Failsafe pressure control valve for controlling or regulating the pressure of a fluid in a pilot pressure chamber, and vibration damper comprising such a pressure control valve

Abstract

The invention relates to a pressure control valve (1), in particular a failsafe pressure control valve (1), for controlling or regulating the pressure of a fluid in a pilot pressure chamber, having a valve housing (10) with at least one inlet (I), which can be fluidically connected to the pilot pressure chamber, and at least one outlet, wherein between the at least one inlet (I) and the at least one outlet (O) is a pilot valve chamber (20) which is fluidically connected to the outlet (O) via a first through-channel (17) and to the inlet (I) via a second through-channel (18), and having a tappet (60) that can be moved along a longitudinal axis (L) by means of an energizable actuation device (70) and can move the pilot seal (65) along the longitudinal axis (L) between a first position, in which the pilot seal (65) sealingly rests against the first valve seat (21) and closes the first through-channel (17), and a second position, in which the pilot seal (65) sealingly rests against the second valve seat (22) and closes the second through-channel (18). The valve housing (10) comprises a spring element (30) which has the first valve seat (21) and which rests against a third valve seat (23) in a biased state and closes a failsafe channel (19) between the at least one outlet (O) and the pilot valve chamber (20).

Description

[0001] Fail-safe pressure control valve for controlling or regulating a pressure of a fluid in a pilot pressure chamber and vibration damper with such a pressure control valve

[0002] The present invention relates to a fail-safe pressure control valve for controlling or regulating a pressure of a fluid in a pilot pressure chamber having the features of patent claim 1. Furthermore, the present invention relates to a vibration damper having such a pressure control valve having the features of patent claim 19.

[0003] Pressure control valves are already known from the prior art in various designs. For example, in the prior art, pressure control valves of this generic type are used in vibration dampers in motor vehicles, with the damping characteristics of the pressure control valve depending on the volume flow of the fluid used flowing through the proportional valve. Depending on the volume flow, a softer, more comfortable damping or a harder, more sporty damping can be set. Vibration dampers use an energizable actuating device with which several damping characteristics can be specified by the driver or automatically set by an on-board computer depending on the driving condition of the motor vehicle or the condition of the floor covering over which the motor vehicle is currently moving.

[0004] The fluid can be hydraulic or pneumatic, typically hydraulic fluid or compressed air. Pilot pressure chambers in hydraulically or pneumatically operated devices are used to control or regulate pilot-operated valves, often also designed as hydraulic or pneumatic spools. If pilot-operated valves are designed as proportional valves or proportional spools, the volume flows through the proportional valve or proportional spool can be continuously adjusted within certain limits using the pressure in the pilot pressure chamber.

[0005] Such pressure control valves have proven themselves in the past, but it must always be guaranteed that in the event of a failure of the electrical power and consequently the failure of the actuating device of the pressure control valve, a failure protection, referred to as a "failsafe", is available. This ensures that even in the event of a failure of the electrical power, the vehicle can continue to be operated with a certain damping characteristic, which is why such pressure control valves are referred to as fail-safe. In this case, a medium damping characteristic is usually aimed for, which is neither too hard nor too soft.

[0006] These requirements result in a relatively complex design of the device, in particular of the vibration damper, as can be seen, for example, from US 2016 0 091 044 A1 and WO 2016 066 314 A1. The design is primarily complex because several slides must be used. Further vibration dampers are disclosed in US 2016 0 369 862 A1, JP 2009 115 319 A, US 5 147 018 A, WO 2011 023 351 A1 and US 2005 0 016 086 A1. In particular, the vibration damper disclosed in EP 2 678 581 B1 offers medium damping characteristics even in the "failsafe" mode.

[0007] A disadvantage of the pressure control valves known from the state of the art is that the failsafe function is implemented using a relatively complex and cost-intensive design, resulting in significant variations in damping behavior due to component tolerances. Furthermore, there are only limited options for adapting the characteristics of the failsafe curve to specific applications.

[0008] This is where the present invention comes in.

[0009] The present invention is dedicated to the task of proposing a generic, drop-proof pressure control valve that expediently eliminates the disadvantages known from the prior art. The proposed pressure control valve should be simple in design and be able to regulate the pressure in the pilot pressure chamber to a specific value even when no electrical energy is available to power the actuating device.

