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Abstract

In a directional control valve with a valve housing (16) in which a slide receiving chamber (18) is formed, extending in a longitudinal direction (15a) along a longitudinal axis (15) and delimited radially on the outside by a peripheral receiving chamber boundary surface (22), into which a plurality of valve channels (24) penetrating the valve housing (16) open at locations of the peripheral receiving chamber boundary surface (22) spaced apart from one another in the longitudinal direction (15), and in which a valve slide (19) is arranged, which can be displaced between a plurality of switching positions by performing a switching movement in the longitudinal direction (15a), which has at least one slide body (28) and at least one check valve member (37) which is movable relative to the slide body (28) depending on the pressure difference applied thereto, a receiving chamber (38) is formed in the slide body (28),in which the check valve member (37) is arranged to be axially movable and which is connected to a feed channel via a connecting channel (40) formed in the slide body (28), wherein the check valve member (37) is opposite a valve seat (41) which frames an overflow opening (42) which is connected to the working channel of the slide receiving chamber (18) via a relief channel (43).

Description

[0001] The invention relates to a directional control valve comprising a valve housing in which a slide receiving chamber is formed, extending in a longitudinal direction along a longitudinal axis and delimited radially on the outside by a peripheral receiving chamber boundary surface, into which a plurality of valve channels penetrating the valve housing open at points on the peripheral receiving chamber boundary surface spaced apart from one another in the longitudinal direction, and in which a valve slide is arranged which can be displaced between a plurality of switching positions by performing a switching movement in the longitudinal direction and which has at least one slide body, wherein the valve channels contain at least one feed channel connectable to a fluid pressure source and at least one working channel connectable to a fluid consumer to be controlled,wherein the feed channel opens into a feed length section and the working channel opens into a working length section of the slide receiving chamber that axially adjoins the feed length section, wherein the valve slide, in a first switching position, separates the feed length section from the working length section in a fluid-tight manner and, in a second switching position, releases a fluid connection between the feed length section and the adjacent working length section, and with at least one check valve having a check valve member that is movable relative to the slide body depending on the pressure difference applied thereto.

[0002] To ensure the safety of a system equipped with a directional control valve, especially a directional control valve, which also includes a fluid consumer, it is sometimes necessary to completely vent the system. In this case, among other things, the supply channel is isolated from the pressure source and, like the vent channels, connected to the atmosphere. This is done by means of an upstream vent valve.

[0003] To ensure that a connected fluid consumer is also completely vented when a system is vented, DE 10 2014 112 110 A1 specifies a residual pressure relief valve mounted on a multi-way valve. The residual pressure relief valve is connected to the two working channels and is controlled by the fluid pressure prevailing 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 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 mounted on the main valve.

[0004] A directional control valve of the type mentioned above is known from DE 10 2020 133 997 A1. The residual pressure venting measures are effected here via at least one venting sealing ring, which is designed as a check valve member movable relative to the spool body of a valve spool depending on the axial pressure difference applied to it.

[0005] The object of the invention is to provide a directional control valve which enables reliable residual pressure relief with minimal design effort and compact dimensions.

[0006] This object is solved by the features of independent claim 1. Further developments of the invention are presented in the subclaims.

[0007] The directional control valve according to the invention is characterized in that a receiving chamber is formed in the slide body, in which the check valve member is arranged to be axially movable and which is connected to the feed length section via a connecting channel formed in the slide body, wherein a valve seat is opposite the check valve member, framing an overflow opening which is connected to the working length section of the slide receiving chamber via a relief channel.

[0008] By integrating the check valve into the valve body, a particularly compact and cost-effective solution for residual pressure relief is achieved. Furthermore, such a check valve has a simple mechanical design and consists of relatively few components.

[0009] In a further development of the invention, the valve channels contain at least one venting channel connectable to a pressure sink, which opens into a venting length section of the slide receiving chamber. In the first switching position, the valve slide fluid-tightly separates the working length section and the venting length section, in the second switching position, fluid-tightly separates the working length section from the venting length section, and in a third switching position, opens a fluid connection between the working length section and the venting length section, while simultaneously fluid-tightly separating the supply length section from the working length section. The directional control valve is expediently designed as a multi-way valve, for example, with a 3 / 3 functionality.

[0010] In a further development of the invention, on the side of the feed length section axially opposite the working length section, there is a further working length section of the slide receiving chamber connected to a further working channel, to which a further venting length section of the slide receiving chamber connected to a further venting channel is axially connected, wherein the valve slide in the first switching position separates the feed length section and the further working length section in a fluid-tight manner, while at the same time the further working length section is separated from the further venting length section in a fluid-tight manner, in the second switching position the feed length section is separated from the further working length section in a fluid-tight manner,while at the same time a fluid connection between the further working length section and the further venting length section is released and in the third switching position a fluid passage between the feed length section and the further working length section is released and at the same time the further working length section is separated from the further venting length section in a fluid-tight manner.

