DE102010007407A1 - Pressure control valve assembly - Google Patents

Abstract

The invention relates to a pressure control valve arrangement (7) for controlling the fluid pressure in a pressure-operated and slip-controlled brake system of a vehicle, the brake pressure being increased, held or reduced in at least one brake cylinder (6) as part of the brake slip control, with a) in a housing (21 ) the pressure control valve arrangement (7) two diaphragm valves (14a, 14b), a holding diaphragm valve (14a) and an outlet diaphragm valve (14b) as well as two electromagnetic pilot valves (15a, 15b) which can be controlled by an electronic control device (10) for piloting the diaphragm valves (14a, 14b) are provided, b) the two electromagnetic pilot valves (15a, 15b) each have a solenoid coil (19a, 19b) and with solenoid valve seats (20a, 20b, 29a, 29b) which cooperate and by energizing the solenoid coils (19a, 19b) ) have magnetic armatures (22a, 22b) which can be actuated against spring means (17a, 17b), c) the magnetic armature (22a) of the holding diaphragm valve (14a) ordered electromagnetic pilot valve (15a) by energizing the solenoid coil (19a) against a solenoid valve seat (20a) of the solenoid valve seats (20a, 29a) is pushed, which can be pressurized by opening the holding diaphragm valve (14a) chamber (26a) in the housing (21) connects with a pressure sink (27a). The invention provides that d) due to the magnet armature (22a) of the electromagnetic pilot valve (15a) associated with the holding diaphragm valve (14a) being pushed against the solenoid valve seat (20a) when the solenoid (19a) is energized, a pressure medium flow along the chamber (26a) Bypass means (31) enabling at least part of the magnet coil (19a) as far as the pressure sink (27a) are provided, e) the bypass means (31) are designed such that the volume flow of the pressure medium flow is smaller than an upper limit volume flow through which the holding diaphragm valve (14a) can be switched from a closed position to an open position.

Description

The invention relates to a pressure control valve arrangement for controlling the fluid pressure in a fluid-actuated and slip-controlled brake system of a vehicle such that in the context of the brake slip control, the brake pressure is increased, maintained or lowered in at least one brake cylinder, according to the preamble of claim 1.

A slip-controlled braking system such as ABS (anti-lock braking system) prevents the wheels from locking and is activated when a greater adhesion is claimed between a tire and the road surface than is transferable. D. H. when overbraking by the driver. When overbraking recognizes the central electronic control unit of the ABS brake system from speed sensor signals the tendency to lock one or more wheels and calculates the control of the force acting on the associated brake cylinder pressure control valve assembly. The brake pressure is then adjusted by means of the pressure control valve assembly by pressure sinks, pressure holding or pressure risers in accordance with the wheel behavior and thus the friction conditions between the tire and the road to an optimal slip.

ABS pressure control valve assemblies without relay effect are used in vehicles such as commercial vehicles, buses, semitrailer tractors and trailers. Pressure control valve assemblies without relay effect usually have 3/2-way solenoid valves as pilot valves of diaphragm valves, an electronic control device controls the 3/2-way solenoid valves to the necessary functions for ABS operation "hold pressure", "pressure sinks" and " Drucksteigern ". During braking without response of the ABS (no tendency to lock a wheel) flows through the pressure medium, usually air when bleeding and bleeding the brake cylinder, the pressure control valve assemblies unhindered in both directions. This ensures that the function of the service brake system is not influenced by the ABS pressure control valve arrangement.

Pressure control valves of the generic type as 1-channel pressure control valves for anti-lock systems of motor vehicles have within the housing depending on a diaphragm valve as a holding valve and as an outlet valve and an electromagnetic control valve for the membrane holding valve and the membrane outlet valve. The two diaphragm valves each contain a membrane which can be acted upon by the pressure in a pilot control chamber, and the electromagnetic control valves each have an armature which can be actuated by means of an electric solenoid and which cooperates with two solenoid valve seats in each case.

A generic pressure control valve assembly of an ABS brake system is for example from the EP 0 266 555 A1 or from the DE-A 28 55 876 known. In the operating mode "pressure hold", that is, when the pressure set by the pressure control valve set brake pressure is maintained, the solenoid of the membrane holding valve associated electromagnetic pilot valve is energized, whereby the armature of the pilot valve is urged sealingly against the action of spring means against the associated solenoid valve seat.