[0010] This object is achieved by a pressure control valve having the features of patent claim 1 and a vibration damper having the features of patent claim 19.

[0011] Further advantageous embodiments of the present invention are specified in the subclaims.

[0012] The drop-proof pressure control valve according to the invention with the features of patent claim 1 for controlling or regulating a pressure of a fluid in a pilot pressure chamber comprises a valve housing with at least one inlet which is fluidically connectable to the pilot pressure chamber.

[0013] Furthermore, the valve housing has a first valve seat arranged between the at least one inlet and the at least one outlet, and a second valve seat arranged in a pilot valve chamber. The pilot pressure chamber is connected to the at least one outlet by means of a first passage channel and to the at least one inlet by means of a second passage channel.

[0014] Furthermore, the pressure control valve according to the invention comprises a tappet and a pilot seal, wherein the tappet is movable along a longitudinal axis between a first and a second position by means of an energizable actuating device. The pilot seal is preferably arranged on the tappet, and the energizable actuating device can move the tappet along the longitudinal axis from the first position to the second position against the force of a return spring.

[0015] In an unactuated state of the actuating device, the pilot seal is preferably arranged in the first position by means of a return spring. In the first position, the pilot seal rests sealingly against the first valve seat and closes the first passage channel.

[0016] In the actuated state of the actuating device, the tappet is in the second position, in which the pilot seal rests sealingly against the second valve seat and closes the second passage channel.

[0017] In addition, it is provided that the valve housing comprises a spring element which has the first valve seat and that the spring element can bear against a third valve seat in a pre-tensioned manner in order to close a fail-safe channel between the at least one outlet and the pilot valve chamber. The present invention is based on the idea of ​​integrating a fail-safe function into the valve housing in that a first housing wall of the housing, which delimits the pilot valve chamber, is formed by a spring element. The first valve seat is arranged or formed on the spring element, as a result of which, in the de-energized or unactuated state of the actuating device, the pilot valve seal bears sealingly against the first valve seat or preferably against the spring element.If pressure is present in the pilot valve chamber when the actuating device is de-energized, this pressure acts against the spring element and deforms it, preferably elastically, whereby the spring element is lifted from the third valve seat and releases the fail-safe channel through which the fluid can flow from the pilot valve chamber to the at least one outlet. The spring element ensures that even in the event of a failure of the vehicle's electrical power, the vehicle can continue to be operated safely and comfortably with a specific damping characteristic.

[0018] By appropriately designing the spring element, i.e. the stiffness, a desired damping characteristic for the "fail-safe" operation can be set, which is, for example, neither too hard nor too soft for the respective vehicle.

[0019] A further development of the present invention provides that the spring element comprises a first sealing section and a second sealing section, and that the first sealing section interacts with the first valve seat, and the second sealing section interacts with the third valve seat. Preferably, the spring element is at least partially disc-shaped or annular, and the first sealing section and the second sealing section lie on a common annular section of the preferably disc-shaped or annular spring element. As a result, no fluid can flow through, in particular, between the two sealing sections.

[0020] Both the first sealing section and the second sealing section are preferably annular.

[0021] A further development of the present invention provides that the first sealing section is arranged within the second sealing section.

[0022] A preferred embodiment of the present invention provides that the first sealing section and the second sealing section are arranged on the side of the spring element facing the pilot valve chamber. Accordingly, in the unactuated state of the actuating device, the pilot seal is sealingly supported by the return spring on the side facing the pilot valve chamber, and a pressure present in the pilot valve chamber acts on the spring element over its entire surface.

[0023] Furthermore, it has proven advantageous if the spring element closes off the pilot valve chamber on one side along the longitudinal axis - preferably at the end. The spring element has - as already explained above - the first valve seat and also has the first passage channel, which is preferably designed in the manner of an opening in the spring element. The opening is preferably arranged coaxially to the longitudinal axis and forms at least part of the first passage channel, through which the fluid can flow from the pilot valve chamber to the at least one outlet. Furthermore, it is preferred that the first valve seat is formed around the opening. A development of the present invention provides that the spring element is concave or flat.Preferably, the spring element is elastically deformed into the concave shape in the state installed in the pressure control valve and further preferably spans a collar of the third valve seat.

