DE102013221051B4 - Valve device, non-return filter - Google Patents

Abstract

Valve device (1), in particular a two-stage valve, for controlling fluids, in particular hydraulic fluid, having at least one first fluid connection (4) and at least one second fluid connection (5), a through-flow opening (15`), which connects the first fluid connection (4) to connects the second fluid connection (5), a valve seat (19) assigned to the through-flow opening (15) and a valve element (13) assigned to the valve seat (19), which can be displaced to open or close the through-flow opening (15'), the first fluid connection (4) and/or the second fluid connection (5) is assigned a non-return filter (27), which directs the fluid through at least one filter element (34) when there is a first flow direction, and a bypass when there is a second flow direction opposite to the first flow direction (37,40) to bypass the filter element (34) releases, and wherein the non-return filter (27) has a filter element t (34) carrying filter body (28), characterized in that the filter body (28) is arranged in a chamber (26) connecting the flow opening (15') to the second fluid connection (5) so that it can be displaced between two end positions in the direction of flow, wherein in one end position the fluid is passed through the filter element (34) and in the other end position the bypass (37) is released, or that the filter body (28) is fixedly arranged in the chamber (26) and that the flat filter element ( 34) is held pivotably on one side on the filter body (28), so that it rests tightly against the filter body (28) when the first flow direction is present, and that it detaches from the filter body to release the bypass (40) when the second flow direction is present .

Description

The invention relates to a valve device, in particular a two-stage valve, for controlling fluids, in particular hydraulic fluids, having at least one first fluid connection and at least one second fluid connection, a flow opening which connects the first fluid connection to the second fluid connection, a valve seat assigned to the flow opening and a the valve element associated with the valve seat, which can be displaced to open or close the through-flow opening.

Furthermore, the invention relates to a non-return filter.

State of the art

Valve devices of the type mentioned are known from the prior art. In motor vehicle construction, such valves are used, for example, in hydraulic brake systems in order to control the inflow or outflow of gases or liquids, in particular brake fluids, or to control and regulate the direction of flow. Such a valve device often connects a primary circuit, which has a brake master cylinder, and a secondary circuit, which has a pump element, the primary circuit being connected to the first fluid connection and the secondary circuit being connected to the second fluid connection. The two hydraulic circuits are then connected to each other by moving a valve element away from a valve seat, so that fluid can flow from the primary circuit to the secondary circuit or vice versa, depending on the pressure ratio. The first fluid connection is often associated with a filter, in particular a radial filter element, which is used to hold back larger dirt particles that should not get into the primary circuit. If, due to the pressure conditions, the flow path leads from the second filter connection to the first filter connection, dirt particles are collected or retained on the filter element accordingly. However, if the pressure conditions change so that the flow path leads from the first fluid connection to the second fluid connection, the dirt particles are removed again and directed in the direction of the secondary circuit or in the preliminary stage of the two-stage valve device.

A generic valve device is from the published application DE 38 15 731 A1 , the disclosure document DE 10 2004 024 673 A1 or the patent DE 602 18 306 T2 known.

Disclosure of Invention

The valve device according to the invention with the features of claim 1 has the advantage that impermissible contamination of the valve device is prevented, with a pressure drop across the valve device being avoided, particularly at low temperatures and the associated possibly high viscosity of the fluid. The valve device according to the invention with the features of claim 1 is characterized in that the first fluid connection and/or the second fluid connection is assigned a non-return filter, which directs the fluid through a filter element when there is a first flow direction and when there is a second, first flow direction opposite flow direction for the fluid releases a bypass to bypass the filter element. As a result, there is a lower flow resistance in the second flow direction than in the first flow direction. At the same time, dirt particles, for example, are retained in front of the valve in the first flow direction, while dirt particles can be flushed out of the valve in the second flow direction.

According to the invention it is provided that the non-return filter has a filter body carrying the filter element. The non-return filter is thus formed by the filter element and the filter body. As a result, the filter element can be arranged in a simple manner on the valve device by means of the filter body. The filter body can be attached to the valve device, in particular in the housing of the valve device.

