WO2015048833A1

WO2015048833A1 - Solenoid spool valve

Info

Publication number: WO2015048833A1
Application number: PCT/AT2014/050226
Authority: WO
Inventors: Andreas Ploeckinger; Rudolf Scheidl; Christoph Gradl; Bernd Winkler; Paul Foschum
Original assignee: Linz Center Of Mechatronics Gmbh
Priority date: 2013-10-02
Filing date: 2014-09-29
Publication date: 2015-04-09
Also published as: DE102013220047A1; DE102013220047B4

Abstract

The invention relates to a solenoid spool valve. According to a first example of the invention, the valve comprises: a valve housing, which has a longitudinal axis; and a valve spool, which is supported in such a way that the valve spool can be moved along the longitudinal axis of the valve housing and which has an armature plate (31). An electromagnet is arranged in the valve housing in such a way that the electromagnet can apply a force to the armature plate in order to move the armature plate from a first end position to a second end position, wherein the end positions are defined by end stops. A half-open damping chamber, which is filled with hydraulic fluid during operation and is formed by at least one peripheral edge, is provided on an end stop or an a side of the armature plate. The armature plate and the associated end stop touch each other along the peripheral edge. If the armature plate lies against the end stop, a return-flow channel is provided between the damping chamber and the surrounding armature chamber.

Description

Magnetic slide valve

The invention is in the field of hydraulic valves and more particularly relates to a solenoid valve.

Solenoid valves are valves that are actuated by electromagnets. Depending on the design, solenoid valves can switch very quickly. In the field of hydraulics different types of solenoid valves are known. Essentially, one can distinguish between (solenoid) slide valves and seat valves. In contrast to seat valves, slide valves have a valve slide (valve piston), which is displaceably mounted in the valve housing along its longitudinal axis. The valve spool has running surfaces which can slide along the corresponding surface in the valve housing. In the valve housing usually inlets or outlets are provided for the hydraulic fluid. The valve spool has control edges, which interact with the inlets and outlets. Depending on the overlap (positive or negative) of the control edge and a corresponding edge of an inlet or an outlet, a volume flow of hydraulic fluid through the control edge is possible. The overlap can be adjusted via the position of the valve slide. In electromagnetic switching valves (switching solenoid valves), the valve spool can be moved by means of an electromagnet from a first end position (rest position) to a second end position, whereby the control edges of the valve spool open or close a flow path for the hydraulic fluid. The electromagnet can work against the restoring force of a spring, which forces the valve spool with de-energized electromagnet in the rest position. Slide valves have - in contrast to valves of other types - generally the advantage that more complex valve types (eg 5/2-way valves) can be relatively easily realized by a suitable design of the control edges and the inlets and outlets. The two end positions, between which the valve slide can move, are defined by corresponding end stops in the interior of the valve housing. Especially with valves that switch very quickly due to the design, the impact of the valve slide on the end stops can lead to wear.

In solenoid valves, the valve spool on a soft magnetic armature, which also forms the movable part of the electromagnetic actuator and cooperates with the electromagnet. That part of the interior of the valve housing which adjoins the electromagnet and in which also the armature reciprocates (hence also the term armature space), can at least partially be filled with hydraulic fluid. A seal of the anchor space would be very expensive. The hydraulic fluid in the armature chamber can slightly dampen the movement of the valve spool. Since this damping is deliberately kept very low by constructive measures in fast-switching spool valves (to enable rapid switching), thereby the above-mentioned problem of wear on the end stops and the valve spool is not avoided. In known valves, it is generally not ensured that the armature space is completely filled with hydraulic fluid, since the armature space substantially fills with leakage. If the armature space is not sufficiently filled with hydraulic fluid, the damping effect of the hydraulic fluid is not or not fully effective and the mentioned wear problem comes to bear sharper.