[0024] According to a preferred embodiment of the present invention, the spring element comprises at least one flow section, through which the fluid can flow from the third valve seat to the at least one outlet. For example, the spring element can be star-shaped or gear-shaped, with the teeth or prongs forming flow sections through which the fluid can flow through the spring element.

[0025] According to a further development of the present invention, the valve housing is inserted into an actuator housing. The spring element is held—preferably clamped—between the actuator housing and the valve housing in such a way that the spring element presses against the third valve seat with a preload in order to form a sealing contact therewith.

[0026] A corresponding recess can be formed in the actuator housing to form a receiving area into which the valve housing can be inserted. A channel can also be provided between the valve housing and the actuator housing, enabling fluid communication between the at least one outlet and the first passage channel and / or the fail-safe channel.

[0027] A further development of the present invention provides that the spring element is held in position by at least one spacer ring, wherein the spacer ring preferably specifies the position of the spring element in a plane transverse to the longitudinal axis.

[0028] Furthermore, it has proven advantageous if the at least one spacer ring has an outflow channel through which the first passage channel and / or the fail-safe channel are or are guided. The spacer ring can, for example, have an interruption formed between two end sections of the spacer ring. The spacer ring is therefore not a completely closed ring and encloses an angular dimension of << 360 °, more preferably of approximately 300 °.

[0029] A further development of the present invention provides that the valve housing comprises a second wall section that closes off the pilot valve chamber on the side opposite the spring element. The second wall section preferably comprises an insert bushing, which further preferably comprises the second valve seat.

[0030] The insert bushing can be inserted in particular in the manner of a press-in bushing into a corresponding opening along the longitudinal axis in a main valve housing part, whereby the position of the second valve seat in the longitudinal axis can be adjusted exactly.

[0031] A preferred development of the present invention provides for a bypass channel to be provided. The bypass channel can, for example, be formed on the second valve seat. The respective bypass channel can preferably be designed in the manner of a groove or recess and enables the fluid to flow through, in particular when the pilot seal bears sealingly against the second valve seat in the second position. According to a development of the present invention, the valve housing comprises a main valve chamber. The main valve chamber is fluidically connected to the at least one inlet and the at least one outlet. A main valve spool, which is prestressed against a main valve seat by means of a main spring, can preferably be arranged in the main valve chamber.Preferably, the pilot valve chamber is fluidically connected to the main valve chamber by means of the second passage channel, whereby the fluid can flow from the inlet through the main valve chamber, inter alia, via the second passage channel and the pilot valve chamber to the at least one outlet.

[0032] A further development of the present invention provides that the main slide is designed as a proportional slide.

[0033] Furthermore, it has proven advantageous if the actuating device is pressure-balanced. In particular, it is preferred if the actuating device comprises a pressure-balance chamber that can communicate with the pilot valve chamber. For this purpose, it is advantageous if the tappet has a compensating bore through which fluid can flow along the longitudinal axis of the tappet.

[0034] A further development of the invention also provides that a fail-safe characteristic curve of the pressure control valve can be adjusted by a thickness of a spacer ring and / or the spring element or the spring washer.

[0035] The spacer ring can preferably determine the position of the spring element, in particular in a plane perpendicular to the longitudinal axis. The spacer ring preferably surrounds the spring element radially and can also specify a distance between the main housing part and the actuator housing. The distance can preferably pre-stress the spring element, whereby the pre-stress can be used to shape the spring element into a concave shape.

[0036] By varying the thickness or stiffness of the spring element, the spring rate of the spring element or spring washer can be adjusted. Therefore, the thickness or stiffness of the spring element and / or the spacer ring can be selected for the specific application to adjust the characteristics of the hydraulic failsafe curve.

[0037] A further aspect of the present invention relates to a vibration damper with a pressure control valve as described above.