[0011] This design can be implemented particularly advantageously with multi-way valves that have a 2 / 2 valve function or a 3 / 3 valve function or a 5 / 3 valve function.

[0012] Particularly preferably, a further check valve is provided, associated with the further working channel, which has a further check valve member that is movable relative to the slide body depending on the pressure difference applied to it. In a multi-way valve with a 5 / 3 valve function, this allows venting or residual pressure relief, for example, of the two working chambers of a fluid consumer, such as a double-acting fluid cylinder, in the first switching position of the directional valve, in which both the ventilation and venting functions are blocked.

[0013] In a particularly preferred manner, the further check valve member of the further check valve is also axially movable in the receiving chamber of the sliding body, which is connected to the feed length section via a further connecting channel formed in the sliding body, wherein the further check valve member is opposite a further valve seat which frames a further overflow opening which is connected to the further working length section of the sliding receiving chamber via a further relief channel.

[0014] Particularly preferably, the connecting channel has a through-channel section aligned coaxially to the longitudinal axis of the slide receiving chamber, which ends at the valve seat of the check valve, and wherein the connecting channel has an end channel section extending radially to the longitudinal axis, which is connected on the one hand to the through-channel section and on the other hand to the feed length section. Expediently, the further connecting channel also has a further through-channel section aligned coaxially to the longitudinal axis of the slide receiving chamber, which ends at the further valve seat of the further check valve, and wherein the further connecting channel has a further end channel section extending radially to the longitudinal axis, which is connected on the one hand to the further through-channel section and on the other hand to the feed length section.

[0015] In a particularly preferred manner, the through-channel section and the further through-channel section are fluidically connected to one another and the end channel section and the further end channel section are one and the same channel.

[0016] However, other designs of the through-channel sections and the end channel sections are also conceivable, for example in such a way that the two end channel sections are designed as separate channels.

[0017] In a further development of the invention, the relief channel has an overflow channel section aligned coaxially to the longitudinal axis of the slide receiving space, the mouth of which, aligned towards the check valve member, forms the overflow opening closable by the check valve member, and wherein the relief channel has an inflow channel section extending in the radial direction to the longitudinal axis, which is connected on the one hand to the working length section and on the other hand to the overflow channel section.

[0018] The further relief channel expediently also has a further overflow channel section aligned coaxially to the longitudinal axis of the slide receiving space, the mouth of which, aligned towards the further check valve member, forms the overflow opening closable by the check valve member, and wherein the relief channel has a further inflow channel section extending in the radial direction to the longitudinal axis, which is connected on the one hand to the further working length section and on the other hand to the further overflow channel section.

[0019] Particularly preferably, the check valve elements are spherical or conical. Designing the check valve elements as balls with a corresponding ball seat allows for the exclusion of faults that do not return to the initial position according to ISO 13849-2. This allows the directional valve to be used for the STO (Safe Torque Off) safety function up to Category 3 Pld.

[0020] In a further development of the invention, the valve seat, in particular the two valve seats, are formed on a valve seat body, which in turn is received in the receiving chamber of the slide body and is fixed there axially immovably.

[0021] In a further development of the invention, the check valve member is axially movable between a closed position resting against the valve seat and closing the overflow opening in a fluid-tight manner and an open position lifted from the valve seat, the open position being predetermined by a stop element projecting into the receiving chamber.

[0022] Advantageously, the further check valve member is also axially movable between a closed position resting against the further valve seat and closing the further overflow opening in a fluid-tight manner and an open position lifted away from the further valve seat, the open position being predetermined by a stop element projecting into the receiving chamber.

[0023] In a particularly preferred manner, the same stop element is used to specify the open positions of the check valve members, which stop element has a first stop surface for the check valve member and a second stop surface, oriented opposite to the first stop surface, for the further check valve member.

[0024] In a further development of the invention, the directional control valve includes a spring device by which the valve spool is held resiliently in the first switching position under preload. When the valve spool is deflected from the first switching position into either the second switching position or the opposite third switching position by applying an actuating force, a one-sided compression of the spring device occurs, which can cause the valve spool to return to the first switching position when the actuating force is removed.

[0025] To generate the actuating force that causes the switching movement, the directional control valve is preferably equipped with an electrofluidic and, in particular, an electropneumatic pilot valve device. However, the multi-way valve can also be designed for direct electromagnetic or pneumatic actuation, for example.