Another problem, which can occur especially with fast switching spool valves, is insufficient cooling of the electromagnet. A fast switching is achieved by a high acceleration of the valve spool, which in turn is due to high magnetic forces (and a low Mass of the valve spool) is effected. For this reason, flow in the electromagnet high currents, which can lead to a strong heating of the magnet in particular in a compact design of the magnet. The object underlying the invention can be seen to provide an improved in relation to the above-mentioned problem of wear solenoid valve. An improved cooling of the electromagnet would also be desirable. The mentioned object is achieved by a solenoid valve according to claim 1 or 8. Various embodiments and further developments are the subject of the dependent claims.

A solenoid valve will be described. According to a first example of the invention, the valve comprises a valve housing having a longitudinal axis and a valve slide displaceably mounted along the longitudinal axis of the valve housing and having an anchor plate. An electromagnet is arranged in the valve housing such that it can exert a force on the armature plate in order to displace it from a first end position to a second end position, the end positions being determined by end stops. At an end stop or on one side of the anchor plate, a semi-open, filled with hydraulic fluid during operation damping space is provided, which is formed by at least one circumferential edge. Anchor plate and associated end stop touch along the peripheral edge. When the anchor plate abuts against the end stop, a return flow channel is provided between the damping chamber and the surrounding armature space.

According to a further example of the invention, the valve comprises a valve housing having a longitudinal axis and a valve slide displaceably mounted along the longitudinal axis of the valve housing and having an anchor plate. An electromagnet is arranged in the valve housing so that it has a force can exert on the anchor plate to move it in an armature space from a first end position to a second end position. The valve body has at least two ports for hydraulic fluid inflow and outflow. The valve spool has at least two control edges and at least two channels, which connect the two ports with the armature space. The control edges are designed such that - depending on the position of the armature plate - a first of the control edges opens or closes a first flow path between the two ports, and at least one second control edge opens or closes a further flow path that leads across the armature space.

The invention will be explained in more detail with reference to the examples shown in the figures. The illustrations are not necessarily to scale and the invention is not limited to the aspects presented. Instead, emphasis is placed on presenting the principles on which the invention is based. In the pictures shows:

1 shows a longitudinal section through a 2/2-way solenoid valve according to an example of the invention, wherein the valve spool is in the first end position (rest position);

Figure 2 is a longitudinal section through the magnetic spool valve according to Figure 1, wherein the valve spool is held by the electromagnet in the second end position; Figure 3 shows a cross section through the magnetic spool valve, wherein the

Magnet facing side of the anchor plate is visible;

Figure 4 is an enlarged view of a portion of the anchor plate of Figure 1 according to an example of the invention. Figure 5 is an enlarged view of a portion of the anchor plate according to another example of the invention;

Figure 6 is an enlarged view of a part of the anchor plate according to another example of the invention;

7 shows a schematic representation of an anchor plate according to the in Fig.

1 embodiment shown and their interaction with the corresponding end stop;

Figure 8 is a schematic representation of an anchor plate according to an alternative embodiment and their interaction with the corresponding end stop; Figure 9 is a schematic representation of an anchor plate according to a further alternative embodiment and their interaction with the corresponding end stop;

Figure 10 is another example of an alternative design of the anchor plate with drilled Nachströmkanälen under the edges along which the armature touches the end stop;

FIG. 11 shows another example of an alternative design of the anchor plate with notches in the edges along which the armature touches the end stop;

Figure 12 is another example of an alternative design of the anchor plate with a symmetrical about the longitudinal axis edge along which the armature touches the end stop; and

Figure 13 shows the hydraulic equivalent circuit of the solenoid valve. In the figures, like reference characters designate like or corresponding components of same or similar meaning.

The following description uses as an illustrative example a 2/2-way solenoid valve. However, the application of the invention is not limited to such 2/2-way valves, but can be easily transferred to other types of solenoid valves. The different valve types differ essentially in the structural design of the valve slide (in particular its control edges) and the valve housing (in particular the inlets and outlets arranged therein for the hydraulic fluid).