[0038] Three exemplary embodiments of a pressure control valve according to the invention are described in detail below with reference to the accompanying drawings. They show:

[0039] Figure 1 is a partially sectioned view of a fail-safe pressure control valve for controlling or regulating a pressure of a fluid in a pilot pressure chamber with an energizable actuating device, comprising a tappet and a pilot seal arranged on the tappet, wherein the actuating device is de-energized and the pilot seal in a first position is in sealing contact with a first valve seat in a pilot valve chamber, Figure 2 is an enlarged detailed view of the pressure control valve according to Figure 1,

[0040] Figure 3 is a detailed view of the pressure control valve according to Figure 1, wherein a pressure is present in the pilot valve chamber, which lifts a spring element from a third valve seat, whereby the fluid can flow through a fail-safe channel from the pilot valve chamber to an outlet,

[0041] Figure 4 is an enlarged view of the spring element according to Figures 1-3 in the initial state, and

[0042] Figure 5 is an enlarged view of a spacer ring for positioning the spring element.

[0043] Identical or functionally equivalent parts or features are identified by the same reference symbols in the following detailed description of the figures. Likewise, not all identical or functionally equivalent parts or features are provided with a reference number in the figures.

[0044] Figure 1 shows a first exemplary embodiment of a fail-safe pressure control valve 1 for controlling or regulating the pressure of a fluid. The pressure control valve 1 can be used, for example, in a vibration damper (not shown), in particular of a motor vehicle, to adjust a damping characteristic of the vibration damper.

[0045] The pressure control valve 1 comprises a valve housing 10 with at least one inlet I and at least one outlet O. The at least one inlet I can be connected to a pilot pressure chamber. In the accompanying figures, the reference symbols "I" and "O" indicate the areas in which the at least one inlet I and the at least one outlet O could be located.

[0046] The valve housing 10 at least partially encloses a pilot valve chamber 20, wherein a first valve seat 21, a second valve seat 22, and a third valve seat 23 are arranged in the pilot valve chamber 20. The first valve seat 21 and the second valve seat 22 are arranged in the valve housing 10, or more precisely in the pilot valve chamber 20, on opposite sides along the longitudinal axis L.

[0047] As can be seen in particular from the detailed representations according to Figure 2, the valve housing 10 comprises a spring element 30 and a second wall section 40, wherein the first valve seat 21 is arranged on the spring element 30 and the second valve seat 22 is arranged in a second wall section 40.

[0048] The spring element 30 and the second wall section 40 are arranged on opposite sides of the pilot valve chamber 20 in the longitudinal axis L and close the pilot valve chamber 20 at the end in the longitudinal axis L.

[0049] The pilot valve chamber 20 is connected, inter alia, to the at least one outlet 0 by means of a first passage channel 17. In addition, the pilot valve chamber 20 is connected to the at least one inlet 1 by means of a second passage channel 18, whereby the fluid can flow through the at least one inlet 1 and the second passage channel 18 into the pilot valve chamber 20 and can flow out through the first passage channel 17 to the at least one outlet 0. The spring element 30 can, for example, as shown in Figure 4, be a substantially disc-shaped spring and comprises a first sealing section 31, a second sealing section 32 and one or more flow sections 35.

[0050] The first sealing section 31 forms the first valve seat 21, and the second sealing section 32 interacts with a third valve seat 23. In Figure 4, the sealing sections 31, 32 are indicated by dotted lines.

[0051] The spring element 30 further comprises the first passage channel 17, wherein the sealing section 31 forming the first valve seat 21 is arranged around the first passage channel 17.

[0052] The first sealing section 31 and the second sealing section 32 are arranged on the side of the spring element 30 facing the pilot valve chamber 20 and are further arranged on a common annular and fluid-tight section of the spring element 30. The first sealing section 31 lies radially inside the second sealing section 32 with respect to the longitudinal axis L.

[0053] With reference to the accompanying Figure 4, it is further apparent that the spring element 30 is gear-shaped or star-shaped and has a plurality of teeth or points, between each of which a flow section 35 is formed. The fluid can flow through the spring element 30 in the respective flow section 35.

[0054] The second wall section 40 comprises the second passage 18 and the second valve seat 22. The valve housing 10 comprises a main housing part 11, the spring element 30 and / or an insert bushing 45 which forms the second wall section 40, wherein the insert bushing 45 can be inserted into a recess in the main housing part 11. The insert bushing 45 comprises the second valve seat 22, wherein the position of the insert bushing 45 along the longitudinal axis L relative to the main housing part 11 enables exact positioning of the second valve seat 22 in the longitudinal axis L.

