An on-off valve is disclosed, especially a fast-acting on-off valve, wherein a plunger is pretensioned in a base position. The plunger has a plurality of parallel control edges via which a plurality of sectional opening cross-sections, arranged in parallel in a hydraulic manner, can be jointly actuated to open or close when the valve is switched.

The invention relates to an on-off valve in accordance with the preamble of claim1.

On-off valves are frequently directly controlled 2/2 directional control valves in a seat or slide design, wherein a plunger is pretensioned in a base position and is adapted to be displaced into a switching position by means of a solenoid. If by on-off valves of such type relatively large pressure medium volume flows (100 l/min with a pressure difference of 5 bar) are to be switched, large nominal widths are required. By virtue of the large nominal widths also the plungers/slides of such conventional on-off valves have to be comparatively large with a considerable mass. In some applications, for instance in mobile hydraulics, it is necessary to switch these on-off valves very quickly (switching times in the range of 1 ms), wherein the required flow may be up to several 100 liters per minute (100 l/min).

These dynamics cannot be achieved by conventional on-off valves inter alia because of the high inductivity of the solenoids required with said nominal parameters and the relatively large mass of the plunger. It is another drawback of conventional on-off valves that they are comparatively expensive especially with large nominal widths.

Compared to this, the object underlying the invention is to provide an on-off valve which permits a quick switch-over even of large pressure medium volume flows by way of a simple device.

This object is achieved by an on-off valve comprising the features of claim1.

In accordance with the invention, the on-off valve comprises a plunger having a plurality of parallel control edges each of which delimits a sectional opening cross-section by a case-fixed control edge. That is to say, according to the invention in the open position of the on-off valve the pressure medium volume flow is divided into several partial volume flows each of which flows through one of the sectional opening cross-sections actuated to be open. By dividing the pressure medium volume flow via plural sectional opening cross-sections switched in parallel the on-off valve can be designed to have substantially smaller sleeve diameters than conventional on-off valves. The diameter of the plunger of the on-off valve is correspondingly smaller than in conventional solutions so that by far better dynamics can be attained by virtue of the reduced mass and the smaller solenoid required and the switching times are reduced to a fraction vis-à-vis conventional solutions. Due to the sectional opening cross-sections switched in parallel, the on-off valve according to the invention is somewhat longer than a conventional on-off valve, to be sure, but this drawback is eliminated by far by the reduction of the plunger diameter and the related more compact valve housing dimensions. The solution according to the invention can also be manufactured in a considerably cheaper way than conventional on-off valves due to the compact modular design.

Basically the on-off valve can be manufactured in a seat or slide design, however the latter construction is preferred in the invention.

The respective case-fixed control edge delimiting the sectional opening cross-section jointly with the parallel control edge of the plunger is formed on a circumferential sealing land of the casing.

In an especially preferred variant of the invention a valve sleeve of the casing receiving the plunger is composed of a plurality of disks. Each of the disks supports one of the sealing lands and has at least one pressure medium conduit which is adjacent to the sealing land and opens in a disk chamber encompassed by the disk.

In such a design it is particularly preferred when the pressure medium conduits of adjacent disks are alternately connected to the first or the second port of the on-off valve in a hydraulic manner.

The pressure loss inside the disks can be minimized when two respective pressure medium conduits radially open into the disk chamber on both sides. In a concrete embodiment three pairs of pressure medium conduits are provided, wherein one pair extends diagonally across the disk, while the two other pairs extend laterally offset with respect thereto.

The ducting in the on-off valve according to the invention is further simplified when four—preferably circular—recesses which are offset by 90° with respect to each other are formed at the outer circumference of the disk. The pressure conduits open at least in one of the recesses. In the assembled state the recesses of the disks arranged in series form respective junction conduits between the pressure fluid conduits and the ports of the on-off valve.

In the afore-described embodiment it is preferred when the pressure medium conduits open in two respective diametrally disposed recesses.

In an embodiment having an especially simple structure all disks are identical in construction, wherein adjacent disks are mounted offset by 90° with respect to each other so that the one disk subset can be easily connected to the first port and the subset arranged offset thereto can be connected to the second port in an equally simple manner.

The casing of the on-off valve includes a mounting bush in which the valve sleeve consisting of valve disks is inserted. Plural radial connecting bores, each of which is hydraulically connected to one of the ports and opens in one of the junction conduits joining the pressure medium conduits of the disks, pass through a shell of the mounting bush.