Figures 1 and 2 show the same solenoid valve. Figure 1 shows the valve spool 3 in its designated as "first end position" rest position (valve closed), Figure 2 shows the valve spool 3 in its second end position (valve open), in which this by the magnetic actuator 4 against the restoring force of a spring 43rd (See also hydraulic equivalent circuit diagram in Fig. 13.) For reasons of clarity, some parts of the valve are labeled only in one of the two FIGS.

In the illustrated example, the solenoid valve includes, inter alia, a valve housing 1 with a housing cover 1 1, a valve slide 3 (valve piston) and a pressure-tight magnetic actuator 4, which has a yoke 41, a coil wound thereon 42, an armature and the spring 43. The armature, ie the movable part of the magnet actuator 4 is formed in the present example by the armature plate 31, which is also part of the valve spool 3. The anchor plate 31 and the remaining part of the valve spool 3 may be made in one piece. Alternatively, the valve spool 3 can also be composed of two or more components (possibly of different materials) (of which one component is, for example, the anchor plate 31). The valve spool 3 is partially hollow to make this as easy as possible, which in turn allows fast switching.

In the example shown, the solenoid valve is essentially rotationally symmetrical about the longitudinal axis L, but this need not necessarily be the case. The (approximately) symmetry results in practice in that the valve housing 1 and the valve slide 3, are usually made by turning. The valve spool 3 is mounted in the interior of the valve housing 1 such that it can slide along the longitudinal axis L (in the axial direction) on the running surfaces 33. That is, the outer dimension (the diameter) of the valve spool 3 and the inner dimension (inner diameter) of that part of the valve housing 1 in which the valve spool 3 is supported are matched according to a clearance fit, so that sliding is possible. In the interior of the valve housing circumferential grooves 15 and 16 are arranged, open into the radial bores, which form the connections for the hydraulic fluid 2. The ports are labeled "Port A" and "Port B" in Figures 1 and 2, both of which ports may function as either an inlet (pump port) or an outlet (working port).

The valve slide 3 also has circumferential grooves whose edges are also referred to as "control edges" 32, 32 ', since the valve is open or closed depending on the overlap of the control edges with the inner wall of the valve housing 2. In the situation illustrated in FIG the valve slide 3 is in its first end position (rest position), the overlap of the control edge 32 with the corresponding part of the inner wall (between the grooves 15 and 16) of the valve housing 1 is positive, the overlap of the control edge 32 'with the corresponding part the inner wall (left of the groove 15) is also positive, that is, the control edges 32 and 32 'close the flow path between port A and port B, the valve is closed. In the situation shown in Fig. 1, the valve spool 3 is in its second end position in which it is held by the solenoid actuator 4. In this case, the overlap of the control edge 32 with the corresponding part of the inner wall (between the grooves 15 and 16) of the valve housing 1 is negative, ie there remains a gap. That is, hydraulic fluid may flow from port A through groove 15 and control edge 32 into groove 16 toward port B (or vice versa), the valve is open. The majority of the volume flow flows over the control edge 32. The overlap of the control edge 32 'with the corresponding part of the inner wall (left of the groove 15) is also negative: Consequently, there is also a flow from the port A via the groove 15, the control edge 32', the channels 35 and 35 ', the armature space 5 and the channel 35 "to the groove 16 and thus to the port B. This second flow path allows a small, but defined volume flow through the armature space 5, the magnetic actuator with open valve 4. This volume flow through the armature space 5 allows efficient removal of the heat generated in the coil 42 and thus ensures cooling of the magnetic actuator 4. Furthermore, it is also ensured that the armature space 5 is (approximately) completely filled with hydraulic fluid and possibly Air present in the armature space 5 is removed after a few switching cycles (eg via the outlet port B).

