Parking brake device for a motor vehicle

Abstract

A parking brake device for motor vehicles has at least one first parking brake unit and one second parking brake unit, wherein the first parking brake unit has at least one first compressed air connector, a first inlet-ventilation solenoid valve unit, a first relay valve, a spring brake valve and at least one first compressed air outlet. The first compressed air connector is connected to the first inlet-ventilation solenoid valve unit and the first relay valve. A first control line is provided in the first parking brake unit in such a way that the first relay valve is connected to the first inlet-ventilation solenoid valve unit, wherein the first control line has a first branch upstream of the first relay valve, and wherein a first outlet line is provided in the first parking brake unit, which first outlet line is connected to the at least one first compressed air outlet and has a first outlet branch. A spring brake line is provided in the first parking brake unit, which spring brake line is connected via a first branch to the first control line and via the first outlet branch to the outlet line. The first parking brake unit has a spring brake valve which is arranged in the spring brake line and is connected to the first relay valve, and a first throttle unit which is arranged in the spring brake line between the first outlet branch of the first outlet line and the first branch of the first control line.

Claims

1. A parking brake device for a motor vehicle, comprising: at least one first parking brake unit; and one second parking brake unit, wherein the first parking brake unit has at least one first compressed-air port, a first inlet ventilation solenoid valve unit, a first relay valve, a spring brake valve and at least one first compressed-air output, wherein the first compressed-air port is connected to the first inlet ventilation solenoid valve unit and to the first relay valve, wherein a first control line is provided in the first parking brake unit such that the first relay valve is connected to the first inlet ventilation solenoid valve unit, wherein the first control line has a first branching point upstream of the first relay valve, wherein a first output line is provided in the first parking brake unit, which first output line is connected to the at least one first compressed-air output and has a first output branching point, wherein a spring brake line is provided in the first parking brake unit, which spring brake line is connected via the first branching point to the first control line and via the first output branching point to the output line, wherein the first parking brake unit has a spring brake valve, which is arranged in the spring brake line and is connected to the first relay valve, and a first restrictor unit, which is arranged in the spring brake line between the first output branching point of the first output line and the first branching point of the first control line.

2. The parking brake device as claimed in claim 1, wherein the spring brake line connected to the first branching point and the first output branching point forms, via the first restrictor unit and the spring brake valve, a feedback connection between a control input and an output of the first relay valve.

3. The parking brake device as claimed in claim 1, wherein the spring brake valve is provided as a solenoid valve which is open when electrically deenergized.

4. The parking brake device as claimed in claim 1, wherein the first inlet ventilation solenoid valve unit is designed such that at least one first inlet solenoid valve is provided between the first compressed-air port and the first control line, and a first ventilation solenoid valve is provided between the first control line and a first ventilation output.

5. The parking brake device as claimed in claim 1, wherein the second parking brake unit has at least one second compressed-air port, a second inlet ventilation solenoid valve unit, a second relay valve and at least one further compressed-air output, the second compressed-air port is connected to the second relay valve, wherein a second control line is provided in the second parking brake unit such that the second relay valve is connected to the second inlet ventilation solenoid valve unit, the second control line has a second branching point upstream of the second relay valve, a second output line is provided in the second parking brake unit, which second output line is connected to the at least one further compressed-air output and has a second output branching point, a feedback line is provided in the second parking brake unit, which feedback line is connected via the second branching point to the second control line and via the second output branching point to the second output line, and the second parking brake unit has a second restrictor unit, which is arranged in the feedback line between the second output branching point of the second output line and the second branching point of the second control line.

6. The parking brake device as claimed in claim 5, wherein the second inlet ventilation solenoid valve unit is connected to the second compressed-air port.

7. The parking brake device as claimed in claim 5, wherein the feedback line connected to the second branching point and the second output branching point forms, via the second restrictor unit, a feedback connection between a control input and an output of the second relay valve.

8. The parking brake device as claimed in claim 5, wherein the second inlet ventilation solenoid valve unit is configured with at least one second inlet valve, one second ventilation valve and one second ventilation output such that the second inlet valve is provided so as to be connected to the second control line and a second ventilation valve is provided between the second control line and a second ventilation output.