The problem is that for a longer "pressure holding" as it is necessary, for example, in the context of a long downhill or ACC (Adaptive Cruise Control) to keep the distance to a vehicle in front and braking, the magnetic coil of the retaining diaphragm valve associated Pilot valve must be constantly energized, which brings a certain temperature load of the solenoid with it. This overheating can lead to damage to the solenoid, which is why from practice the ABS control unit only allows a certain maximum drive or energization time of the solenoid coil. If this maximum activation time is exceeded, then the energization of the magnetic coil is stopped, whereby the pressure-maintaining state can not be maintained, however. Only when the solenoid has cooled down after a time known from experience, it is powered by the ABS control unit again.

The invention has the object of providing a pressure control valve arrangement of the type mentioned in such a way that the temperature load of the solenoid coil of the retaining diaphragm valve associated pilot valve is reduced during energization.

This object is achieved by the features of claim 1.

Disclosure of the invention

The invention solves this problem by proposing, on the one hand, that a pressure medium flow from the chamber along at least a portion of the magnetic coil to the pressure sink enabling bypassing means are provided by energized by energizing the solenoid against the solenoid valve seat armature of the holding diaphragm valve associated electromagnetic pilot valve ,

Of the two solenoid valve seats, with which the magnet armature of the membrane holding valve associated control valve cooperates, while the solenoid valve seat is affected, against which the armature is urged sealingly by the energized solenoid in the state "pressure hold".

The arranged in the housing chamber is connected in the context of the function "pressure risers" by opening the holding diaphragm valve to the pressure medium connection and thereby pressurized or ventilated, whereby the chamber is set to a higher than atmospheric pressure brake pressure. This pressure or the amount of air generating this pressure is then enclosed in the chamber during the transition from the state of "pressure increase" to the state "pressure hold" during the closing of the membrane holding valve and can generate via the bypass means the pressure of the solenoid coil cooling fluid flow.

The by-pass means then effectively bridge the flow cross-section closed by the magnet armature sealingly abutting the magnet valve seat and thereby permit a flow of pressure medium along at least part of the magnet coil. Due to this pressure fluid flow, this magnetic coil is cooled in the state "pressure hold", in which the flow cross-section is actually closed by the solenoid valve seat. Due to this measure, on the one hand, the time duration of the energization of the solenoid coil and thus the duration can be extended, with which the pressure control valve assembly in the state "pressure hold" can be operated. Furthermore, the life of the solenoid increases.

On the other hand, the bypass means are designed such that the volume flow of the pressure medium flow is smaller than an upper limit volume flow through which the holding diaphragm valve is switchable from a closed position to an open position. This prevents the volume flow of the bypass flow from becoming so great that it can influence the (switching) state of the membrane holding valve. Because the volume flow of the bypass flow flowing through the bypass means to serve only the cooling of the magnetic coil of the diaphragm holding valve associated pilot valve.

The measures listed in the dependent claims advantageous refinements and improvements of claim 1 invention are possible.

Particularly preferably, the bypass means are formed by a trained on the circumference of the solenoid valve seat bypass channel so that remains at least partially open when sealed against the magnetic valve seat armature of the flow cross section of the bypass channel. Such a bypass channel on the circumference of the solenoid valve seat can be produced in a simple manner, in particular by a local recess on the circumference of the solenoid valve seat.

Further measures improving the invention will be described in more detail below together with the description of a preferred embodiment of the invention with reference to the drawing. In the drawing shows

1 a schematic diagram of an ABS brake system as a general diagram of a 4S / 4K ABS brake system of a vehicle,

2a a schematic representation of a brake cylinder controlling pressure control valve assembly in the state "pressure increase",

2 B a schematic representation of the pressure control valve assembly of 2a in the state "pressure lowering",

2c a schematic representation of the pressure control valve assembly of 2a in the state "pressure hold".

Description of the embodiment

According to 1 For example, a vehicle equipped with an ABS brake system has a front axle 1 and a rear axle 2 on. At the front axle 1 are wheels 3a and 3b arranged; the rear axle 2 For example, each has wheels equipped with twin tires 4a and 4b on. The braking of these wheels 3a . 3b and 4a . 4b Serving ABS brake system is designed here in the manner of a 4S / 4K system (four sensors, four channels). This means that here are a total of four speed sensors 5a - 5d and four pressure control valve assemblies 7a - 7d be available. The pressure control valve assemblies 7a - 7d serve to control each associated brake cylinders 6a - 6d , About a branching pneumatic brake pressure line 8th stand all pressure control valve arrangements 7a - 7d with a foot brake valve 9 in connection.