According to a preferred development of the invention, it is provided that the non-return filter is arranged between the second fluid connection and the valve seat. The non-return filter, which works differently depending on the flow direction of the fluid, is therefore assigned to the second fluid connection. In particular, the non-return filter is designed in such a way that the first direction of flow leads from the second fluid connection to the valve seat, while the second direction of flow points from the valve seat to the second fluid connection. In the first direction of flow, all of the fluid is routed through the filter element of the non-return filter, so that all of the fluid is filtered and any particles carried along are retained in front of the valve device. If the direction of flow changes due to changed pressure conditions, the non-return filter opens a bypass, as a result of which at least parts of the fluid can be conveyed past the filter element. This avoids a high back pressure building up in this direction of flow, which would correspondingly affect the pressure drop across the valve device. If fluid is thus discharged from the valve device through the second fluid connection, this takes place without flow-impeding filtering, while an inflow into the valve device through the second filter connection can only take place in a filtered manner. Provision is particularly preferably made for the filter or radial filter element already mentioned at the beginning to be assigned to the first fluid connection. Any dirt particles retained on this filter are then carried out of the valve or the valve device when the fluid flows in the second flow direction in the direction of the second fluid connection. Overall, this ensures particularly safe operation of the valve device. According to an alternative embodiment, it is preferably provided that the non-return filter is not assigned to the second fluid connection but to the first fluid connection. The non-return filter can be designed as described above and below. In this case, the filter mentioned in the introduction is preferably assigned to the second fluid connection. According to a further embodiment, it is preferably provided that a correspondingly designed non-return filter is assigned to each of the two fluid connections.

In one embodiment, it is provided according to the invention that the filter body is arranged in a chamber connecting the through-flow opening with the second fluid connection so that it can be displaced in the direction of flow between two end positions, with the fluid being guided through the filter element in one end position and the bypass being released in the other end position. It is therefore provided here that the non-return filter is arranged in the chamber so that it can be displaced in the direction of flow. In particular, the filter body is moved into one or the other end position by the flowing fluid. If the non-return filter is in one end position, the chamber is completely closed by the filter element, so that the fluid can only flow through the filter element. If the non-return filter is in the other end position, the bypass is released. The bypass can be formed, for example, by a bypass recess on the inside of the chamber, which is sealingly covered by the check valve in one end position and released in the other end position.

Furthermore, it is preferably provided that the filter element is held as a radial filter on the at least essentially cylindrical filter body. Due to the configuration as a radial filter, the filter element forms in particular a casing wall section of the cylindrically configured cylinder body. The fluid thus flows radially through the wall of the filter body. This allows a particularly compact non-return filter to be implemented.

According to an advantageous development of the invention, it is provided that the non-return filter has a cylinder section which lies axially in the through-flow opening at least in certain areas. The non-return filter thus lies at least in regions in the through-flow direction, as a result of which the non-return filter and in particular the filter body are guided in the through-flow opening.

According to a preferred development of the invention, it is provided that the cylinder section described above bears sealingly with a free end face in one end position on the valve element and is arranged at a distance from the valve element in the second end position. Because the cylinder section protrudes into the through-flow opening, it is possible to select its axial length such that it protrudes through the through-flow opening in at least one position. The length of the cylinder section is expediently selected in such a way that the cylinder section can rest against the valve element in a sealing manner in any position thereof. The sealing contact with the valve element means that, when the valve is open, the fluid can only pass through the filter element in a direction of flow from the second fluid connection to the first fluid connection.

The cylinder body is preferably designed in the form of a sleeve in such a way that a flow can flow through it axially. As soon as the check valve moves to the other end position, the cylinder section detaches from the valve element, so that the fluid can flow through the axially open end faces of the filter body, thereby bypassing the filter element.

The cylinder section preferably has a cross section that is smaller than the cross section of the through-flow opening. On the one hand, this ensures the mobility of the non-return filter and, on the other hand, allows a further bypass past the outside of the filter body. Provision is preferably made for the non-return filter with the filter body to be in sealing contact with the rear side of the valve seat in one end position, so that the hydraulic medium cannot bypass the filter body.

