ELECTRO-MAGNETIC PRESSURE CONTROL VALVE WITH INTERNAL COMPRESSED AIR GUIDE

Description

Electro-magnetic pressure control valve with internal compressed air supply

[0001] The invention relates to an electromagnetic pressure control valve for controlling an air pressure according to the preamble of claim 1. Furthermore, the invention also relates to a pressure control valve device for pneumatically actuated vehicle brake systems according to claim 12 and to a pneumatically actuated vehicle brake system according to claim 13.

[0002] A generic electromagnetic pressure control valve is known from EP 0 433 673 B1. There, an axial compressed air flow is guided along the outer circumference of the armature, which is guided in a bore of the housing. For this to happen, either a certain amount of clearance must be present between the radially outer circumferential surface of the armature and the radially inner circumferential surface of the bore, or the armature must have axial grooves on its radially outer circumferential surface for the compressed air flow. In both cases, this adversely affects the sliding properties and stability of the armature's movement in the bore, and thus, wear.

[0003] Against this background, the object of the invention is to further develop an electromagnetic pressure control valve in such a way that wear is reduced. Likewise, a pressure control valve device for pneumatically actuated vehicle brake systems with at least one such electromagnetic pressure control valve and a pneumatically actuated vehicle brake system with at least one such pressure control valve device are to be provided.

[0004] This object is achieved by the features of claims 1, 12 and 13. Disclosure of the invention

[0005] The invention is based on an electromagnetic pressure control valve for controlling an air pressure, with a) a housing having a compressed air supply connection for connection to a compressed air supply, a compressed air outlet connection for connection to a consumer, and a compressed air vent connection for connection to a vent, and with b) an armature, which carries a valve body on each of its opposite end faces, a particularly cylindrical first valve body and a particularly cylindrical second valve body, and which is displaceable within the housing by magnetic forces against a spring force of at least one first spring such that it connects the compressed air outlet connection selectively to the compressed air supply connection or the compressed air vent connection, and with c) a particularly cylindrical first valve seat, which is connected to the compressed air supply connection, and with d) a particularly cylindrical second valve seat, which is connected to the compressed air vent connection,where e) the first valve body together with a first valve seat forms an inlet valve and the second valve body together with the second valve seat forms an outlet valve.

[0006] In other words, the intake valve is closed when the first valve body is sealingly seated on the first valve seat, and open when the first valve body is lifted off the first valve seat. Similarly, the exhaust valve is closed when the second valve body is sealingly seated on the second valve seat, and open when the second valve body is lifted off the second valve seat.

[0007] According to the invention, the following is then provided: f) A permanent axial compressed air connection through the first valve body, through the interior of the armature and through the second valve body, which comprises at least one, in particular cylindrical, central axial through-bore of the armature, at least one first axial through-opening in the first valve body and at least one second axial through-opening in the second valve body, wherein g) the first valve body has a, in particular cylindrical, first radially inner section which seals the first valve seat when the inlet valve is closed, and a, in particular cylindrical, first radially outer section which has the at least one first axial through-opening, and h) the second valve body has a, in particular cylindrical, second radially inner section which seals the second valve seat when the outlet valve is closed,and a particularly cylindrical second radially outer portion, which has the at least one second axial through-opening. ,

[0008] Permanent axial compressed air connection means that the axial compressed air connection is always present, regardless of whether compressed air actually flows through the compressed air connection or not.

[0009] By means of this axial compressed air connection inside the armature, an external compressed air connection around the armature with the disadvantages described above can be avoided, whereby the wear of the electromagnetic pressure control valve can be reduced.

[0010] Preferably, the at least one first axial through-opening of the first valve body is arranged radially outwardly with respect to the first radially inner portion of the first valve body, which in particular interacts exclusively with the first valve seat. Consequently, no flow connection can be established through the first valve seat when the first valve body rests with its radially inner portion on the first valve seat. The first radially outer portion of the first valve body, however, cannot close the first valve seat because it is arranged radially outside of it.

