Control valve having switchable control edge

Abstract

The invention relates to a control valve having at least one switchable control edge, comprising: • a main control piston (4), which is linearly movable in a valve body (1), wherein the main control piston (4) has an axial bore (50) and is designed to provide at least two switching states by way of a linear movement, • a secondary control piston (5), which is coaxially arranged in the axial bore (50) of the main control piston (4) and is designed to switch at least one control edge of the main control piston (4), wherein the axial bore (50) of the main control piston (4) is closed by a closure screw (16), • an actuating piston (9), which is arranged in the closure screw (16) and is designed to move the secondary control piston (5), • a switching valve (19), which is hydraulically connected to the actuating piston (9) and is designed to hydraulically actuate the actuating piston (9), wherein the main control piston (4) has at least one longitudinal groove which forms at least part of the hydraulic connection between the switching valve (19) and the actuating piston (9).

Description

[0001] Control valve with switchable control edge

[0002] Description

[0003] The invention relates to a control valve having the features of independent patent claim 1.

[0004] Hydraulic control valves are used in a wide variety of applications to control the flow, pressure, and / or flow direction of hydraulic fluid. Control valves can be represented by proportional and / or servo valves.

[0005] In a control valve, control edges (sometimes also referred to as control edge profiles) are the areas where the valve body control edges and the control edge of the valve spool or control spool / piston come into contact to control the flow of the medium. The control edge can be understood as a sharp edge or profile on the shell side of the valve spool, while the valve body control edge is the mating surface on the inside of the valve housing. When the valve spool is moved, the distance between the control spool control edge and the valve body control edge changes, which affects the flow of the medium through the valve.

[0006] In order to achieve control using control edges, these have a so-called sealing length, also known as overlap. Depending on the size of the sealing length, a distinction is made between positive (piston is longer than the annular groove; when switching, the overlap must first be passed through before a volume flow can flow) and negative (piston is shorter than the annular groove; in the rest position all ports are connected to each other) overlap as well as zero overlap (control edges of the piston and annular groove coincide with great precision; in this position almost no volume flow flows, but it is released even with very small piston movements). i As a rule, the control edges or their overlaps for a control valve are designed for one application and are not changed afterwards. However, this represents a restriction for the possible switching states of the valve.Particularly for so-called fail-safe states, it can be advantageous if the control edge, in particular its sealing length, is changeable, since the adjustment to the fail-safe state can have a different requirement for the control edge or the sealing length than in a regular state.

[0007] The failsafe state represents a safe machine state in which the control valve is not in active electronic control - it is usually de-energized and de-energized, and the control piston is not in active position control.

[0008] In principle, it is possible to meet such partially conflicting requirements regarding sealing lengths and switching states by interconnecting several valves. However, this increases the complexity of the design, the space required, and the costs.

[0009] Alternatively, a switching mechanism can be provided in a control valve. In this case, a valve is described that has a second, inner control piston in the main control piston, in particular to make the A (actuator)-T (tank) control edge of the entire valve switchable between the covered state and the zero cut.

[0010] It is therefore an object of the present invention to at least partially overcome at least one of the disadvantages described above. In particular, the object of the invention is to provide a control valve that provides a switchable control edge and is simultaneously particularly compact and efficient.

[0011] According to the invention, a control valve with at least one switchable control edge is provided, comprising: a main control piston which is arranged linearly movable in a valve body, wherein the main control piston has an axial bore and is designed to provide at least two switching states by a linear movement, a secondary control piston which is arranged coaxially in the axial bore of the main control piston and is designed to switch at least one control edge of the main control piston, wherein the axial bore of the main control piston is closed by a screw plug, an actuating piston which is arranged in the screw plug and is designed to move the secondary control piston, a switching valve which is hydraulically connected to the actuating piston and is designed to hydraulically actuate the actuating piston, wherein the main control piston has at least one longitudinal groove,which forms at least part of the hydraulic connection between the switching valve and the actuating piston.

[0012] In other words, the control valve can comprise two linearly movable pistons, wherein an inner piston is axially movable within an outer main piston such that a change in the control edge can be effected. The main piston has a closure in which a third piston is at least partially arranged, which is designed to adjust the inner piston. The third piston can be hydraulically actuated by a switching valve, wherein the hydraulic fluid actuating the third piston is provided through a recess in the outer main piston, wherein the recess is formed at least partially in the longitudinal direction of the main piston.

