Valve together with suspension device

Abstract

1. Valve 2. Disclosed is a valve, at least consisting of a valve housing (26) and a valve slide (28) which is guided in a longitudinally movable manner therein and actuates individual fluid connection points in the valve housing (26), such as at least one - pressure supply connection, - return connection, and - a plurality of accumulator connections, which are arranged in the valve housing (26) according to a predefinable distribution plan, characterized in that - a first accumulator connection (S1) is provided between a first pressure supply connection (P1) and an adjacently arranged return connection (T1), - a second accumulator connection (S2) and a third accumulator connection (S3) are provided between the first pressure supply connection (P1) and a further pressure supply connection (P2), and - a fourth accumulator connection (S4) is provided between the further pressure supply connection (P2) and a further adjacently arranged return connection (T2).

Description

[0001] Valve and suspension device

[0002] The invention relates to a valve, at least consisting of a valve housing and a valve slide which is guided longitudinally therein and which controls individual fluid connection points in the valve housing, such as at least one - pressure supply connection,

[0003] A return connection, and a plurality of storage connections arranged in the valve housing according to a predeterminable distribution plan. The invention further relates to a suspension device, in particular for vehicles, such as mobile work machines, with at least one suspension cylinder and a valve according to the invention.

[0004] DE 10 2016 01 1 860 A1 discloses a valve having a valve housing which has at least one utility connection, a pressure supply connection and a return connection and in which a control or valve slide is guided so as to be longitudinally movable in order to control these individual connections, wherein the supply pressure present at the pressure supply connection is guided via an orifice device and a control channel to at least one control side of the control slide in order to control a consumer connected to the respective utility connection, which control side is arranged so as to be movable in a control chamber in the valve housing which is connected to the return connection via a further orifice device.This means that the supply pressure at the valve's pressure supply port is not used for damping, as is usual, so that a control element hydraulically connected upstream of the valve, in the form of a pressure compensator, is not adversely affected by the damping. This makes the known valve solution particularly suitable for controlling hydraulic consumers susceptible to vibration, such as slewing gear for crane or excavator superstructures on mobile machinery.

[0005] DE 10 2005 062 246 A1 discloses a hydropneumatic axle suspension for vehicles, in particular for their respective front axles. The suspension interacts with at least one suspension cylinder, which is connected by both its ring side and its piston side to a hydraulic accumulator, which can be controlled by an electronic control system via a valve unit assigned to it. The ring side of the suspension cylinder is connected to a pressure transducer, which transmits its measured pressure values ​​to the electronic control system. Furthermore, the ring-side pressure transducer is connected to the output side of the valve unit, which can be assigned to the ring side of the suspension cylinder. The actual control is thus achieved cost-effectively using commercially available 2 / 2-way valves, which are considered highly reliable.

[0006] From DE 10 2004 040 636 A1 a suspension device is known, in particular for vehicles with changing road conditions, with at least one suspension cylinder, each having pressure chambers such as an annular chamber and a piston chamber, a load sensing system for pressure generation, - two main branches forming supply lines between these chambers and a pump and a tank connection, wherein a valve is connected to each main branch, of which at least one valve is a pressure control valve, via which the pressure is set for the respective predeterminable pressure chamber of the respective suspension cylinder, and a level control, wherein

[0007] - in addition to the pressure setting, the level control is carried out by means of this pressure control valve, and for this purpose the pressure control valve can be electrically controlled by means of a control device.

[0008] This eliminates the need for additional switching valves for the actual level control, reducing manufacturing effort and thus helping to save costs. Furthermore, since no additional switching valves are required, maintenance effort and the potential for error sources are reduced.

[0009] Based on this prior art, the object of the invention is to provide a valve together with an associated suspension device which further improves the known solutions, in particular enabling a large number of different suspension functions in a cost-effective manner with a reduced valve expenditure.

[0010] A valve having the features of patent claim 1 in its entirety and a suspension device having the features of patent claim 10 solves this problem.

