Patent ID: 12214761

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the drawings, the same reference numerals and/or characters are used for identical or similar parts or parts having an identical or similar function.

An electropneumatic parking-brake valve unit1has a first supply connection2, via which the electropneumatic parking-brake valve unit1receives supply pressure pV. The supply pressure pV can be provided by a compressed-air supply (not shown) or can come directly from the air-conditioning unit. The electropneumatic parking-brake unit1furthermore has at least one spring brake connection6for the connection of at least one spring brake cylinder (not shown here). More than one spring brake cylinder can also be connected to the spring brake connection6, namely in particular two or four, which are provided at a rear axle of the vehicle. The electropneumatic parking-brake valve unit1is configured to provide a spring brake pressure pF at the spring brake connection6. When a spring brake pressure pF is present, that is, when the spring brake connection6is aerated, the correspondingly connected spring brake cylinders are released; conversely, they are applied when the spring brake connection6is deaerated.

In order to provide the spring brake pressure pF, the electropneumatic parking-brake valve unit1has a parking-brake valve arrangement10. The parking-brake valve arrangement10has a plurality of valves, namely in particular a first bistable valve12. The first bistable valve12has a first and a second switching position, wherein the spring brake pressure pF is output or not output according to the switching positions of the first bistable valve12. The two switching positions of the first bistable valve12are stable, that is, they are also maintained in the de-energized state This is generally realized in that two corresponding end magnets are provided, which hold the armature in the end positions in a stable manner. The first bistable valve12has a first bistable-valve connection12.1, a second bistable-valve connection12.2and a third bistable-valve connection12.3. In the first switching position (shown inFIG.1), the first bistable-valve connection12.1is connected to the second bistable-valve connection12.2. In the second switching position (not shown inFIG.1), the second bistable-valve connection12.2is connected to the third bistable-valve connection12.3. The third bistable-valve connection12.3is connected to a deaerator5, which, as a central deaerator, forms the electropneumatic parking-brake valve unit1, or it can be provided separately therefrom. In the second switching position (not shown inFIG.1), the second bistable-valve connection12.2is therefore deaerated.

A pneumatically switchable holding valve14is connected between the first bistable valve12and the first supply connection2. The pneumatically switchable holding valve14has a first holding-valve connection14.1, a second holding-valve connection14.2, a third holding-valve connection14.3and a holding-valve control connection14.4. The holding valve is monostable and preloaded into the first switching position shown inFIG.1. In the first switching position (shown inFIG.1), the third holding-valve connection14.3is connected to the second holding-valve connection14.2. The third holding-valve connection14.3is in turn connected to a deaerator5, so that the second holding-valve connection14.2is deaerated. The second holding-valve connection14.2is connected to the first bistable-valve connection12.1. In the switching position shown inFIG.1, the first bistable-valve connection12.1is therefore connected to the deaerator5via the holding valve14, so that the second bistable-valve connection12.2is deaerated irrespective of the switching position of the first bistable valve12. The output of a spring brake pressure pF is not possible in this case. The spring brake connection6remains deaerated irrespective of the switching position of the first bistable valve12.

In order to bring the holding valve14into the second switching position (not shown inFIG.1), in which the first holding-valve connection14.1is connected to the second holding-valve connection14.2, wherein the first holding-valve connection14.1is connected to the supply connection2, a control valve20is provided according to the embodiment shown here. The control valve20is configured as an electrically switchable 3/2-way valve, which has a first control-valve connection20.1, a second control-valve connection20.2and a third control-valve connection20.3. The first control-valve connection20.1is connected to a pressure-conducting line22, which will be described in more detail below. The pressure-conducting line22conducts an operating pressure pD continuously during operation. The operating pressure pD is preferably only present when service brakes of the vehicle can also be supplied with pressure. In the first switching position (shown inFIG.1) of the control valve20, the third control-valve connection20.3is connected to the second control-valve connection20.2. The third control-valve connection20.3is connected to a or the deaerator5, the second control-valve connection20.2is connected to a first control-pressure line24, which is in turn connected to the holding-valve control connection14.4. This means that, in the first switching position (rest position) (shown inFIG.1), the holding-valve control connection14.4is deaerated and the holding valve14is consequently in the first switching position (shown inFIG.1). If the control valve20is now switched to the second position (not shown inFIG.1), in particular as a result of providing a first switching signal S1, the operating pressure pD is fed through by the control valve20and provided as a first control pressure p1at the holding-valve control connection14.4. As soon as this pressure exceeds a first threshold value, the holding valve14switches to the second switching position (not shown inFIG.2), in which the third holding-valve connection14.3is connected to the second holding-valve connection14.2so that the supply pressure pV is fed through the holding valve14by the first supply connection2and provided at the first bistable valve12.