[0011] Analogously, the at least one second axial through-opening of the second valve body is arranged radially outside with respect to the second radially inner portion of the second valve body, which in particular interacts exclusively with the second valve seat. Consequently, no flow connection can be established through the second valve seat if the second valve body rests with its radially inner portion on the second valve seat. The second radially outer portion of the second valve body, on the other hand, cannot close the first valve seat because it is arranged radially outside it.

[0012] Preferably, the permanent axial compressed air connection only carries compressed air from the compressed air supply connection to the compressed air outlet connection when the inlet control valve is open and the first valve body is lifted from the first valve seat, and when the outlet control valve is closed, the second valve body is sealingly seated on the second valve seat. However, when the first valve body is seated on the first valve seat, i.e., when the inlet valve is closed, the permanent axial compressed air connection does not carry compressed air.

[0013] The first valve body can also represent a first separate body that is received in the axial through-bore of the armature. According to a further development, the first valve body can be received in the axial through-bore of the armature in an axially displaceable manner, for example, at its first end.

[0014] Preferably, the second valve body can represent a second separate body and can be received in the axial through-bore of the armature, in particular in an axially and rotationally fixed manner. In particular, the second valve body can be received in the axial through-bore of the armature, for example, at its second end, by a press fit and / or caulking.

[0015] Particularly preferably, the first valve body, which is mounted axially displaceably in the axial through-bore of the armature, can be axially supported on the second valve body by at least one second spring. This achieves a certain damping effect when the first valve body strikes the first valve seat, which is particularly advantageous when the electromagnetic pressure control valve is used with a relatively high switching frequency, such as for controlling brake pressure in the context of brake slip control. On the other hand, the axial spring force of the second spring acting on the first valve body reinforces the sealing effect when the armature with the first valve body is forced against the first valve seat, for example by magnetic forces resulting from energizing the at least one magnetic coil.Last but not least, the spring force of the at least one second spring, which tensions the first valve body against the first valve seat, prevents the first valve body from lifting off the first valve seat as a result of the pressure at the compressed air supply connection present at the first valve seat, which pressure is formed, for example, by a brake pressure in the case of a pressure-medium-actuated brake system of a vehicle.

[0016] The first valve body can also form or support a first flexible sealing element made of at least one elastomer. In particular, the first valve body can consist exclusively of the first sealing element.

[0017] According to a further development, the first radially outer section of the first valve body and / or the second radially outer section of the second valve body can have, in particular, radially outer slots or radially outer grooves distributed around the circumference, which run in particular in the axial direction and therefore serve for the axial guidance of compressed air.

[0018] The outer peripheral surface of the second valve body deviating from the slots or grooves can then contact the radial inner peripheral surface of the axial through-bore of the armature, for example by means of a press fit.

[0019] Preferably, the second valve body can form or support a second flexible sealing element made of at least one elastomer, which seals against the second valve seat when the outlet valve is closed. In a further development, the second valve body can be designed as a compressed air-permeable cage, in which the second sealing element is then held, wherein the surface of the sealing element facing the second valve seat, which interacts with the second valve seat, is left free of the cage.

[0020] In the electromagnetic pressure control valve, at least one electrical magnetic coil can be accommodated in the housing, wherein the armature can be axially actuated depending on an electrical excitation or de-excitation of the at least one magnetic coil between a first axial position in which the second valve body seals against the second valve seat and the first valve body is lifted from the first valve seat and a second axial position in which the first valve body seals against the first valve seat and the second valve body is lifted from the second valve seat.

[0021] The electromagnetic pressure control valve can a) be designed as a "normally open" pressure control valve, in which the inlet valve is opened and the outlet valve is closed when the solenoid coil is de-energized, or b) be designed as a "normally closed" pressure control valve, in which the inlet valve is closed and the outlet valve is open when the solenoid coil is de-energized.

[0022] In the "normally open" pressure control valve, the at least one first spring biases the armature toward the second valve seat such that the second valve body arranged on the armature on one end face is tensioned sealingly against the second valve seat, and the first valve body arranged on the armature on the other end face is lifted from the first valve seat. The at least one solenoid coil is then de-energized and, consequently, no magnetic forces act on the armature. When the at least one solenoid coil is energized, the armature is actuated against the spring force of the at least one first spring such that the second valve body is lifted from the second valve seat and the first valve body abuts sealingly against the first valve seat.

