DE4227084B4 - Pressure control module of a compressed air vehicle brake system - Google Patents

Abstract

Pressure control module (100) of a compressed air vehicle brake system for regulating the pressure in brake cylinders, in particular for commercial vehicles, with a two-channel valve unit (1) with a relay valve (3; 4) and a solenoid valve (7; 8) assigned to this on the input side and with one Electronic unit (2) with a microcomputer for controlling the valve unit (1), the solenoid valves (7; 8) on the input side together. a single 3/2-way solenoid valve (9), which serves on the one hand for supplying control compressed air to control chambers of the relay valves (3; 4) and on the other hand for venting these control chambers.

Description

The The invention relates to a pressure control module.

A pressure control module is out of the EP-A-0 467 112 is known, in which an electronic braking system for road vehicles is described with electronics used to control brake pressure modulators, which is divided into a plurality of wheel modules assigned to the individual wheels, provided with at least one microcomputer, and into at least one superordinate central module provided with a microcomputer, with the possibility is indicated to combine two wheel modules of one axle to form an axle module.

An electronic braking system for road and Rail vehicles of the type described above, the wheel-related Actuators are provided with their own control electronics and that, starting from a centrally arranged electronics, via interfaces be coordinated and these interfaces can also exchange data with each other in principle suitable, the demands on a modern, electronic Brake system to meet. However, it has been shown that the Additional costs of such a system compared to a conventional brake system through that actually achievable functional advantages can not be weighed.

From the DE 40 30 980 A1 An electropneumatic brake system is known in which a relay valve can be actuated by means of corresponding control valves and ventilation valves, which is intended to prevent the vehicle from being misaligned due to different brake pressures on the left and right when the electric brake is predominantly applied, with a temporary comparison of the target and actual values Values via an electronic control unit.

From the DE 40 25 584 C2 discloses a method for controlling the pressure in a control chamber of a relay valve for an anti-lock brake system, by means of which an inadmissible increase in working pressure in the consumer circuit can be largely prevented.

The invention is based on the object Specify pressure control module, its use by a possible small number of system components a significant reduction the manufacturing costs allowed and at the same time the system security improved.

This task is due to the characteristics of claim 1 solved.

Advantages of invention

By the solenoid valves according to claim 1 on the input side together a single one, on the one hand for supplying Control compressed air to the control chambers of the relay valves and on the other hand for ventilation upstream of this control chamber serving 3/2-way solenoid valve the functions of the relay valve such as pressure build-up, pressure maintenance and Pressure drops timed using only three valves. With the help of a single 3/2-way solenoid valve, control compressed air is consequently generated switched to the downstream solenoid valves and relay valves or to a ventilation point directed. These measures require a small number of valves used and others also a small number of connecting lines between the valves, which has a positive effect on the manufacturing costs of the pressure control module.

By the measures listed in the subclaims are advantageous developments and improvements in the claim 1 specified pressure control module possible.

The 3/2-way solenoid valve is particularly preferred formed such that it is the control compressed air when de-energized through to the solenoid valves and the latter in the energized state a vent combines.

Such training can, for example, by a spring-loaded solenoid valve can be realized.

According to a first embodiment solenoid valves are 2/2-way high-cycle valves and switchable by the electronic unit. Continue to be the two relay valves are supplied directly with compressed air supply. On thus formed pressure control module is preferably for conventionally braked trailer vehicles can be used with an ABS function is realized.

In the case of braking initiated by the driver for example during during a braking phase, the control pressure is switched through by the 3/2-way solenoid valve, to control it in the control chambers of the downstream relay valves and around in both channels first same size brake pressures to create.

exceeds the wheel slip of the permissible values of the trailer vehicle wheels assigned to one of the two channels, the braking pressure of this channel must be temporarily reduced. on the other hand the brake pressure should be in the channel not affected by the blocking cannot be lowered. As a result, the 3/2-way solenoid valve briefly in its venting position switched, but previously that which does not tend to block Channel-assigned solenoid valve is switched to the locked position, to prevent the control pressure in that channel from being lowered becomes.

If the wheel slip has then fallen below the permissible throws again, can then ßend the control pressure in the critical channel with regard to the risk of blocking by increasing the 3/2-way solenoid valve and clocked switching of the associated solenoid valve in order to achieve the greatest possible braking effect with optimal wheel slip.

For However, vehicles with drive axles are often also in addition to the ABS function an ASR function (traction control system) is required. To one Realizing such ASR function is, according to a further embodiment another 3/2-way solenoid valve is connected upstream of the 3/2-way solenoid valve, that depends from its switching position control compressed air or supply compressed air at entrances of the 3/2-way solenoid valve.

The further 3/2-way solenoid valve is preferably designed such that it is in a de-energized state the control compressed air and, when energized, the supply compressed air to the 3/2-way solenoid valve. In particular, they are further 3/2-way solenoid valve and the solenoid valves as part of the Drive slip control depending on Wheel slip switchable.

As soon as the electronics unit turns on while driving a drive axis assigned to a channel different via speed sensor Determines wheel speeds that are not based on cornering this as undesirable Slip interpreted. Since when the drive wheels spin the Brake value transmitter normally not actuated and at one input further 3/2-way solenoid valve therefore no control pressure is present, it is switched by the electronics unit so that it has the supply pressure at its other entrance via the corresponding open Solenoid valve as control pressure on the relay valve switches to Brake pressure for to increase the slipping wheel.