[0011] Because, according to the characterizing part of patent claim 1, the distribution plan in the valve housing provides that a first storage connection S1 is provided between a first pressure supply connection P1 and an adjacent return connection T1, a second storage connection S2 and a third storage connection S3 are provided between the first P1 and a further pressure supply connection P2, and a fourth storage connection S4 is provided between the further pressure supply connection P2 and a further adjacent return connection T2, a plurality of suspension functions can essentially be realized with only a single valve as an entity.Since only a single valve is required as the central control device, manufacturing effort is reduced, which leads to cost savings. This is also because, given the reduced number of valves required, such as switching valves, a high degree of reliability is achieved compared to the aforementioned prior art, and maintenance effort is therefore low. The valve is also designed to be inherently stable, so that unwanted vibrations that could impair the control behavior cannot occur during operation. The two pressure supply connections are used to connect and supply at least one suspension and / or damping cylinder, preferably several suspension and / or damping cylinders, with fluid of a predefined pressure. This pressure is provided by individual suspension and / or damping accumulators, in particular hydraulic accumulators, which are connected to the accumulator connections in the valve housing in a fluid- or media-carrying manner.For the sake of simplicity, the following will primarily refer to suspension cylinders and suspension or hydraulic accumulators. The return ports are designed as tank ports in the valve housing, at least one of which establishes a fluid connection to a fluid storage tank.

[0012] With the valve according to the invention it is preferably possible that, depending on

[0013] Slide position in the valve housing - an adaptive damped suspension,

[0014] - an adaptive, released suspension,

[0015] - suspension, pressure equalization for the suspension after locking, and suspension locking are enabled. In this way, a multitude of different suspension functions are combined in a single main control block with a single integrated valve. This allows the valve or main control block to be installed in a space-saving manner on mobile work machines, including trucks, while simultaneously reducing operating weight. This is particularly important when mobile work machines, such as trucks, are converted to battery operation, where the battery requires a correspondingly large amount of installation space on the work machine and is also heavy.

[0016] In a preferred embodiment of the valve according to the invention, it is provided that, for adaptive damped suspension, the valve spool in the valve housing assumes positions in which the fluid connection between the one pressure supply connection P1 and the first storage connection S1 as well as the further pressure supply connection P2 and the third storage connection S3 is blocked and the one pressure supply connection P1 and the second storage connection S2 as well as the further pressure supply connection P2 and the fourth storage connection S4 is guided via an opening cross-section in each case, the size of which depends on the respective position of the valve spool.

[0017] In this way, an orifice or throttle is implemented, which, as a flow control valve, regulates the fluid flow rate and thus enables the realization of a spring or damping effect. Preferably, the varying opening cross-section is also implemented by individual control grooves on the outer circumference of the control spool.

[0018] In a further preferred embodiment of the valve according to the invention, it is provided that for an adaptive, released or open suspension, the valve slide in the valve housing assumes positions in which the fluid connection between the one pressure supply connection P1 and the first storage connection S1 as well as the further pressure supply connection P2 and the third storage connection S3 is blocked and the one pressure supply connection P1 and the second storage connection S2 as well as the further pressure supply connection P2 and the fourth storage connection S4 is released.

[0019] This allows for quick adjustment of the suspension.

[0020] In a further preferred embodiment of the valve according to the invention, it is provided that, for a conventional spring action, the valve slide in the valve housing assumes positions in which the fluid connection between the one pressure supply connection P1 and the first and second accumulator connections S1 and S2, respectively, as well as the further pressure supply connection P2 and the third and fourth accumulator connections S3 and S4, respectively, is released or substantially released.

[0021] In this way, the suspension or hydraulic accumulators connected to the respective accumulator ports can be connected to the pressure supply ports of the suspension cylinders to create a complete suspension. In a further preferred embodiment of the valve according to the invention, it is provided that, for pressure equalization for the suspension, after locking, the valve spool assumes positions in the valve housing in which the fluid connection between the two pressure supply ports P1 and P2 and all accumulator ports S1, S2, S3, S4 is damped, in that the valve spool accordingly varies the associated opening cross-sections between it and the valve housing.

[0022] In a further preferred embodiment of the valve according to the invention, it is provided that, in order to lock the suspension, the valve spool in the valve housing assumes positions in which the fluid connection between the two pressure supply ports P1 and P2 and all storage ports S1, S2, S3, S4 is blocked. In this way, the suspension is held in a locked position and thus in the so-called "hard" position. For example, an excavator bucket locked in this way can selectively pick up and move load or bulk material without causing unwanted deflection of the associated work machine.

[0023] In a further preferred embodiment of the valve according to the invention, the valve spool has a connecting channel that connects the two return ports T1 and T2 at the respective ends of the valve spool. Thus, only one of the two return ports T1 or T2 needs to be directly connected to a fluid reservoir, such as a tank, which helps save space and reduces costs by eliminating the need for additional bores in the valve housing for the additional return port T2 or T1.

