Directional control valve

Abstract

The invention relates to a directional control valve (11), comprising a valve housing (16) in which a slide receiving space (18) extending in a longitudinal direction (15a) along a longitudinal axis (15) and delimited radially on the outside by a peripheral receiving space delimiting surface (22) is formed, wherein a plurality of valve channels (24a to 24d) open into the slide receiving space (18) and a valve slide (19) which can be moved between a plurality of switch positions is arranged, wherein the valve slide (19) is assigned a sealing structure which has at least one sealing ring and which co-produces a switching movement (20), wherein the valve channels (24a to 24d) contain a feed channel (24a), which can be connected to a fluidic pressure source, and at least one working channel (24b), which can be connected to a fluid consumer (40) to be controlled, and wherein a sealing ring of the sealing structure is designed as an aeration sealing ring (41a), and wherein at least one section of the aeration sealing ring (41a) is designed as a non-return valve element which is movable relative to the slide body (25) depending on the pressure difference applied to said sealing ring and which, in the shut-off position of the aeration sealing ring (41a), can be moved into an open position permitting a fluid flow out of the working channel (24b) into the feed channel (24a) when the fluid pressure in the working channel (24b) is higher by a predetermined amount than in the feed channel (24a), and wherein, in the open position, the non-return valve element bears against a contact section (43) of the slide body (25), and wherein the contact section (43) is penetrated by at least one deaeration opening.

Description

[0001]

[0002] March 6, 2026

[0003] Festo SE & Co. KG, Ruiter Straße 82, 73734 Esslingen

[0004] Directional control valve

[0005] The invention relates to a directional control valve with a valve housing in which a spool receiving chamber extending longitudinally along a longitudinal axis and bounded radially on the outside by a peripheral receiving chamber boundary surface is formed, into which several valve channels penetrating the valve housing open at longitudinally spaced locations of the peripheral receiving chamber boundary surface, and in which a valve spool is arranged which is displaceable longitudinally between several switching positions by performing a switching movement, the valve spool having at least one spool body which carries a sealing structure having at least one sealing ring which participates in the switching movement, wherein the valve channels include a feed channel connectable to a fluidic pressure source and at least one working channel connectable to a fluid consumer to be controlled.and wherein a sealing ring of the sealing structure is designed as a vent sealing ring which, in a first switching position of the valve slide, assumes a shut-off position and, in a second switching position of the valve slide, a venting position, wherein, in the shut-off position, it fluidly separates the feed channel from the working channel by interacting with the peripheral receiving chamber boundary surface, and in the venting position, it allows a fluid connection between the feed channel and the working channel, wherein at least one section of the vent sealing ring is designed as a check valve element movable depending on the pressure difference applied to it relative to the slide body, which, in the shut-off position of the vent sealing ring, allows a fluid flow from the working channel into the feed channel,

[0006] P 35817 / PCT

[0007] March 6, 2026, the open position is movable when the fluid pressure in the working channel is higher by a predetermined amount than in the feed channel, and the check valve element rests against a section of the valve body in the open position.

[0008] For the safety of a system equipped with a directional control valve, especially one that also includes a fluid consumer, it is sometimes necessary to completely vent the system. In this case, the feed line is disconnected from the pressure source and, like the vent lines, connected to the atmosphere. This is done by means of an upstream vent valve.

[0009] To ensure that an enclosed fluid consumer is completely vented during the venting of a system, DE 102014112 110 Al provides for a residual pressure relief valve attached to a multi-way valve. The residual pressure relief valve is connected to the two working channels and is controlled by the fluid pressure in the feed channel. When the feed channel is vented, the residual pressure relief valve switches to a venting position, in which it connects the two working channels to the atmosphere independently of the valve channels of the multi-way valve, causing a venting fluid consumption. However, the design effort associated with these residual pressure venting measures is considerable and increases the dimensions of the valve assembly, since the residual pressure relief valve is attached to the main valve.

[0010] A directional control valve of the type mentioned above is known from DE 102020133997 A1. Residual pressure venting is achieved here via a vent sealing ring, which is designed as a check valve element whose movement depends on the axial pressure difference applied to it relative to the spool body of a valve spool. However, it has been shown that the vent sealing ring inflates during the venting process, so that it can tear after only several tens of thousands of switching cycles.

[0011] The object of the invention is therefore to create a directional control valve of the type mentioned above, which enables reliable residual pressure relief with minimal design effort and compact dimensions.

[0012] P 35817 / PCT

[0013] March 6, 2026. This problem is solved by the features of independent claim 1. Further developments of the invention are presented in the dependent claims.

[0014] The directional control valve according to the invention is characterized in that the system section is penetrated by at least one vent opening.