[0026] The directional control valve is particularly suitable for controlling a gaseous pressure medium, especially compressed air, but can also be used to control liquid pressure media. The term "venting" used in some cases is to be understood as a synonym for pressure relief, particularly to atmospheric pressure, regardless of the type of fluid pressure medium used.

[0027] The invention further comprises a valve slide having the features of independent claim 18.

[0028] The valve slide according to the invention is characterized in that a receiving chamber is formed in the slide body, in which at least one check valve is received, which has a check valve member arranged axially movable in the receiving chamber.

[0029] Finally, the invention comprises a method for converting a directional control valve, comprising a valve housing in which a slide receiving chamber is formed, extending in a longitudinal direction along a longitudinal axis and delimited radially on the outside by a peripheral receiving chamber boundary surface, into which a plurality of valve channels penetrating the valve housing open at points of the peripheral receiving chamber boundary surface spaced apart from one another in the longitudinal direction, and in which a valve slide is arranged, which can be displaced between a plurality of switching positions by executing a switching movement in the longitudinal direction and which has at least one slide body, the method comprising the following steps: - Remove the valve spool from the directional control valve and - replacing the removed valve slide by installing a valve slide in which a receiving chamber is formed in which at least one check valve is received, which has a check valve member arranged axially movable in the receiving chamber.

[0030] A preferred embodiment of the directional control valve according to the invention is illustrated in the drawing and explained in more detail below. The drawing shows: Fig. 1 a perspective view of a preferred embodiment of the directional control valve according to the invention, Fig. 2 a longitudinal section through the directional control valve of Fig. 1, with the valve spool in the second switching position, Fig. 3 a longitudinal section through the directional control valve of Fig. 1, with the valve spool in the first switching position and the residual pressure relief not active, Fig. 4 a longitudinal section through the directional control valve of Fig. 1, wherein the valve spool is in the first switching position and a residual pressure relief of the working channel takes place via the working length section and the feed channel with the feed length section, Fig. 5 a longitudinal section through the directional control valve of Figure 1, wherein the valve spool is in the first switching position and a residual pressure relief of the further working channel takes place via the further working length section and the feed channel with the further feed length section and Fig. 6 an enlarged view of the number X from Fig. 3.

[0031] The Fig. 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 using a multi-way valve as an example. In principle, however, the invention could also be applied to a "one-way valve," for example, in the form of a 2 / 2-way valve, in which "one way" is selectively open or closed depending on the valve's switching position.

[0032] The directional control valve 11 is expediently of an electrofluidic and, in particular, electropneumatic pilot-controlled design. This applies to the illustrated embodiment. In this respect, the directional control valve 11 has a main valve 12 equipped with an electrically actuated pilot valve device 13. The pilot valve device 13 has at least one, and, for 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.

[0033] The directional control valve extends along a longitudinal axis 15, the axial direction of which is referred to below as the longitudinal direction 15a.

[0034] The directional control valve 11 has a valve housing 16, which is, for example, a component of the main valve 12. In the example shown, the pilot valve device 13 is arranged on one of the two end faces 17 ( Fig. 3) of the valve housing 16.

[0035] An elongated cavity extending in the longitudinal direction 15a is formed in the valve housing 16, which forms a spool receiving space 18 for receiving a valve spool 19. In the illustrated pilot-operated valve design, the spool receiving space 18 and the valve spool 19 belong to the main valve 12. The valve spool 19 has a longitudinal shape and extends in the spool receiving space 18 in the longitudinal direction 15a.

[0036] The valve spool 19 is movable back and forth in the spool receiving chamber 18 relative to the valve housing 16 in the longitudinal direction 15a, executing a linear switching movement 20 indicated by a double arrow. In this way, it can be positioned in different axial switching positions relative to the valve housing 16. The actuating force for generating the switching movement 20 and preferably also for holding the valve spool 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 acted upon in a controlled manner by means of the pilot valve device 13.For example, in the valve spool 19, two first and second drive surfaces 21a, 21b are assigned, which are oriented in opposite directions along the longitudinal direction 15a and which can each be alternatively pressurized with the pilot fluid or relieved of pressure via a pilot channel (not shown) communicating with the pilot valve device 13.

[0037] For example, in each of the two axial end regions of the valve spool 19, one of two drive pistons 60a, 60b is assigned, on each of which one of the two drive surfaces 21a, 21b is formed and which can be axially supported on the valve spool 19 for transmitting a drive force.

[0038] Compressed air is used as the pilot fluid, although another pressure fluid can also be used alternatively.