[0024] In a further preferred embodiment of the valve according to the invention, the valve spool is moved on at least one side by means of a rod drive that can be controlled by a controller. In this way, the valve spool can be controlled smoothly and without jerking in both opposing directions. The valve spool can be controlled hydraulically, as shown, for example, in DE 10 2016 011 860 A1, or using an electric motor via a rack and pinion drive, as shown, for example, in DE 10 2015 001 883 A1.

[0025] The invention also relates to a suspension device, particularly for vehicles such as mobile work machines, comprising at least one suspension cylinder and a valve as described above. The suspension device serves to connect the respective suspension cylinder to individual hydraulic accumulators, which are spatially and fluidically separated from one another and connected to the accumulator ports S1 to S4 of the valve described above. This achieves a type of closed circuit for the suspension device, enabling particularly energy-efficient operation.

[0026] In the following, the valve according to the invention together with the suspension device is explained in more detail using an embodiment according to the drawing.

[0027] The diagrams are shown in principle and not to scale.

[0028] Figure 1 shows, in the form of a hydraulic circuit diagram, the essential functional components of a suspension device including a valve for various suspension functions; and

[0029] Figures 2 to 6 show the valve used in Figure 1 in a longitudinal section and arranged below and each designated with a and the same number an associated circuit diagram.

[0030] The hydraulic circuit diagram shown in Figure 1 is designed in the form of a closed hydraulic circuit, with a central pressure supply connection P and a central tank return connection T. A hydraulic medium can be introduced in the usual way via the pressure supply connection P under a predeterminable fluid pressure, which is provided by a hydraulic pump (not shown), which draws the hydraulic medium from a storage tank (not shown), into which hydraulic medium from the hydraulic working circuit shown can also be fed again via the tank return connection T. The hydraulic circuit shown in Figure 1 is therefore a component of a suspension device, in particular for vehicles such as mobile work machines, with individual suspension cylinders 10, of which only one example is shown in Figure 1 as an example and for the sake of simplicity of illustration.The respective suspension cylinder 10 is connected in the usual way via an associated connection point 12 on both the piston side and the rod side to the hydraulic circuit for a convenient fluid supply. Furthermore, the suspension cylinder 10 interacts with wheel sets of a vehicle (not shown), whereby such a wheel set may also have only a single wheel. It is understood that such suspension or damping cylinders 10 can also be used for other applications outside of mobile work machines, for example, in the context of landing gear for aircraft, etc.

[0031] In particular, the hydraulic supply circuit comprises a first valve 14 according to the invention, as shown by way of example in Figures 2 to 6, as well as a second valve 16, which interacts with the first valve 14. Both valves 14, 16 are designed as proportional valves and are controlled by an electric motor M using a rack and pinion drive, as shown by way of example in DE 10 2015 001 883 A1. For use as a suspension device, the hydraulic circuit is equipped with individual hydraulic accumulators 18, which determine the suspension and / or damping characteristics for each suspension cylinder 10. Furthermore, the hydraulic circuit has a plurality of sensors 20, such as pressure detection devices.In addition to the previously mentioned valves 14, 16, there is also a central valve control 22 with several individual valves 24, which serve to control the suspension system as a whole in a conventional manner (which will therefore not be described in more detail). The ring-side connection of the suspension cylinder 10 belongs to the proportional valve 24, and the rebound movement is damped by the associated proportional valve 24.

[0032] As Figure 2 shows in particular, the first valve 14 has a valve housing 26 in which a valve slide 28 is guided for longitudinal movement. This valve slide 28 can be moved back and forth in the opposite direction by the associated electric motor M via the rack and pinion drive 30 (not shown in detail) for a practical connection or interruption of individual fluid lines between fluid connection points, which will be discussed in more detail below. The valve housing 26 is closed on one side by parts of a drive or motor housing 32 which guides the rack and pinion drive 30. On the opposite side, the valve housing 26 is sealed off from the environment in a media-tight manner by a closing part 34. The closing part 34 is inserted or screwed in the manner of a screw-in cartridge via a threaded section 36 into an associated receptacle 38 in the valve housing 26.The valve spool 28 is penetrated in its longitudinal or displacement axis 40 by a central connecting channel 42, which permanently connects two opposite return connections T1 and T2 in a fluid- or media-conducting manner. This channel opens into the receptacle 38 in the valve housing 26 or into a rod chamber 44 as part of the motor housing 22 and the adjoining valve housing 26 with the valve spool 28 in this area. As can be seen in particular from Figure 1, the two return connections T1 and T2 are connected to the central return connection T. Viewed in the direction of Figure 2, the valve slide 28 is in its left stop or maximum position relative to the end part 34 and the connecting channel 42 opens into a channel guide 46, formed from a longitudinal channel 48 and a plurality of transverse channels 50, which pass through the end part 34 in pairs opposite one another and open at the end into the space of the receptacle 38.An additional insert screw 52, ​​which is screwed centrally into the end piece 34 in a correspondingly sealed manner, serves to close the longitudinal channel 48 of the channel guide 46 from the environment. At the other end, the connecting channel 42 opens into a transverse channel section 54 in the valve spool 28, which in turn enters the rod chamber 44, to which the return connection T2 is connected.