[0023] In the "normally closed" pressure control valve, the at least one first spring biases the armature toward the first valve seat such that the first valve body arranged on the end face of the armature is tightly clamped against the first valve seat, and the second valve body arranged on the other end face of the armature is lifted from the second valve seat. The at least one solenoid coil is then de-energized and, consequently, no magnetic forces act on the armature. When the at least one solenoid coil is energized, the armature is actuated against the spring force of the at least one first spring such that the first valve body is lifted from the first valve seat, and the second valve body abuts the second valve seat, forming a seal.

[0024] The invention is therefore applicable to both valve types, "Normally Closed" and "Normally Open".

[0025] The invention also relates to a pressure control valve device for pneumatically actuated vehicle brake systems, which is particularly designed to control a brake pressure dependent on brake slip and which comprises at least one pneumatically pilot-controlled diaphragm valve. The pressure control valve device can then comprise at least one electromagnetic pressure control valve as described above, in which the compressed air supply connection is connected to a device generating the brake pressure, the compressed air output connection is connected to the at least one pneumatically pilot-controlled diaphragm valve for piloting the at least one diaphragm valve, and the compressed air vent connection is connected to a vent.The pressure controlled by the electromagnetic pressure control valve at its compressed air output connection can act in particular on a diaphragm of the diaphragm valve, for example to lift it from a diaphragm valve seat or to tighten it sealingly against a diaphragm valve seat.

[0026] The invention also relates to a compressed air-operated vehicle brake system with at least one such pressure control valve device.

[0027] Furthermore, the invention also relates to a vehicle, in particular a commercial vehicle, comprising such a compressed air-operated vehicle brake system. drawing

[0028] An embodiment of the invention is explained in more detail in the following description with reference to the figures. They show: Fig. 1 shows a longitudinal section through an electromagnetic pressure control valve according to a preferred embodiment in a ventilation position; Fig. 2 shows a perspective view of a sealing element of the electromagnetic pressure control valve of Fig. 1 ; Fig. 3 a longitudinal section through the electromagnetic pressure control valve of Fig. 1 in a venting position. Description of the embodiment

[0029] Fig. 1 shows a longitudinal section through an electromagnetic pressure control valve 1 according to a preferred embodiment in a ventilation position.

[0030] The pressure control valve 1 comprises a housing 2 with a total of three connections, namely a compressed air supply connection 3 for connection to a compressed air supply, a compressed air output connection 4 (not directly visible here) for connection to a consumer and a compressed air vent connection 5 for connection to a vent.

[0031] The compressed air supply connection 3 represents an opening of a stepped bore 9 extending along a longitudinal axis 6 of the pressure control valve 1 in a cylindrical insert 8 received in a central blind bore 7 of the housing 2, which at the other end opens into a first valve seat 10 formed in the insert 8. The compressed air outlet connection 4 is located with reference to the longitudinal section of Fig. 1 in a different plane of the housing 2 and is therefore not visible there. The compressed air vent connection 5 represents the opening of a further stepped bore 11 running coaxially with the longitudinal axis 6 in the housing 2, which opens into a second valve seat 12 at the other end.

[0032] The housing 2 further has a cylindrical chamber 13 inside, which is axially bounded on the one hand by an end face of an armature 14, which is displaceably guided in the central blind bore 7 of the housing 2, and on the other hand by a bottom surface of the blind bore 7 of the housing 2, in which the second valve seat 12 is also formed. The chamber 13 has a flow connection to the compressed air outlet connection 4.

[0033] The armature 14 further has a central axial through-bore 15, at the first end of which a first valve body 16 is arranged and at the second end of which a second valve body 17 is arranged, so that the first and second valve bodies 16, 17, together with the armature 14, are axially displaceable within the blind bore 7 of the housing 2. The first valve body 16, together with a first valve seat 10, forms an inlet valve, and the second valve body 17, together with the second valve seat 12, forms an outlet valve.