Provision is particularly preferably made for the cylinder body to have at least one stop for determining one end position or the other, with the stop being designed in particular in such a way that it ensures that the fil terkörpers guaranteed on the back of the valve seat in one end position. Alternatively or additionally, it is preferably provided that the filter body has at least one inflow surface, which causes the non-return filter to be displaced by the flow of the fluid. The inflow surface is characterized in that it prevents the flow path of the fluid, so that a dynamic pressure is built up on it, which leads to the displacement of the filter body. Particularly in connection with the advantageous cross-section of the cylinder section, which is smaller than that of the through-flow opening, it is also possible to flow against a corresponding inflow surface when the cylinder body is in close contact with the valve element.

In an alternative embodiment, the invention provides that the filter body is arranged fixedly in the chamber, and that the flat filter element is held pivotably on the filter body, so that when the first flow direction is present, it rests on a filter body, covering a flow opening of the filter body, and that it is detached from the filter body to release the through-flow opening when the second flow direction is present. By detaching the filter element from the filter body, a bypass is released, which allows the fluid to bypass the filter element and flow directly through the flow opening of the filter body. In particular, it is provided that the filter element is designed to be elastically deformable, wherein it is preferably attached to the filter body on one side, and its elastic deformation opens or closes the bypass. Alternatively, it is conceivable to design the filter element to be rigid and to hold it on the filter body by means of a joint. It is particularly preferably provided that the filter body is designed in the shape of a circular ring and that the filter element does not have a circular cross-section that has a diameter larger than the inner diameter of the filter body.

• 1 ein zweistufiges Magnetventil in einer Längsschnittdarstellung,
• 2A und 2B eine vorteilhafte Weiterbildung des Ventils, jeweils in einer Längsschnittdarstellung, und
• 3 eine alternative Weiterbildung des Magnetventils.

The invention is to be explained in more detail below using exemplary embodiments. The following show this:

• 1 a two-stage solenoid valve in a longitudinal section,
• 2A and 2 B an advantageous further development of the valve, each in a longitudinal sectional view, and
• 3 an alternative development of the solenoid valve.

1 shows a valve device 1 in a simplified longitudinal sectional view, which is designed as a two-stage valve, which is designed as a high-pressure switching solenoid valve for a brake system of a motor vehicle. The valve has a preliminary stage 2 and a main stage 3, with the preliminary stage 2 and the main stage 3 both being fluidically arranged between a first fluid connection 4 and a second fluid connection 5 of the valve. The fluid port 4 is used to connect the valve to a primary circuit of the brake system, such as a master brake cylinder, while the second fluid port 5 is used to connect to a secondary circuit, such as a pump device.

The preliminary stage 2 is formed by a first valve element 6 , which is designed as a valve ball in the present case, and a first valve seat 7 . The valve element 6 is firmly connected to an actuating element 8 which can be displaced axially in a first valve sleeve 9 .

For displacement of the actuating element 8, a valve sleeve 9, a pole core 10 is fixedly arranged at an axial distance thereto, to which a magnet coil (not shown here) is assigned. By energizing the magnetic coil, a magnetic field is generated by means of the pole core 10, which pulls the actuating element 8, which is designed as a magnet armature, in the direction of the pole core 10. A compression spring 11 , here in the form of a helical spring, is arranged prestressed between the pole core 10 and the actuating element 8 , against which the actuating element 8 is pulled to actuate the valve 1 .

In this respect, the valve is a normally closed solenoid valve. In the unactuated state, the helical spring 11 presses the first valve element 6 against the first valve seat 7 by means of the actuating element 8. The actuating element 8 protrudes axially in some areas into a second valve sleeve 12, in which the preliminary stage 2 or the first valve seat 7 lies.