[0039] The slide receiving space 18 is bounded radially outward by a peripheral receiving space boundary surface 22 pointing radially inward. Viewed in a cross-section perpendicular to the longitudinal axis 15, the receiving space boundary surface 22 has a round and preferably a circular contour.

[0040] The slide receiving space 18 has a plurality of slide receiving space length sections 23 arranged successively in the longitudinal direction 15a, into which at the receiving space boundary surface 22 ( Fig. 4) one of a plurality of valve channels 24 penetrating the valve housing 16 opens into each of these. The opening regions of the plurality of valve channels 24 are spaced apart from one another in the longitudinal direction 15a.

[0041] Preferably, the directional control valve 11 is a 5 / 3-way valve with a total of five valve channels 24, which can be connected to and / or separated from one another by the valve spool 19 in different control configurations. Such a configuration is present in the illustrated embodiment. Here, the directional control valve 11 is preferably designed as a 5 / 3-way valve, whose valve spool 19 can be positioned in three alternative switching positions to specify different control configurations.

[0042] In the drawing, Fig. 3 shows the valve slide 19 in a first switching position. This is preferably a middle position, from which the valve slide 19 can be switched by a right-directed switching movement 20 into a second switching position or by a left-directed switching movement 20 into a third switching position. The second switching position is in Fig. 2. The third switching position is not shown in the figures.

[0043] Preferably, the valve spool 19 is held in the first switching position by spring force, so that the first switching position is a basic position assumed by the valve spool 19 when no actuating force is present. By applying an actuating force, the valve spool 19 can be displaced in either the one or the other axial direction and positioned either in the second switching position or in the third switching position, from which it is moved back into the first switching position by the spring force as soon as the actuating force that is currently extending it is removed. The spring force is provided by a spring device 26 of the directional control valve 11, which is supported between the valve spool 19 and the valve housing 16. By way of example, the spring device 26 ( Fig. 5) consists of two compression springs 27a, 27b ( Fig. 5), each of which is axially interposed between a slide body 28 of the valve slide 19 extending in the slide body receiving space 18 and one of the two drive pistons 60a, 60b. In this case, the drive pistons 60a, 60b are axially movable relative to the slide body 28 and are provided with end surfaces 29 ( Fig. 4) of the valve housing 16, which axially limit the slide receiving space 18 on both sides.

[0044] In the following, the slide receiving chamber length sections 23 are also individually named. Accordingly, the slide receiving chamber length sections 23 contain a feed length section 23a, which is axially flanked on one side by a working length section 23b and on the other side by a further working length section 23c. For better differentiation, the working length section 23b is also referred to below as the first working length section 23b, and the further working length section 23c is also referred to as the second working length section 23c.

[0045] The first working length section 23b is followed axially by a venting length section 23d, which is also referred to as the first venting length section 23d for better differentiation, while the second working length section 23c is followed by a further venting length section 23e, which is also referred to as the second venting length section 23e for better differentiation.

[0046] The valve channels 24 are, for example, a feed channel 24a opening into the feed length section 23a, a working channel 24b opening into the first working length section 23b, which is also referred to below as the first working channel 24b, a further working channel 24c opening into the second working length section 23c, which is also referred to below as the second working channel 24c, a vent channel 24d opening into the first vent length section 23d, which is also referred to below as the first vent channel 24d, and a further vent channel 24e, which is also referred to below as the second vent channel 24e and opens into the second vent length section 23e.

[0047] Between slider receiving space length sections 23 immediately adjacent in the longitudinal direction 15a, a transition section 30 ( Fig. 5), in the area of ​​which the receiving space boundary surface 22 has a cylindrical sealing surface 31 ( Fig. 6), which is also referred to below as the transition sealing surface 31 for ease of differentiation. The diameter of the slide receiving chamber 18 is smaller in the area of ​​the transition longitudinal sections 30 than in the area of ​​the slide receiving chamber longitudinal sections 23, into which one of the valve channels 24 opens.

[0048] The spool body 28 carries, in the region of its radial outer circumference, a sealing structure 32 belonging to the valve spool 19, which moves uniformly with the spool body 28 during the switching movement. The purpose of the sealing structure 32 is to define the individual control configurations of the valve channels 24 by selectively sealing the interaction with the transition sealing surfaces 31. When the sealing structure 32 bears sealingly against a transition sealing surface 31, it separates the two axially adjacent spool receiving space length sections 23 from each other in a fluid-tight manner. Accordingly, the valve channels 24 communicating with the respective spool receiving space length sections 23 are then also separated from each other.If the valve spool 19 is positioned such that the sealing structure 32 does not rest against one of the transition sealing surfaces 31 because it has been moved out of the area of ​​the spool receiving chamber 18 enclosed by the transition sealing surface 31, there is an open fluid connection between the spool receiving chamber length sections 23 axially adjoining the transition sealing surface 31 on both sides, so that the valve channels 24 connected thereto are also connected to one another in a fluid-tight manner.