The first bistable valve12and the holding valve14are part of a pilot unit30. The pilot unit30outputs a first pilot pressure pS1overall, which is then provided at a main valve unit40. In addition to the bistable valve12and the holding valve14, the pilot unit in the embodiment shown inFIG.1additionally has a first 2/2-way valve32. The 2/2-way valve32has a first 2/2-way valve connection32.1and a second 2/2-way valve connection32.2. The first 2/2-way valve connection32.1is connected to the first bistable valve12, more precisely to the second bistable-valve connection12.2. The 2/2-way valve32is pre-tensioned under a spring load into a first, open switching position (shown inFIG.1) and can be closed through energization. The second 2/2-way valve connection32.2is connected to a shuttle valve34via a corresponding pneumatic line33. The shuttle valve34is then in turn connected to a first relay valve42, which is part of the main valve unit40. The first pilot pressure pS1is provided at the main valve unit40by the pilot unit30via the shuttle valve34. The main valve unit40here consists of the first relay valve42.

The first relay valve42has a first relay-valve supply connection42.1, which, inFIG.1, is connected to a second supply connection4at which supply pressure is likewise provided. However, the first relay-valve supply connection42.1could equally be connected to the first supply connection2. Moreover, the first relay valve42has a first relay-valve working connection, at which the first relay valve42outputs the spring brake pressure pF. The first relay valve42furthermore has a first relay-valve deaeration connection42.3, which is connected to the deaerator5, and a first relay-valve control connection42.4, which receives the first pilot pressure pS1. The first relay valve42then outputs the spring brake pressure pF at a corresponding level based on the supply pressure pV in accordance with the receipt of the first pilot pressure pS1.

The shuttle valve34is also connected to a release connection50in addition to the pneumatic line33. A manual pressure pM can be supplied manually via the release connection50in order to be able to release the spring brakes in the event that the vehicle is parked and de-energized, that is, the spring brakes are engaged. The shuttle valve34is configured such that the higher pressure in each case, which is provided by the 2/2-way valve32or the release connection50, is fed through at the first relay-valve control connection42.4.

A return line16is furthermore provided in the pilot unit30. The return line16branches off directly downstream of the second holding-valve connection14.2and returns the pressure output by the holding valve14at the second holding-valve connection14.2back to the holding-valve control connection14.4. As a result, as soon as the holding valve14has switched to the second switching position (not shown inFIG.1), this switching position can be maintained. This means that, during operation of the vehicle, the second switching position assumed by the holding valve14is maintained so long as supply pressure pV is provided at the first supply connection2. During operation, the operation of the spring brakes can then only be regulated by the pilot unit30irrespective of the switching of the control valve20.

As is furthermore revealed inFIG.1, the pilot unit30is in particular controlled by a control ECU. The control ECU in particular provides a bistable signal SR at the bistable valve12, and a second switching signal S2at the 2/2-way valve32. The 2/2-way valve32can then be operated in particular in a pulsed manner in order to aerate or deaerate the spring brake connection6in a pulsed manner. The control valve20does not necessarily have to be controlled by the control ECU, but can be controlled by another or superordinate control unit. The switching signal S1can also be a derived switching signal, which is provided in particular by another module.