[0015] This prevents the pressure exerted during the venting process from seeping under the venting seal and potentially causing it to bulge. This significantly increases the service life of the venting seal, for example, to up to 800,000 to 1,000,000 switching cycles. Compared to conventional directional control valves, the service life of the venting seal is approximately ten times longer.

[0016] In a further development of the invention, the contact section projects radially outwards from a central section of the slide body, which is particularly cylindrical. The contact section can, for example, be designed as a type of ring collar and has a larger diameter than the central section.

[0017] In a further development of the invention, the system section has a first flank region facing the ventilation sealing ring and a second flank region facing away from the ventilation sealing ring. In a particularly preferred embodiment, the first flank region is conically shaped.

[0018] In a further development of the invention, the system section has several ventilation openings distributed around its circumference. Advantageously, the ventilation openings are arranged at regular intervals from one another around the circumference.

[0019] In a particularly preferred embodiment, the at least one vent opening is designed as a vent slot extending radially outwards from a central region of the system section and terminating freely at the outer circumference of the system section. The at least one vent slot is thus open at its edge. Advantageously, several vent slots are provided.

[0020] P 35817 / PCT

[0021] 6 March 2026 Ventilation slots are provided, which are expediently arranged at regular intervals to each other in the circumferential direction of the plant section.

[0022] In a further development of the invention, the vent slot has a slot base and two slot flanks extending radially outwards from the slot base, in particular arranged parallel to each other. Advantageously, the slot base is located at the level of the outer circumference of the central section of the slide body.

[0023] Advantageously, the feed channel opens into a feed section and the working channel into a working section of the valve receiving chamber that is axially connected to the feed section.

[0024] In a further development of the invention, the ventilation sealing ring is axially displaceable on the slide body depending on the pressure difference between the feed channel and the associated working channel between a starting position and the open position, wherein in the open position it comes into contact with the contact section and in the starting position comes into contact with a support section of the slide body in such a way that in the first switching position of the valve slide it seals the fluid connection between the feed channel and the working channel in a fluid-tight manner.

[0025] In a further development of the invention, the valve channels include a venting channel that can be connected to a pressure sink and opens into the slide valve receiving chamber, in particular into a venting section that is axially connected to the working section on the side opposite the feed section.

[0026] Advantageously, a further sealing ring of the sealing structure is designed as a vent sealing ring, which assumes a shut-off position in the first and second switching positions of the valve slide and a venting position in a third switching position of the valve slide, wherein in its shut-off position it fluidly separates the associated working channel from the venting channel by means of the interaction of the peripheral receiving chamber boundary surface and in the venting position

[0027] P 35817 / PCT

[0028] March 6, 2026 releases a fluid connection between the associated working channel and the venting channel, with the venting sealing ring assuming the shut-off position in the third switching position of the valve slide.

[0029] In a further development of the invention, a further venting channel connected to a further working channel is provided. Advantageously, the further working channel opens into the valve receiving chamber at a further working section located on the side of the feed section axially opposite the working section. Advantageously, a further sealing ring of the sealing structure is designed as a further venting sealing ring, which assumes a shut-off position in the first switching position of the valve slide and a venting position in the third switching position of the valve slide, wherein, in its shut-off position, the further venting sealing ring, by interacting with the peripheral receiving chamber boundary surface, fluid-tightly separates the feed channel from the further working channel and, in the venting position, allows a fluid connection between the feed channel and the further working channel.and wherein a further sealing ring of the sealing structure is designed as a further vent sealing ring, which assumes a shut-off position in the first and third switching positions of the valve slide and a venting position in the second switching position of the valve slide, wherein in its shut-off position, by interacting with the peripheral receiving chamber boundary surface, it fluidly separates the further working channel from the further venting channel and in its venting position, it releases a fluid connection between the further working channel and the further venting channel, wherein the further vent sealing ring assumes its shut-off position in the second switching position of the valve slide.

[0030] In a particularly preferred embodiment, at least one section of the further ventilation sealing ring is designed as a check valve element that is movable depending on the pressure difference applied to it relative to the slide body, and which, in the closed position of the further ventilation sealing ring, can be moved into an open position allowing fluid flow from the further working channel into the feed channel when the

[0031] P 35817 / PCT

[0032] March 6, 2026, fluid pressure in the further working channel is higher by a predetermined amount than in the feed channel, and wherein the check valve element in the open position rests against a further system section of the valve body, wherein the further system section is penetrated by at least one vent opening.

[0033] In a further development of the invention, the slide body has a first slide part and a second slide part designed as a separate component, wherein the two slide parts are movably attached to each other by means of connecting means.

[0034] In a particularly preferred manner, the two slide parts are designed identically to each other.