9. The parking brake device as claimed in claim 8, wherein the first and second inlet valve are provided as solenoid valves which are closed when electrically deenergized.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows an exemplary embodiment of a parking brake device with a first and a second parking brake unit in a parked state;

(2) FIG. 2 shows the exemplary embodiment of a parking brake device with a first and a second parking brake unit in a switching state between a parked state and a driving state;

(3) FIG. 3 shows the exemplary embodiment of a parking brake device with a first and a second parking brake unit in a driving state;

(4) FIG. 4 shows the exemplary embodiment of a parking brake device with a first and a second parking brake unit in a switching state between a driving state and a parked state;

(5) FIG. 5 shows the exemplary embodiment of a parking brake device with a first and a second parking brake unit in a graduable braking state.

DETAILED DESCRIPTION OF THE DRAWINGS

(6) FIG. 1 shows, in a schematic illustration, a parking brake device 1 for a motor vehicle, in this case a utility vehicle.

(7) The parking brake device 1 has a first parking brake unit 1a for a tractor vehicle and a second parking brake unit 1b for a trailer.

(8) The first parking brake unit 1a and the second parking brake unit 1b are preferably used in combination with one another as a parking brake device 1.

(9) The first parking brake unit 1b has a first compressed-air port 10a, a first inlet ventilation solenoid valve unit 20a and a first relay valve 40a.

(10) The first relay valve 40a is provided with an input 43a, with an output or working output 44a, a control input 45a and a ventilation output 46a. The first compressed-air port 10a is connected to the input 40a of the first relay valve 40a.

(11) The first relay valve 40a constitutes a bistable element.

(12) In a manner dependent on the pressure at the control input 45a, it is possible at the output 44a of the first relay valve 40a to replicate different operating states of the first parking brake unit 1a in the form of air pressures, in particular a parked state, a driving state and a graduated braking state.

(13) In particular, the exemplary embodiment is illustrated in the parked state in FIG. 1.

(14) Furthermore, in the context of the first exemplary embodiment as per FIG. 1, it is also possible for a stretch-brake state to be provided.

(15) The first inlet ventilation solenoid valve unit 20a is provided with a first inlet valve 21a and a first ventilation valve 22a. As per FIG. 1, the first ventilation valve 22a has a first ventilation output 23a.

(16) The first inlet valve 21a and the first ventilation valve 22a are provided as 2/2 directional valves.

(17) The first inlet valve 21a first is configured to be closed when electrically deenergized. The first ventilation valve 22a is configured to be closed when electrically deenergized.

(18) The first compressed-air port 10a is connected to the first inlet input solenoid valve unit 20a, in particular to the first inlet valve 21a.

(19) The first compressed-air port 10a is in this case represented by a compressed-air source (not illustrated in any more detail) and by a depicted first check valve 11a.

(20) The first parking brake unit 1 is furthermore provided with a first control line 41a.

(21) The first control line 41a is connected to the first inlet ventilation solenoid valve unit 20a such that the first inlet valve 21a and the first ventilation valve 22a are connected independently of one another to the first control line 41a.

(22) The first control line 41 is connected to the control input 45a of the first relay valve 40a. A connection is thus available between the first inlet ventilation solenoid valve unit 20a and the first control input 45a of the first relay valve 40a.

(23) The first control line 41a has, upstream of the first relay valve 40a, a first branching point 42a.

(24) Furthermore, the first parking brake unit 1a has a spring brake line 51. The spring brake line 51 is connected via the first branching point 42a to the first control line 41a.

(25) There is thus a connection between the spring brake line 51 and the control input 45a of the first relay valve 40a.

(26) Furthermore, the spring brake line 51 is connected via a first output branching point 81a to a first output line 80a.

(27) The first output line 80a is connected to the output 44a of the first relay valve 40a, and likewise to at least one compressed-air output 71 and 72 of the first parking brake unit 1a.

(28) Thus, the spring brake line 51 is connected via the first output branching point 81a to the output or working output 44a of the first relay valve 40a.

(29) In this context, the spring brake line 51 forms a feedback connection between the output 44a and the control input 45a of the first relay valve 40.