[0033] The valve spool 28 also defines, together with the valve housing 26, annular channel sections 56 in the usual way, the free diameter of which is larger than the outer diameter of the valve spool 28. The channel sections 56 in the valve housing 26 are at least partially separated in a series arrangement by transverse webs 58, which protrude inwardly beyond the edge of the channel sections 56. Furthermore, the valve spool 28 has annular recesses 60 on its outer circumference, which serve to improve fluid guidance. Furthermore, individual control grooves 62 are introduced into the outer circumference of the valve spool 28, which serve to guide the fluid flow between two adjacent channel sections 56 and recesses 60 in this area and, depending on the displacement position of the valve spool 28, can gradually release or block a fluid flow in a throttling manner.Several control grooves 62 can be arranged on the outer circumference of the valve slide 28, wherein the respective control groove 62 opens with its free frontal opening cross-section in the direction of an annular channel section 56 with the respective pressure supply connection P1 and P2.

[0034] The valve housing 26 has a total of four storage connections S1 ,

[0035] S2, S3, and S4, to which the hydraulic accumulators 18 are connected individually or in groups according to Figure 1. Furthermore, there are two pressure supply connections P1 and P2, which are connected on the inlet side both to the central pressure supply connection P and to the corresponding connection points P1 and P2 on the outlet side of the second valve 16.

[0036] Based on the above, the function of the first valve 14 according to the invention will now be explained, as will later the interaction with the second valve 16.

[0037] As Figures 2 to 6 in particular show, the individual connections are arranged in the valve housing 26 according to a predeterminable distribution plan, wherein in the valve 14 there is a first storage connection S1 between a first pressure supply connection P1 and an adjacent return connection T1, a second S2 and a third storage connection S3 are provided between the first P1 and a further pressure supply connection P2, and a fourth storage connection S4 is provided between the further pressure supply connection P2 and a further adjacent return connection T2.

[0038] In the first spool position according to Figures 2 and 2a, adaptive damped suspension is realized with the suspension device shown. For this purpose, the valve spool 28 in the valve housing 26 assumes positions in which the fluid connection between the one pressure supply port P1 and the first accumulator port S1, as well as between the further pressure supply port P2 and the third accumulator port S3, is blocked and the one pressure supply port P1 and the second accumulator port S2, as well as between the further pressure supply port P2 and the fourth accumulator port S4, each passes through an opening cross-section whose size depends on the respective position of the valve spool 28.

[0039] In this valve position, as viewed in the direction of Figure 2, the valve spool 28 is located on the far left and in a stop position or a predeterminable maximum deflection position relative to the end part 34 at the end of the valve housing 26. The possible fluid flows in this regard are represented in Figure 2 by arrows, and the flow through them occurs via the control grooves 62 in the valve spool 28 already mentioned. The relevant valve position according to Figure 2 is represented symbolically in Figure 2a and relates to the circuit symbol shown on the far left and outlined. Furthermore, in Figure 2, the blocked and partially released fluid connections are represented by dashed circles, later also in ellipses, for the sake of clarity.

[0040] The following Figures 3 to 6a relate to the same valve solution 14 as shown in Figures 2, 2a with the proviso that different additional valve positions are shown with different valve functions which have an influence on the respective desired suspension property.

[0041] Thus, Figures 3 and 3a relate to an adaptive, released, or open suspension, in which the valve spool 28 in the valve housing 26 assumes positions in which the fluid connection between the one pressure supply port P1 and the first accumulator port S1, as well as the further pressure supply port P2 and the third accumulator port S3, is blocked, and the one pressure supply port P1 and the second accumulator port S2, as well as the further pressure supply port P2 and the fourth accumulator port S4, is opened. In this respect, the respective fluid connection is also represented by arrows pointing in the direction of flow, and the blocking and release positions are again enclosed by dashed circles for clarity.In this valve position, the respective control grooves 62 in the valve spool 28 release the adjacent fluid cross-sections relative to the second S2 and fourth accumulator connection S4 without further overlap, so that the hydraulic accumulators 18 connected in this respect can release their stored pressure energy to the respective suspension cylinder 10 connected to the hydraulic circuit. The corresponding circuit symbol can be found in Figure 3a to the left of the center position and is again marked with a dashed frame.