As mentioned above, the specific configuration of the control edges and the inner wall of the valve housing depends on the valve type, with a 2/2-way valve being described here by way of example. The design of the armature and the electromagnet is largely independent of the valve type and will be described in more detail below. In the present example, the electromagnet is essentially constructed as a pot magnet. The yoke 41 serves as an iron core for the coil 42 and also provides the magnetic return. The pot magnet, like the armature plate 31, is symmetrical about the longitudinal axis L. assigns. Joch 41 and anchor plate 31 are for example made of a magnetic material, such as a soft magnetic or ferromagnetic material. In the present example, the pot magnet (ie the yoke 41 and the coil 42) is embedded in the housing cover 1 1, which in turn can be screwed into the valve housing 1. Housing cover 1 1 and valve housing 1 have corresponding thread. In order to concentrate the magnetic flux on the yoke and the armature, the valve housing 1 together with the housing cover 1 1 can be made of non-magnetic stainless steel. Between the yoke 41 and the anchor plate 31 at least one spring 43 is arranged, which presses the anchor plate 31 away from the yoke 41. The solenoid thus operates against the spring force of the spring 43 and in the currentless coil, the spring 43 presses the armature in the first end position (rest position), which is defined by a corresponding end stop on the inside of the housing 1 (see Fig. 1). The region inside the valve housing 1 in which the armature plate 31 can reciprocate is referred to as the armature space 5 (essentially the area between the end stops which define the end positions of the armature).

Different examples of an inventive design of the anchor plate 31 and the associated end stops are described in more detail below with reference to Figures 3 to 6. 3 shows the illustration of a cross section through the magnetic slide valve, wherein the end face 313 of the anchor plate 31 facing the magnet is visible (see FIG. 4). FIG. 4 shows a corresponding longitudinal section through the anchor plate 31. It is merely an enlarged view of a part of the anchor plate of FIG. 1. The armature plate 31 has a plurality of bores 34, which serve to reduce the flow resistance of the armature plate 31. When the valve is switched, hydraulic fluid 2 can thus flow from one side of the armature plate 31 (end face 313, oriented toward the magnet) through the bores 34 to the other side of the armature plate 31 (rear side 313 '). So it does not have the entire displaced by the anchor plate 31 Hydraulic fluid 2 outside flow past the anchor plate 31. The bore in the middle of the armature plate 31 forms the flow channel 35 'which connects the interior of the (hollow) valve slide with the armature space 5 and thus a flow from the port A via the radially extending channel 35, the interior of the valve slide towards the armature space 5 allows. Reflux of hydraulic fluid from the armature space 5 to the port B is facilitated by another bore in the armature plate 31, which is designated as channel 35 "in Figures 3 and 4. Through the channels 35, 35 'and 35" becomes parallel to the main flow path (From the groove 15 via the control edge 32 in the groove 16) allows a further flow path over the armature space 5 (from the groove 15 via the control edge 32 'in the armature space and back to the groove 16). This further flow path, which is also sketched in the hydraulic equivalent circuit diagram in FIG. 13, permits continuous flushing of the armature space 5 with hydraulic fluid 2. In this way, the heat generated by the coil 42 is efficiently dissipated and the magnetic actuator is cooled. The hydraulic fluid 2 serves as a coolant. At the same time it is ensured that the armature space is filled with hydraulic fluid and any air pockets are removed.

In the example shown in FIG. 4, recesses 38 and 38 'are provided on the front side 313 of the armature plate 31 and on its rear side 313'. The recesses 38 and 38 'do not extend radially to the outer edge of the anchor plate 31, whereby the edges 322 and 322' are formed. When moving the valve spool 3, the hydraulic fluid 2 from the recess 32 or 32 'via the edges 321 and 322 or 321' and 322 'must be displaced. This creates a pressure in the recesses 23 and 32 ', which counteracts the respective movement. The smaller the residual gap h between the stationary stop and the edges 321 and 322 or 321 'and 322', the greater the pressure becomes (compare also FIG. With switching times in the range of 1 ms, pressures of around 100 bar result. To go in The edges 321 and 322 (and 322 'and 321') have a height difference of Ah on the end positions only linearly on one edge 321 or 321 'as possible. This lies in the range of a few micrometers (eg

Ah = 15pm) and does not have to be the same on both sides of the anchor plate.