[0013] A control valve can be considered a continuously adjustable directional control valve, whereby the static and / or dynamic behavior, in particular, can be comparable to that of servo valves. An electromechanical converter of the control valve can be designed at least as a proportional solenoid, linear motor, or plunger coil actuator.

[0014] It can be provided that the control valve has at least two connections. Furthermore, the control valve can have at least one P (port, main connection of the control valve, via which the pressure medium can be supplied), A (outlet, working connection to which the consumer, e.g. an injection cylinder of an injection unit of an injection molding machine, can be connected), B (outlet, working connection to which the consumer, e.g. an injection cylinder of an injection unit of an injection molding machine, can be connected), T (tank, T-connection via which the pressure medium can be drained into a tank), X (inlet / outlet, can be used in particular to supply pressure to a pilot valve), or a Y (auxiliary, can be used for various purposes in the valve arrangement, in particular for a tank connection of the pilot valve) connection.A control edge can be a movable edge in a valve that regulates the flow of liquids or gases between the ports on the valve. It can be actuated by a force, e.g., a lever or an electromagnetic and / or pneumatic actuator, and can act by opening or closing a flow channel between two control ports in the valve body. In particular, the movable edge or control edge can be a surface of the main control piston and / or the secondary control piston that can cover an opening of a flow channel of one and / or more control ports of the valve body, thereby partially or completely opening and / or blocking a passage or flow path between control ports.

[0015] A main control piston and a secondary control piston according to the disclosure can be a hydraulic control piston. The control pistons can be used in directional control valves of the spool valve type. The secondary control piston can be formed within the first main control piston according to the disclosure. The actuation direction of the two control pistons is coaxial along their longitudinal axes, so that the respective control edges of the control pistons completely, partially, and / or not at all cover the openings of the control ports in the valve body, depending on the position of the displaced control piston. The main control piston and the secondary control piston can each comprise at least two piston shoulders from the piston shaft, which form the control edges on the control piston. The main control piston can form a first and second piston shoulder. The main control piston can also form a third piston shoulder. Furthermore, the main control piston can form a fourth piston shoulder.The secondary control piston can also form a first piston and a second piston shoulder. Depending on the position of the main control piston and / or the secondary control piston, the piston shoulders can cover control port openings in the valve body and thus regulate the flow between the control ports. The piston shoulders of the control pistons can be arranged in a connection area of ​​the control ports. A piston shoulder of a control piston, which covers a control port opening depending on the setting, can form a control edge with this opening in the valve body.

[0016] Within the scope of the invention, "linearly movable" can be understood as mobility along at least one axis, in particular exactly one axis. The valve body can be understood as a spatially physical part of the control valve. The valve body can form the housing of the control valve. Furthermore, the valve body can be designed to accommodate at least the main control piston and the secondary control piston.

[0017] An axial bore is a bore in the valve body and the main control piston along the longitudinal axis of the main control piston, so that the main control piston is slidably received in the bore of the valve body and the secondary control piston is slidably received in the bore of the main control piston. The axial bore can be centered in the main control piston.

[0018] The connecting holes from the end cap to the valve body can be cast into the end cap. This offers the advantage that no machining or reduction processes are required. Furthermore, the end cap can be made of cast material. This eliminates the need to create the connecting holes by drilling. Furthermore, no plugs would be required to seal the holes.

[0019] The screw plug can be understood as a spatially physical device that closes the axial bore of the main control piston, particularly in a fluid-tight manner. Alternatively, the screw plug can also be referred to as an end section. The screw plug can be screwed to the main control piston and / or connected to it in some other way.

[0020] The switching valve can be a hydraulic valve designed to move the actuating piston into at least two different positions. The switching valve can be designed as a 3 / 2-way seat valve. This can be open or closed in the de-energized state, depending on the required fail-safe position of the second secondary control piston. Alternatively, the switching valve can also be designed as a 4 / 2-way switching valve, with which two control surfaces of the actuating piston can be pressurized.

[0021] A longitudinal groove can be understood as a groove or a recess that runs along the longitudinal direction of the main control piston.

