advantageously be such that the control chamber has a further subspace adjacent to a subspace into which the unfiltrate port discharges in fluid-conducting manner as soon as it is released from the bimetallic element. In this case, the control chamber may be encompassed by a further control chamber on the edge, which is separated from the one control chamber with the valve body closed and on housing parts of the bypass device and which is permanently connected to the unfiltrate side in a fluid-conducting manner.

Advantageously, the unfiltered port can be received in a cover of the control chamber, which is firmly connected to the housing parts of the bypass device, wherein the filtrate port is passed through the valve body. In this design, the bypass device with little need for space can be integrated into the filter device.

For sealing against the housing parts of the bypass device, the valve body may carry a sealing cap and be permanently acted upon by a compression spring which extends between a receiving housing for the valve body and this, wherein the interior of the receiving housing via at least one passage permanently fluid carrying connected to the filtrate side of the filter element is.

In this case, the receiving housing for the valve body can be connected as an additional housing part with the other housing parts of the bypass device, which are part of an end cap of the filter element with particular advantage.

In this arrangement of the bypass device on an end cap, the bypass device may at least partially protrude into the hollow cylindrical filter element, which is provided on the bottom side with a further Ednkappe having a Filtratauslass. In operation, the filter element is flowed through inwardly from the outside of the filter material.

The invention is also a filter device housing for receiving a filter device according to one of the claims 1 to 12, wherein the filter device housing has the features of claim 13.

According to the claim 14, the invention is also the use of a filter device according to one of the claims 1 to 12 and a filter device housing according to claim 13.

• 1 einen zentralen Längsschnitt eines Ausführungsbeispieles der erfindungsgemäßen Filtervorrichtung;
• 2 einen gegenüber 1 vergrößert gezeichneten Teillängsschnitt lediglich des der Bypasseinrichtung benachbarten Bereichs des Filterelements der Filtervorrichtung, wobei der Betriebszustand der Bypasseinrichtung bei einer Temperatur unterhalb eines Temperaturschwellenwertes gezeigt ist;
• 3a, 3b die Projektion von oberer bzw. unterer Druckfläche des Ventilkörpers der Bypasseinrichtung, wobei die Druckverteilung beim Betriebszustand unterhalb des Temperaturschwellenwertes angegeben ist;
• 4 einen der 2 entsprechenden Teillängsschnitt, wobei der Betriebszustand der Bypasseinrichtung oberhalb des Temperaturschwellenwertes dargestellt ist, und
• 5a, 5b den 3a, 3b entsprechende Darstellungen, wobei die Druckverteilung beim Betriebszustand oberhalb des Temperaturschwellenwertes dargestellt ist.

The invention with reference to an embodiment shown in the drawing will be explained in detail. Show it:

• 1 a central longitudinal section of an embodiment of the filter device according to the invention;
• 2 one opposite 1 enlarged drawn partial longitudinal section only of the adjacent portion of the bypass device of the filter element of the filter device, wherein the operating state of the bypass device is shown at a temperature below a temperature threshold;
• 3a . 3b the projection of upper or lower pressure surface of the valve body of the bypass device, wherein the pressure distribution in the operating state is indicated below the temperature threshold value;
• 4 one of the 2 corresponding partial longitudinal section, wherein the operating state of the bypass device is shown above the temperature threshold, and
• 5a . 5b the 3a . 3b corresponding representations, wherein the pressure distribution is shown in the operating state above the temperature threshold.

The 1 shows an embodiment of the filter device according to the invention including a designated as a whole by 1 device housing which accommodates the filter device according to the invention, which is a filter element 3 and a bypass device 5 having. The housing 1 has a housing body 7 in the form of a circular cylindrical Pot on, at the bottom part 9 a centrally located filtrate outlet 11 located. At the upper open end of the main part 7 is the case 1 through a housing head 13 closed, at which a lateral Unfiltrateinlass 15 located. As a receptacle for the filter element 3 located at the bottom part 9, the filtrate outlet 11 concentric, an inwardly projecting nozzle 17. This forms with its outside the seat for a lower end cap 19, which in a conventional manner a skirt for a hollow cylinder forming filter material 21 forms. The end cap 19 has a central opening 23 on, the opening edge of an axially downwardly projecting connection piece 25 surrounded, which is built-in filter element 3 the outer surface of the neck 17 of the bottom part 9 overlaps. This is about the opening 23 the end cap 19 the fluid passage from the inner filter cavity 26 of the filter element 3 to the filtrate outlet 11 educated. With inflow of unfiltrate through the inlet 15 to the outside of the filter material 21 of the filter element 3 forms the inner filter cavity 26 the clean side (filtrate side) while the filter material 21 surrounding space inside the housing forms the dirty side (non-filtrate side).