[0034] The armature 14 is prestressed by a first spring 18, here for example against the second valve seat 12, which is supported on the one hand on an end face of the insert 8 and on the other hand on a radially inner collar 19 of the central axial through-bore 15 of the armature 14.

[0035] Furthermore, the housing 2 forms an integral solenoid coil body for holding a solenoid coil 20 by having a radially outer recess 21 in which the solenoid coil 20 is wound with a plurality of turns. The radially outer recess 21 is circumferentially covered by a separate solenoid coil housing 22, which forms a component of the housing 2 and has terminals 23 for supplying power to the solenoid coil 20, which are connected to the solenoid coil 20.

[0036] The armature 14 therefore carries a valve body on each of its opposite end faces, namely the first valve body 16 and the second valve body 17. The armature 14 can then be slidably displaced in the blind hole 7 by the spring force of the first spring 18 and magnetic forces resulting from energizing the solenoid coil 20 in such a way that it connects the compressed air output connection 4 optionally with the compressed air supply connection 3 or the compressed air vent connection 5.

[0037] In Fig. 1 the ventilation position of the armature 14 is shown, in which the compressed air outlet connection 4 is connected to the compressed air supply connection 3 and in Fig. 2 the venting position of the armature 14, in which the compressed air output connection 4 is connected to the compressed air vent connection 5, the compressed air flow being illustrated by arrows 24.

[0038] The electromagnetic pressure control valve can a) be designed as a "normally open" pressure control valve, in which the inlet valve is open and the outlet valve is closed when the solenoid coil 20 is de-energized, or b) as a "normally closed" pressure control valve, in which the inlet valve is closed and the outlet valve is open when the solenoid coil 20 is de-energized.

[0039] In the "normally open" pressure control valve 1, as described here, the first spring 18 biases the armature 14 in the direction of the second valve seat 12 such that the second valve body 17 arranged on the armature 14 on one end face is tightly tensioned against the second valve seat 12 and the first valve body 16 arranged on the armature 14 on the other end face is lifted off the first valve seat 10 in a state in which the solenoid coil 20 is de-energized and consequently no magnetic forces act on the armature 14.

[0040] When the solenoid coil 20 is energized, the armature 14 is then actuated by magnetic forces against the action of the spring force of the first spring 18 in such a way that the second valve body 17 is lifted off the second valve seat 12, but the first valve body 16 abuts against the first valve seat 10 in a sealing manner.

[0041] The inlet valve is therefore closed when the first valve body 16 is sealingly seated on the first valve seat 10, and open when the first valve body 16 is lifted from the first valve seat 10. When the inlet valve is open or when the armature 14 is in the vented position, a flow connection is established between the pressure supply port 3 and the pressure outlet port 4, whereby the pressure at the pressure outlet port 4 increases.

[0042] The outlet valve is closed when the second valve body 17 is sealingly seated on the second valve seat 12, and open when the second valve body 17 is lifted from the second valve seat 12. When the outlet valve is open or in the venting position of the armature 14, a flow connection is established between the pressure vent port, the chamber 13, and the pressure output port 4, whereby the pressure at the pressure output port 4 drops.

[0043] As explained above, the electromagnetic pressure control valve 1 is designed here, for example, as a "normally open" pressure control valve, in which the inlet valve is open and the outlet valve is closed when the solenoid coil 20 is de-energized. In the "normally open" pressure control valve, the first spring 18 therefore biases the armature 14 toward the second valve seat 12. When the solenoid coil is de-energized, i.e., when no magnetic forces act on the armature 14, the second valve body 17 seals against the second valve seat 12 (vent valve closed) and thus prevents venting, but the first valve body 16 lifts off the first valve seat (inlet valve open) to vent the compressed air outlet port 4.

[0044] When the solenoid coil 20 is energized, however, the armature 14 is actuated against the action of the spring force of the first spring 18 in such a way that the second valve body 17 is lifted from the second valve seat 12 (outlet valve open) and the first valve body 16 abuts sealingly against the first valve seat 10 (inlet valve closed).