[0055] The main housing part 11 comprises the third valve seat 23. The third valve seat 23 can comprise a valve collar 12 arranged around a pocket forming the pilot valve chamber 20. The valve collar 12 protrudes from the end face of the main housing part 11 facing away from the pilot valve chamber 20.

[0056] In the operating state of the pressure control valve 1 shown in Figures 1 and 2, the spring element 30 rests against the third valve seat 23 in a pre-tensioned manner and closes a fail-safe channel 19 between the at least one outlet 0 and the pilot valve chamber 20.

[0057] Furthermore, it can be seen from Figures 1-3 that the valve housing 10 has a main valve chamber 50, which is fluidically connected on the one hand to the at least one inlet I and on the other hand to the at least one outlet O. According to the illustrated embodiment, a main valve slide 54 can be arranged in the main valve chamber 50, which is held prestressed against a main valve seat 51 by a main valve spring 55.

[0058] The main valve chamber 50 is fluidically arranged between the at least one inlet I and the pilot valve chamber 20. This means that the fluid from the at least one inlet I must first flow through the main valve chamber 50 before it can enter the pilot valve chamber 20 through the second passage 18. For this purpose, the main valve slide 54 has a passage 58, which is shown in Figures 1-3.

[0059] In addition, the pressure control valve 1 has an energizable actuating device 70, wherein the energizable actuating device 70 can preferably be formed by an electromagnetic actuator hidden in Figure 1.

[0060] The actuating device 70 can be accommodated in an actuator housing 72, wherein the actuating device 70 further comprises an excitation coil, an armature, and a return spring. The armature can be moved along a longitudinal axis L in a known manner when the excitation coil is energized, counter to the spring force of the return spring.

[0061] The actuator housing 72 has a receiving area formed by a recess, into which the valve housing 10 can be at least partially inserted. The valve housing 10 can be fixedly arranged in the receiving area of ​​the actuator housing 72, for example by a positive, non-positive and / or material connection, in particular by pressing it into the receiving area.

[0062] The spring element 30 is clamped between the actuator housing 72 and the main housing part 11. For this purpose, a contact section 33, which can be formed by the free ends of the teeth or prongs, is in operative contact with the actuator housing 72, and the second sealing section 32 is in operative contact with the main housing part 11. As a result, the spring element 30 is preloaded against the third valve seat 23 and can form a sealing contact against the third valve seat 23, closing the fail-safe channel 19.

[0063] A spacer ring 36 can determine the position of the spring element 30, in particular in a plane perpendicular to the longitudinal axis L. The spacer ring 36 is shown in Figure 5 and preferably surrounds the spring element 30 radially and can also specify a distance between the main housing part 11 and the actuator housing 72. The distance determines the preload of the spring element 30, whereby the preload causes the spring element 30 to be brought into a concave shape.

[0064] By varying the thickness of the spacer ring 36 and / or the spring element 30, the preload or spring rate of the spring element 30 and thus the characteristics of the hydraulic failsafe characteristic curve can be varied and adapted to customer requirements.

[0065] The spacer ring 36 is not completely closed, but forms an outflow channel 37 through which the fluid can flow from the first and / or third valve seat 21, 23 to the at least one outlet 0. The spacer ring 36 is therefore not a completely closed ring and encloses an angular dimension ß << 360 °, more preferably ß » 300 °.

[0066] The pressure control valve 1 also has a tappet 60, wherein the tappet 60 can be moved by the actuating device 70 along the longitudinal axis L against a force of a return spring (not shown). For this purpose, the tappet 60 is preferably connected to the armature and can furthermore - as shown in Figure 1 - be held movably mounted on the actuator housing 72 along the longitudinal axis L by means of bearing elements 74. The tappet 60 projects from the actuator housing 72 into the valve housing 10. In particular, as can be seen from the detailed illustrations in Figures 2 to 3, a first free end 61 of the tappet 60 projects into the pilot valve chamber 20.