The bypass device 5 forms part of the upper end cap 27 covering the top of the filter material 21 forms. This end cap 27 has an upper housing part 29 that is, from the outer perimeter edge 31 offset radially inward, extending in a stepped form axially upwards. This upper housing part 29 forms a centrally located passage opening 33 the end cap 27 and a first control chamber 35 and a second control chamber 37 , Through a housing cover 39 at the top of the upper housing part 29 are the control chambers 35 . 37 closed at the top. The end cap 27 has a lower, second housing part 41 on, which is the receiving housing for a movable valve body 43 forms. The lower housing part 41 extends from the one between the opening 33 and the filter material 21 located area of the end cap 27 away axially into the inner filter cavity 26 in and has the shape of a to the case back 45 conically tapered pot, in whose side wall fluid passages 47 are formed.

From the central area of the soil 45 of the lower housing part 41 extends a hollow pin 49 axially upwards in the direction of the upper housing part 29 , On the inside forms the hollow pin 49 the guide for the axially movable valve body 43 , This has on the whole in the form of a mushroom with a closing body forming headboard 51 and a hollow shaft adjoining the underside thereof 53 in the hollow pin 49 is movably guided. The shaft 53 has recessed grooves on the outside 55 on, the fluid communication between the clean side forming the filter cavity 26 and the entrance opening 57 of the hollow shaft 53 form. The outside of the valve body 43 leading hollow pin 49 forms the centering body for a closing spring in the form of a helical compression spring 50 that is between the ground 45 the housing part 41 and the underside of the head part 51 of the valve body 43 is tense. The top of the headboard 51 forms in itself at the inner passage 56 of the shaft 53 adjoining central area 59 a surface extending in a radial plane and adjoining it radially outward a cone part having the shape of a stepped cone consisting of two flat surface parts 62 and 63 educated. Of these forms the outer surface part 63 the valve sealing area with which the valve body 43 at the in 2 and 4 shown closed position on a sealing line 65 at a stage of the upper housing part 29 is applied.

On the top of the headboard 51 of the valve body 43 more precisely on the central area 59 and a part of the first lateral surface part 61 , is a sealing cap 67 made of an elastomer. In the closed position shown ( 2 and 4 ), forms the sealing cap 67 by abutment on the edge of one of the upper housing part 29 axially projecting annular body 69 the seal between the inner first control chamber 35 and the outer control chamber 37 , The latter is over in the upper housing part 29 located slots 85 with the housing part 29 surrounding, dirt-side space, so that in the second control chamber 37 permanently the pressure of the non-filtrate side is effective. The sealing cap 67 has coaxial with the shaft 53 a tubular body 71 on, with his lower tube section in the passage 56 of the shaft 53 extends and with its upper pipe section in the first control chamber 35 protrudes. With his end 73 forms the upwardly projecting tubular body 71 a valve opening. Coaxial with the pipe body 71 is in a central opening of the upper housing cover 39 a short piece of pipe 75 used that like the sealing cap 67 is formed of an elastomer and as the tubular body 71 with his in the control chamber 35 located end 77 forms a valve opening. The through the pipe ends 73 and 77 formed valve openings are alternately released by a bimetallic temperature dependent or closed.

The bimetallic element has the form of a membranous, thin, circular disk 79 , which is dish-like depending on the temperature on one side or the other side. When the temperature changes over a temperature threshold, the curvature changes abruptly. The bimetal disc 79 thereby forms a kind of snap element. At below the threshold temperature is the disc 79 arched upward, as in 2 is shown in the operating state of the bypass device 5 shown below the temperature threshold. The 4 shows the operating state above the temperature threshold, the disc 79 is curved down. In the control chamber 35 the disc 79 is mounted so that when curving up through the end 77 of the pipe section 75 closed valve opening closes (see 2 ) and when curving down (see 4 ) the valve opening at the end 73 of the tubular body 71 closes. For this control or valve function is the bimetal disc 79 in the first control chamber 35 with its disc edge on wall parts of the upper housing part 29 not stored in a full-surface system, but are on the peripheral suspension of the bimetallic disc 79 Passage sites 82 formed, the fluid connections between upper subspace 80 and lower subspace 81 the control chamber 35 form (see 4 ).