[0022] The hydraulic connection between the switching valve and the actuating piston is designed such that a switching operation of the switching valve causes a hydraulically induced change in the position of the actuating piston. In other words, hydraulic fluid is conveyed through the switching valve in such a way that a movement of the actuating piston occurs.

[0023] Overall, the control valve according to the invention offers the advantage of providing a switchable control edge, while at the same time being particularly compact and efficient. The secondary control piston located in the main control piston provides the switchable control edge through actuation of the actuating piston. This type of switching of the control edge represents an efficient way of replicating a multitude of switching states, particularly compared to the use of additional, interconnected valves. The hydraulic connection of the switching valve to the actuating piston via the longitudinal groove in the main control piston means that the control valve according to the invention can be designed particularly compactly. This means it takes up less space, allowing it to be used in a particularly versatile manner.

[0024] Within the scope of the invention, it can be advantageous to provide at least one second longitudinal groove, wherein the second longitudinal groove is arranged on the main control piston rotated by 180° with respect to the at least one longitudinal groove. In other words, a second hydraulic connection from the switching valve to the actuating piston can be provided, which is designed at least partially as a recess in the main control piston, wherein this second hydraulic connection is arranged essentially opposite one another, in particular rotated by 180°, on the main control piston. The two longitudinal grooves on the main control piston at least partially compensate for compressive forces that cause a transverse force on a piston shoulder of the main control piston and thus on the main control piston as a whole. A second longitudinal groove rotated exactly 180° ensures complete compensation of the transverse forces. Overall, a design free of transverse forces can increase the accuracy with which the valve can move to the switching positions.In addition, wear and tear is minimized.

[0025] Furthermore, additional longitudinal grooves can be provided. The longitudinal grooves can be arranged on the main control piston in such a way that transverse forces balance each other. It can be provided that a plurality of n longitudinal grooves are distributed on the main control piston at an angular spacing of 360° / n. This evenly balances the transverse forces.

[0026] Within the scope of the invention, it is conceivable for the secondary control piston and / or the actuating piston to be arranged entirely within the main control piston. This type of arrangement allows the control valve to be designed particularly compactly, thus requiring minimal installation space.

[0027] Within the scope of the invention, it can be provided that the main control piston has two main control surfaces, to which a force can be applied to move the main control piston, wherein, in particular, the two main control surfaces have areas of equal size. Alternatively, the main control surfaces can be designed asymmetrically. The two surfaces can be hydraulically balanced, especially if they are of equal size. Hydraulically balanced control surfaces enable the valve to be controlled more precisely and are less sensitive to pressure fluctuations in the system, since these compensate for each other immediately without any active measures.

[0028] It is also conceivable to provide a pilot control valve designed to control the main control spool. It can also be provided that a left and right control chamber of the valve body can be pressurized with flow and pressure via the pilot control valve. The pilot control valve can thus deflect the main control spool to the left or right from the center position and thus open up flow paths, for example PA and BT or PB and AT. Thanks to the pilot control valve provided on the control valve, the control valve as a whole has a particularly compact design and can be used in a variety of ways. In addition, even complex switching states, in particular fail-safe states, can be mapped with great accuracy without having to make compromises regarding switching speed and accuracy in regular operating conditions.

[0029] It is also conceivable to provide a switching valve designed to move the main control piston into a safe, de-energized position, with the switching valve, in particular, being arranged between a pilot valve and the valve body. The switching valve (this switching valve can also be referred to as a second switching valve) allows even complex circuits to be implemented using only the control valve according to the invention. Due to its arrangement between the pilot valve and the valve body, the control valve nevertheless remains compact, so that it requires little installation space overall.

[0030] Within the scope of the invention, it is optionally possible for a screw plug to seal a fluid system formed in the axial bore from the control chamber of the valve body, in particular via an elastomer seal. This allows the main control piston and secondary control piston to be hydraulically actuated independently of one another, so that the control edge of the main control piston can be switched. By switching the control edge, the switching positions can be achieved with switching characteristics adapted to the respective situation.

[0031] Furthermore, within the scope of the invention, it can be provided that the end cap fluidically seals one end of the valve body and is designed to accommodate at least part of the switching valve. The end cap accommodates the switching valve compactly and securely on the control valve.