[0045] Alternatively, the electromagnetic pressure control valve could also be designed as a "normally closed" pressure control valve, in which the inlet valve is closed and the outlet valve is open when the solenoid coil 20 is de-energized. In a "normally closed" pressure control valve, the first spring 18 biases the armature 14 toward the first valve seat 10 such that the first valve body 16 is tightly clamped against the first valve seat 10 (inlet valve closed) and the second valve body 17 is lifted from the second valve seat 12 (outlet valve open) when the solenoid coil 20 is de-energized and, consequently, no magnetic forces act on the armature 14.When the solenoid coil 20 is energized, the armature 14 is then actuated against the action of the spring force of the first spring 18 in such a way that the first valve body 16 is lifted from the first valve seat 10 (inlet valve open) and the second valve body 17 abuts sealingly against the second valve seat 12 (outlet valve closed).

[0046] In both valve types, a permanent axial compressed air connection 25 through the first valve body 16, the armature 14 and the second valve body 17 is proposed, which comprises the central axial through-bore 15 of the armature 14, at least one first axial through-opening 26 in the first valve body 16 and at least one second axial through-opening 27 in the second valve body 17. The first valve body 16 has a first radially inner section 28, which seals the first valve seat 10 when the inlet valve is closed, and a first radially outer section 29, which has the at least one first axial through-opening 26.Furthermore, the second valve body 17 has a second radially inner portion 30, which sealingly closes the second valve seat 12 when the outlet valve is closed, and a second radially outer portion 31, which has the at least one second axial through-opening 27.

[0047] The first radially outer section 29 of the first valve body 16 with the at least one first axial through-opening 26 and the second radially outer section 31 of the second valve body 17 with the at least one second axial through-opening 27 are therefore provided for axially guiding compressed air along the permanent axial compressed air connection 25, but preferably do not contribute to closing the first valve seat 10 and the second valve seat 12. In contrast, the first radially inner section 28 of the first valve body 16 is provided for closing the first valve seat 10 and the second radially inner section 30 of the second valve body 17 is provided for closing the second valve seat 12.

[0048] Due to this geometry, the permanent axial compressed air connection 25 only carries compressed air from the compressed air supply connection 3 into the compressed air outlet connection 4 when the inlet valve is open. However, if the inlet valve is closed, the permanent axial compressed air connection 25 does not carry any compressed air because, on the one hand, the first radially inner section 28 of the first valve body 16 closes the first valve seat 10 and, consequently, no compressed air can pass from the compressed air supply connection 3 into the permanent axial compressed air connection 25. On the other hand, the compressed air supply connection 3 cannot be vented because the inlet valve is then closed.

[0049] The first valve body 16, for example, represents a first separate body, which is received in particular at the first end of the central axial through-bore 15 of the armature 14 in an axially displaceable or sliding manner. The second valve body 17 also represents a second separate body, which is received in a second end of the axial through-bore 15 of the armature 14 in an axially and rotationally fixed manner, in particular by being held there by means of a press fit and / or caulking.

[0050] Here, the first valve body 16, which is mounted axially displaceably in the central axial through-bore 15 of the armature 14, is axially supported on the second valve body 17 by a second spring 32, which preloads the first valve body 16 with its end face facing the first valve seat 10 against the radially inner collar 19 of the armature 14. The second spring 32 is supported on the one hand on an end face of the first valve body 16 facing away from the first valve seat 10 and on the other hand on a step 33 of the second valve body 17, which, viewed here in cross-section, is T-shaped, for example, and has a first cylindrical section facing the first valve body 16 with a diameter that is smaller than the diameter of a second cylindrical section that contacts the radially inner circumferential surface of the central axial through-bore 15 of the armature 14.Therefore, a radial annular gap 34 is present between the first section with the smaller diameter and the radially inner circumferential surface of the central axial through-bore 15 of the armature 14, in which the second spring 32 is also arranged. This annular gap 34 forms, in particular, a section of the permanent axial compressed air connection 25.