The driver generates when the foot brake valve 9 a brake pressure via the pneumatic brake pressure line 8th the pressure control valve assemblies 7a - 7d passing to the wheels 3a . 3b as well as the wheels 4a . 4b associated brake cylinders 6a - 6d is forwarded.

The pressure control valve assemblies 7a - 7d are about integrated, in 2a . 2 B and 2c shown solenoid valves 15a . 15b controllable and are for this purpose with a central electronic control unit, in particular an ABS control device 10 electrically connected.

On the input side is the electronic control unit 10 with the four speed sensors determining the wheel speeds 5a - 5b in connection. In case of blocking a wheel 3a - 3d That is, when an optimal brake slip is exceeded, according to an ABS control in accordance with the electronic control unit 10 that of the driver via the foot brake valve 9 controlled brake pressure through the corresponding pressure control valve assembly 7a - 7d reduced until the blocking is eliminated. The ABS brake system of the present embodiment further includes an ASR function, which is an ASR unit 11 to reduce engine torque like an ASR solenoid valve 12 and a shuttle valve 13 includes.

The according to 2a in the context of the ABS brake system used for the purpose of ABS control pressure control valve assembly 7 is constructed here in the manner of a 1-channel pressure control valve assembly and consists essentially of two integrated diaphragm valves 14a and 14b and two of these driving, by spring elements 17a . 17b in one of two closing directions biased solenoid valves 15a . 15b , membrane 18a . 18b the diaphragm valves 14a and 14b are each by spring elements 16a . 16b loaded in the single closing direction and are via the respective associated solenoid valves 15a and 15b pilot. From the diaphragm valves 14a . 14b one is a holding or inlet diaphragm valve 14a and the other an outlet diaphragm valve 14b ,

A housing 21 the pressure control valve assembly 7 also has a pressure medium connection 23 for pressurizing and / or depressurizing the pressure control valve arrangement 7 as well as in work connection 24 for connecting the brake cylinder 6 on. The pressure medium connection 23 is like 2a to 2c show, over the brake pressure line 8th with the foot or service brake valve 9 the pressure medium-operated braking device connected and is in accordance with an operation of the foot brake valve 9 aerated or vented.

How best in detail 2c shows, the two solenoid valves 15a . 15b one solenoid each 19a . 19b on, by energizing the magnetic coils 19a . 19b with solenoid valve seats 20a . 20b respectively. 29a . 29b the solenoid valves 15a . 15b cooperating armature 22a . 22b be operated as valve closing members. This act the magenta tanker 22a . 22b depending on the switching position, each with two solenoid valve seats 20a . 20b respectively. 29a . 29b together.

This will be the armature 22a . 22b due to the bias of the spring means 17a . 17b in the de-energized state of the magnetic coils 19a . 19b against the upper solenoid valve seats 29a . 29b pressed. The spring means 17a . 17b clamp the armature 22a then in particular in one of the lower solenoid valve seat 20a lifted position before, in which a flow cross-section is released, the one in the housing 21 trained chamber 26a with a pressure sink 27a in the form of a vent connection connects. When the solenoid coils are energized 19a . 19b become the armature 22a . 22b against the action of the spring means 17a . 17b against the lower solenoid valve seats 20a . 20b crowded.

The chamber 26a comes with the pressure medium connection 23 and thus with the foot brake valve 9 connected when the diaphragm 18a the holding diaphragm valve 14a from its associated diaphragm valve seat 28a takes off. The work connection 24 and thus the brake cylinder 6 device with another pressure sink 30 in conjunction, if the membrane 18b the outlet diaphragm valve 14b from its associated diaphragm valve seat 28b takes off.