[0032] With regard to the present invention, it is conceivable that the end cap has an anti-rotation device designed to block unwanted rotational movement of the main control piston and / or that an anti-rotation device is mounted on the side of the valve body opposite the end cap. The anti-rotation device enables particularly safe operation of the control valve.

[0033] Furthermore, it is conceivable that the anti-rotation device is completely accommodated, in particular screwed in, in the end cap, and wherein, in particular, the anti-rotation device is sealed from the environment via a sealing element, and / or that the anti-rotation device is completely accommodated, in particular screwed in, in the valve body, and wherein, in particular, the anti-rotation device is sealed from the environment via a sealing element. By completely accommodating the anti-rotation device in the end cap, the control valve can be realized in a particularly compact manner.

[0034] Within the scope of the invention, it may be advantageous for the actuating piston to be arranged in a bushing, wherein the bushing is arranged coaxially with the axial bore and is particularly designed to guide the actuating piston in its axial movement. This offers the advantage that the actuating piston does not require any additional installation space, allowing the control valve to be designed particularly compactly.

[0035] Within the scope of the invention, it is conceivable for the secondary control piston to have a transverse bore connected to the actuating piston via a cylindrical pin. This connection serves to compensate for manufacturing-related axial and angular misalignments between the axial bore and a bore in the actuating piston's bushing. Within the scope of the invention, the actuating piston can be provided with a right-hand control chamber and a left-hand control chamber. This allows the actuating piston to move relative to the secondary control piston along its longitudinal axis, in particular coaxially.

[0036] It is also conceivable for a compression spring to be provided on the actuating piston, which rests on the locking screw and is designed to preload the actuating piston. The spring-assisted preload allows the actuating piston to be moved into the preloaded position without any additional measures, in particular without an electric or hydraulic drive.

[0037] It is also conceivable for the switching valve to be designed as a 3 / 2-way seat valve or a 4 / 2-way switching valve. Using a 3 / 2-way or 4 / 2-way seat or switching valve, complex circuits, especially fail-safe states, can be implemented compactly and efficiently with the control valve according to the invention.

[0038] Within the scope of the invention, it is optionally possible for the end cap to have at least one bore that connects the switching valve to a pilot oil supply and / or to a system pressure connection of the valve body, wherein the bore is particularly sealed with a plug. The pilot oil supply directly at the end cap enables a particularly compact design of the control valve.

[0039] Furthermore, within the scope of the invention, it can be provided that the actuating piston has at least one relief groove on its outer circumference. The relief groove reduces pressure and mechanical stresses, thus enabling particularly precise and reliable operation of the control valve.

[0040] With regard to the present invention, it is conceivable that at least the locking screw, the actuating piston, the secondary control piston, or the bushing are at least partially, in particular completely, hardened. This hardened design makes the control valve particularly durable.

[0041] Furthermore, it is conceivable for the actuating piston to have at least one left control surface or one right control surface, to which a force can be applied to move the actuating piston. The actuating piston is movable by applying a force through the control surfaces. Within the scope of the invention, it can be advantageous for at least one left control surface or one right control surface to have a slot. The slot provides the advantage that the actuating piston cannot become stuck to the screw plug due to adhesive forces and, in particular, can be easily released from the compression spring.

[0042] Further advantages, features, and details of the invention will become apparent from the following description, in which several embodiments of the invention are described in detail with reference to the drawings. The features mentioned in the claims and in the description may be essential to the invention individually or in any combination.

[0043] Fig. 1 is a side sectional view of the control valve,

[0044] Fig. 2 is another side sectional view of the control valve,

[0045] Fig. 3 is another side sectional view of the control valve,

[0046] Fig. 4 a front sectional view of the control valve,

[0047] Fig. 5 is another front sectional view of the control valve,

[0048] Fig. 6 is another front sectional view of the control valve, and

[0049] Fig. 7 another front view of the control valve.

[0050] In the following figures, identical reference numerals are used for the same technical features, even in different embodiments. Reference numerals have been omitted in some figures to ensure clarity of presentation.

[0051] Fig. 7 shows a front view of the control valve showing the sections shown in Figs. 1 to 3. The central section CC through the center of the control valve is shown in Fig. 1, and Figs. 2 and 3 show the sectional views HH and JJ.