(30) From the output 44a of the first relay valve 40a, compressed air can, as per FIG. 1, be conducted along the first output line 80a via a shuttle-type check valve 70 to a spring-loaded brake cylinder output 71 of the first parking brake unit 1a for the tractor vehicle of a motor vehicle.

(31) The shuttle-type check valve 70 is connected via the first output line 80a to the spring brake line 51, to the spring-loaded brake cylinder output 71 and to a service brake output 72 of the first parking brake unit 1a for a tractor vehicle.

(32) In this context, the spring-loaded brake cylinder output 71 and the service brake output 72 constitute compressed-air outputs of the first parking brake unit 1a.

(33) With regard to its switching behavior, the shuttle-type check valve 70 follows the prevailing pressure gradient.

(34) The shuttle-type check valve 70 is preferably provided as a so-called select-high valve.

(35) It is thus possible for the spring-loaded brake cylinder output 71 to be aerated with a high pressure of the output 44a of the first relay valve 40a, wherein the connection to the service brake output 72, at which a relatively low pressure prevails, is blocked.

(36) Furthermore, in the event of an actuation of the service brake and an associated pressure build-up at the service brake output 72, a transfer of compressed air from the service brake output 72 to the spring-loaded brake cylinder output 71 is possible via the shuttle-type check valve 70.

(37) If a higher pressure prevails at the service brake output 72 than at the output 44a of the first relay valve 40a, the shuttle-type check valve 70 opens a connection between the service brake output 72 and the spring-loaded brake cylinder output 71, in accordance with the pressure gradient.

(38) A combined braking action in the event of actuation of the service brake of the tractor vehicle at the service brake output 72 in combination with at least one spring-loaded brake cylinder of the tractor vehicle at the spring-loaded brake cylinder output 71 can be attained by means of the shuttle-type check valve 70.

(39) Furthermore, a spring brake valve 50 is arranged in the spring brake line 51. Thus, the spring brake valve 50 is connected to the control input 45a and to the output 44a of the first relay valve 40a.

(40) The spring brake valve 50 is switched into the electrically deenergized open position.

(41) In FIG. 1, the spring brake valve 50 is provided as a 2/2 directional valve.

(42) A first restrictor unit 52a is arranged in the spring brake line 51 between the first relay valve 40a and the first branching point 42a of the first control line 41a, in particular between the spring brake valve 50 and the first branching point 42a of the first control line 41a.

(43) In general, in the context of the present invention, it is preferably always provided that the first restrictor unit 52a and the spring brake valve 50 are arranged along the spring brake line 51 between the first branching point 41a of the first control line 41a and the first output branching point 81a of the first output line 80a.

(44) A connection of the first relay valve 40a, in particular of the output 44a, and of the shuttle-type check valve 70, in particular of the service brake output 72 and/or of the spring-loaded brake cylinder output 71, to the first control line 41a along the spring brake line 51 is controllable by means of the spring brake valve 50 and the first restrictor unit 52.

(45) By means of the spring brake line 51, which provides feedback and which has the first restrictor unit 52a and the spring brake valve 50, the fluid pressure or air pressure at the output 44a of the first relay valve 40a can be targetedly set and controlled in open-loop and/or closed-loop fashion.

(46) A first compressed-air sensor 73a is furthermore arranged between the spring brake valve 50 and the output 44a of the first relay valve 40a. The air pressure or fluid pressure at the output 44a of the first relay valve 40a can thus be targetedly controlled in open-loop and/or closed-loop fashion.

(47) Furthermore, in FIG. 1, the second parking brake unit 1b is shown.

(48) The second parking brake unit 1b has a second compressed-air port 10b, a second relay valve 40b and a second inlet ventilation solenoid valve unit 20b.

(49) The second compressed-air port 10b is represented here by a compressed-air source (not illustrated in any more detail) and a depicted second check valve 11b.

(50) In particular, in the context of the present invention, it may be provided that the first and second compressed-air port 10a and 10b are connected to a common compressed-air source.

(51) Alternatively, in the context of the present invention, it may be provided that the first and second compressed-air port 10a and 10b are formed as a common compressed-air port.

(52) The second inlet ventilation solenoid valve unit 20b is shown with a second inlet valve 21b, a second ventilation valve 22b and a second ventilation output 23b.