[0035] The connecting means can, for example, have at least one connecting bolt which, on the one hand, is fixed relatively immovably to one of the slide parts, particularly in a blind hole bore, for example by means of a screw connection, and on the other hand, is mounted relatively movable to the other slide part, wherein, in particular, a spring element as part of the connecting means acts on the connecting bolt and presses it into a starting position in which, expediently, the two slide parts are axially spaced as far apart as possible.

[0036] The identical construction of the two slide parts is advantageously justified by the fact that each of the two slide parts has a blind hole and an adjoining spring mounting space, so that either one or the other slide part can be fitted with the spring element.

[0037] A preferred example of the invention is shown in the drawing and is explained in more detail below. The drawing shows:

[0038] Figure 1 shows a perspective view of a preferred embodiment of the directional control valve according to the invention.

[0039] P 35817 / PCT

[0040] March 6, 2026 Figure 2 shows a longitudinal section through the directional control valve from Figure 1, with the valve spool in the first switching position and the vent sealing rings in the shut-off positions,

[0041] Figure 3 shows the directional control valve from Figure 2, with one of the two ventilation sealing rings in the open position,

[0042] Figure 4 shows the directional control valve from Figure 2, with one of the two ventilation sealing rings in an intermediate position.

[0043] Figure 5 shows a perspective view of one of the slide parts of the slide body of the valve slide and

[0044] Figure 6 shows a longitudinal section through the sliding part of Figure 5.

[0045] Figures 1 to 6 show a preferred embodiment of the directional control valve 11 according to the invention. The directional control valve 11 is shown and described by way of example using a multi-way valve. In principle, however, the invention could also be applied to a "one-way valve", for example in the form of a 2 / 2 valve, in which, depending on the switching position of the valve, "one way" is selectively opened or closed.

[0046] The directional control valve 11 is expediently of an electrofluidically and, in particular, electropneumatically piloted design. This applies to the illustrated embodiment. In this case, the directional control valve 11 has a main valve 12, which is equipped with an electrically actuated pilot valve assembly 13. The pilot valve assembly 13 has at least one, and by way of example, two electrically actuated pilot valves 14a, 14b, which are expediently solenoid valves. The design of the pilot valves will not be discussed in detail below.

[0047] The directional control valve 11 extends along a longitudinal axis 15, the axial direction of which is hereinafter referred to as longitudinal direction 15a.

[0048] P 35817 / PCT

[0049] March 6, 2026. The directional control valve 11 has a valve housing 16, which is shown as an example of a component of the main valve 12. In the example shown, the pilot valve assembly 13 is mounted on one of the two end faces 17 (Figure 2) of the valve housing 16 oriented in the longitudinal direction 15a.

[0050] The valve housing 16 has an elongated cavity extending in the longitudinal direction 15a, which forms a valve receiving chamber 18 for receiving a valve spool 19. In the illustrated pilot-operated valve design, the valve receiving chamber 18 and the valve spool 19 belong to the main valve 12. The valve spool 19 has an elongated shape and extends into the valve receiving chamber 18 in the longitudinal direction 15a.

[0051] The valve spool 19 is movable back and forth in the spool receiving chamber 18 relative to the valve housing 16 in a linear switching movement 20, indicated by a double arrow, in its longitudinal direction 15a. In this way, it can be positioned relative to the valve housing 16 in different axial switching positions. The actuating force for generating the switching movement 20, and preferably also for holding the valve spool 19 in the set switching position, is, for example, a fluid force that can be generated by a pilot fluid with which the valve spool 19 can be axially actuated by means of the pilot valve assembly 13.For example, the valve slide 19 is assigned two first and second drive surfaces 21a, 21b pointing in opposite directions in the longitudinal direction 15a, each of which can be supplied with the pilot fluid or relieved of pressure via a pilot control channel (not shown) communicating with the pilot control valve assembly 13.

[0052] As an example, each of the two axial end regions of the valve slide 19 is assigned one of two drive pistons 60a, 60b (Fig.2), on which one of the two drive surfaces 21a, 21b is formed and which can axially support themselves on the valve slide 19 to transmit a drive force.

[0053] P 35817 / PCT

[0054] March 6, 2026 Compressed air is primarily used as the pilot fluid, although alternatively another pressure fluid can also be used.

[0055] The slide receiving chamber 18 is bounded radially on the outside by a peripheral receiving chamber boundary surface 22 pointing radially inwards. Viewed in a cross-section perpendicular to the longitudinal axis 15, the receiving chamber boundary surface 22 has a round and preferably a circular contour.

[0056] The valve receiving chamber 18 has several longitudinal chamber sections 23 arranged successively in the longitudinal direction 15a, into which one of several valve channels 24, which penetrate the valve housing 16, opens at the receiving chamber boundary surface 22. The opening areas of the several valve channels 24 are spaced apart from each other in the longitudinal direction 15a.