The pressure control valve arrangement 7 is in 2a shown in its open position, in which a pressure build-up to the connected brake cylinder 6 takes place ("pressure increase"). This is none of the solenoid valves 15a and 15b electrically controlled. In the position shown presses the foot brake valve 9 Coming compressed air designed as an inlet or holding valve diaphragm valve 14a on, ie due to the on the right effective surface of the membrane 18a from the connection 23 forthcoming brake pressure is this from the diaphragm valve seat 28a against the action of the spring means 16a lifted. By in its spring-loaded basic position against the upper solenoid valve seat 29a closed solenoid valve 15a prevents the associated retaining diaphragm valve 14a is closed again. By opened in its spring-loaded basic position second solenoid valve 15b is the one of the foot brake valve 9 upcoming brake pressure on the diaphragm 18b the outlet diaphragm valve 14b from the right and urges them against their diaphragm valve seat 28b , which makes the outlet diaphragm valve 14b remains closed. Thus, the pressurized air under brake pressure passes unhindered through the pressure control valve assembly 7 , In this the compressed air passing state is the pressure control valve assembly 7 even if there is no ABS control.

Starting from the in 2a shown state "pressure risers" is to keep constant the brake pressure in a brake cylinder 6a to 6d ("Pressure hold") according to 2c only the magnetic coil 19a of the solenoid valve 15a to energize. The solenoid valve 15b on the other hand, it remains de-energized, whereby the outlet-side diaphragm valve 14b remains closed. By energizing the solenoid 19a of the solenoid valve 15a raises its armature 22a from the upper solenoid valve seat 29a against the action of the spring means 17a and pushes against the lower solenoid valve seat 20a , Then there is the foot brake valve 9 over the initially still open retaining diaphragm valve 14a zoomed brake pressure in a housing 21 trained chamber 26a on and on the membrane 18a also act from the left side. Now the pressure is on the right and left sides of the membrane 18a of the diaphragm valve 14a same size. But because the effective area on the left side of the membrane 18a larger, becomes the holding diaphragm valve 14a closed, ie the membrane 18a goes against the diaphragm valve seat 28a crowded. The pressure control valve arrangement 7 closes to keep the pressure constant so that of the foot brake valve 9 to the brake cylinder 6 extending pneumatic brake pressure line 8th ,

It is the foot brake valve 9 brought brake pressure but still in the now closed chamber 26a at. In the area of the lower solenoid valve seat 20a against which the armature 22a of the solenoid valve 15a in the energized state of the solenoid 22a is crowded, is a bypass channel 31 formed, through which a compressed air flow from the chamber 26a along at least part of the magnetic coil 19a of the membrane holding valve 14a associated solenoid valve 15a to the pressure sink 27a can flow. This compressed air flow can then be under current solenoid coil 19a cool.

The bypass channel 31 bypasses the through the solenoid valve seat 20a sealingly fitting armature 22a closed flow cross section and allows a flow of compressed air along at least part of the magnetic coil 19a , preferably along its entire longitudinal extension and parallel to it, as indicated by the arrow 32 in 2c is indicated.

On the other hand, the bypass channel 31 executed in particular in terms of its cross-section such that the volume flow of compressed air flow through the bypass channel 31 is less than an upper limit flow rate through which the holding diaphragm valve 14a could be switched from its closed position back to its open position. Because due to the bypass channel 31 through and to the pressure sink 27a flowing compressed air decreases the pressure in the chamber 26a and thus also the pressure on the left active surface of the membrane 18a the holding diaphragm valve 14a , This prevents the volume flow of the bypass flow from becoming so great that it influences the (switching) state of the membrane holding valve 14a is able to take. Because the volume flow through the bypass channel 31 flowing bypass flow is intended solely for cooling the solenoid coil 19a serve. The bypass channel 31 is preferred at the periphery of the solenoid valve seat 20a formed and parallel to the central axis of the magnet armature 22a or to the coil 19a , and despite that against the solenoid valve seat 20a sealing magnet armature 36a open a certain flow cross-section.

According to 2 B is a pressure reduction ("pressure drop") in the brake cylinder 6 achieved by both solenoid valves 15a and 15b be energized. For the solenoid valve 15a and the associated holding diaphragm valve 15a the same applies to the pressure maintenance described above. On the other hand, the magnet armature 22b the other solenoid valve 15b because of the energization of its magnetic coil 19b against the action of the spring means 17b from the lower solenoid valve seat 20b lifted and against the upper solenoid valve seat 29b crowded. Therefore, the pressure in the chamber decreases 26b , so that from the brake cylinder 6 coming pressure the diaphragm 18b the outlet diaphragm valve 14b from the diaphragm valve seat 28b can take off, leaving the work connection 24 and thus the brake cylinder 6 for venting with the pressure sink 30 is connected.