For reducing or preventing a pulsation or cavitations or for decoupling switching shocks reservoirs or other appropriate elements can be connected ahead of or behind the on-off valve. In a variant of the invention the casing is provided with plural recesses formed outside the mounting bush in which such reservoirs or the like can be inserted.

In another embodiment of an on-off valve casing pressure medium is supplied and discharged via a head plate of the casing.

The sealing lands formed in the disks are preferably formed to have inclined surfaces connected to the sealing faces. This variant permits to design the sealing lands in a very thin-walled manner, wherein even in the case of high working pressures no deformations occur which might entail sticking of the plunger. Due to the small width of the sealing lands the disks can be very thin so that the on-off valve requires a short building space despite the plurality of parallel control edges connected in series. Since this geometry of the sealing lands is the subject matter of an independent parallel application, further explanations can be dispensed with.

The on-off valve is preferably actuated by means of a magnet. The use of a fast acting flat armature magnet acting upon the plunger via a lever transmission is especially preferred. Said lever transmission is in the form of a solid-state joint in a preferred embodiment of the invention.

In a particularly preferred embodiment of the invention six disks are arranged in series so that the pressure medium volume flow is guided via three sectional opening cross-sections. Of course, the on-off valve can also have more or fewer disks.

Other advantageous further developments of the invention are the subject matter of further subclaims.

InFIG. 1a longitudinal section across a first embodiment of a fast-acting on-off valve1is represented. The fast-acting on-off valve1comprises an input port and an output port which are not visible in the representation according toFIG. 1. One of the ports, for instance the input port A indicated in broken lines, is located approximately in the plane of projection, while the other port, for instance the output port B, is located in a plane extending normally to the plane of projection. The fast-acting on-off valve1in a slide design includes a casing2having a valve sleeve4in which a plunger or valve actuator6is guided to be axially movable (in vertical direction inFIG. 1). The valve actuator6is operated by a magnet, which in the shown embodiment is a flat armature magnet8acting via a lever transmission10upon the valve actuator6. The valve sleeve4is formed of a plurality of disks12a,12b,12cand13a,13b,13c, wherein a sealing land28interacting with a control collar (see72,74inFIGS. 1 and 44,46,48inFIG. 3) of the valve actuator6is formed on each of the disks12,13. The individual disks12,13have an identical structure and are inserted in the casing2being merely offset by 90° with respect to each other. Details of the sleeve4composed of a plurality of disks12,13will be described hereinafter by way ofFIGS. 2 and 3.

FIG. 2ais a view corresponding to that onto the disks12a,12band12cinFIG. 1.FIG. 2bshows a front view onto said disks. As all disks12,13basically have the same structure, merely the structure of the disk12ais explained by way ofFIG. 2. In the front view said disk has a circular large surface of the outer diameter D. Offset by 90° with respect to each other four recesses18,19,20,21are formed at the outer circumference of the disk12awhich are approximately semicircular in the front view (FIG. 2a). On a common pitch diameter d four fastening bores22offset with respect to the recesses18,19,20,21are formed through which locking screws of the valve sleeve4extend. In the center of the disk12aa disk bore24is provided whose circumferential surface visible inFIG. 2bconstitutes a sealing face26of a sealing land28. The circumferential sealing face26of the sealing land28is transformed into two inclined surfaces30,32arranged obliquely with respect thereto which are by far more distinct than the conventional chamfers. The width b of the sealing land28is comparatively small. Without said inclined surfaces30,32the sealing land28would deform such that in the case of greater differences in pressure this results in sticking of the valve actuator6. It turned out that a lateral bending is prevented by these inclined surfaces30,32and even a better centering of the valve actuator6is made possible. The configuration of the sealing land28with the two inclined surfaces30,32is the subject matter of a further patent application deposited in parallel—as mentioned before.

As one can take from the cut top view shown inFIG. 2b, the disk bore24is expanded into a disk chamber34subsequent to the inclined surface32. In accordance with the front view arranged inFIG. 2a, pressure medium conduits36,37,38,39,40,41open into said disk chamber34, wherein each of the pressure medium conduits36,37;40,41and38,39form a coaxially arranged pair and open on both sides into the disk chamber34. The other end portion of the conduits36,38,40opens in the circumferential edge of the recess18, the other end portion of the three further pressure medium conduits37,39,41opens in the recess20arranged diametrally thereto. As can be taken fromFIG. 2, the pair of pressure medium conduits36,38is disposed in a diagonal of the disk12a, the two other pressure medium pairs38,39;40,41are offset in parallel thereto.