[0042] In the embodiment according to Figures 4 and 4a, the valve slide 28 in the valve housing 26 assumes positions for springing, in which the fluid connection between the one pressure supply connection P1 and the first and second accumulator connections S1 and S2, respectively, as well as the further pressure supply connection P2 and the third and fourth accumulator connections S3 and S4 is released or substantially released.

[0043] In this respect, the possible fluid paths are also shown with arrows and all hydraulic accumulators 18 are equally connected to the pressure supply connections P1 and P2 of the valve 14 and in this way the suspension for the respective suspension cylinder 10 is fully active, so that a kind of switched-through state results for the suspension cylinders 10 with the damping accumulators 18.

[0044] In the valve position according to Figures 5 and 5a, a so-called pressure equalization for the suspension or the suspension device is achieved after locking. In this valve position, the valve spool 28 in the valve housing 26 assumes positions in which the fluid connection between the two pressure supply connections P1 and P2 and all accumulator connections S1, S2, S3, S4 is dampened by the valve spool 28 varying the opening cross-sections between the valve spool 28 and the valve housing 26 accordingly, with the possible fluid connections again being shown with arrows pointing in the fluid direction. The corresponding functional position is again shown in Figure 5a as a circuit symbol in outline form, and each of the fluid connections between the individual pressure supply connections P1, P2 and the associated accumulator connections S1, S2, S3, S4 is throttled accordingly.This time, the control grooves are not used, but rather the throttling takes place via the control edges, formed by the transverse webs 58 on the valve housing 26 and the adjacent annular channel sections 56 in the valve slide 26.

[0045] The last possible suspension position with the valve 14 is a suspension lock as shown in Figures 6 and 6a. To lock the suspension in this way, the valve spool 28 in the valve housing 26 assumes positions in which the fluid connection between the two pressure supply ports P1 and P2 and all accumulator ports S1, S2, S3, S4 is correspondingly blocked by the valve spool 28 passing over the inner sides of the crosspieces 58 with its uninterrupted outer circumference. When the suspension is locked in this way, the suspension cylinders 10 are "clamped" with their respective fluid columns on the piston and rod sides, so that the associated chassis of the work machines is locked accordingly.In this locked position, a working device of a work machine, such as an excavator bucket, can pick up and transport bulk material without causing the undercarriage of the work machine to swing up unintentionally. In summary, it can be stated that a variety of suspension functions for a vehicle suspension can be achieved with just one valve 14 according to the invention, which is surprising to a person skilled in the art of suspension devices. This has no equivalent in the prior art.

[0046] The circuit diagram according to Figure 1 shows a further second valve 16 in the form of a proportional valve, whose valve piston 64 is guided longitudinally in a housing 66 with individual fluid connection points. Similar to the first valve 14, the valve piston 64 of the second valve 16 can also be moved in opposite directions by means of a rack and pinion drive 30 using an electric motor M.

[0047] The second valve 16 has two fluid connection points P1 and P2, each of which is in fluid communication with the first pressure supply connection P1 and the second pressure supply connection P2 on the inlet side of the first valve 14. Furthermore, the second valve 16 has further connection points in the form of a first utility connection R1 and a second utility connection R2. The respective utility connections R1 and R2 of the second valve 16 are in fluid communication with a row of suspension cylinders 10 on the left and right sides of the circuit diagram arrangement according to Figure 1 upon actuation of the two proportional valves 68. Furthermore, the second valve 16 has tank connection points T3 and T4, which in turn are permanently in fluid communication with one another via a fluid connection 70.The relevant connection 70 is secured at the end by two pressure relief valves 72, one connected to the central pressure supply connection P and the other connected to the central tank return connection T. The aforementioned valves 68 and 70 are, in this respect, individual valves 24 that are to be assigned to the overall valve control 22. On the output side, the two utility connections R1 and R2, when the proportional valves 68 are actuated, are in fluid communication with the respective associated connection points 12, to which the suspension cylinders 10 are functionally connected.