[0052] Fig. 1 shows a control valve according to the invention with at least one switchable control edge. The control valve has a main control piston 4, which is arranged for linear movement in a valve body 1, wherein the main control piston 4 has an axial bore 50 and is designed to provide at least two switching states through a linear movement. Furthermore, the control valve has a secondary control piston 5, which is arranged coaxially in the axial bore 50 of the main control piston 4 and is designed to switch at least one control edge of the main control piston 4, wherein the axial bore 50 of the main control piston 4 is closed off by a screw plug 16. In addition, the control valve has an actuating piston 9, which is arranged in the screw plug 16 and is designed to move the secondary control piston 5.Finally, the control valve also has a switching valve 19, which is hydraulically connected to the actuating piston 9 and is designed to hydraulically actuate the actuating piston 9. The main control piston 4 has at least one longitudinal groove 24, 41, which forms at least part of the hydraulic connection between the switching valve 19 and the actuating piston 9.

[0053] Overall, the control valve according to the invention offers the advantage of providing a switchable control edge, while at the same time being particularly compact and efficient. The secondary control piston 5 arranged in the main control piston 4 provides the switchable control edge through the actuation of the actuating piston 9. This type of switching of the control edge represents an efficient way of replicating a multitude of switching states, particularly compared to the use of additional, interconnected valves. The hydraulic connection of the switching valve 19 to the actuating piston 9 via the longitudinal groove 24, 41 in the main control piston 4 means that the control valve according to the invention can be designed particularly compactly. This takes up less space, allowing it to be used in a particularly versatile manner.

[0054] The function of the control valve is explained below using the figures.

[0055] The first main control piston 4 can move within the valve body 1. The first main control piston 4 can be controlled by a pilot valve 3. As shown in Figs. 1 to 3, a (second) switching valve 2, in particular a fail-safe valve, can be arranged between the pilot valve 3 and the valve body 1, with which the main control piston 4 can be brought into a safe, de-energized position.

[0056] The secondary control piston 5 is arranged in an axial bore 50 of the first main control piston 4. In Fig. 1, the main control piston 4 is closed at its left outer shaft diameter with the screw plug 16, which has a longitudinal groove 8. The screw plug 16 seals the internal system to a control chamber 80 of the valve body 1 via a (second) elastomer seal 13.

[0057] In addition, an anti-rotation device 6 is arranged in the valve body 1, which is screwed into an end cap 18 and provided with a sealing element 7. The anti-rotation device 6 can also be attached to the end cap 18 laterally or at the top, or at any angular position perpendicular to the longitudinal axis of the main control piston 4.

[0058] The secondary control piston 5 has a transverse bore on its left shaft diameter, which is connected to an actuating piston 9 via a cylindrical pin 54. This connection serves to compensate for manufacturing-related axial and angular misalignments between the axial bore 50 and the bore of the cylinder liner 15.

[0059] Also shown in Fig. 1 is that the actuating piston 9 has a right 10 and a left 11 control chamber. The actuating piston 9 can alternatively be designed as a rotary valve (not shown).

[0060] The actuating piston 9 shown can move coaxially to the longitudinal axis of the secondary control piston 5 in a bushing 15, which has an annular groove on a right-hand end face in which a (first) elastomer seal 12 is located. A recess is provided at the left end of the bushing, in which a further (third) elastomer seal 14 is located.

[0061] The actuating piston 9 is preloaded by a compression spring 17, which rests on the locking screw 16. The compression spring 17 can be mounted on the left or right side of the actuating piston 9.

[0062] 1 to 3, the valve body 1 is closed on the left side with an end cap 18. The end cap 18 can alternatively be mounted on the right side of the valve body 1 instead of on the left side (not shown). Located in the end cap 18 (Fig. 1) is a switching valve 19, e.g. a 3 / 2-way seat valve. This switching valve 19 can be open or closed in the de-energized state, depending on the required fail-safe position of the secondary control piston 5. Alternatively, a 4 / 2-way switching valve can also be provided, with which the two control surfaces 33 (Fig. 1) and 34 (Fig. 2) of the actuating piston 9 can be actively pressurized accordingly. In principle, the switching valve 19 can be open or closed in the de-energized state, depending on the required fail-safe position of the secondary control piston 5.The switching valve 19 can be supplied with pressure either via the system pressure port P or the control pressure port X. The pressure can be relieved via the switching valve 19 either via the return port T or via the control oil return port Y.