[0057] Preferably, the directional control valve 11 is a 5 / 4-way valve with a total of five valve channels 24, which can be connected and / or disconnected from each other in different control configurations by the valve spool 19. Such a configuration is present in the illustrated embodiments. Here, the directional control valve 11 is preferably designed as a 5 / 4-way valve whose valve spool 19 can be positioned in four alternative switching positions to specify different control configurations.

[0058] However, the invention can also be readily applied to a 5 / 3-way valve in which the valve spool can be positioned in three alternative switching positions to specify different control configurations.

[0059] The following 5 / 4-way valve is characterized by the fact that the valve spool 19 has a spool body 25 which has two spool parts 26a, 26b that are movable relative to each other.

[0060] In the described example, the two slide parts 26a and 26b are configured differently. The first slide part 26a has the first drive piston 60a with

[0061] P 35817 / PCT

[0062] March 6, 2026, is assigned to its first drive surface 21a. The second drive piston 60b with its second drive surface 21b is assigned to the second slide section 26b. The second slide section 26b has a cavity 27 extending axially through the entire slide section 26b, in which connecting elements 28, described in more detail below, are accommodated. The cavity 27 extends from a cavity opening assigned to the second drive piston 60b in the axial direction and longitudinal direction 15a towards the first slide section 26a. The cavity 27 has a first cavity section 27a with a larger cross-section than a subsequent cavity section 27b (Fig. 4). The cavity 27, or rather the cavity sections 27a and 27b, expediently have a circular cylindrical cross-section.The smaller diameter second cavity section 27b opens at another cavity opening on an end face of the second slide part 26b, this end face being directed towards the first slide part 26a. A connecting bolt 30 belonging to the connecting means 28 is received in the cavity 27 of the second slide part 26b such that a bolt head 31 is supported on a step between the larger diameter first cavity section 27a and the smaller diameter second cavity section 27b, penetrates the first second cavity section, and projects into a mounting bore 32 in the first slide part 26a in the manner described below. The connecting bolt 30 is fixed relatively immovably to the first slide part 26a, while it is movably mounted in the cavity 27 of the second slide part 26b relative to it. The connecting means 29 also include a spring element 33, which is also accommodated in the cavity 27.In the example shown, the spring element 33 is a compression spring which is mounted in the first cavity section 27a with a larger diameter in such a way that it is supported on one side by the bolt head 31 of the connecting bolt 30 and on the other side by an abutment, for example in the form of a ball 34.

[0063] The configuration of compression spring and connecting bolt 30 ensures that the spring force of the compression spring presses the connecting bolt 30 against the step between the first and the second cavity section 27a, 27b, meaning that in this position the two slide parts 26a, 26b have the greatest possible distance from each other.

[0064] P 35817 / PCT

[0065] March 6, 2026 During a switching movement 20 to the left, the first slide part 26a can thus be displaced relative to the second slide part against the spring force of the compression spring, so that the axial distance between the two slide parts 26a, 26b is reduced.

[0066] As already indicated above, the bolt shaft 35 of the connecting bolt 30 projects into the fastening bore 32 of the first slide part 26a and is anchored or fastened there, for example by means of a screw connection through an internal thread on the fastening bore 32 and a corresponding external thread on the bolt shaft 35.

[0067] In an embodiment not shown, the two slide parts are identical in construction and each has a cavity penetrating the slide parts with two cavity sections, as is the case with the first slide part of the described embodiment. This design eliminates one component, since the two slide parts are identical in construction and either the first or the second slide part can be equipped with the compression spring.

[0068] Figure 2 of the drawing shows the valve spool 19 in a first switching position. This is preferably a neutral position, from which the valve spool 19 can be switched to a second switching position by a clockwise switching movement 20. In another position of the valve spool 19, not shown in Figure 2, the valve spool can be switched to a third switching position by a counterclockwise switching movement. Furthermore, the valve spool can be switched to a fourth switching position by the relative movement of the two spool parts towards each other.

[0069] Of the switch positions, only the first switch position is shown in the figures.

[0070] In the following, the slide valve chamber length sections 23 are also individually named. Accordingly, the slide valve chamber length sections 23 contain a feed length section 23a, which is axially bordered on one side by a working length section 23b and on the other side by another working length section.

[0071] P 35817 / PCT

[0072] March 6, 202623c is flanked. For better distinction, the working length section 23b will also be referred to as the first working length section 23b and the further working length section 23c will also be referred to as the second working length section 23c.

[0073] The first working length section 23b is followed axially by a venting length section 23d, which for better distinction is also referred to as the first venting length section 23d below, while the second working length section 23c is followed axially by another venting length section 23e, which for better distinction is also referred to as the second venting length section 23e.