When operating both below the temperature threshold, this operating condition is in 2 . 3a and 3b shown, as well as when operating above the temperature threshold, this operating state is in 4 . 5a and 5b represented, prevails in the second control chamber 37 permanently the pressure of the unfiltrate side, because the control chamber 37 over the slots 85 in the housing part 29 is in communication with the outer Unfiltratseite. Also prevails in the pipe section open to the outside 75 the pressure of the unfiltrate side. When operating below the temperature threshold ( 2 . 3a and 3b ) closes the bimetallic disc 79 the valve opening at the end 77 of the pipe section 75 and opens the valve opening at the end 73 of the tubular body 71. At the by the compression spring 50 in the closed position biased valve body 43 therefore results in the pressure distribution in 3a and 3b is clarified. As the effect of the compression spring 50 reinforcing additional closing force acts on the in 3b A1 area of the entire underside of the closing body 43 pending pressure of the filtrate side.

When the valve opening is closed at the end 77 of the pipe section 75 and simultaneous opening of the end 73 of the tubular body 71 acts via the connection of the control chamber 35 with the passage 56 of the valve stem 53 the pressure of the filtrate side also at the top of the valve body 43 in the area of in 3a Area designated A3 as a force that the valve body 43 acted in the opening direction. At the same time acts on the top of the valve body 43 in the outer region in the area designated by a dash pattern A2 and the pressure of the non-filtrate side, in the outer second control chamber 37 is present, and generates a force in the opening direction. In combination of this pressure distribution with the closing force of the compression spring 50 As a result, an increased bypass opening pressure of, for example, five bar can be specified.

When operating above the threshold temperature, this condition is in 4 . 5a and 5b shown, the valve opening is at the end 77 of the pipe section 75 open while the valve opening at the end 73 of the tubular body 71 closed is. About the pipe section 75 Therefore prevails in the control chamber 35, the unfiltered pressure. Since this permanently in the outer, second control chamber 37 is effective, the entire area of the upper side of the valve body is now available as differential pressure area A2 during hot operation ( 5a During cold operation, the differential pressure area A2 ( 3a ), only by the edge area outside the area A3 is available. The opposite 3a Increased differential pressure area A2 of FIG. 5a leads to an increased, generated by the fluid pressure force in the opening direction and thus to a reduction of the bypass opening pressure, which is interpretable in hot operation, for example, three bar against the opening pressure of five bar in cold operation. It then opens the bypass valve means and gives the flow from the unfiltrate side over the valve body 43 in its open position to Filtratseite free, which depends on increasing blocking of the filter material 21 steadily increasing, with up to the complete blocking and hitherto only partially completed opening of the bypass device, a portion of the fluid flow still over non-blocked parts of the filter material 21 can be further cleaned.

mit

p₁ =

Druck auf der Filtratseite 26;

p₂ =

Druck auf der Unfiltratseite 15;

A1 =

druckwirksame Fläche des Ventilkörpers 43 auf der Filtratseite 26;

A2 =

druckwirksame Fläche des Ventilkörpers 43 auf der Unfiltratseite 15 innerhalb der zweiten Steuerkammer 37;

A3 =

druckwirksame Fläche des Ventilkörpers 43 auf der Unfiltratseite 15 und innerhalb der ersten Steuer-Kammer 35;

F_c =

Kraft der auf den Ventilkörper 43 einwirkenden Druck-Feder 50.

For the forces acting on the valve body 43 operate in cold mode, in which by means of the bimetallic disc 79 the unfiltered connection on the pipe section 75 is closed, the following applies: $$0={\text{p}}_1\times \text{A1}+{\text{F}}_{\text{c}}-{\text{p}}_2\times \text{A2}-{\text{p}}_1\times \text{A3}$$

With

p ₁ =

Pressure on the filtrate side 26 ;

p ₂ =

Pressure on the unfiltrate side 15 ;

A1 =

pressure-effective area of the valve body 43 on the filtrate side 26 ;

A2 =

pressure-effective area of the valve body 43 on the unfiltrate side 15 within the second control chamber 37 ;

A3 =

pressure-effective area of the valve body 43 on the unfiltrate side 15 and within the first control chamber 35 ;

F _c =

Force the on the valve body 43 acting pressure spring 50.

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

• WO 0155563 A2 [0002]

Claims (14)