[0063] The end cap 18 is provided with bores 48 (Fig. 6) that connect the switching valve 19 to the pilot oil supply 52 of the valve body 1. Alternatively or additionally, the switching valve 19 can also be connected to the system pressure port of the control valve. The bore 48 is closed with a plug 36, as shown in Figs. 3 and 5.

[0064] Further holes 35, 37 can be provided in the end cap 18, as shown in Fig. 3. Another hole 20 is shown in Fig. 2. The holes 35, 37, 20 can be closed with plugs 36 (Fig. 3).

[0065] The bore 20 (Figs. 4, 5) opens into a vertical bore 23 in the valve body, which is closed at the bottom with a plug 22 (Fig. 6). As shown in Fig. 2, the bore 20 can be sealed between the end cap 18 and the valve body 1 by a seal 21, in particular a (fourth) elastomer seal 21. Similarly, the second connecting bore 37 between the end cap 18 and the valve body 1 can be sealed by a seal 38, in particular an elastomer seal 38.

[0066] The bore 37 (Fig. 5) opens into a bore 40 (Fig. 3) in the valve body 1, which is closed at the bottom with a plug 39 (Fig. 6).

[0067] The bore 23 (Fig. 3) opens into a first longitudinal groove 24 (Fig. 2, Fig. 6) on the underside of the main control piston 4, which opens into an annular space 30 (Fig. 2) between the cylinder sleeve 15 and the plug screw 16 (Fig. 1) via a first transverse bore 26, a first longitudinal bore 28 and a relief cut 29 (Fig. 2). This bore system is connected to the left control chamber 11 of the actuating piston 9 via a third transverse bore 31 (Fig. 2) in the cylinder sleeve. The bore system is in turn connected to the annular space 30 and the relief cut 29 via a fourth transverse bore 32 in the cylinder sleeve 15, which opens into a second longitudinal groove 25 via a second longitudinal bore 280 and a second transverse bore 27. Because the first longitudinal groove 24 and the first transverse bore 26 are substantially opposite each other, in particular rotated by 180°, to the second longitudinal groove 25 and the second transverse bore 27, the second longitudinal groove 25 opens into the vertical bore 40 of the valve body 1.By this rotation, the pressure forces which cause a transverse force on the first piston shoulder 49 of the main control piston 4 in the longitudinal grooves 24 and 25 are balanced.

[0068] Similarly, the vertical bore 40 opens into a third longitudinal groove 41 (Fig.

[0069] 3) on the underside of the main control piston 4, which opens into the right control chamber 10 of the actuating piston 9 via a fifth transverse bore 43 and a third longitudinal bore 45. This bore system opens into a fourth longitudinal groove 42 via a fourth longitudinal bore 46 and a sixth transverse bore 44. Because the third longitudinal groove 41 and the fifth transverse bore 43 are essentially opposite one another, in particular rotated by 180°, to the fourth longitudinal groove 42 and the sixth transverse bore 44, the fourth longitudinal groove 42 opens into the (first) vertical bore 23 of the valve body 1. This rotation balances out the pressure forces in the longitudinal grooves 41 and 42 which cause a transverse force on the first piston shoulder 49 of the main control piston 4.

[0070] Furthermore, Fig.3 shows that the actuating piston 9 can have at least one relief groove 47 on its outer circumference.

[0071] Referring again to Fig. 1, by actuating the switching valve 19 via the described bore systems in a switching position, the right control chamber 10 and thus the right control ring surface 34 of the actuating piston 9 can be subjected to system or pilot pressure and moved against the compression spring 17.

[0072] Thus, the actuating piston 9 can be actively opened. In the other switching position of the switching valve 19, the right control ring surface 34 (Fig. 2) can be relieved accordingly to the return port T or, alternatively, the control oil outlet Y.

[0073] The longitudinal grooves 24, 25 and 41, 42 can be designed in such a way that they are still connected to the vertical bores 23 and 40 at + / -100% of the control piston stroke.