In one embodiment, a peripheral recess 36 (a circumferential groove) may be provided along the narrow side of the anchor plate, so that on both sides of the groove 36 (on the groove flanks) narrow, resilient webs 37 and 37 'arise. The depth d (e.g., d = 1, 5 mm) of the circumferential groove 36 and the depth of the recesses 38 are matched to each other such that the

Webs 37 and 37 'are elastically deformed (bent) during braking of the movement of the anchor plate by the pressure occurring in the groove 32 (or 32') (eg around 100 bar), so that the height difference Ah of the edges 322 and 321 (or 322 '). and 321 ') is virtually compensated, whereby the effective attenuation characteristic does not deviate significantly from the attenuation characteristic that could be observed if edges 322 and 321 were equally high (Ah = 0). The effect of unequal high edges 322 and 321 (or 322 'and 321') with respect to the damping characteristic (which may be undesirable) is thus compensated by the compliance of the web 37 (or 37 ').

After the contact between the anchor plate 31 with an end stop, it lifts off again from the end stop (due to the restoring force of the elastically deformed web 31 or 37 ') and only one contact line remains along the higher edge 321 or 321'. Between the other edge 322 or 322 'and the respective end stop remains a gap of dimension Ah. This remaining gap forms a Nachströmkanal (for the hydraulic fluid), by which a pressure equalization between the pressure in the recesses 32 and 32 'and the remaining armature space 5 is ensured. When the valve is actuated, hydraulic fluid can flow into the recess 32 or 32 'through the gap (which arises due to the height difference Ah), as a result of which a negative pressure (in comparison to the pressure in the armature space 5) in the recess 32 (or 32 ') avoided and a "sticking" of the armature is prevented at the end stop.

The peripheral webs 37 and 37 'shown in FIG. 4 have on their outer sides (thus peripherally on the outer edge of the end face 313 and the rear side 323' of the anchor plate 31) the aforementioned groove-shaped recesses 32 and 32 '. The contour of the groove corresponds e.g. approximately a circular arc (diameter D, for example D = 5mm). At the edge of the grooves 32, 32 'each form two sharp (acute-angled) edges. At the end face 313, a first edge 321 extends along the circumference of the anchor plate 31 and a second edge 322 concentric with the first, which adjoins the recess 38. At the back the edges 321 'and 322' are arranged in the same way. The arrangement of the webs 37 is substantially symmetrical with respect to a plane of symmetry E, which is perpendicular to the longitudinal axis L. The plane of symmetry E is shown in FIG. 4. However, a symmetrical design is not mandatory. The grooves 32, 32 'have the advantage that only their sharp edges 321 and 322 or 321' and 322 'abut the respective end stops. The anchor plate is thus not flat on an end stop, but along the line defined by an edge (eg 321 or 321 '), which in turn has the consequence that the anchor plate 31 does not "stick" to the end stop even at high pressures Adhesive is thereby prevented that, for example, by the mentioned height difference Ah between two adjacent edges (eg 321 and 322) a Nachströmkanal is formed, can flow through the release of the armature from the end stop hydraulic fluid into the respective groove 32 (or 32 ').