[0049] Between axially adjacent sections of the sealing structure 32, the valve slide 18 has a reduced-diameter constricted length section 33 ( Fig. 6), which promotes fluid flow when the fluid connection is open.

[0050] The feed channel 24a is connectable 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 connectable to a fluidic-controlled fluid consumer 34 and is connected to such a fluid consumer 34 during normal operation of the directional control valve 11. The fluid consumer 34 is, in particular, a fluid-operated drive, for example, a pneumatic cylinder. Each vent channel 24d, 24e is connected to a pressure sink R, which is, in particular, the atmosphere.

[0051] For the fluid connection with the fluid pressure source P and the fluid consumer 34, fluid lines connected to the respective valve channels on the valve housing 16 are expediently used. For connection to the atmosphere, the vent channels 24d, 24e can open directly outside the valve housing 16.

[0052] The sealing structure 32 expediently contains a plurality of sealing rings 35 arranged coaxially on the slide body 28 and fixed to the slide body 28 at an axial distance from one another. Between adjacent sealing rings 35, one of the above-mentioned longitudinal sections 33 is located. Each of the sealing rings 35 is assigned to one of the transition sealing surfaces 31, with which it is in radial sealing contact when it occupies a position in the transition longitudinal section 30 enclosed by the associated transition sealing surface 31. In this case, the slide receiving space longitudinal sections 23 arranged axially adjacent to the transition longitudinal section 30 are separated from one another in a fluid-tight manner.In addition, the valve spool 24 can assume positions in which at least one sealing ring 35 has left the transition length section 30 assigned to it, so that between the assigned transition sealing surface 31 and a constricted length section 33 of the valve spool 24 there is an annular space through which the fluid pressure medium can flow.

[0053] Each transition sealing surface 30 extends between two of the slide receiving length sections 23, in the region of which the diameter of the slide receiving space 18 is larger than in the transition length section 30 enclosed by the transition sealing surface 31, so that a sealing ring 35 does not exert a sealing effect when it is positioned in the region of one of the slide receiving space length sections 23.

[0054] As already mentioned, in the first switching position, the valve spool is in a basic position, which, as mentioned, is also referred to as the center position. If no pilot pressure is applied, the valve spool is switched to the first valve position, or basic position, by the force of the compression springs 27a, 27b.

[0055] As particularly in Fig. 3, in the first valve position, the feed channel 24a is fluid-tightly separated from the first and second working channels 24b, 24c, which are located to the left and right of the feed channel 24a in the axial direction. In other words, the feed length section 23a is fluid-tightly separated from the first and second working channel length sections 23a, 23b by the two sealing rings 35. In this first valve position, the two vent channels 24d, 24e are also fluid-tightly separated from the working channels 25d, 25c because, here, likewise associated sealing rings 35 bear fluid-tightly against corresponding transition sealing surfaces 31. This means that the working length sections 23b, 23c are fluid-tightly separated from the vent length sections 23d, 23e.

[0056] For the safety of a system equipped with a directional control valve 11, which also includes the fluid consumer 34, it is sometimes necessary to completely vent the system, i.e. to relieve the residual pressure

[0057] For this purpose, the directional control valve 11 has at least one check valve 36, which has a check valve member 37, which is movable relative to the slide body 28 depending on the pressure difference applied to it. An essential aspect is that a receiving chamber 38 is formed in the slide body 28, in which the check valve member 37 is arranged axially movable and which is connected to the pressure vessel 12 via a connecting channel 40 ( Fig. 6) is connected to the feed length section 23a, wherein the check valve member 37 is opposite a valve seat 41 which frames an overflow opening 42 which is connected via a relief channel 43 to the working length section 23b of the slide receiving space 18.

[0058] In the case of the preferred embodiment of the 5 / 3-way valve described here, in addition to the check valve 36a, which is referred to below as the first check valve 36a for the sake of simplicity, a further check valve 36b is provided, which is referred to below as the second check valve. Thus, the first check valve 36a has a first check valve member 37a and the second check valve 36b has a second check valve member 37b. In the example shown, the check valves 36a, 36b are constructed identically to one another. A ball is used as the check valve member 37a, 37b, for example. Thus, the valve seat 41a, 41b of the first and second check valves 36a, 36b is designed as a ball seat. As can be seen in particular in the Fig. 3 and Fig. As shown in Figure 6, each of the two check valves 36a, 36b is assigned a connecting channel 40. The connecting channels are each connected to the feed channel 24a, which opens into the feed length section 23a, and end at the associated overflow opening 42a, 42b of the associated valve seat 41a, 41b. The connecting channels 40a, 40b each consist of two channel sections.