[0074] Thus, the secondary control piston 5 can be adjusted via the actuating piston 9. This actuating system is located in the moving main control piston 4. A particular advantage over previous control valves is that the effective main control surfaces 51, 53 of the first main control piston 4 are the same size on both sides and thus hydraulically balanced.

[0075] As shown in Figs. 2, 3, and 1, the angular position of the anti-rotation device relative to the longitudinal grooves 24, 25 and 41, 42, respectively, can be configured at, for example, 45°, so that the anti-rotation device 6 points downward toward a mounting surface of the valve body 1. The anti-rotation device 6 ensures that the longitudinal grooves 24, 25 and 41, 42 of the main control piston 4 remain aligned with the vertical bores 23 and 40.

[0076] According to the invention, it can be provided that optional insert orifices can be screwed into the bores 20, 35, 37 or 48 (Fig. 2, 3, 6) in order to make the pressure build-up slow, so that the actuating piston 9 is switched in a damped manner.

[0077] It is conceivable that at least the locking screw 16 (Fig. 1), the actuating piston 9, the secondary control piston 5 or the bushing 15 is at least partially, in particular completely, hardened.

[0078] The left control surface 33 of the actuating piston 9 can have a slot to prevent the actuating piston 9 from becoming stuck to the locking screw 16 due to adhesive forces and thus allow it to be easily released by the compression spring 17. As an alternative to the slot in the left control surface 33 of the actuating piston 15, the slot can also be provided on the counter surface of the locking screw 16 (not shown).

[0079] In an embodiment not shown, the compression spring 17 can also be arranged to the right of the actuating piston 9.

[0080] The above explanation of the embodiments describes the present invention exclusively within the framework of examples. Of course, individual features of the embodiments can be freely combined with one another, provided that they are technically feasible, without departing from the scope of the present invention. Reference ua sze ichenli ste

[0081] 1 valve body

[0082] 2 second switching valve

[0083] 3 pilot valve

[0084] 4 main control pistons

[0085] 5 secondary control pistons

[0086] 6 Anti-twist device

[0087] 7 Sealing element

[0088] 8 Longitudinal groove for anti-twist protection

[0089] 9 actuating pistons

[0090] 10 right control room

[0091] 11 left control room

[0092] 12 first elastomer seal

[0093] 13 second elastomer seal

[0094] 14 third elastomer seal

[0095] 15 Cylinder liner

[0096] 16 Locking screw

[0097] 17 compression spring

[0098] 18 End cap

[0099] 19 Switching valve

[0100] 20 holes

[0101] 21 fourth elastomer seal

[0102] 22 first sealing plug

[0103] 23 first vertical borehole

[0104] 24 first longitudinal groove

[0105] 25 second longitudinal groove

[0106] 26 first cross hole

[0107] 27 second cross hole

[0108] 28 first longitudinal bore

[0109] 29 undercut

[0110] 30 annular space

[0111] 31 third cross hole

[0112] 32 fourth cross hole

[0113] 33 left control surface 34 right control surface

[0114] 35 second vertical hole

[0115] 36 second sealing plug

[0116] 37 second connecting hole

[0117] 38 fifth elastomer seal

[0118] 39 third sealing plug

[0119] 40 third vertical borehole

[0120] 41 third longitudinal groove

[0121] 42 fourth longitudinal groove

[0122] 43 fifth cross hole

[0123] 44 sixth cross hole

[0124] 45 third longitudinal bore

[0125] 46 fourth longitudinal bore

[0126] 47 Relief groove

[0127] 48 bore

[0128] 49 first piston paragraph

[0129] 50 axial bore

[0130] 51 Main control surface

[0131] 52 Pilot oil supply

[0132] 53 Main control surface

[0133] 54 cylindrical pin

[0134] 80 control room

[0135] 280 second longitudinal bore

Claims

Patent claims 1. Control valve with at least one switchable control edge, comprising: - a main control piston (4) which is arranged to be linearly movable in a valve body (1), wherein the main control piston (4) has an axial bore (50) and is designed to provide at least two switching states by a linear movement, - a secondary control piston (5) which is arranged coaxially in the axial bore (50) of the main control piston (4) and is designed to switch at least one control edge of the main control piston (4), wherein the axial bore (50) of the main control piston (4) is closed by a screw plug (16), - an actuating piston (9) which is arranged in the screw plug (16) and is designed to move the secondary control piston (5), - a switching valve (19) which is hydraulically connected to the actuating piston (9) and is designed to hydraulically actuate the actuating piston (9), wherein the main control piston (4) has at least one longitudinal groove (24, 41) which forms at least part of the hydraulic connection between the switching valve (19) and the actuating piston (9).