FIGS.2and3now illustrate an electropneumatic parking-brake module100, which also has a multi-circuit protection valve unit102in addition to an electropneumatic parking-brake valve unit1. Identical and similar elements are denoted by the same reference signs as the first embodiment. In this regard, please refer to the above description in its entirety and the differences will be explained in particular below.

The electropneumatic parking-brake valve unit1in turn has a spring brake connection6, at which the spring brake pressure pF can be output. The pilot unit30and the main valve unit40are configured identically to the first embodiment according toFIG.1. The pilot unit30more precisely includes the first bistable valve12, the holding valve14and the 2/2-way valve32. The main valve unit40includes the first relay valve42.

The supply pressure pV is provided via the multi-circuit protection valve unit102, which shall not be described in detail here. Multi-circuit protection valves are generally known. To provide the supply pressure pV, a first supply pressure line52branches off from the multi-circuit protection valve unit102and is connected to the first holding-valve connection14.1. The point at which the first supply pressure line52branches off forms the first supply connection2in this case. A second supply pressure line55further branches off from the multi-circuit protection valve unit102, which second supply pressure line leads to the first relay valve42, more precisely to the first relay-valve supply connection42.1. The second supply pressure line55branches off at a point which forms the second supply connection4.

In addition to several valves and various connections, the multi-circuit protection valve unit102also has an inlet104, which can be connected to the compressed-air conditioning system or the like. The multi-circuit protection valve unit102also has the control valve20, which, within the framework of the multi-circuit protection valve unit102, is used to enable a restricted return flow of dry regeneration air from the system volume during the regeneration phase of an air dryer. To this end, the control valve20can then be brought into the second switching position (not shown inFIG.2). However, since, in this case, the line22which generally conducts pressure is connected via the control valve20to the second control-valve connection20.2from which the first control-pressure line24branches, the first control pressure p1is provided at the holding valve14in the manner described above via this control-pressure line. The control valve20is controlled by the control ECU, which, in the embodiment shown inFIG.2, is provided both for the multi-circuit protection valve unit102and for the electropneumatic parking-brake valve unit1, so that they are controlled by the common control ECU.

FIG.3shows a further embodiment of the electropneumatic parking-brake module100. Identical and similar elements are denoted by the same reference signs as the previous embodiments, so please refer to the above description in its entirety. The difference with respect to the first embodiment of the electropneumatic parking-brake module100(FIG.2) is essentially described below.

The essential difference with respect to the embodiment according toFIG.2consists in that the electropneumatic parking-brake module100according toFIG.2is provided for utility vehicles without a trailer, and the electropneumatic parking-brake module100according toFIG.3is provided for utility vehicles with a trailer. In this regard, both the pilot unit30and the main valve unit40include a duplication of the necessary valves and the electropneumatic parking-brake module100furthermore includes a trailer connection8, at which a trailer pressure pT can be provided in order to release or apply spring brakes of the trailer. The provision of the trailer pressure pT takes place analogously to the provision of the spring brake pressure pF. To this end, the pilot valve30has a second bistable valve35and a second 2/2-way valve54, which are likewise connected in the manner of the first bistable valve12and the first 2/2-way valve32. The main valve unit40furthermore has a second relay valve44, which is likewise connected in the manner of the first relay valve42. It therefore has a second relay-valve supply connection44.1, which is likewise connected to the second supply pressure line55in the manner of the first relay-valve supply connection42.1. It moreover has a second relay-valve working connection44.2, which is connected to the trailer connection8, a second relay-valve deaeration connection44.3, which is connected to the deaerator5, and a second relay-valve control connection44.4, which is connected to the pilot unit30, more precisely to the second bistable valve35via the second 2/2-way switching valve54. The holding valve14is connected upstream of both the first bistable valve12and the second bistable valve35. With respect to the holding valve14, there is no further difference here in the control.