[0074] The valve channels 24 are, by way of example, a feed channel 24a opening into the feed section 23a, a working channel 24b opening into the first working section 23b, which is hereinafter also referred to as the first working channel 24b, a further working channel 24c opening into the second working section 23c, which is hereinafter also referred to as the second working channel 24c, a vent channel 24d opening into the first vent section 23d, which is hereinafter also referred to as the first vent channel 24d, and a further vent channel 24e opening into the second vent section 23e, which is hereinafter also referred to as the second vent channel 24e.

[0075] Between longitudinally adjacent valve receiving chamber sections 23 in the longitudinal direction 15a, a transition section 36 extends, in which the receiving chamber boundary surface 22 forms a cylindrical sealing surface 37, which is hereinafter also referred to as the transition sealing surface 37 for better distinction. The diameter of the valve receiving chamber 18 is smaller in the area of ​​the transition sections 36 than in the area of ​​the valve receiving chamber sections 23, into which one of the valve channels 24 opens.

[0076] The slide body 25 carries a sealing structure 38 belonging to the valve slide 19 in the area of ​​its radial outer circumference, which moves with the slide body 25 during the switching movement.

[0077] P 35817 / PCT

[0078] March 6, 2026 In the described example of the 5 / 4-way valve, the sealing structure 38 extends to both the first valve part 26a and the second valve part 26b.

[0079] The purpose of the sealing structure 38 is to define the individual control configurations of the valve channels 24 by selectively sealing together with the transition sealing surfaces 37. When the sealing structure 38 abuts a transition sealing surface 37, it fluidly separates the two axially adjacent valve receiver chamber sections 23 from each other. Accordingly, the valve channels 24 communicating with the respective valve receiver chamber sections 23 are also separated from each other.If the valve slide 19 is positioned such that the sealing structure 38 does not rest against one of the transition sealing surfaces 37 because it has been moved out of the area of ​​the slide receiving chamber 18 enclosed by the transition sealing surface 37, there is an open fluid connection between the slide receiving chamber longitudinal sections 23 which adjoin the transition sealing surface 37 axially on both sides, so that the valve channels 24 connected to them are also connected to each other.

[0080] Between axially adjacent sections of the sealing structure 38, the valve slide 19 has a reduced-diameter, constricted longitudinal section 39 (Fig.4) which promotes fluid flow when the fluid connection is open.

[0081] The feed channel 24a can be connected to a fluidic pressure source P, and is connected to this fluidic pressure source P during normal operation of the directional control valve 11. The fluidic pressure source P provides a fluidic pressure medium, for example, compressed air. Each working channel 24b, 24c is connected to a fluidically controlled fluid consumer 40 (Fig. 2). The fluid consumer 40 is, in particular, a fluid-actuated actuator 40a, for example, a pneumatic cylinder. Each vent channel 24d, 24e is connected to a pressure sink R, which is, in particular, the atmosphere.

[0082] P 35817 / PCT

[0083] March 6, 2026 For the fluid connection with the fluidic pressure source P and the fluid consumer 40, fluid lines (not shown) connected to the relevant valve channels 24 on the valve housing 16 are expediently used. For connection to the atmosphere, the vent channels 24d, 24e can open directly on the outside of the valve housing 16.

[0084] The sealing structure 38 expediently comprises several sealing rings 41 arranged coaxially on the slide body 25 and fixed to the slide body 25 at an axial distance from one another. Between adjacent sealing rings 41 is one of the aforementioned constricted longitudinal sections. Each of the sealing rings 41 is associated with one of the transition sealing surfaces 37, with which it is in radial sealing contact when it occupies a position enclosed by the associated transition sealing surface 37 within the transition longitudinal section 36. In this case, slide receiving chamber longitudinal sections 23 arranged axially adjacent to the transition longitudinal section 36 are fluid-tightly separated from one another.Furthermore, the valve slide 19 can assume positions in which at least one sealing ring 41 has left the transition length section 36 assigned to it, so that an annular space exists between the assigned transition sealing surface 37 and a constricted length section 39 of the valve slide 19, through which the fluidic pressure medium can flow.

[0085] Each transition sealing surface 37 extends between two of the valve receiver length sections 23, in the area of ​​which the diameter of the valve receiver space 18 is larger than in the transition length section 36 enclosed by the transition sealing surface 37, so that a sealing ring 41 does not have a sealing effect when it is positioned in the area of ​​one of the valve receiver space length sections 23.