In the sectional view according toFIG. 2bmerely the two diagonally extending pressure medium conduits36,37and40,41are visible, wherein the two latter conduits40,41are confluent in the opening area of the pressure chamber34.

As mentioned in the foregoing, respective adjacent disks12,13are disposed offset by 90° with respect to each other. I.e. in the representation according toFIG. 1the disks12a,12b,12care provided in the mounting position shown inFIG. 2b, while the adjacent disks13a,13b,13care arranged offset by 90° with respect thereto so that the axes of the pressure medium conduits36to41extend normally to the plane of projection, whereas in the case of the other disks12a,12b,12cthey are arranged in parallel to the plane of projection.

On the assumption that the disks13a,13b,13care rotated clockwise by 90° with respect to the disks12a,12b,12c, in the representations according toFIGS. 1 and 3the opening cross-sections of the pressure medium conduits39,41into the disk chambers34of the disks13a,13b,13care seen.

According toFIG. 1, the valve actuator6includes five control collars the control collars44,46,48of which are visible inFIG. 3. In the shown base position they are designed to have a positive overlap with respect to the sealing faces26of the sealing lands28. The end faces of the control collars44,46,48are beveled, wherein respective control edges50,52,54are formed which interact with the circumferential edge of the sealing face26on top in FIG.3—hereinafter referred to as case-fixed control edges56,58,60.

In accordance withFIG. 1, two guiding collars62,64are formed at the end portions of the valve actuator6. An axial projection66which is operatively connected to the lever transmission10is linked to the upper guiding collar64at the top inFIG. 1.

As one can take especially fromFIG. 3, in the shown base position of the valve actuator6the control edges50,52,54and the corresponding control edges68marked inFIG. 1of the control collars72,74not shown inFIG. 3are arranged approximately centrally with respect to the sealing face26so that the axial sealing length between the control collars44,46,48,72,74and the associated sealing faces26is about half the axial length of the sealing faces26.

As one can take especially fromFIG. 1, the four recesses18,20evenly distributed along the circumference of the disks12a,12b,12cas well as the recesses19,21of the disks13a,13b,13cmounted offset by 90° with respect thereto are in alignment so that four junction conduits extending axially in parallel to the valve axis are formed, the junction conduits76,78of which are visible inFIG. 1, while the two other junction conduits offset by 90° with respect thereto are arranged above and below the plane of projection. The respective pressure medium conduits36,37,38,39,40of the disks12a,12b,12copen in the represented junction conduits76,78, while the respective pressure medium conduits of the disks13a,13b,13carranged offset by 90° open in the non-visible junction conduits.

As can be inferred fromFIG. 1, the disks12,13are inserted in a mounting bush80which is formed integrally at the casing2. The structure of the casing is illustrated in detail hereinafter by way ofFIGS. 4 and 5.FIG. 4bis a top view (FIG. 1) onto the valve housing andFIG. 4ashows a bottom view onto the valve casing2.FIG. 5ashows a horizontal section across the casing in the representation according toFIG. 4band inFIG. 5ba vertical section across the casing2corresponding to the sectional view ofFIG. 1is shown.

The diameter of an inner circumferential wall82(seeFIG. 5b) of the mounting bush80substantially corresponds to the outer diameter D of the disks12,13. As one can take especially from the horizontal section shown inFIG. 5a, four radial connecting bores84,86,88,90offset by 90° with respect to each other pass through the wall of the mounting bush80, wherein according toFIG. 1the connecting bores84,88open into the junction conduits78and76formed by the disks and the other two connecting bores86,90extending normally thereto open into the two other junction conduits not shown inFIG. 1. It is assumed that a port of the on-off valve1, for instance the input port A, is connected to the two junction conduits78,76, whereas the output port B is connected to the other junction conduits not represented which are formed by the disks13. I.e. the disks are alternately connected to the working port A and the working port B, wherein pressure medium is supplied to the disk chambers34on both sides via the pressure medium conduits36to41. The ports A, B are formed in a bottom plate146whose structure will be explained in detail by way ofFIG. 6.

In accordance with the illustrations inFIGS. 1 and 5, the mounting bush80is transformed into a cover plate92which is clearly visible also on the right inFIG. 4. The flat armature magnet8is fastened on said cover plate by means of a fastening flange94immersing in a mounting hole96formed coaxially with respect to the mounting bush (seeFIG. 4b) which is downwards stepped back.