[0067] Furthermore, it can be seen from the accompanying figures that the tappet 60 has a pressure equalization bore 64 through which the tappet 60 can be flowed through along the longitudinal axis L. Consequently, the fluid can flow from the first free end 61 through the tappet 60 into a pressure equalization chamber (not shown) opposite the armature, whereby pressure equalization can take place and the pressure control valve 1 can be designed to be pressure-balanced.

[0068] The plunger 60 further comprises a pilot seal 65, which is fixedly arranged on the plunger 60, preferably adjacent to the free end 61. The pilot seal 65 can, for example, be attached to the plunger 60 by means of a retaining ring 68, as shown in the accompanying figures.

[0069] The pilot seal 65, according to the embodiments shown in Figures 1 to 5, comprises a disk element which is preferably designed in the manner of a disk-shaped flat spring element.

[0070] In the illustrated unactuated state of the actuating device 70 according to Figures 1 - 3, the pilot seal 65 is arranged in a first position by means of the return spring. In the first position, the pilot seal 65 lies sealingly against the first valve seat 21 and closes the first

[0071] Passage channel 17. In the first position of the pilot seal 65, the fluid from the pilot valve chamber 20 cannot flow through the first passage channel 17 in the direction of the at least one outlet 0. In other words, the pilot valve chamber 20 is closed on the outlet side in this first position A.

[0072] In an actuated state (not shown) of the actuating device 70, the excitation coil of the actuating device 70 is slightly energized, for example by means of 0.4A, and the pilot seal 65 is moved from the first valve seat 21 in the direction of the second valve seat 22.

[0073] In this position of the pilot seal 65, the fluid can flow both from the pilot valve chamber 20 through the first passage channel 17 in the direction of the at least one outlet and from the at least one inlet I through the second passage channel 18 into the pilot valve chamber 20.

[0074] In a further (not shown) actuated state of the actuating device 70, the excitation coil of the actuating device 70 is energized more strongly, and the pilot seal 65 comes into contact with the second valve seat 22. In the second position B, the pilot seal 65 bears sealingly against the second valve seat 22 and closes the second passage 18.

[0075] In this second position of the pilot seal 65, the pilot seal 65 presses sealingly against the second valve seat 22 and, depending on the current supply, controls that the pilot seal only lifts off the second valve seat 22 at higher pressures and the fluid can flow from the at least one inlet 1 into the pilot valve chamber 20. Figure 3 shows a state of the pressure control valve 1 in which the fail-safe channel 19 is open and the fluid can flow from the pilot valve chamber 20 to the at least one outlet 0 in the unactuated state of the actuating device 70, the flow path being represented by a dashed line.

[0076] This condition can occur, for example, in the event of a power failure and / or failure of the actuating device 70. As soon as pressure is applied in the pilot valve chamber 20, this pressure acts against the spring element 30 and can further deform it, causing the second sealing section 32 to be lifted from the third valve seat 23. This opens the fail-safe channel 19, and a damping characteristic can be realized despite the failure.

[0077] The pilot seal 65 continues to lie sealingly against the first valve seat 21 formed by the spring element, since it can follow the displacement of the first valve seat 21 along the longitudinal axis L within an idle stroke due to the spring force of the return spring.