[0086] The transition length section 36 located between the feed length section 23a and the first working length section 23b is associated with a sealing ring 41, hereinafter referred to as the first vent sealing ring 41a, while the transition length section 36 extending between the feed length section 23a and the second working length section 23c is associated with a sealing ring 41, which is described in P 35817 / PCT

[0087] March 6, 2026. The following is designated as a further, second vent sealing ring 41b. The axial distance between the two vent sealing rings 41a, 41b, measured in the longitudinal direction 15a, is selected such that both vent sealing rings 41a, 41b assume a closed position when the valve spool 19 is in the first switching position. This closed position is characterized by the fact that the respective vent sealing ring 41a, 41b lies within the associated transition length section 36 and bears there with radial sealing contact against the transition sealing surface 37. This interrupts the fluid connection between the feed channel 24a and each working channel 24b, 24c.

[0088] In this first switching position of the valve slide 19, a further sealing ring 41, axially spaced from the first venting sealing ring 41a and designated as the first venting sealing ring 41c, in turn assumes a shut-off position in which it radially seals against the transition sealing surface 37 of the transition length section 36 which extends between the first working length section 23b and the first venting length section 23d.

[0089] In the first switching position of the valve slide 19, a further sealing ring 41, referred to below as the second vent sealing ring 41d, which lies on the side of the second vent sealing ring 41b axially opposite to the first vent sealing ring 41a, does not touch its transition sealing surface 37, is thus in its open position, which makes venting of the second working channel 24c via the second vent channel 24e possible.

[0090] In this switching position, a fluid volume located in the first working channel 24b is confined. By applying an actuating force, for example via the pilot valve assembly 13, the valve spool 19 can be moved from the first switching position shown in Figure 2, either to a second switching position (not shown) moved to the left or to a third switching position moved to the right, by performing a switching movement 20. The second switching position is established by the relative displacement of the two spool parts 26a, 26b to each other, whereby the first vent sealing ring 41a moves from its closed position to the left in P 35817 / PCT

[0091] On March 6, 2026, its ventilation position is shifted so that ventilation of the first working channel 24b via the feed channel 24a is possible. The establishment of the third switching position is achieved by shifting the slide body 25 to the right by pressurizing the second drive piston, whereby the two slide parts 26a, 26b are shifted together, so that the second ventilation sealing ring is shifted from its shut-off position shown in Figure 2 to its ventilation position, thereby enabling ventilation of the second working channel 24c via the feed channel 24a.

[0092] During normal use of the directional control valve 11, a constant supply pressure provided by the pressure source P is present at the feed channel 24a, representing the highest pressure level within the fluid power system equipped with the directional control valve 11. Each vent sealing ring 41a, 41b is axially supported on its rear side, facing away from the feed section 23a of the valve housing 18, by a rear support section 42 of the associated valve body 25, such that it cannot be bent by the supply pressure prevailing in the feed section 23a. In this way, an undesired fluid flow between the feed section 23a and the working section 23b, 23c is reliably prevented when the respective vent sealing ring 41a, 41b is in a closed position.

[0093] The rear support section 42 is expediently designed as a radially projecting annular collar of the slide body 25.

[0094] A special feature of the two vent sealing rings 41a, 41b is that at least one section of each vent sealing ring 41a is designed as a check valve element that is movable depending on the axial pressure difference applied to it relative to the valve body 25. The check valve element is designed such that, in the closed position of the associated vent sealing ring 41a, 41b, it assumes a closed position, sealing against the associated transition sealing surface 37, when the feed pressure prevailing in the feed channel 24a is greater than or equal to the pressure prevailing in the working channel 24b, 24c, which is separated from the feed channel 24a.

[0095] P 35817 / PCT

[0096] March 6, 2026. Fluid pressure. On the other hand, the check valve element in the closed position of the respective vent sealing ring 41a, 41b can assume an open position lifted from the transition sealing surface 37 if the fluid pressure prevailing in the separated working length section 23b, 23c is higher by a predetermined amount than the fluid pressure prevailing in the feed length section 23a. With such a pressure difference, the check valve element moved into the open position allows fluid flow from the adjacent working length section 23b, 23c into the feed length section 23a and thus into the feed channel 23a.

[0097] The operating state of the directional control valve 11 described above is a residual pressure relief operating state, which can be provoked by disconnecting the feed channel 24a from the fluidic pressure source P and instead venting it and thus relieving the pressure.

[0098] As shown in particular in Figure 3, one of the two ventilation sealing rings 41a, 41b, in the example shown the first ventilation sealing ring which forms the check valve element, rests against a component section 43 of the slide body 25 in the open position.

[0099] A key element of the invention is that the system section 43 is penetrated by at least one vent opening 44.

[0100] As shown in particular by the combined view of Figures 5 and 6, the contact section 43 projects radially outwards from a central section 45 of the valve body 25, which is cylindrical in particular. The contact section 43 has a first flank region 46 facing the first and second ventilation sealing rings 41a and 41b, respectively, and a second flank region 47 facing away from the first and second ventilation sealing rings 41a and 41b, respectively.