In Fig. 5, an alternative embodiment of a solenoid valve according to the invention is shown, the difference being only in the design of the anchor plate 31 and the end stops. According to the example of FIG. 5, the armature plate 31 is constructed substantially identical to that in the previous example of FIG. 4. The only difference is that the circumferential recess 36 is missing and no resilient webs are formed (see webs 37 and 37 'in Fig. 4). In the present example, the resilient webs are now in the end stops (with EA and EA ') realized, which are formed by the webs 13 and 13'. In the present example, a circumferential groove 12 is provided in the housing cover 1 1, so that the remaining web 13, which serves as an end stop EA, is thin enough to have the desired resilient property. The opposite end stop EA 'is formed by the surface of the web 13'. Structurally this is realized by a sleeve with L-shaped profile, wherein a leg of the L-shape forms the resilient web 13 '. The operation of the arrangement is the same as in the previous example. The spring effect is achieved in both cases by thin webs. In the first example (FIG. 4), the webs are arranged on the armature and the end stops EA, EA 'are rigid. In the second example (FIG. 5), the webs are realized in the end stops EA, EA ', and the armature is rigid. A combination of both variants (webs at the end stop and at the anchor) would also be possible.

In Figure 6, yet another embodiment is shown. This example corresponds essentially to the example from Fig. 4, but in addition to the channel 35 'which leads from the interior of the valve slide 3 into the armature space 5, also the channel 35 "' is provided, but this opens at the rear side 313 ' Anchor plate 31, whereas the channel 35 'opens at the end face of the anchor plate 31. Through the additional channel 35' 'not the entire volume flow (cross-sectional area of the valve spool 3 times Ver shift) must be passed through the channel 35' and in addition the flushing the armature space 5 and thus the cooling of the magnet further improved.

The mode of operation of the damping of the impact of the armature plate 31 on an end stop EA will be explained in more detail on the basis of the schematic representation in FIG. FIGS. 8 and 9 show alternative embodiments with which, however, essentially the same damping effect is achieved. figure 7A shows the edge of an anchor plate 31 at a distance of approximately h from the end stop EA. The armature plate 31 has - as in the example of FIGS. 1 to 4 - a groove-shaped recess 32 which is bounded by two sharp (acute-angled) edges 322 and 321. Without elastic deformation of the anchor plate 31 (see Fig. 4) or the end stop EA (see Fig. 5), the distance between the (outer) edge 321 and the end stop EA is h and the distance between the (inner) Edge 322 and the end stop EA equal h + Ah. As already mentioned, for small values of h, the difference Ah is compensated by an elastic deformation of the armature plate 31 or of the end stop EA. As the armature plate 31 moves toward the end stop EA, hydraulic fluid is displaced from the volume X between the armature plate 31 and the end stop EA, with the displaced hydraulic fluid having to flow over the edges 321 and 322 (see dashed arrows in FIG. 7A). Due to the groove-shaped recess 32 between the edges 321 and 322, the flow across the edges 321 and 322 behaves similar to a flow through an orifice and the damping force is (in the simplified model) proportional to v ² / h ² , where v is the velocity of the Ankers designated. In contrast, the damping force of a simple gap (ie without groove 32) would be proportional to v / h ³ , which also explains the "sticking" of the anchor at low velocities v and very small gaps h for the case where the anchor plate 31 would lie approximately flat against the end stop EA.

In FIG. 7B, the armature plate 31 rests against the end stop EA along the outer edge 321 (h = 0), leaving a residual gap of length Ah between the inner edge 322 and the end stop. This residual gap forms a downstream channel through which, when the armature accelerates away from the end stop EA, hydraulic fluid can flow into the recess 32 (see dashed arrow in FIG. 7B). As already mentioned a "sticking" of the anchor plate is prevented at the end stop EA. FIG. 8 shows an alternative embodiment to FIG. 7. The difference Ah of the effective gap length between the end stop and the two edges 322 and 321 is not realized by unequal high edges, but by a level of height Ah in the end stop. Analogous to FIG. 7A, in FIG. 8A the gap length between end stop EA and edge 321 is h and between end stop EA and edge 322 it is h + Ah. The two solutions according to FIG. 7 and FIG. 8 can therefore be regarded as equivalent. Fig. 8A shows the situation when approaching between armature plate 31 and end stop EA and the displacement of hydraulic fluid via the edges 322 and 321 analogous to the example of Fig. 7A. Fig. 8B shows the situation of acceleration of the armature plate 31 away from the end stop EA. Analogous to the previous example (FIG. 7B), the residual gap of the length Ah between end stop EA and edge 322 allows a subsequent flow (see dashed arrow) of hydraulic fluid from the armature space 5 into the volume defined by the recess 32 between the armature plate 31 and the end stop EA ,