As one can take in particular fromFIGS. 4 and 5, the connecting bores are extended step-shaped toward end faces98,100,102,104of mounting chambers106,108,110,111of the housing2. According toFIG. 4, the circumferential walls of these receiving chambers are curved in spherical segment shape and open via cylindrical surface sections112,114,116,118(seeFIG. 4b) into side faces120,122,124and126of the cube casing2. According toFIG. 4, the mounting chambers106,108,110,111are offset downwards vis-à-vis the cover plate92so that they extend into the bottom area, while the cover plate is not intersected by the mounting chambers106,108,110,111. This bottom area is visible inFIG. 4a. The bottom plate146(FIG. 6) is screwed onto said bottom area. The bottom of the casing2shown inFIG. 4is formed by the central mounting bush80and the remaining casing walls forming a cross which extend to the corner areas of the casing in which respective fastening bores128extending over the entire height of the casing2are formed. As one can take especially from the horizontal section inFIG. 5a, the diameter of the spherical segment shaped mounting chambers106,108,110,111is selected such that the circumferential walls of adjacent mounting chambers intersect so that four breakthroughs130,134,136and138are formed. By this design, on the one hand, the weight of the casing2is minimized and, on the other hand, the mounting chambers serve for mounting, completely or in portions, reservoirs or other component parts providing elasticity which contribute to preventing pressure pulsations and switching shocks and to reducing cavitation phenomena. These reservoirs can be connected in the pressure medium volume flow ahead of and/or behind the opening cross-sections of the on-off valve1and are communicated with the junction conduits76,78via the connecting bores84,86,88,90.

The flat armature magnet is a commercial component part so that detailed descriptions can be dispensed with. As mentioned in the beginning, an armature plate174of the flat armature magnet8is operatively connected via the lever transmission10to the axial projection66of the valve actuator6.

In the embodiment shown inFIG. 1the lever transmission10consists of plural—for instance four—levers166,167which are linked to the armature plate174by tension rods172indicated by dot-dash lines. The tension rods172have heads173immersing in corresponding pockets176of a spacer plate158forming the end stop of the valve sleeve4. The levers166,167are seated with their radially outer end sections on the one hand on an annular shoulder168of the spacer plate158, wherein the annular shoulder is delimited in radial direction by a spacer sleeve175. The levers166,167are clamped between the annular shoulder of the spacer plate158and a shoulder of the spacer sleeve175extending in parallel thereto so that they protrude freely in radial direction. A reset spring180which is connected to the axial projection66of the valve actuator6is supported on a radially protruding shoulder of said spacer sleeve175. The armature plate174is arranged by forming a small gap with respect to the not represented flat armature of the flat armature magnet8.

The end portions of the levers166,167grasp behind a collar164disposed at the end of the axial projection66upon which the reset spring180acts. In the shown embodiment said reset spring is a spiral spring.

If current is supplied to the flat armature magnet8, in the representation according toFIG. 1the armature plate174moves upwards and the tension rods172deflect the levers166that are laterally supported at the casing cover170so that the stroke of the valve actuator6is transmitted according to the lever principle, wherein the transmission ratio corresponds to the ratio between the distance of the bearing face of the levers166on the spacer sleeve175and the spacer plate158and the point of action at the valve actuator6as well as the distance of the tension rods172from the above-mentioned bearing face of the levers166. When switching dead the armature plate174returns and the levers166spring back to the shown home position. The reset motion of the valve actuator6is assisted by the reset spring180.

It is assumed that a high supply pressure is applied to the working port A and thus to the two connecting bores84,88, while low pressure or tank pressure is applied to the two other connecting bores86,90. Accordingly, when the on-off valve1is closed the higher supply pressure is also applied to the disk chambers34of the disks12a,12b,12c, whereas the tank pressure is prevailing in the disk chambers34of the disks13a,13b,13c. The pressure chambers subjected to different pressures are blocked against one another by the control collars44,46,48,72,74which are tightly adjacent to the circumferential surfaces of the sealing faces26of the sealing lands28. When current is supplied to the flat armature magnet8, the motion of the flat armature is transmitted via the lever transmission10to the valve actuator6so that the latter is moved upwards in the representation according toFIG. 1. By the control edges50,52,54,68,70sectional opening cross-sections which are delimited by said control edges and by the case-fixed control edges56,58,60are then actuated to open. Said sectional opening cross-sections connect the respective adjacent disk chambers34to each other so that several pressure medium partial flows stream from the two junction conduits76,78through the opened sectional opening cross-sections into the disk chambers of the disks13a,13b,13c, from there via the pressure fluid conduits36to41into the not shown junction chambers (above or below the plane of projection inFIG. 1) and then, summed up, flow off or are combined into possibly connected reservoirs via the connecting bores86,90.