[0101] As shown in particular in Figure 2, the arrangement of the mounting section 43 and the support section on both slide parts 26a, 26b of the slide body 25 is identical.

[0102] P 35817 / PCT

[0103] 6 March 2026, wherein the two valve parts 26a, 26b are arranged in a mirror-symmetrical manner, so that the two system sections of one and the other valve part 26a, 26b are opposite each other.

[0104] As shown particularly in Figure 6, the first flank region of each system section 43 is conical. As shown particularly in Figure 3, the associated vent sealing ring 41a, 41b can rest against the conical first flank region in its open position. The at least one vent opening 44 ensures that the vent sealing ring 41a, 41b cannot be undermined and inflated by the applied pressure, in this case the pressure gradient from the working channel to the feed channel 24a. This prevents the vent sealing ring 41a, 41b from tearing, thereby increasing its service life tenfold, up to 800,000 to 1,000,000 switching cycles.

[0105] Advantageously, at least one ventilation opening 44 is designed as a ventilation slot. Advantageously, several ventilation openings 44 in the form of ventilation slots are provided, distributed circumferentially around the system section 42, for example four in number, although fewer or more than four ventilation openings 44 may also be provided.

[0106] The vent slots are characteristically designed and each has a slot base 48 and two slot flanks 49a, 49b extending radially outwards from the slot base 48, arranged parallel to each other in the example shown. The slot base is located approximately at the level of the outer circumference of the central section 45 of the associated slide part 26a, 26b.

[0107] When the valve spool 19 is in the first switching position shown in Figure 2, the feed channel 24a is, as already mentioned, separated from the two working channels 24b and 24c. Furthermore, the first working channel 24b is separated from the first vent channel 24d. The other working channel 24c can be vented via the second vent channel 24e. Thus, the pressure in the first working channel 24b is contained. For residual pressure relief,

[0108] P 35817 / PCT

[0109] On March 6, 2026, when the first working channel is vented, the first vent sealing ring 41a, designed as a check valve element, becomes active. When the pressure source is removed, a pressure difference develops between the first working channel and the feed channel, with the fluid pressure in the first working channel 24b being a predetermined amount higher than in the feed channel 24a. This causes the vent sealing ring 41a to move from its closed position shown in Figure 2 to the open position shown in Figure 3, by moving, if necessary over a certain axial distance, towards the system section 43, where it folds over and comes to rest on the conical first flank area 46. This opens a fluid connection between the first working channel 24b and the feed channel 24a, allowing residual pressure relief to occur.

[0110] Figure 4 shows a situation after activation of the pressure source, whereby, as a result of the now higher pressure on the side of the feed channel 24a compared to the first working channel 24b, the first vent sealing ring 41a is moved from the open position shown in Figure 2 back towards the support section 42. In doing so, the corresponding vent sealing ring 41a comes into contact with a control edge 50, which is the transition between the feed channel longitudinal section 23a and the transition longitudinal section 36.

[0111] The processes for residual pressure relief of the second working channel 24c proceed in the same manner as described above with the second ventilation sealing ring 41b.

[0112] P 35817 / PCT

[0113] March 6, 2026

Claims

Claims 1. Directional control valve, comprising a valve housing (16) in which a spool receiving chamber (18) extending in a longitudinal direction (15a) along a longitudinal axis (15) and bounded radially on the outside by a peripheral receiving chamber boundary surface (22) is formed, into which several valve channels (24) penetrating the valve housing (16) open at points of the peripheral receiving chamber boundary surface (22) spaced apart from each other in the longitudinal direction (15a), and in which a valve spool (19) is arranged which is displaceable in the longitudinal direction (15a) between several switching positions by performing a switching movement (20), and which has at least one spool body (25) which carries a sealing structure (38) having at least one sealing ring (41) and participating in the switching movement (20),wherein the valve channels (24) comprise a feed channel (24a) connectable to a fluidic pressure source (P) and at least one working channel (24b) connectable to a fluid consumer (40) to be controlled, and wherein a sealing ring (41) of the sealing structure (38) is designed as a venting sealing ring (41a) which assumes a shut-off position in a first switching position of the valve slide (19) and a venting position in a second switching position of the valve slide (19), wherein in the shut-off position it separates the feed channel (24a) from the working channel (24b) in a fluid-tight manner by interacting with the peripheral receiving chamber boundary surface (22) and in the venting position releases a fluid connection between the feed channel (24a) and the working channel (24b),wherein at least one section of the vent sealing ring (41a) is designed as a check valve element movable depending on the pressure difference applied to it relative to the slide body (25), which in the closed position of the vent sealing ring (41a) opens into a fluid flow from the working channel (24b) into the feed channel (24a), P 35817 / PCT 6 March 2026 is movable and in the open position rests on a system section (42) of the valve body (25) when the fluid pressure in the working channel (24b) is higher by a predetermined amount than in the feed channel (24a), characterized in that the system section (43) is penetrated by at least one vent opening (44).