An electropneumatic parking-brake module100is now illustrated inFIG.4, which, in addition to the electropneumatic parking-brake valve unit1and possibly also the multi-circuit protection valve unit102(c.f.FIG.2,3), additionally includes a trailer control unit200. All three units, the electropneumatic parking-brake valve unit1, the multi-circuit protection valve unit102and the trailer control unit200, are integrated together in a module. For the sake of simplicity, the elements of the multi-circuit protection valve unit102are not shown inFIG.4. Identical and similar elements are in turn denoted by the same reference signs, so please refer to the above description in its entirety.FIG.4is a schematic illustration and the integration is represented in particular by the commonly provided control ECU. The differences with respect to the first embodiments are discussed below.

The significant difference consists in the trailer control unit200, which can be constructed in a manner which is fundamentally known. It has a trailer-control valve unit202with valves integrated therein, which shall not be described in detail here. The trailer control unit200moreover has a coupling head “brake”204, and a coupling head “supply”206. A control pressure for service brakes of the trailer is transferred via the coupling head “brake”204, whilst a supply pressure for the trailer is transferred via the coupling head “supply”206. The integration between the parking-brake valve unit1and the trailer control unit200is in particular advantageous when a so-called Scandinavian trailer control is to be implemented, or in the case of functionalities such as a trailer test position, anti-jackknife braking or additional braking. If spring brakes are used for particular functions in the tractor and the spring brake connection6is therefore deaerated, the service brakes shall be applied for such functionalities in trailers. To this end, the electropneumatic parking-brake valve unit1according to this fourth embodiment has a trailer valve56, which is connected downstream of the first relay valve42and is connected to a trailer control connection58. More precisely, the trailer valve56is configured as a 3/2-way valve and has a first trailer valve connection56.1, a second trailer valve connection56.2and a third trailer valve connection56.3. The first trailer valve connection56.1is connected to the first supply connection2via a supply branch line60. The second trailer valve connection56.2is connected to the trailer control connection. The third trailer valve connection56.3is connected to a second branch line62, which branches off between the first relay-valve working connection42.2and the spring brake connection6, that is, it provides the spring brake pressure pF at the third trailer valve connection56.3. Depending on the switching position of the trailer valve56, either the supply pressure pV or the spring brake pressure pF can therefore be provided at the trailer control connection. Via a trailer control line64, this pressure is then provided at the trailer control unit200, possibly inverted there, in order to then also brake service brakes of the trailer accordingly based on the engagement of spring brakes of the tractor.

It is understood that the foregoing description is that of the preferred embodiments of the invention and that various changes and modifications may be made thereto without departing from the spirit and scope of the invention as defined in the appended claims.

LIST OF REFERENCE SIGNS (PART OF THE DESCRIPTION)

1Electropneumatic parking-brake valve unit2First supply connection4Second supply connection5Deaerator6Spring brake connection8Trailer connection10Parking-brake valve arrangement12First bistable valve12.1First bistable-valve connection12.2Second bistable-valve connection12.3Third bistable-valve connection14Pneumatically switchable holding valve14.1First holding-valve connection14.2Second holding-valve connection14.3Third holding-valve connection14.4Holding-valve control connection16Return line20Control valve20.1First control-valve connection20.2Second control-valve connection20.3Third control-valve connection22Pressure-conducting line24First control-pressure line30Pilot unit32First 2/2-way valve32.1First 212-way valve connection32.2Second 2/2-way valve connection33Pneumatic line34Shuttle valve35Second bistable valve40Main valve unit42First relay valve42.1First relay-valve supply connection.42.2First relay-valve working connection42.3First relay-valve deaeration connection42.4First relay-valve control connection44Second relay valve44.1Second relay-valve supply connection44.2Second relay-valve working connection44.3Second relay-valve deaeration connection44.4Second relay-valve control connection50Release connection52First supply-pressure line54Second 2/2-way switching valve55Second supply pressure line56Trailer valve56.1First trailer valve connection56.2Second trailer valve connection56.3Third trailer valve connection58Trailer control connection60Supply branch line62Second branch line64Trailer control line100Electropneumatic parking-brake module102Multi-circuit protection valve unitpV Supply pressurepF Spring brake pressurepD Operating pressurep1First control pressurepS1First pilot pressurepT Trailer pressureS1First switching signal