The first valve seat 7 is formed by a second valve element 13 which is arranged on the second valve sleeve 12 in an axially displaceable manner. In this case, the second valve element 13 is assigned a further compression spring 14 , in the present case in the form of a helical spring, which urges the second valve element 13 in the direction of the actuating element 8 . The second valve element 13 also has a throughflow opening 15 to which the first valve seat 7 is assigned. In the non-actuated state of the solenoid valve 1, the flow opening 15 is thus closed by the first valve element 6.

The second valve element 13 has an axial section 16 which protrudes through an opening 17 on the end face of the valve sleeve 12 . The valve 1 also has a third valve sleeve 18, which is multi-stage, in particular in the manner of a deep-drawn part is trained. The valve sleeve 12 and the axial section 16 protrude into the third valve sleeve 18, with the third valve sleeve 18 forming a second valve seat 19 which interacts with the valve element 13 to form the main stage 3 and is assigned to a flow opening 15' to the fluid connection 5. The valve sleeve 18 also has the fluid connection 5 at its free end. The valve sleeve 18 is arranged in a valve housing 20 on which the fluid connection 4 is formed radially. The valve sleeve 18 has a plurality of radial openings 21 which are distributed over the circumference of the valve sleeve 13 and are located axially at the level of the fluid connection 4, which is also assigned a filter 22 designed as a radial filter element, which is designed to retain larger dirt particles.

If the pressure in the secondary circuit is greater than in the primary circuit during operation, the hydraulic medium will release the closing body 13 from the second valve seat 19 and flow to the fluid connection 4 through the filter 22, as indicated by an arrow 23, with larger dirt particles possibly being trapped in the filter 22 be held back. If the pressure conditions are reversed, the valve element 13 detaches from the valve element 6, so that the hydraulic medium passes from the fluid connection 4 through the flow opening 15 to the fluid connection 5, with hydraulic medium flowing from the primary circuit into the secondary circuit, as indicated by an arrow 24. if the pressure in the primary circuit is higher than that in the secondary circuit.

In the latter case, dirt particles previously retained on the filter 22 are conveyed back into the secondary circuit, where they have to pass through the preliminary stage. Since the preliminary stage has relatively small dimensions, even small dirt particles can lead to the preliminary stage 2 jamming and thus to an impairment of the operation of the valve 1 .
the 2 and 3 showed an advantageous development of the valve device 1, which relates to the provision of a non-return filter 27 on the second fluid connection 5.

The second fluid connection 5 is formed by a further valve sleeve 25, which is shaped in such a way that it forms a chamber 26 between the fluid connection 5 and the through-flow opening 15'. In this chamber 26, a non-return filter 27 is arranged. The non-return filter 27 has a filter body 28 which is essentially sleeve-shaped so that it can be flowed through axially. The filter body 28 is arranged so that it can be displaced axially and thus in the direction of flow of the fluid in the chamber 26 . The filter body 28 has a cylinder section 29, the cross section of which is selected to be smaller than the inner diameter of the through-flow opening 15, and an actuating section 30, which adjoins the cylinder section 29 axially and has a diameter that is larger than that of the through-flow opening 15'.

The filter body 28 is arranged in the chamber 26 in such a way that the cylinder section 29 protrudes into the through-flow opening 15', the axial longitudinal extension of the cylinder section 29 being greater than the longitudinal extension of the through-flow opening 15', so that the cylinder section 29 can protrude completely through the through-flow opening 14 , as in 2 B shown.

Since the actuation section 30 has a larger diameter than the flow opening 15 ′, the filter body 28 can only be moved up to a stop 31 formed by the actuation section 30 on the rear side of the valve seat 19 . The stop 31 defines a maximum end position of the filter body 28 .

The cylinder section 29 also has a plurality of openings 33 in its jacket wall, which are arranged evenly distributed over the circumference, and in each of which a filter element 34 is arranged as a radial filter, completely filling the opening. The filter element 34 is preferably designed like the filter 22 so that it retains correspondingly large dirt particles.