2. Directional control valve according to claim 1, characterized in that the system section (43) extends radially outwards from a central section (45) of the valve body (25), which is in particular cylindrical.

3. Directional control valve according to claim 1 or 2, characterized in that the system section (43) has a first flank area (46) facing the vent sealing ring (41a) and a second flank area (47) facing away from the vent sealing ring (41a), wherein preferably the first flank area (46) is conical.

4. Directional control valve according to one of the preceding claims, characterized in that the system section (43) has several vent openings (44) arranged distributed in the circumferential direction of the system section (43).

5. Directional control valve according to one of the preceding claims, characterized in that the at least one vent opening (44) is designed as a vent slot which extends radially outwards from a central area of ​​the system section (43) and terminates freely at the outer circumference of the system section (43).

6. Directional control valve according to claim 5, characterized in that the vent slot has a slot base (48) and two slot flanks (49a, 49b) extending radially outwards from the slot base (48), in particular arranged parallel to each other, wherein preferably the slot base (48) is located at the level of the outer circumference of the central section (45) of the valve body (25).

7. Directional control valve according to one of the preceding claims, characterized in that the vent sealing ring (41a) is dependent on the pressure difference between the P 35817 / PCT March 6, 2026 feed channel and the associated working channel (24b) is axially displaceable on the slide body (25) between a starting position and the open position, wherein in the open position it comes into contact with the system section (43) and in the starting position comes into contact with a support section (42) of the slide body (25) such that in the first switching position of the valve slide (19) it shuts off the fluid connection between the feed channel (24a) and the working channel (24b) in a fluid-tight manner. 8.Directional control valve according to one of the preceding claims, characterized in that the valve channels (24) include a vent channel (24d) connectable to a pressure sink, which opens into the spool receiving chamber (18), wherein a further sealing ring (41) of the sealing structure (38) is designed as a vent sealing ring (41c), which assumes a shut-off position in the first and second switching positions of the valve spool (19) and assumes a venting position in a third switching position of the valve spool (19), wherein in its shut-off position, it fluidly separates the associated working channel (24b) from the vent channel (24c) by the interaction of the peripheral receiving chamber boundary surface (22), and in the venting position, it releases a fluid connection between the associated working channel (24b) and the vent channel (24d), wherein the vent sealing ring (41a) in the third switching position of the Valve slide (19) assumes the shut-off position.

9. Directional control valve according to claim 8, characterized in that a further venting channel (24e) connected to a further working channel (24c) is provided, wherein a further sealing ring (41) of the sealing structure (38) is designed as a further venting sealing ring (41b), which assumes a shut-off position in the first switching position of the valve slide (19) and a venting position in the third switching position of the valve slide (19), wherein the further venting sealing ring (41b) in its shut-off position, by interacting with the peripheral receiving chamber boundary surface (22), fluid-tightly separates the feed channel (24a) from the further working channel (24c) and in the venting position allows a fluid connection between the feed channel (24a) and the further working channel (24c), and wherein a further sealing ring P 35817 / PCT 6 March 2026(41) of the sealing structure (38) is designed as a further vent sealing ring (41d) which assumes a shut-off position in the first and third switching positions of the valve slide (19) and a venting position in the second switching position of the valve slide (19), wherein in its shut-off position it fluidly separates the further working channel (24c) from the further venting channel (24e) by interacting with the peripheral receiving chamber boundary surface (22) and in its venting position releases a fluid connection between the further working channel (24c) and the further venting channel (24e), wherein the further vent sealing ring (41b) assumes its shut-off position in the second switching position of the valve slide (19).

10. Directional control valve according to claim 9, characterized in that at least one section of the further vent sealing ring (41b) is designed as a check valve element movable depending on the pressure difference applied to it relative to the valve body (25), which in the closed position of the further vent sealing ring (41b) is movable into an open position allowing fluid flow from the further working channel (24c) into the feed channel (24a) and in the open position bears against a further component section (43) of the valve body (25) when the fluid pressure in the further working channel is higher by a predetermined amount than in the feed channel (24a), and wherein the further component section (43) is penetrated by at least one vent opening (44).

11. Directional control valve according to one of the preceding claims, characterized in that the valve body (25) has a first valve part (26a) and a second valve part (26b) designed as a separate component thereof, wherein the two valve parts (26a, 26b) are movably attached to one another by means of connecting means (29) relative to each other.

12. Directional control valve according to claim 11, characterized in that the two valve parts (26a, 26b) are identical to each other. P 35817 / PCT March 6, 2026

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