(53) The second ventilation input 23b may, as per FIG. 1, be provided so as to be integrated in the second ventilation valve 22b.

(54) The second inlet ventilation solenoid valve unit 20b is thus of similar configuration to the first inlet ventilation solenoid valve unit 20a.

(55) The second inlet valve 21b is preferably connected to the second compressed-air port 10b.

(56) Furthermore, the second parking brake unit 1b has a second control line 41b.

(57) The second inlet ventilation solenoid valve unit 20b and the second relay valve 40b are connected to one another via the second control line 41b.

(58) Like the first relay valve 40a, the second relay valve 40b has an input 43b, an output 44b, a control input 45b and a ventilation output 46b.

(59) The second control line 41b is connected to the control input 45b of the second relay valve 40b.

(60) The functioning of the first and second relay valve 40a; 40b is preferably identical.

(61) A second branching point 42b is provided in the second control line 41b upstream of the second relay valve 40b.

(62) Furthermore, the second parking brake unit 1b has a feedback line 53 which is connected via the second branching point 42b to the second control line 41b.

(63) The feedback line 53 is connected via a second output branching point 81b to a second output line 80b.

(64) The second output line 80b is connected to the output 44b of the second relay valve 40b.

(65) The feedback line 53 thus provides feedback from the output 44b of the second relay valve 40b via the second output line 80b, the second output branching point 81, the second branching point 42b and the control line 41b to the control input 45b of the second relay valve 40b.

(66) In the feedback line 53, a second restrictor unit 52b is arranged between the second output branching point 81b of the second output line 80b and the second branching point 42b of the second control line 41b.

(67) With the feedback line 53 and the second restrictor unit 52b, there is thus continuously feedback between the output 44b and the control input 45b of the second relay valve 40b.

(68) The second parking brake unit 1b furthermore has a trailer control output 74 as a further compressed-air output for connection to at least one spring-loaded brake cylinder of a trailer.

(69) In general, in the context of the present invention, it is preferably always provided that the second restrictor unit 52b is arranged along the feedback line 53 between the second branching point 42b of the second control line 41b and the second output discharge line 81b of the second output line 80b.

(70) A connection of the second relay valve 40b, in particular of the output 44b, and of the trailer control output 74 to the second control line 41b along the feedback line 53 is available via the second restrictor unit 52b.

(71) Furthermore, a second pressure sensor 73b is arranged along the second output line 80b. In this way, it is possible to detect a set pressure at the output 44b of the second relay valve 40b, which pressure can propagate to the trailer control output 74.

(72) The first parking brake unit 1a and the second parking brake unit 1b are thus substantially of similar construction to one another.

(73) The first parking brake unit 1a differs, as per FIG. 1, substantially by the arrangement of the spring brake valve 50 in the spring brake line 51 that provides feedback.

(74) Furthermore, substantial differences of the first parking brake unit 1a lie in the arrangement of the shuttle-type check valve 70 for the connection of the spring-loaded brake cylinder output 71 and of the service brake output 72 to the output 44a of the first relay valve 40a.

(75) The functioning of the parking brake device 1 as per FIGS. 1 to 5 will be discussed below.

(76) In a parked state (as illustrated in FIG. 1), the first and the second inlet valve 21a; 21b are switched into an electrically deenergized closed position. It is thus not possible for compressed air from the first compressed-air port 10a or from an external compressed-air source to pass into the first control line 41a or the second control line 41b.

(77) The spring brake valve 50 of the first parking brake unit 1a is switched into the electrically deenergized open position. There is thus feedback in each case between the output 44a; 44b and the control input 45a; 45b of the first and second relay valve 40a; 40b.

(78) Furthermore, compressed air is supplied to the input 43a; 43b of the first and second relay valve 40a; 40b.

(79) By virtue of the fact that no pressure prevails at the control inputs 45a; 45b of the first and second relay valve 40a; 40b, the respective ventilation outputs 46a; 46b are open.

(80) The spring brake line 51 and the feedback line 53 are ventilated via the ventilation outputs 46a; 46b.