[0051] In particular, the first valve body 16 consists exclusively of a first cylindrical sealing element 35, which has in its first radially outer section 29 radially outer grooves arranged in a distributed manner on the circumference as first axial through-openings 26, which run in the axial direction and serve for the axial guidance of compressed air, as in Fig. 2 is shown. The above-mentioned at least one first axial through-opening 26 is therefore formed here, for example, by the radially outer grooves arranged distributed around the circumference.

[0052] In an analogous manner, the second radially outer portion 31 of the second valve body 17 has radially outer slots arranged distributed in particular around the circumference as second axial through-openings 27, as can be seen from Fig. 1 which extend in the axial direction and serve to guide the compressed air axially. The radially outer circumferential surface of the second valve body 17, which deviates from the slots, then contacts the radially inner circumferential surface of the central axial through-bore 15 of the armature 14, here, for example, in the form of a press fit.

[0053] Here, the second valve body 17 preferably carries a second flexible sealing element 36 made of an elastomer, which seals against the second valve seat 12 when the outlet valve is closed. For this purpose, the second valve body 17 can be designed, in particular, as a compressed air-permeable cage in which the second sealing element 36 is then held, wherein the end face of the second sealing element 36 facing the second valve seat 12, which interacts with the second valve seat 12, is left free of the cage.

[0054] Against this background, the functioning of the pressure control valve 1 is as follows: When the solenoid coil is de-energized, no magnetic force is exerted on the armature 14, whereby the pressure control valve 1 or The armature 14 then Fig. 1 shown ventilation position, in which the armature 14 is prestressed by the spring force of the first spring 18 in the direction of the second valve seat 12, in Fig. 1downwards. Then, the second valve body 17, and more precisely its central second sealing element 36, sits as the second radially inner section 30 on the second valve seat 12, whereby the outlet valve is closed and then no venting can take place. Because in this position the at least one second axial through-opening 27 of the second valve body, here for example in the form of the radially outer slots, is arranged radially outside with respect to the second radially inner section 30 of the second valve body 17, no flow connection is possible between the compressed air vent connection 5 and the compressed air outlet connection 4.

[0055] On the other hand, the inlet valve is then open because the first valve body 16 is lifted off the first valve seat 10. Consequently, compressed air present at the compressed air supply connection 3, for example a brake pressure of a compressed air-operated brake system of a vehicle, can pass via the stepped bore 9 to the first valve seat 10 and from there via the permanent axial compressed air connection 25, namely the radially outer grooves of the first sealing element 35, the annular gap 34 in the central axial through-bore 15 of the armature 14 and the radially outer slots of the second valve body 17 to the compressed air outlet connection 4 and from there to a consumer, here for example to a diaphragm valve of a pressure control device for brake slip-dependent control or regulation of the brake pressure.

[0056] By electrical excitation of the magnetic coil 20 and the magnetic force generated thereby, the armature 14 is moved against the force of the first spring 18 along the longitudinal axis 6 in such a way that the electromagnetic pressure control valve 1 or the armature 14 Fig. 3, in which the compressed air outlet connection 4 is connected to the compressed air vent connection 5. In detail, the first valve body 16 is then pressed with its first radially inner section 28 against the first valve seat 10 and closes it, so that no more compressed air can flow in from the compressed air supply connection 3. The first valve body 16, which is tensioned against the radially inner collar 19 by the spring force of the second spring 32, can lift off from the radially inner collar 19 and move towards the second valve body 17. The spring force of the second spring 32 acting on the first valve body 16, which is mounted axially displaceably in the direction of the longitudinal axis 6, in combination with the elastic behavior of the first sealing element 35, thus ensures that an axial elasticity is created, by means of which the stop of the first valve body 16 orof the first sealing element 35 is stabilized on the first valve seat 10.

[0057] Because in this position the at least one first axial through-opening 26 of the first valve body 16, here for example in the form of the radially outer grooves, is arranged radially outside with respect to the first radially inner section 28 of the first valve body 16, no flow connection is possible between the compressed air supply connection 3 and the central axial through-bore 15 of the armature 14.