The functions of the pressure control valve arrangement described above 7 be in accordance with the electronic control unit 10 carried out in the context of an ABS / ASR regulation in the sense described above.

LIST OF REFERENCE NUMBERS

1

Front

2

rear axle

3

wheel

4

wheel

5

Speed sensor

6

brake cylinder

7

Pressure control valve assembly

8th

Brake pressure line

9

foot brake valve

10

control unit

11

ASR unit

12

ASR solenoid valve

13

shuttle valve

14a / b

diaphragm valve

15a / b

Solenoid valve

16a / b

spring element

17a / b

spring element

18a / b

membrane

19a / b

solenoids

20a / b

Solenoid valve seats

21

casing

22a / b

armature

23

Pressure medium connection

24

working port

26a / b

chamber

27a / b

pressure sink

28a / b

Membrane valve seat

29a / b

Solenoid valve seat

30

pressure sink

31

bypass channel

32

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QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 0266555 A1 [0005]
• DE 2855876 A [0005]

Claims (6)

Pressure control valve arrangement ( 7 ) for controlling the fluid pressure in a fluid-operated and slip-controlled brake system of a vehicle, wherein in the context of the brake slip control of the brake pressure in at least one brake cylinder ( 6 ), held or lowered, wherein a) in a housing ( 21 ) of the pressure control valve arrangement ( 7 ) two diaphragm valves ( 14a . 14b ), a holding diaphragm valve ( 14a ) and an outlet diaphragm valve ( 14b ) and two from an electronic control device ( 10 ) controllable electromagnetic pilot valves ( 15a . 15b ) for pilot controlling the diaphragm valves ( 14a . 14b ), b) the two electromagnetic pilot valves ( 15a . 15b ) one magnet coil each ( 19a . 19b ) as well as with magnetic valve seats ( 20a . 20b . 29a . 29b ) acting together and by energizing the magnetic coils ( 19a . 19b ) against spring means ( 17a . 17b ) actuatable armature ( 22a . 22b ), c) the armature ( 22a ) of the holding diaphragm valve ( 14a ) associated electromagnetic pilot valve ( 15a ) by energizing the magnetic coil ( 19a ) against a solenoid valve seat ( 20a ) of the solenoid valve seats ( 20a . 29a ), which one by opening the holding diaphragm valve ( 14a ) pressurizable chamber ( 26a ) in the housing ( 21 ) with a pressure sink ( 27a ), characterized in that d) by energizing the magnetic coil ( 19a ) against the solenoid valve seat ( 20a ) urged magnet armature ( 22a ) of the holding diaphragm valve ( 14a ) associated electromagnetic pilot valve ( 15a ) a pressure medium flow from the chamber ( 26a ) along at least a part of the magnetic coil ( 19a ) to the pressure sink ( 27a ) enabling by-pass means ( 31 ), e) the bypass means ( 31 ) are designed such that the volume flow of the pressure medium flow is smaller than an upper limit volume flow through which the holding diaphragm valve ( 14a ) is switchable from a closed position to an open position. Pressure control valve arrangement according to claim 1, characterized in that the bypass means by a at the periphery of the solenoid valve seat ( 20a ) trained bypass channel ( 31 ) are formed such that when against the solenoid valve seat ( 20a ) urged magnet armature ( 22a ) the flow cross-section of the bypass channel ( 31 ) remains at least partially open. Pressure control valve arrangement according to claim 1 or 2, characterized in that the housing ( 21 ) at least one pressure medium connection ( 23 ) for pressurization or depressurization and at least one working connection ( 24 ) for connection to the brake cylinder ( 6 ) having. Pressure control valve arrangement according to claim 3, characterized in that the pressure medium connection ( 23 ) for connection to an operating or foot brake valve ( 9 ) is provided a pressure medium-operated braking device of the vehicle. Pressure control valve arrangement according to claim 3 or 4, characterized in that in the housing ( 21 ) arranged chamber ( 26a ) by opening the membrane holding valve ( 14a ) with the pressure medium connection ( 23 ) connected is. Brake-slip-controlled and pressure-medium-actuated brake device of a vehicle, comprising at least one pressure control valve arrangement ( 7 ) according to any one of the preceding claims.

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