[0048] The second valve 16 allows different functions to be implemented for each suspension cylinder depending on the slide position of the valve piston 64 in the housing 66, thus further supporting the suspension functions provided by the first valve 14. Thus, as viewed in Figure 1, the suspension function shown on the far left implements enabled or open suspension for each individual suspension cylinder 10. The circuit or function representation arranged to the right of it achieves damped suspension for each suspension cylinder 10. In the circuit diagram shown in Figure 1, damped roll stabilization for the chassis is enabled, and the rightmost functional position relates to enabled or open roll stabilization for the entire chassis with the individual suspension cylinders 10.Between the damped roll stabilization and the damped independent wheel suspension, the valve 16 can be blocked in a switching or intermediate position not shown, in which the two useful connections R1, R2 are separated from the pressure supply connections P1, P2 of the second valve 16, so that the second valve 16 assumes its blocking position.

[0049] By combining both valves 14, 16, all essential suspension, damping, and roll stabilization functions are achieved with just two main valves 14, 16, which previously required a large number of individual valves with corresponding piping and control complexity. The solution shown in Figure 1 is very space- and weight-saving, allowing the suspension device to be installed preferably in battery-powered vehicles, where the battery itself already occupies a very large weight and installation volume.

Claims

Patent claims 1 . Valve, at least comprising a valve housing (26) and a valve slide (28) which is guided longitudinally therein and which controls individual fluid connection points in the valve housing, such as at least one pressure supply connection, Return connection, and a plurality of storage connections which are arranged in the valve housing (26) according to a predeterminable distribution plan, characterized in that a first storage connection (S1) is provided between a first pressure supply connection (PI) and an adjacently arranged return connection (TI), a second (S2) and a third storage connection (S3) are provided between the first (PI) and a further pressure supply connection (P2), and a fourth storage connection (S4) is provided between the further pressure supply connection (P2) and a further adjacently arranged return connection (T2).

2. Valve according to claim 1, characterized in that depending on the slide position of the valve slide (28) in the valve housing (26) - an adaptive damped suspension, - an adaptive, released suspension, - a suspension, a pressure equalization for the suspension after locking, and a locking of the suspension is possible.

3. Valve according to claim 1 or 2, characterized in that for an adaptive damped suspension the valve slide in the valve housing assumes positions in which the fluid connection between the one pressure supply connection (PI ) and the first storage connection (S1 ) as well as the further pressure supply connection (P2) and the third storage connection (S3) is blocked and the one pressure supply connection (PI ) and the second storage connection (S2) as well as the further pressure supply connection (P2) and the fourth storage connection (S4) each leads via an opening cross-section whose size depends on the respective position of the valve slide.

4. Valve according to one of the preceding claims, characterized in that for an adaptive, released open suspension, the valve slide in the valve housing assumes positions in which the fluid connection between the one pressure supply connection (PI ) and the first storage connection (S1 ) and the further pressure supply connection (P2) and the third storage connection (S3) is blocked, and the one pressure supply connection (PI ) and the second storage connection (S2) and the further pressure supply connection (P2) and the fourth storage connection (S4) is released.

5. Valve according to one of the preceding claims, characterized in that for a spring the valve slide (28) in the valve housing (26) assumes positions in which the fluid connection between the one pressure supply connection (PI ) and the first and second storage connections (S1) and (S2) as well as the further pressure supply connection (P2) and the third and fourth storage connections (S3) and (S4) is released or substantially released.

6. Valve according to one of the preceding claims, characterized in that for pressure equalization of the suspension after locking the valve slide (28) in the valve housing (26) assumes positions in which the fluid connection between the two pressure supply connections (PI) and (P2) and all storage connections (S1, S2, S3, S4) is damped by the valve slide (28) varying the associated opening cross sections between the valve slide (28) and the valve housing (26) accordingly.

7. Valve according to one of the preceding claims, characterized in that for locking the spring, the valve slide (28) in the valve housing (26) assumes positions in which the fluid connection between the two pressure supply connections (PI) and (P2) and all storage connections (S1, S2, S3, S4) is blocked.

8. Valve according to one of the preceding claims, characterized in that the valve slide has a connecting channel (42) which connects the two return connections (TI) and (T2) to one another.

9. Valve according to one of the preceding claims, characterized in that the valve slide is moved on at least one side by means of a rod drive which can be controlled by a controller.

10. Suspension device, in particular for vehicles such as mobile work machines, with at least one suspension cylinder and a valve according to one of the preceding claims, which serves to connect the respective suspension cylinder (10) to individual hydraulic accumulators which are connected separately from one another to the accumulator connections (S1 to S4) of the valve.

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