[0059] A through-channel section 44 is provided, which is aligned coaxially with the longitudinal axis 15 of the slide receiving chamber 18 and ends at the valve seat 41a, 41b of the check valve 36a, 36b. Furthermore, the connecting channels 40a, 40b each have an end channel section 45 extending radially with respect to the longitudinal axis 15, which is connected on the one hand to the through-channel section 44 and on the other hand to the feed length section 23a. As exemplified in Fig. As shown in Figure 6, the two through-channel sections 40 are fluidically connected to each other and are formed by a common channel formed in the slide body. The two end channel sections 45 are one and the same channel.

[0060] The relief channels 43a, 43b also each have two channel sections. An overflow channel section 46 is provided, aligned coaxially with the longitudinal axis 15, whose mouth, aligned toward the associated check valve member 37a, 37b, forms the overflow opening 42 that can be closed by the check valve member 37a, 37b. Furthermore, the relief channels 43a, 43b have an inflow channel section 47 extending radially with respect to the longitudinal axis 15, which is connected on the one hand to the associated working length section 23b, 23c and on the other hand to the associated overflow channel section 46.

[0061] As particularly in Fig. 6, the two valve seats 41a, 41b are each formed on an associated valve seat body 48a, 48b, which on the one hand is received in the receiving chamber 38 of the slide body 28 and is fixed there axially immovably, for example, is pressed in there.

[0062] The check valve members 37a, 37b are each movable between a closed position 49 resting on the associated valve seat 41a, 41b and closing the overflow opening 42 in a fluid-tight manner and an open position 50 lifted from the valve seat 41a, 41b ( Fig.5) axially movable, wherein the open position 50 is predetermined by a stop element 51 projecting into the receiving chamber 38. The same stop element 51, which has a first stop surface 52 for the first check valve member 37a and a second stop surface 53, oriented opposite the first stop surface 52, for the second check valve member 37b, expediently serves to specify the open positions 50 of the check valves 36a, 36b.

[0063] It should also be noted that in the respective open position of the check valve member 37a, 37b, which is expediently designed as a ball, a flow of fluid between the outer surface of the ball and the inner wall of the receiving chamber 38 is made possible, for example by a corresponding contouring, for example in the form of overflow channels (not shown).

[0064] During normal use of the directional control valve 11, a constant feed 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. In this state, the feed pressure applied also acts via the connecting channel 40 on the check valve elements 37a, 37b of the check valves 36a, 36b, which are pushed into their respective closed positions 49 by the applied feed pressure. The directional control valve 11 can then be switched from the first switching position to the second or third switching position as required, whereby either the first or the second working channel is vented. At the same time, venting takes place in the other non-vented working channel via the associated vent channel. This makes it possible, for example, to control a fluid consumer in the form of a double-acting pneumatic cylinder.Either one or the other working chamber 55a, 55b of the pneumatic cylinder is ventilated or vented, so that the piston of the pneumatic cylinder moves in or out.

[0065] If the directional control valve 11 is in the center position, i.e., in the first switching position, ventilation of the working channels 24b, 24c via the feed channel 24a is blocked, but venting of the working channels 24b, 24c via the associated vent channels 24d, 24e also does not occur. This means that any pressure still present in the working chambers of the fluid consumer is "locked in." If, despite the absence of feed pressure, the system, particularly the double-acting pneumatic cylinder, needs to be vented, the residual pressure relief provided by the two check valves 36a, 36b is activated.If there is residual pressure in one of the two working channels 24b, 24c, which is connected in particular to one of the two working chambers 55a, 55b, and no feed pressure is present, the then prevailing pressure difference causes the check valve to open, i.e., the check valve member 37a, 37b is moved to the open position, allowing the residual pressure to escape via the connecting channel and the relief channel. The same applies if residual pressure is present in the other working channel 24b, 24c; the other check valve opens, and the other check valve member 37a, 37b is moved to its open position, allowing residual pressure to escape via the connecting channel and the relief channel. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2014 112 110 A1

[0003] DE 10 2020 133 997 A1

[0004]