(81) By means of the spring brake valve 50 switched into the electrically deenergized open position, the first control line 41a is also ventilated via the ventilation output 46a, and likewise the second control line 41b is ventilated via the ventilation output 46b.

(82) Thus, the spring-loaded brake cylinder output 71 of the first parking brake unit 1a and the trailer control output 74 of the second parking brake unit 1b are also ventilated. In this context, the spring-loaded brake cylinders of the tractor vehicle and of the trailer are activated and impart a braking force.

(83) The service brake output 72 of the first parking brake unit 1b is ventilated in the parked state. In this context, the service brake of the tractor vehicle is released.

(84) In order to move from a parked state to a driving state the first and the second inlet valve 21a; 21b are, as per FIG. 2, switched into an open or flow-conducting position relative to the parked state (as shown in FIG. 1).

(85) The spring brake valve 50 is shut off or switched into a closed position. The spring brake line 51 is shut off during the change of the operating state.

(86) Compressed air is introduced into the first and second control lines 41a; 41b through the inlet valves 21a; 21b switched into an open position. Via the control lines 41a; 41b, the control inputs 45a; 45b of the first and second relay valve 40a; 40b are aerated.

(87) If a threshold pressure is reached or overshot, a connection between the input 43a; 43b and the output 43a; 43b is produced in each of the relay valves 40a; 40b, such that compressed air is provided at the outputs 44a; 44b.

(88) If the threshold pressure is reached or overshot at the control inputs 45a; 45b, the ventilation outputs 46a; 46b of the first and second relay valve 40a; 40b are closed.

(89) In the first parking brake unit 1a, the high pressure of the output 44a is, in accordance with the prevailing pressure difference, conducted onward along the second output line 80b via the shuttle-type check valve 70 to the spring-loaded brake cylinder output 71.

(90) In the second parking brake unit 1b, the high pressure of the output 44b is conducted onward to the trailer control output 74.

(91) The spring-loaded brake cylinder output 71 and the trailer control output 74 are thus aerated. In this context, the parking brakes of the tractor vehicle and of the trailer are released, such that no braking force is imparted.

(92) By means of the spring brake valve 50 switched into a closed position, it is the case at least in the first parking brake unit 1a that no loss of compressed air occurs via the feedback connection in the form of the spring brake line 51. The spring-loaded brake cylinder output 71 can be aerated in a targeted and efficient manner.

(93) As soon as the spring-loaded brake cylinder output 71 and the trailer control output 74 have been adequately aerated, the first and the second inlet valve 21a; 21b are switched into a shut-off or closed position as per FIG. 3. The spring brake valve 50 is, as per FIG. 3, switched into an open or flow-conducting position.

(94) Thus, the trailer control output 74 and the spring-loaded brake cylinder output 71 are aerated. The service brake output 72 for a tractor vehicle is ventilated.

(95) In accordance with FIG. 3, a driving state of the motor vehicle, with a tractor vehicle and a trailer, is attained.

(96) In order to move from a driving state into a parked state again, the first and the second ventilation valve 22a; 22b are, as per FIG. 4, in relation to the driving state (as illustrated in FIG. 3), switched into an open or flow-conducting state, such that compressed air can exit via the first and second ventilation output 23a; 23b.

(97) The spring brake valve 50 is switched into a shut-off position.

(98) A high pressure of the first and second control line 41a; 41b connected to the control inputs 45a; 45b is dissipated or ventilated.

(99) By means of the decreasing pressure in the control inputs 45a; 45b, the respective connection between the inputs 43a; 43b and the outputs 44a; 44b of the first and second relay valve 40a; 40b is shut off. The ventilation outputs 46a; 46b are opened.

(100) A high pressure from the spring brake line 51 connected to the spring brake cylinder output 71 and from the feedback line 53 connected to the trailer control output 74 is ventilated via the ventilation outputs 46a; 46b.

(101) Owing to the continuously present feedback via the feedback line 53 with the second restrictor unit 52b, ventilation of the trailer control output 74 likewise occurs via the second ventilation valve 22b switched into an open position.

(102) As soon as the spring-loaded brake cylinder output 71 and the trailer control output 74 have been adequately ventilated, the ventilation valves 22a; 22b are switched into a closed position, as per the parked state in FIG. 1.