FIG. 9 shows a further alternative embodiment of the magnetic slide valve. In the present example, the anchor plate 31 has a front surface on a flat surface and the end stop EA is designed similar to the anchor plate in the previous example. The end stop EA has a groove-shaped recess 32a, which is bounded by the (acute-angled) edges 322a and 321a. The edges have a height difference of Ah, so that the effective gap length between armature plate 31 and end stop - as in the previous examples - at one edge (321 a) h and at the other edge (322 a) is h + Ah. The operation is identical as explained with reference to FIG. 7 with the only difference that the edges 322a and 321a (and thus the recess 32a) are realized on the end stop EA instead of on the anchor plate 31. The example from FIG. 9 could still be modified analogously to the example from FIG. 8. In the present example (FIG. 9), the end stop EA is made retrograde. That is, the end stop EA is realized on a thin web, so that it is before the contact between the armature plate 31 and end stop to the aforementioned elastic deformation comes (see also the example of Fig. 5, web 13).

FIGS. 10 and 11 show further alternatives to the previously described examples. In both cases, an anchor plate 31 is shown, which is constructed substantially the same as the anchor plate 31 of FIG. 5. The operation of the thus realized damping mechanism has been explained with reference to FIG. A significant difference between the previous example according to FIGS. 5 and 7 and the anchor plate according to FIG. 10 is that the inflow channel, which according to FIG. 7 is formed by the height difference Ah of the edges 322 and 321, now passes through small holes 36 is formed, which connects under the edge 322 (and 322 ') through the area in the recess 32 (and 32') with the surrounding armature space 5. When the armature is accelerated away from an end stop EA or EA ', hydraulic fluid can flow through these flow-through channels 36 into the region between the edges 322 and 321 (or 322' and 321 '), which, as described with reference to FIG. Elastic deformation of the end stop EA (or EA ') as in the example according to Fig. 5 or elastic deformation of the anchor plate (the webs 37 and 37') as in the example according to FIG is no longer necessary in the present example, however, the backflow channels should be dimensioned (with respect to their flow resistance) so that the damping effect of the edges 322 and 321 (or 322 'and 321') is not unduly compromised Fig. 1 1 is an alternative to the previous example of Fig. 10, wherein the Nachströmkanäle 36 are not formed by bores, but by distributed over the circumference "notch n "in the edge 322. FIG. 11A shows a longitudinal section and FIG. 11 B the associated side view. Incidentally, the explanations to FIGS. 5, 7 and 10 apply accordingly. FIG. 12 shows a further example of an alternative embodiment of the valve slide 3, in particular the anchor plate 31. However, instead of a circumferential groove-shaped recess 32 delimited by two concentrically extending edges 321, 322, the front side of the anchor plate has a central recess 32b which extends from a circumferential edge 322b becomes limited. The edge 322b has Nachströmkanäle, such as the edge 322 in the examples of FIG. 10 or 1 1. The operation is substantially the same as described with reference to FIG. 7. As the armature plate moves toward the end stop EA, hydraulic fluid is displaced from the area between the recess 32b and the end stop EA and flows via the edge 322b into the adjacent part of the armature space 5. The edge 322b achieves a diaphragm effect as described with reference to FIGS Fig. 7 has been explained. That is, the flow across the edge 322b out of the recess 32b behaves similarly to flow through an orifice and

Damping force is (in the simplified model) proportional to v ² / h ² , where v denotes the speed of the armature. Compared to an ordinary damping gap (ie, without a recess defined by edges), according to the examples described here, the damping force is also less dependent on the viscosity of the hydraulic fluid, and thus temperature-induced fluctuations in the viscosity are less pronounced.