Due to the very small diameter of the valve actuator (e.g. 6 mm) and the extremely small width B of the sealing lands28, the valve can be switched with a very small stroke at extremely high speed so that extremely short switching times of e.g. 1 ms can be obtained in the case of a pressure medium volume flow of 75 l/min (with a pressure drop of 5 bar). Such on-off valves can be used for a plurality of safety functions as well as control functions such as, for instance, positioning tasks and, e.g., also in a switching hydraulic transformer.

InFIG. 6another embodiment of an on-off valve1according to the invention is described.

In contrast to the afore-described embodiment, in the design shown inFIG. 6a different casing structure and a somewhat different lever transmission for the flat armature magnet8are used. The structure of the valve sleeve4composed of plural disks12,13is substantially identical with the above-described embodiment, wherein the disks13are not formed to include the recesses19,21. They are orientated transversely to the axis of the pressure medium conduits36to41. Instead of the recesses, breakthroughs19′,21′ indicated in dot-dash lines which assume the function of the recesses19,20are provided in the disks13. The section according toFIG. 6thus extends up to the outer circumferential edge of the disks13.

In the embodiment shown inFIG. 6the valve sleeve4is held in a casing bush142which is closed at the base by a bottom plate146in which the ports A and B of the fast-acting on-off valve1are formed. Both ports A, B are double ports for the supply of pressure medium on both sides and are connected to branching areas of an input line and an output line. The port A is connected in a hydraulic manner to two connecting bores84,88which are arranged diametrally with respect to each other and are communicated via an input conduit148. Said input conduit148extending transversely to the valve axis is intersected by two blind bores150,152opening into the two junction conduits76,78of the valve sleeve4.

Said junction conduits76,78are then communicated, for instance, with the pressure medium conduits36to41of the disks13. Accordingly, the disks12are connected to the port B in a hydraulic manner. The double ports of the latter are located above and below the plane of projection, wherein in the section according toFIG. 6merely the junction conduit154is visible between the two not represented connecting bores. I.e. said junction conduit154extends offset by 90° below (FIG. 6) the junction conduit148and opens on both sides into said connecting bores. The connection to the two junction conduits not visible inFIG. 6and formed by the disks12,13is again provided by respective blind bores150,152arranged above and below the plane of projection. That is to say, the ducting for the double port B is carried out in the same way as for the double port A with the only difference that the conduits are arranged offset by 90° with respect to each other. Such a bottom plate146is also placed onto the casing in the embodiment according toFIG. 1.

In the end face of the bottom plate146facing the casing bush142furthermore a hollow156is provided which is delimited in portions by the end face of the valve actuator6. Said end face is relieved toward a tank port.

The head-sided end of the housing bush142is formed by a spacer plate158, wherein a spacer disk160is provided between the latter and the adjacent disk13so that the disks12,13are pressed against each other in a sealing manner. The spacer plate158includes a breakthrough through which the axial projection66of the valve actuator6extends. In the shown embodiment the axial projection66has a collar164on which the levers166are supported. They act upon the axial projection66and are adjacent from the bottom (view according toFIG. 6) to the end face of the collar164and are supported by their radially outer portions in an annular recess168of a casing cover170. The levers166include a breakthrough through which a respective tension rod172extends which, one the one hand, is connected to the armature plate174of the flat armature magnet8and, on the other hand, acts upon the lower side (FIG. 6) of the levers166. These portions of action of the tension rods172immerse in pockets176in the upper end face of the spacer plate158in the shown embodiment.

A spring plate178upon which a reset spring180acts which in this embodiment is in the form of a spiral spring and is supported on the flat armature174is supported at the upper side of the collar164.

The spring chamber for the reset spring180and the upper end face of the valve actuator6are in turn relieved toward a tank T or toward a low-pressure port. The flat armature magnet8is fastened in the same way as in the afore-described embodiment by means of a mounting flange74.

An on-off valve is disclosed, especially a fast-acting on-off valve, wherein a plunger is pretensioned in a base position. The plunger has a plurality of parallel control edges via which a plurality of sectional opening cross-sections, arranged in parallel in a hydraulic manner, can be jointly actuated to open or close when the valve is switched.

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