If the valve device 1 is actuated, as in 2A and 2 B shown, the valve element 16 is pulled away from the valve seat 19, so that the flow opening 15 'and thus the connection between the fluid ports 4 and 5 is released. If the pressure in the primary circuit is higher than in the secondary circuit, as in 2A shown, the fluid flows, as described above, from the fluid port 4 to the fluid port 5. The flow ensures that the non-return filter 27 in the in 2A end position shown is shifted, in which the actuating section 30 rests against the end of the valve sleeve 25, with a region of the cylinder section 29 remaining in the flow opening 15', so that the non-return filter 27 is guided securely. As a result of the displacement into this end position, the cylinder body 28 is released from the valve element 16 so that the fluid can flow directly through the sleeve-shaped filter body 28 in an axial direction, as indicated by arrows 35 . By moving the non-return filter 27, a bypass 37 was released. However, some of the fluid can also pass through the filter elements 34 . In the present case, the cross section of the cylinder section 29 is chosen such that in a peripheral segment a distance to inner wall of the flow opening 15 ′, so that fluid can also flow past the non-return filter 27 outside of the filter body 28 , as indicated by an arrow 36 . For this purpose, the filter body 28 has at least one throughflow opening in the area of the actuation section 30 through which the fluid can reach the fluid connection 5 or into the interior of the sleeve-shaped filter body 28 .

If the pressure conditions change so that the pressure in the secondary circuit increases compared to the pressure in the primary circuit, the flow direction of the fluid also changes. The flow shifts the filter body 28 in the direction of the valve element 16 until it rests against the valve element 16 with the free end face 32, as shown in FIG 2 B shown. The filter body 28 penetrates so far into the through-flow opening 15' that a section of the actuating section also penetrates into the flow opening 15, this section of the actuating section 30 having an outer diameter which corresponds to the inner diameter of the through-flow opening 15', so that the flow path is on the outside is closed past the filter body 28 . The fluid can thus only flow through the filter elements 34 from the fluid connection 5 to the fluid connection 4 . This prevents dirt particles from penetrating into the interior of the valve device 1 right from the start.

The non-return filter 27 thus protects the valve device 1 from unwanted dirt particles and at the same time ensures, at least in one flow direction, that the fluid flows freely without a drop in pressure through the valve device 1.

3 shows an alternative embodiment of the non-return filter 27 in a perspective view. According to this exemplary embodiment, the filter body 28 is designed in the shape of a circular ring. In this case, the filter element 34 is flat and circular and has an outer diameter that protrudes beyond the inner diameter of the filter body 28 , which is designed in the shape of a circular ring. The filter element 34 rests on one side of the filter body 28 so that it completely covers it. The filter element 34 is firmly connected to the filter body 28 at at least one point. In the present case, for this purpose, the filter element 34 is firmly connected to the filter body 28 at a fastening point 38, while the filter element 34 is otherwise free. If flow now flows through the non-return filter 27 in that fluid flows axially through the filter body 28 from the side having the filter element 34 to the opposite side, the filter element 34 is pressed against the annular filter body 28 . The filter body 28 is expediently held tightly laterally in the chamber 26 and fastened immovably, with the filter element 34 being arranged on the side of the filter body 28 opposite the through-flow opening 15', so that when the fluid flows according to arrow 39 from the fluid connection 5 to the fluid connection 4 flows, the filter element 34 is pressed against the filter body 28 and as a result all of the fluid is forced through the filter element 34 .

If the direction of flow changes, the one-sided attachment of the filter element 34 lifts or removes the latter on its free side from the filter body 28 , as indicated by dashed lines, as a result of which a bypass 40 is released. The filter element 34 is expediently designed to be elastically deformable for this purpose. Alternatively, the filter element 34 could also be rigid and connected to the filter body 28 by a joint at the attachment point 38 . The aforementioned advantages also result from this exemplary embodiment of the non-return filter 27 . The filter body 28 is preferably made of plastic.