Filter device comprising a filter element (3) and a bypass device (5) which has a spring-loaded valve body (43) which opens from a predefinable bypass opening pressure and a fluid-carrying connection between a non-filtrate (15) and a filtrate (26) of the filter element (3 ) with at least partial bypassing of the filter material (21) of this filter element (3), wherein a control device (79) is provided, by means of which the bypass opening pressure is temperature-controlled variable, characterized in that the control device (79) the bypass opening pressure from reaching a predetermined temperature threshold lowers from a high pressure value to a low pressure value. Filter device after Claim 1 , characterized in that the control device comprises a bimetallic element (79), the temperature-controlled from the predetermined temperature threshold, a fluid-conducting connection between the Unfiltratseite (15) and one in the bypass device (5) recorded control chamber (35) produces below this temperature threshold value to the Filtratseite (26) of the filter element (3) is connected. Filter device after Claim 1 or 2 , characterized in that the temperature threshold value is 20 ° C and / or that the control device (79) lowers the bypass opening pressure from the high value of 5 bar to the low pressure value of 3 bar. Filter device according to one of the preceding claims, characterized in that in a closed state of the valve body (43), in which this rests on housing parts (29,65) of the bypass device (5), the control chamber (35) of these housing parts (29,65 ) is limited and in that in the control chamber (35) each have a Unfiltrat- (15) and a filtrate port (71) open, which are alternately closed depending on the fluid temperature of the bimetallic element (79). Filter device according to one of the preceding claims, characterized in that the bimetallic element in the manner of a snap-action forming round control disc (79) is formed, the edge fixed in the control chamber (35) by means of a fixing device, in their the filtrate (26) shut off Position a fluid path (82) from the unfiltered side (15) in a subspace (81) of the control chamber (35) releases, in the otherwise the filtrate port (71) opens. Filter device according to one of the preceding claims, characterized in that the control chamber (35) has a further, adjacent to the one subspace (81) further subspace (80) into which the unfiltered port (75) discharges fluid, as soon as this of the bimetallic element ( 79) is released. Filter device according to one of the preceding claims, characterized in that the control chamber (35) by a further control chamber (37) is peripherally encompassed, with closed, on housing parts (29,65) of the bypass device (5) fitting valve body (43) of the a control chamber (35) is separated and the permanent fluid leading to the unfiltrate side (15) is connected. Filter device according to one of the preceding claims, characterized in that the unfiltered port (75) is accommodated in a cover (35) of the control chamber (35) which is fixedly connected to the housing parts (29,65) of the bypass device (5), and the filtrate port (71) is passed through the valve body (43). Filter device according to one of the preceding claims, characterized in that the valve body (43) for sealing relative to the housing parts (26,65) of the bypass device (5) carries a sealing cap (67) and is permanently acted upon by a compression spring (50) which between a receiving housing (41) for the valve body (43) and this extends, and that the interior of the receiving housing (41) via at least one passage (47) is permanently fluid-carrying connected to the filtrate side (26) of the filter element (3). Filter device according to one of the preceding claims, characterized in that the receiving housing (41) for the valve body (43) as an additional housing part with the other housing parts (29) of the bypass device (5) is connected, which is part of an end cap (27) of the filter element ( 3) are. Filter device according to one of the preceding claims, characterized in that in the case of the unfiltrate connection (75) closed by means of the bimetal element (79), the following formula of forces applies to the valve body (43): $$0={\text{p}}_1\times \text{A1}+{\text{F}}_{\text{c}}-{\text{p}}_2\times \text{A2}-{\text{p}}_1\times \text{A3}$$

with p ₁ = pressure on the filtrate side (26); p ₂ = pressure on the non-filtrate side (15); A1 = pressure-effective area of the valve body (43) on the filtrate side (26); A2 = pressure-effective area of the valve body (43) on the non-filtrate side (15) within the second control chamber (37); A3 = pressure-effective area of the valve body (43) on the non-filtrate side (15) and within the first control chamber (35); F _c = force of the pressure spring (50) acting on the valve body (43). Filter device according to one of the preceding claims, characterized in that the bypass device (5) at least partially protrudes into the hollow cylindrical filter element (3), which is provided on the bottom side with a further end cap (19) having a Filtratauslass (23). Filter device housing for receiving a filter device according to any one of the preceding claims, characterized in that it comprises a Unfiltratzufuhr (15) and a filtrate discharge (11,17) formed step-like manner a receptacle (17) for the bottom side (19) of the filter element (3) forms that the bypass device (5) as a component of the housing (1) interchangeable designed filter element (3) protrudes with a supernatant into a housing head (13) of the housing (1) with the Unfiltratzufuhr (15) having a housing pot (7 ), which encloses the filter element (3) received in the housing (1) at a radial distance. Use of a filter device according to one of Claims 1 to 12 and a filter device housing (1) Claim 13 , characterized in that at cold start of hydraulic machines, such as mobile machines, a higher opening pressure for the bypass device (5) is allowed to bring low-temperature fluid through the filter material (21) of the filter element (3) and that with increasing fluid temperature means a control device (79) the opening pressure of the bypass device (5) is reduced from a higher pressure value to a lower pressure value, in which with increasing blocking of the filter material (21) of the filter element (3), the bypass device (5) at least partially bypassing the filter material ( 21) of the filter element (3) connects the non-filtrate side (15) with the filtrate side (26).

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