FIG. 13 shows the previously mentioned hydraulic equivalent circuit diagram of the valve including the second flow path through the armature space for cooling the magnetic actuator 4.

Claims

claims:

1 . Hydraulic valve, comprising:

a valve housing (1,1,1) having a longitudinal axis (L); a valve spool (3) slidably mounted along the longitudinal axis (L) of the valve housing (1) and having an armature plate (31), an electromagnet (41, 42) arranged in the valve housing (1) to apply a force the anchor plate (31) can exert to move them from a first end position (EA) in a second end position (ΕΑ '), the end positions by end stops (EA, EA') are defined, wherein at an end stop (EA , EA ') or one side of the anchor plate (31) is a semi-open, in operation with hydraulic fluid filled damping chamber, which is formed by at least one circumferential edge (321, 321', 322, 322 ') is arranged and anchor plate (31) and associated end stop (EA, EA ') along the peripheral edge (321, 321', 322, 322 ') touch, and

wherein at the end stop (EA, EA ') fitting anchor plate (31) is provided a return flow channel (36, 36') between the damping chamber and the surrounding armature space (31).

2. Hydraulic valve according to claim 1, wherein the end stop (EA, EA ') or the corresponding side of the armature plate (31) are designed yielding.

3. A hydraulic valve according to claim 1 or 2, wherein the damping space by two peripheral edges (321, 322) is defined, so that between them in the

Anchor plate (31) or the end stop (EA, EA ') a circumferential groove-shaped recess (32, 32') is formed.

4. Hydraulic valve according to claim 3, wherein one of the edges (321, 322) by a height difference (Ah) further from the end stop (EA, EA ') or the anchor plate (31) protrudes, whereby in the corresponding end position, a return flow channel (36 , 36 ') is formed below the lower edge (322, 322').

5. Hydraulic valve according to one of claims 1 to 4, wherein return flow channels (36, 36 ') by notches in the edge (322, 322') or by under the edge (322, 322 ') through extending bores (36,36') be formed.

6. Hydraulic valve according to one of claims 1 to 5, wherein the valve housing (1) has at least two ports (A, B) for inflow and outflow of hydraulic fluid,

wherein the valve slide (3) has at least two control edges (32, 32 ') and at least two channels (35', 35 "), which connect the two ports (A, B) with the armature space (5), and

wherein the control edges (32, 32 ') are designed such that - depending on the position of the anchor plate (31) - a first of the control edges (32) opens or closes a first flow path between the two ports (A, B), and at least a second control edge (32 ') opens or closes a further flow path which leads over the armature space (5).

7. A hydraulic valve according to any one of claims 1 to 5, wherein the edge (s) (321, 321 ', 322, 322') which limit / limit the damping space are acute-angled and the damping space is limited by a concave shape.

8. Hydraulic valve, comprising:

a valve housing (1,1,1) having a longitudinal axis (L); a valve slide (3), which is displaceably mounted along the longitudinal axis (L) of the valve housing and has an anchor plate (31),

an electromagnet (41, 42) disposed in the valve housing (1) so as to be able to exert a force on the armature plate (31) to move them in an armature space (5) from a first end position (EA, EA ') to a second end position (EA, EA');

wherein the valve housing (1) has at least two ports (A, B) for inflow and outflow of hydraulic fluid,

wherein the valve spool (3) has at least two control edges (32, 32)

32 ') and at least two channels (35', 35 "), which connect the two ports (A, B) with the armature space (5), and

wherein the control edges (32, 32 ') are designed such that - depending on the position of the anchor plate (31) - a first of the control edges (32) opens or closes a first flow path between the two ports (A, B), and at least a second control edge (32 ') opens or closes a further flow path which leads across the armature space (5).