Claims

[1] Directional control valve, comprising a valve housing (16) in which a slide receiving chamber (18) is formed, extending in a longitudinal direction (15a) along a longitudinal axis (15) and delimited radially on the outside by a peripheral receiving chamber boundary surface (22), into which a plurality of valve channels (24) penetrating the valve housing (16) open at locations of the peripheral receiving chamber boundary surface (22) spaced apart from one another in the longitudinal direction (15), and in which a valve slide (19) is arranged, which can be displaced between a plurality of switching positions by performing a switching movement in the longitudinal direction (15a), said valve slide having at least one slide body (28), wherein the valve channels (24) contain at least one feed channel (24a) connectable to a fluid pressure source (P) and at least one working channel (24b, 24c) connectable to a fluid consumer (34) to be controlled, wherein the feed channel (24a) into a feed length section (23a) and the working channel (24b,24c) opens into a working length section (23b, 23c) of the slide receiving chamber (18) which is axially adjacent to the feed length section (23a), wherein the valve slide (19) in a first switching position separates the feed length section (23a) from the working length section (23b, 23c) in a fluid-tight manner and in a second switching position releases a fluid connection between the feed length section (23a) and the adjacent working length section (23b, 23c), and with at least one check valve (36) which has a check valve member (37) which is movable relative to the slide body (28) depending on the pressure difference applied thereto, characterized byin that a receiving chamber (38) is formed in the slide body (28), in which the check valve member (37) is arranged to be axially movable and which is connected to the feed length section (23a) via a connecting channel (40) formed in the slide body (28), wherein the check valve member (37) is opposite a valve seat (41) which frames an overflow opening (42) which is connected to the working length section (23b, 23c) of the slide receiving chamber (18) via a relief channel (43). [2] Directional control valve according to claim 1, characterized byin that the valve channels (24) contain at least one venting channel (24d, 24e) which can be connected to a pressure sink (R) and which opens into a venting length section (23d, 23e) of the slide receiving space (18), wherein the valve slide (19) in the first switching position separates the working length section (23b) and the venting length section (23d) in a fluid-tight manner, in the second switching position separates the working length section (23b) from the venting length section (23d) in a fluid-tight manner and in a third switching position releases a fluid connection between the working length section (23b) and the venting length section (23d), while at the same time the feed length section (23a) is separated from the working length section (23b) in a fluid-tight manner. [3] Directional control valve according to claim 1 or 2, characterized bythat on the side of the feed length section (23a) axially opposite the working length section (23b), there is a further working length section (23c) of the slide receiving chamber (18) connected to a further working channel (24c), to which a further venting length section (23e) of the slide receiving chamber is axially connected and connected to a further venting channel (24e), wherein the valve slide (19) in the first switching position separates the feed length section (23a) and the further working length section (23c) in a fluid-tight manner, while at the same time the further working length section (23c) is separated from the further venting length section (23e) in a fluid-tight manner,in the second switching position, the feed length section (23a) is separated from the further working length section (23c) in a fluid-tight manner, while at the same time a fluid connection between the further working length section (23c) and the further venting length section (23e) is released, and in the third switching position, a fluid passage between the feed length section (23a) and the further working length section (23c) is released, and at the same time the further working length section (23c) is separated from the further venting length section (23e) in a fluid-tight manner. [4] Directional control valve according to claim 3, characterized by a further check valve (36b) associated with the further working channel (23c), which has a further check valve member (37b) which is movable relative to the slide body (28) depending on the pressure difference applied to it. [5] Directional control valve according to claim 4, characterized bythat the further check valve member (37b) of the further check valve (36b) is also received in an axially movable manner in the receiving chamber (38) of the slide body (28), which is connected to the feed length section (23a) via a further connecting channel (40b) formed in the slide body (28), wherein the further check valve member (37b) is opposite a further valve seat (41b) which frames a further overflow opening (42b) which is connected to the further working length section (23c) of the slide receiving chamber (18) via a further relief channel (43b). [6] Directional control valve according to one of the preceding claims, characterized byin that the connecting channel (40a) has a through-channel section (44) which is aligned coaxially with the longitudinal axis (15) of the slide receiving space (18) and which ends at the valve seat (41a) of the check valve (36a), and wherein the connecting channel (40a) has an end channel section (45) which extends in the radial direction to the longitudinal axis (15) and which is connected on the one hand to the through-channel section (44) and on the other hand to the feed longitudinal section (23a). [7] Directional control valve according to claim 5 or 6, characterized byin that the further connecting channel (40b) has a further through-channel section (44) which is aligned coaxially with the longitudinal axis (15) of the slide receiving space (18) and which ends at the further valve seat (41b) of the further check valve (36b), and wherein the further connecting channel (40b) has a further end channel section (45) which extends in the radial direction to