[0058] In the electromagnetic pressure control valve 1, the armature 14 is therefore axially actuatable depending on an electrical excitation or de-excitation of the magnetic coil 20 between the ventilation position, in which the second valve body 17 seals against the second valve seat 12, but the first valve body 16 is lifted from the first valve seat 10 (inlet valve open, outlet valve closed) and a venting position, in which the first valve body 16 seals against the first valve seat 10, but the second valve body 17 is lifted from the second valve seat 12 (inlet valve closed, outlet valve open).

[0059] As already indicated above, the pressure control valve 1 is preferably a component of a pressure control valve device (not otherwise shown here) for a compressed air-operated vehicle brake system, which is particularly designed to control a brake pressure as a function of brake slip and which, in addition to at least one electromagnetic pressure control valve 1 described above, comprises at least one diaphragm valve pneumatically pilot-controlled by the electromagnetic pressure control valve 1.

[0060] In the electromagnetic pressure control valve 1, the compressed air supply port 3 is connected to a (brake) pressure-generating device, for example, a foot brake valve, a foot brake module, or a pressure control module; the compressed air output port 4 is connected to the pneumatically pilot-controlled diaphragm valve for piloting the diaphragm valve; and the compressed air vent port 5 is connected to a pressure sink. The pressure delivered by the electromagnetic pressure control valve 1 at its compressed air output port 4 then acts in particular on a diaphragm of the diaphragm valve, for example, to lift it from a diaphragm valve seat or to tighten it sealingly against the diaphragm valve seat.

[0061] The excitation and de-excitation of the magnetic coil 20 is then carried out, for example, by an electronic ABS control unit in which ABS or brake slip control routines are implemented in order to modulate the pressure output at the compressed air output connection 4 depending on the brake slip, for example by alternately setting the electromagnetic pressure control valve 1 from the venting position to the ventilation position and vice versa, ie by repeatedly raising and lowering the pressure. LIST OF REFERENCE SYMBOLS

[0062] 1 Pressure control valve 2 Housing 3 Compressed air supply connection 4 Compressed air output connection 5 Compressed air exhaust connection 6 Longitudinal axis 7 Blind hole 8 Insert 9 Stepped bore 10 First valve seat 11 Stepped bore 12 Second valve seat 13 Chamber 14 Armature 15 Central through-bore 16 First valve body 17 Second valve body 18 First spring 19 Radial inner collar 20 Solenoid coil 21 Radial outer recess 22 Solenoid coil housing 23 Connections 24 Arrows 25 Compressed air connection 26 First axial through-hole 27 Second axial through-hole 28 First radial inner section 29 First radial outer section 30 Second radial inner section 31 Second radial outer section 32 Second spring 33 Step 34 Annular gap 35first sealing element 36second sealing element

Claims

1. An electromagnetic pressure control valve (1) for controlling an air pressure, with a) a housing (2) which has a compressed air supply connector (3) for connection to a compressed air supply, a compressed air outlet connector (4) for connection to a load, and a compressed air ventilating connector (5) for ventilation, and with b) an armature (14) which, on its end sides which face away from one another, supports in each case one valve body, a first valve body (16) and a second valve body (17), and which can be displaced within the housing (2) by way of magnetic forces counter to a spring force of at least one first spring (18), in such a way that it connects the compressed air outlet connector (4) selectively to the compressed air supply connector (3) or the compressed air ventilating connector (5), and with c) a first valve seat (10) which is connected to the compressed air supply connector (3), and with d) a second valve seat (12) which is connected to the compressed air ventilating connector (5), wherein e) the first valve body (16) forming, together with a first valve seat (10), an inlet valve, and the second valve body (17) forming, together with the second valve seat (12), an outlet valve, characterized by f) a permanent axial compressed air connection (25) through the first valve body (16), through the interior of the armature (14) and through the second valve body (17), which compressed air connection comprises at least one central axial through bore (15) of the armature (14), at least one first axial through opening (26) in the first valve body (16), and at least one second axial through opening (27) in the second valve body (17), wherein g) the first valve body (16) having a first radially inner portion (28) which closes the first valve seat (10) sealingly when the inlet valve is closed, and a first radially outer portion (29) which has the at least one first axial through opening (26), and wherein h) the second valve body (17) having a second radially inner portion (30) which closes the second valve seat (12) sealingly when the outlet valve is closed, and a second radially outer portion (31) which has the at least one second axial through opening (27).