2. Control valve according to claim 1, characterized in that at least one second longitudinal groove (25, 42) is provided, wherein the second longitudinal groove (25, 42) is arranged on the main control piston (4) rotated by 180° with respect to the at least one longitudinal groove (24, 41).

3. Control valve according to claim 1 or 2, characterized in that the secondary control piston (5) and / or the actuating piston (9) is arranged completely within the main control piston (4).

4. Control valve according to one of the preceding claims, characterized in that the main control piston (4) has two main control surfaces (51, 53) on which a force for moving the main control piston (4) can be applied, wherein in particular the two main control surfaces (51, 53) have areas of equal size.

5. Control valve according to one of the preceding claims, characterized in that a pilot valve (3) is provided which is designed to control the main control piston (4).

6. Control valve according to one of the preceding claims, characterized in that a switching valve (2) is provided which is designed to move the main control piston (4) into a safe, energy-free position, wherein in particular the switching valve (2) is arranged between a pilot valve (3) and the valve body (1).

7. Control valve according to one of the preceding claims, characterized in that an end cap (18) is provided and the screw plug (16) seals a fluid system formed in the axial bore (50) to the control chamber (80) of the valve body (1), in particular via an elastomer seal (13).

8. Control valve according to one of the preceding claims, characterized in that the end cap (18) fluidically closes one end of the valve body (1) and is designed to accommodate at least part of the switching valve (19).

9. Control valve according to claim 8, characterized in that the end cap (18) has an anti-rotation device (6) which is designed to block an undesired rotary movement of the main control piston (4) and / or that an anti-rotation device (6) is mounted on the side opposite the end cap (18) in the valve body (1).

10. Control valve according to claim 9, characterized in that the anti-rotation device (6) is completely accommodated, in particular screwed, in the end cap (18), and wherein in particular the anti-rotation device (6) is sealed from the environment by a sealing element (7), and / or that the anti-rotation device (6) is completely accommodated, in particular screwed, in the valve body (1), and wherein in particular the anti-rotation device (6) is sealed from the environment by a sealing element (7).

11. Control valve according to one of the preceding claims, characterized in that the actuating piston (9) is arranged in a bushing (15), wherein the bushing (15) is arranged coaxially to the axial bore (50) and is designed in particular to guide the actuating piston (9) in its axial movement.

12. Control valve according to one of the preceding claims, characterized in that the secondary control piston (5) has a transverse bore which is connected to the actuating piston (9) via a cylindrical pin (54).

13. Control valve according to one of the preceding claims, characterized in that the actuating piston (9) has a right control chamber (10) and a left control chamber (11).

14. Control valve according to one of the preceding claims, characterized in that a compression spring (17) is provided on the actuating piston (9), which is supported on the screw plug (16) and is designed to preload the actuating piston (9).

15. Control valve according to one of the preceding claims, characterized in that the switching valve (19) is designed as a 3 / 2-way seat valve or as a 4 / 2-way switching valve.

16. Control valve according to one of the preceding claims, characterized in that the end cap (18) has at least one bore (48) which connects the switching valve (19) to a pilot oil supply and / or to a system pressure connection of the valve body (1), wherein in particular the bore (48) is closed with a plug (36).

17. Control valve according to one of the preceding claims, characterized in that the actuating piston (9) has at least one relief groove (47) on its outer circumference.

18. Control valve according to one of the preceding claims, characterized in that at least the closure screw (16), the actuating piston (9), the secondary control piston (5) or the bushing (15) is at least partially hardened.

19. Control valve according to one of the preceding claims, characterized in that the actuating piston (9) has at least one left control surface (33) or one right control surface (34) to which a force for moving the actuating piston (9) can be applied.

20. Control valve according to claim 19, characterized in that at least one left control surface (33) or one right control surface (34) has a slot.

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