According to the present embodiment, the non-return filter 27 is assigned to the second fluid connection 5 and the filter 22 to the first fluid connection 4. According to an alternative embodiment, not shown here, it is provided that the arrangement is reversed, so that the non-return filter 27 is assigned to the first fluid connection 4 and the Filter 22 is assigned to the second fluid port 5 . According to a further exemplary embodiment, which is not shown here, it is provided that both fluid connections 4 and 5 are each assigned a corresponding non-return filter 27 . In both cases, the non-return filter 27 assigned to the first fluid connection preferably works in such a way that the first direction of flow leads into the valve device and the second direction of flow leads in the direction of the respective fluid connection. Of course, instead of the two-stage valve, a single-stage valve with appropriate connections and one or more non-return filters 27 can also be provided as the valve device.

Claims (9)

Valve device (1), in particular a two-stage valve, for controlling fluids, in particular hydraulic fluid, having at least one first fluid connection (4) and at least one second fluid connection (5), a through-flow opening (15`), which connects the first fluid connection (4) to the second fluid connection (5) connects, one of the flow opening (15) associated with the valve seat (19) and the valve seat (19) associated with the valve element (13) for Freige ben or closing of the through-flow opening (15'), wherein the first fluid connection (4) and/or the second fluid connection (5) is assigned a non-return filter (27) which, when there is a first flow direction, the fluid through at least one filter element (34 ) directs, and in the presence of a second flow direction opposite to the first flow direction releases a bypass (37,40) for bypassing the filter element (34), and wherein the non-return filter (27) has a filter body (28) carrying the filter element (34), characterized in that the filter body (28) is arranged in a chamber (26) connecting the flow opening (15') to the second fluid connection (5) so that it can be displaced in the flow direction between two end positions, with the fluid passing through the filter element (34 ) passed and released in the other end position of the bypass (37), or that the filter body (28) fixed in the chamber (26) angeor dnet, and that the flat filter element (34) is held pivotably on one side on the filter body (28), so that it lies tightly against the filter body (28) when the first flow direction is present, and that when the second flow direction is present it moves from the filter body to release the bypass (40) solves. Valve device according to one of the preceding claims, characterized in that the non-return filter is arranged between the second fluid connection (5) and the valve seat (7). Valve device according to one of the preceding claims, characterized in that the filter element (34) is held on the at least essentially cylindrical filter body (28). Valve device according to one of the preceding claims, characterized in that the non-return filter (27) has a cylinder section (29) which at least partially lies axially in the flow opening (15'). valve device claim 4 , characterized in that the cylinder section (29) with a free end face (32) in one end position on the valve element (13) rests sealingly and in the second end position spaced from the valve element (13) is arranged. Valve device according to one of the preceding claims, characterized in that the filter body (28) is designed in the form of a sleeve in such a way that a flow can flow through it axially. Valve device according to one of Claims 4 until 6 , characterized in that the cylinder section (29) has a cross section which is smaller than the cross section of the flow opening (15 '). Valve device according to one of the preceding claims, characterized in that the filter body (28) has at least one inflow surface which causes the non-return filter (27) to be displaced by the flow of the fluid, and/or at least one stop (31) for determining one or other end position. Non-return filter (27) for a valve device (1) according to one or more of the preceding claims, wherein the non-return filter (27) directs a fluid through at least one filter element (34) when there is a first direction of flow, and when there is a second direction of flow opposite to the first direction of flow direction of flow releases a bypass (37,40) for bypassing the filter element (34), and wherein the non-return filter (27) has a filter body (28) carrying the filter element (34), characterized in that the filter body (28) has a through-flow opening in a (15') of the valve device (1) with a second fluid port (5) of the valve device (1) connecting chamber (26) can be arranged displaceably in the direction of flow between two end positions, with the fluid being guided through the filter element (34) in one end position and in the other end position of the bypass (37) is released, or that the filter body (28) fixed in the chamber (26) anor is possible, and that the flat filter element (34) is held pivotably on one side on the filter body (28), so that it lies tightly against the filter body (28) when the first direction of flow is present, and that when the second direction of flow is present, it moves from the filter body to release the bypass (40) solves.

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