(103) Likewise, the spring brake valve 50 is moved into the electrically deenergized open switching state again.

(104) Thus, a parked state as per FIG. 1 with the ventilated spring-loaded brake cylinder output 71 and the ventilated trailer control output 74 is attained. The parking brakes of the tractor vehicle and of the trailer, in the form of spring-loaded brake cylinders, are activated and impart a corresponding braking action.

(105) Furthermore, proceeding from the driving state, a graduated braking state as per FIG. 5 can be implemented.

(106) The spring brake valve 50 is switched into a shut-off position in FIG. 5.

(107) Preferably, the inlet valves 21a; 21b and the ventilation valves 22a; 22b are switched into a partially open or flow-conducting position, in particular by means of multiple short successive actuations.

(108) Compressed air is thus introduced into the first and second control line 41a; 41b. The control inputs 45a; 45a of the first and second relay valve 40a; 40b are aerated with a specific pressure which lies between 0 bar and the maximum system pressure.

(109) The specific pressure is settable in a manner dependent on the degree of opening of the inlet valves 21a; 21b and of the ventilation valves 22a; 22b.

(110) On the basis of the specific pressure at the control inputs 45a; 45b, preferably proportional pressures are provided at the outputs 44a; 44b of the first and second relay valve 40a; 40b.

(111) The spring-loaded brake cylinder output 71 and the trailer control output 74 are, in accordance with FIG. 5, aerated such that a partial braking action of the tractor vehicle and of the trailer is applied.

(112) A graduated braking state with a partial braking action of the motor vehicle can be provided.

(113) In this context, it is possible for constant pressures to be held over a specific period of time, and varied in stepped fashion, at the outputs 44a; 44b of the first and second relay valve 40a; 40b.

(114) By virtue of the spring-loaded brake cylinder output 71 and the trailer control output 74 being aerated with temporarily constant pressures which are changed in stepped fashion, the braking action of the tractor vehicle and of the trailer can be varied in stepped fashion.

(115) Furthermore, it is also possible to implement a stretch-brake state with the exemplary embodiment in the context of FIGS. 1 to 5, in particular proceeding from a driving state as per FIG. 3. The switching into the operating state for the stretch-brake function is substantially based on the switching processes described above.

(116) The spring-loaded brake cylinder output 71 is preferably aerated in the stretch-brake state.

(117) The trailer control output 74 can be ventilated and aerated in accordance with demand, in particular by means of the second relay valve 40b connected to the second inlet ventilation solenoid valve unit 20b.

(118) It is thus possible for the trailer control output 74 to be aerated with compressed air in an expedient, in particular graduable, manner. A graduable braking action of the trailer is available in order to stretch and thereby stabilize the motor vehicle.

(119) In general, in the context of the present invention, advantageous switching between the operating states is thus attained by means of the first and second restrictor unit 52a; 52b and in particular by means of the spring brake valve 50 by virtue of the fact that the spring brake line 51, which provides feedback, can be shut off as required.

LIST OF REFERENCE DESIGNATIONS

(120) 1 Parking brake device 1a First parking brake unit 1b Second parking brake unit 10a First compressed-air port 10b Second compressed-air port 11a First check valve 11b Second check valve 20a First inlet ventilation solenoid valve unit 20b Second inlet ventilation solenoid valve unit 21a First inlet valve 21b Second inlet valve 22a First ventilation valve 22b Second ventilation valve 23a First ventilation output 23b Second ventilation output 40a First relay valve 40b Second relay valve 41a First control line 41b Second control line 42a First branching point 42b Second branching point 43a Input of the first relay valve 43b Input of the second relay valve 44a Output of the first relay valve 44b Output of the second relay valve 45a Control input of the first relay valve 45b Control input of the second relay valve 46a Ventilation output of the first relay valve 46b Ventilation output of the second relay valve 50 Spring brake valve 51 Spring brake line 52a First restrictor unit 52b Second restrictor unit 53 Feedback line 70 Shuttle-type check valve 71 Spring-loaded brake cylinder output 72 Service brake output 73a First compressed-air sensor 73b Second compressed-air sensor 74 Trailer control output 80a First output line 80b Second output line 81a First output branching point 81b Second output branching point