the longitudinal axis (15) and is connected on the one hand to the further through-channel section (44) and on the other hand to the feed longitudinal section (23a). [8] Directional control valve according to claim 7, characterized by that the through-channel section (44) and the further through-channel section (44) are fluidically connected to one another and the end channel section (45) and the further end channel section (45) are one and the same channel. [9] Directional control valve according to one of the preceding claims, characterized byin that the relief channel (43a) has an overflow channel section (46) aligned coaxially to the longitudinal axis (15) of the slide receiving space (18), the mouth of which, aligned towards the check valve member (36a), forms the overflow opening (42a) which can be closed by the check valve member (37a), and wherein the relief channel (43a) has an inflow channel section (47) extending in the radial direction to the longitudinal axis (15), which is connected on the one hand to the working length section (23b) and on the other hand to the overflow channel section (46). [10] Directional control valve according to one of claims 5 to 9, characterized byin that the further relief channel (43b) has a further overflow channel section (46) which is aligned coaxially to the longitudinal axis (15) of the slide receiving space (18), the mouth of which, which is aligned towards the further check valve member (47b), forms the overflow opening (42b) which can be closed by the check valve member (47b), and wherein the further relief channel (43b) has a further inflow channel section (47) which extends in the radial direction to the longitudinal axis (15) and which is connected on the one hand to the further working length section (23c) and on the other hand to the further overflow channel section (46). [11] Directional control valve according to one of the preceding claims, characterized by that the check valve member (37a, 37b) is spherical or conical. [12] Directional control valve according to one of the preceding claims, characterized bythat the valve seat (41), in particular the two valve seats (41a, 41b), is formed on a valve seat body (48) which in turn is received in the receiving chamber (38) of the slide body (28) and is fixed there axially immovably. [13] Directional control valve according to one of the preceding claims, characterized by that the check valve member (37) is axially movable between a closed position (49) resting on the valve seat (41) and closing the overflow opening (42) in a fluid-tight manner and an open position (50) lifted off the valve seat (41), the open position (50) being predetermined by a stop element (51) projecting into the receiving chamber (38). [14] Directional control valve according to one of claims 5 to 13, characterized bythat the further check valve member (37b) is axially movable between a closed position (49) lying against the further valve seat (41b) and closing the further overflow opening (42b) in a fluid-tight manner and an open position (50) lifted off the further valve seat (41b), the open position (50) being predetermined by a stop element (51) projecting into the receiving chamber (38). [15] Directional control valve according to claims 13 and 14, characterized by in that the same stop element (51) is used to specify the open positions of the check valve members (37a, 37b), which has a first stop surface (51) for the check valve member (37a) and a second stop surface (53) for the further check valve member (37b), which is oriented opposite to the first stop surface. [16] Directional control valve according to one of the preceding claims, characterized bythat it contains a spring device (26) by means of which the valve slide (19) is held resiliently under prestress in the first switching position. [17] Directional control valve according to one of the preceding claims, characterized by that it is equipped with an electronic pilot valve device (13) for the electronic actuation of the valve slide (19). [18] Valve spool for a directional control valve, wherein the directional control valve has a valve housing (16) in which a spool receiving space (18) is formed, extending in a longitudinal direction (15a) along a longitudinal axis (15) and delimited radially on the outside by a peripheral receiving space boundary surface (22) for receiving the valve spool, into which a plurality of valve channels (24) penetrating the valve housing (16) open at points of the peripheral receiving space boundary surface (22) spaced apart from one another in the longitudinal direction (15), and wherein the valve spool (19) has a spool body (28), characterized by that a receiving chamber (38) is formed in the slide body (28), in which at least one check valve (36) is received, which has a check valve member (37) arranged axially movable in the receiving chamber (38). [19] Valve slide according to claim 18, characterized bythat it can be or is accommodated in a directional control valve (11) according to one of claims 1 to 17. [20] Method for converting a directional control valve, comprising a valve housing (16) in which a slide receiving chamber (18) is formed, extending in a longitudinal direction (15a) along a longitudinal axis (15) and delimited radially on the outside by a peripheral receiving chamber boundary surface (22), into which a plurality of valve channels (24) penetrating the valve housing (16) open at locations of the peripheral receiving chamber boundary surface (22) spaced apart from one another in the longitudinal direction (15), and in which a valve slide is arranged, which can be displaced between a plurality of switching positions by executing a switching movement in the longitudinal direction (15a), said valve slide having at least one slide body (28), the method comprising the following steps: - Remove the valve spool from the directional control valve and - replacing the removed valve slide by installing a valve slide (19) in which a receiving chamber (38) is formed, in which at least one check valve (36) is received, which has a check valve member (37) arranged axially movable in the receiving chamber (38). [21] Method according to claim 20, characterized by that the method is carried out on a directional control valve (11) according to one of claims 1 to 17.

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