2. The electromagnetic pressure control valve as claimed in claim 1, characterized in that the permanent axial compressed air connection (25) conducts compressed air from the compressed air supply connector (3) into the compressed air outlet connector (4) when, in the case of an open inlet valve, the first valve body (16) is lifted from the first valve seat (10) and, in the case of a closed outlet valve, the second valve body (17) is seated sealingly on the second valve seat (12).

3. The electromagnetic pressure control valve as claimed in either of the preceding claims, characterized in that the first valve body (16) is a first separate body which is received within the central axial through bore (15) of the armature (14).

4. The electromagnetic pressure control valve as claimed in one of the preceding claims, characterized in that the first valve body (16) is received axially displaceably within the central axial through bore (15) of the armature (14).

5. The electromagnetic pressure control valve as claimed in one of the preceding claims, characterized in that the second valve body (17) is a second separate body and is received in an axially fixed and non-rotational manner in the central axial through bore (15) of the armature (14).

6. The electromagnetic pressure control valve as claimed in claims 4 and 5, characterized in that the first valve body (16), which is mounted axially displaceably in the central axial through bore (15) of the armature (14), is supported axially on the second valve body (17) by way of at least one second spring (32).

7. The electromagnetic pressure control valve as claimed in one of the preceding claims, characterized in that the first valve body (16) forms or supports a first flexible sealing element (35) which is made from at least one elastomer and seals against the first valve seat (10) when the inlet valve is closed.

8. The electromagnetic pressure control valve as claimed in one of the preceding claims, characterized in that the second valve body (17) forms or supports a second flexible sealing element (36) which is made from at least one elastomer and seals against the second valve seat (12) when the outlet valve is closed.

9. The electromagnetic pressure control valve as claimed in one of the preceding claims, characterized in that the first radially outer portion (29) of the first valve body (16) and / or the second radially outer portion (31) of the second valve body (17) have / has at least one radially outer slot or at least one radially outer groove for the axial compressed air routing.

10. The electromagnetic pressure control valve as claimed in one of the preceding claims, characterized in that at least one electric magnet coil (22) is received in the housing (2), wherein it is possible for the armature (14) to be actuated axially in a manner which is dependent on an electric excitation or de-energization of the at least one magnet coil (14) between a first axial position, in which the second valve body (17) seals against the second valve seat (12) and the first valve body (16) is lifted from the first valve seat (10), and a second axial position, in which the first valve body (16) seals against the first valve seat (10) and the second valve body (17) is lifted from the second valve seat (12).

11. The electromagnetic pressure control valve as claimed in claim 10, characterized in that it a) is configured as a "normally open" pressure control valve, in the case of which, when the magnet coil (20) is not energized, the inlet valve is open and the outlet valve is closed, or b) is configured as a "normally closed" pressure control valve, in the case of which, when the magnet coil (20) is not energized, the inlet valve is closed and the outlet valve is open.

12. A pressure control valve device for compressed air-actuated vehicle brake systems, which pressure control valve device is configured, in particular, such that it controls a brake pressure in a manner which is dependent on brake slip, comprising at least one pneumatically pilot-controllable diaphragm valve, characterized in that it comprises at least one electromagnetic pressure control valve (1) as claimed in at least one of the preceding claims, in the case of which the compressed air supply connector (3) is connected to an apparatus which generates the brake pressure, the compressed air outlet connector (4) is connected to the at least one pneumatically pilot-controllable diaphragm valve for pilot-controlling the at least one diaphragm valve, and the compressed air ventilating connector (5) is connected to a pressure sink.

13. A compressed air-actuated vehicle brake system, characterized in that it comprises at least one pressure control valve device as claimed in claim 12.