[0078] Reference symbol list

[0079] 1 pressure control valve

[0080] 10 valve housings

[0081] 11 Main housing part

[0082] 12 valve collars

[0083] 17 first passage channel

[0084] 18 second passage channel

[0085] 19 Fail-Safe Channel

[0086] 20 Pilot valve chamber

[0087] 21 first valve seat

[0088] 22 second valve seat

[0089] 23 third valve seat

[0090] 30 spring element

[0091] 31 first sealing section

[0092] 32 second sealing section

[0093] 33 Contact section

[0094] 34 Breakthrough

[0095] 35 Flow section

[0096] 36 spacer ring

[0097] 37 Outflow channel

[0098] 40 second wall section

[0099] 45 insert socket

[0100] 50 Main valve chamber

[0101] 51 Main valve seat

[0102] 54 main valve spool

[0103] 55 Main valve spring

[0104] 60 pestles

[0105] 61 free end

[0106] 64 Pressure equalization hole

[0107] 65 Pilot seal

[0108] 68 Retaining ring 70 Actuating device

[0109] 72 actuator housings

[0110] 74 bearing element

[0111] L Longitudinal axis

Claims

Patent claims 1. Pressure control valve (1), in particular fail-safe pressure control valve (1), for controlling or regulating a pressure of a fluid in a pilot pressure chamber, comprising - a valve housing (10) with at least one inlet (I) which is fluidically connectable to the pilot pressure chamber, and with at least one outlet (O), wherein between the at least one inlet (I) and the at least one outlet (O) a pilot valve chamber (20) is arranged, which is fluidically connected to the outlet (0) via a first passage channel (17) and to the inlet (I) via a second passage channel (18), - a tappet (60) which is movable along a longitudinal axis (L) by means of an energizable actuating device (70) and which can move the pilot seal (65) along the longitudinal axis (L) between a first position in which the pilot seal (65) bears sealingly against the first valve seat (21) and closes the first passage channel (17), and a second position in which the pilot seal (65) bears sealingly against the second valve seat (22) and closes the second passage channel (18), characterized in that the valve housing (10) comprises a spring element (30) which has the first valve seat (21) and which bears prestressed against a third valve seat (23) and closes a fail-safe channel (19) between the at least one outlet (0) and the pilot valve chamber (20).

2. Pressure control valve (1) according to one of the preceding claims, characterized in that the spring element (30) comprises a first sealing section (31) and a second sealing section (32) and that the first sealing section (31) cooperates with the first valve seat (21) and the second sealing section (32) cooperates with the third valve seat (23).

3. Pressure control valve (1) according to one of the preceding claims, characterized in that the first sealing section (31) is arranged within the second sealing section (32).

4. Pressure control valve (1) according to one of the preceding claims, characterized in that the first sealing section (31) and the second sealing section (32) are arranged on the side facing the pilot valve chamber (20).

5. Pressure control valve (1) according to one of the preceding claims, characterized in that the spring element (30) closes off the pilot valve chamber (20) on one side along the longitudinal axis (L).

6. Pressure control valve (1) according to one of the preceding claims, characterized in that the spring element (30) has an opening (34), around which the first valve seat is formed.

7. Pressure control valve (1) according to one of the preceding claims, characterized in that the spring element (30) is concave or flat.

8. Pressure control valve (1) according to one of the preceding claims, characterized in that the spring element (30) has at least one flow section (35) through which the fluid can flow from the third valve seat (23) to the at least one outlet (0).

9. Pressure control valve (1) according to one of the preceding claims, characterized in that the valve housing (10) is inserted into an actuator housing (72), and that the spring element (30) is held between the actuator housing (72) and the valve housing (10).

10. Pressure control valve (1) according to one of the preceding claims, characterized in that the spring element (30) is held in position by a spacer ring (36).

11. Pressure control valve (1) according to one of the preceding claims, characterized in that the spacer ring (36) has an outflow channel (37), through which the first passage channel (17) and / or the fail-safe channel (19) are or are led.

12. Pressure control valve (1) according to one of the preceding claims, characterized in that the pilot valve chamber (20) is formed in the valve housing (10), and that the first valve seat (21) and the second valve seat (22) are arranged on opposite sides of the pilot valve chamber (20).

13. Pressure control valve (1) according to one of the preceding claims, characterized in that the valve housing (10) has a second wall section (40) which comprises the second valve seat (22).

14. Pressure control valve (1) according to one of the preceding claims, characterized in that the second wall section (40) comprises an insert bushing (45).

15. Pressure control valve (1) according to one of the preceding claims, characterized in that the valve housing (10) comprises a main valve chamber (50) in which a main valve slide (54) is arranged, which is prestressed against a main valve seat (51) by means of a main valve spring (55).

16. Pressure control valve (1) according to one of the above-mentioned Sayings, characterized in that the main valve slide (54) is designed as a proportional slide.

17. Pressure control valve (1) according to one of the preceding claims, characterized in that the actuating device (70) is pressure-balanced.

18. Pressure control valve (1) according to one of the preceding claims, characterized in that a failsafe characteristic curve can be adjusted by a thickness of the spacer ring (36) and / or the spring washer (30).

19. Vibration damper with a pressure control valve (1) according to one of the preceding claims.

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