Doing so will build a corresponding Brake pressure for the brake cylinder of the non-slipping wheel by locking the this solenoid valve associated prevented. The advantage of thus further developed pressure control module results from that with his help without additional Valve devices implemented an electronic differential lock is.

Further refinements and improvements are the further subclaims refer to.

The invention is illustrated below preferred embodiments explained in connection with the drawing. He show

1 a preferred embodiment of a 2-channel pressure control module according to the invention;

2 another embodiment of a 2-channel pressure control module according to the invention;

3 a highly schematic representation of a vehicle brake system, which according to using pressure control modules 1 or 2 is constructed;

4 a likewise highly schematic representation of essential parts of a vehicle brake system constructed using a pressure control module according to the invention.

description of the embodiments

In detail shows 1 a pressure control module 100 , which is designed according to the invention as a 2-channel pressure control module and a valve unit 1 as well as an electronic unit that is mechanically and electrically connected to it 2 includes.

The valve unit 1 has two separate pressure control channels, each with a separate relay valve 3 respectively. 4 include. The pneumatic control input 5 of the relay valve 3 is from one of these relay valve 3 individually assigned 2/2 solenoid valve 7 supervised. The pneumatic control input 6 of the relay valve 4 is monitored by a further 2/2 solenoid valve 8 individually assigned to this relay valve.

The two 2/2 solenoid valves 7 . 8th is a changeover valve in the form of a 3/2 solenoid valve 9 upstream, which, as will be described in more detail below, the venting of the relay valves 3 . 4 or the associated brake cylinder (not shown) via an outside air connection 10 . 11 serves.

The 3/2 solenoid valve for ventilation 9 is another 3/2 solenoid valve 12 connected upstream as a changeover valve, which is also assigned to both pressure control channels together. In its in 1 shown spring-actuated basic position or, in its de-energized state, connects the further 3/2-way valve 12 a connection 13 of the pressure control module 100 , to which a control pressure is applied via lines 14 and 15 and the 3/2 solenoid valve 9 and each of the 2/2 solenoid valves 7 . 8th with the control inputs 5.6 of the relay valves 3 respectively. 4 , In the current-charged state, ie when the excitation winding is activated, the further 3/2 solenoid valve 12 connects a connection 17 over lines 16 . 15 with the inlet side of the 3/2 solenoid valve 9 , so that a supply pressure at the connection 17 via the solenoid valves 7 . 8th to the pneumatic control inputs 5 . 6 of the relay valves 3 . 4 can be placed.

Each of the two relay valves 3 . 4 has its own work connection 18 respectively. 19 , each in two connections 20 . 22 respectively. 21 . 23 branched. Any connection 20 . 22 respectively. 21 . 23 leads to a brake cylinder, not shown, of a vehicle wheel. For monitoring the work connections 18 . 19 can, as indicated by dashed lines, optionally one pressure sensor each 24 respectively. 25 to these connections 18 , 19 connected, the two pressure transmitters 24 . 25 electrical directly with the electronics unit 12 are connected.

The electronics unit 2 comprises at least one microcomputer, which has its own intelligence, as well as further, not specified here, electronic or electrical components, which have a connection 26 are supplied with a supply voltage U _B and are able to process incoming analog and digital signals and to exchange information with at least one further electronic system unit via at least one interface and to issue control commands and signals to at least one further electronic or electrical unit, in particular to the valves 7 . 8th . 9 . 12 the valve unit 1 according to 1 or to the valves of the modified valve unit according to 2 ,

For this purpose the electronic unit has 2 via interface connections 27 , Connections 28 for sending and receiving analog and / or digital signals and connections 29 corresponding to the number of sensed vehicle wheels for the sensor turning signals reflecting the wheel turning behavior.

The 2-channel pressure control module 100 according to 1 can be used in different ways in both an electronic and a conventional brake system and works as follows:
When the brake value transmitter is not activated 33 (see. 3 ) - such a brake value transmitter is described, for example, in an earlier, unpublished application by the applicant (German patent application P 41 41 995.2) - there are all magnetically actuated valve units 7 . 8th . 9 . 12 in the in 1 shown state, ie in their spring-operated basic position. As soon as the tread plate of the brake valve or brake value transmitter 33 is operated. the current position of the tread plate is in the form of an electrical signal, for example generated with the aid of a potentiometer, possibly via an electrical system unit - in the exemplary embodiment according to FIG 3 a central control unit 34 - to the interface connections 27 of the pressure control module 100 placed its electronics unit 2 thereupon corresponding electrical signals are generated which lead to the fact that the first time the movement of the tread plate of the brake value transmitter is measurable 33 the 3/2 solenoid valve 12 switches to its working position. Furthermore, depending on the size of the output signal of the brake value transmitter 33 from the electronics unit 2 corresponding output signals for the two 2/2 solenoid valves 7 and 8th generated,
which according to the embodiment 1 For example, so-called high-cycle valves and the pneumatic control inputs 5 . 6 of the two relay valves 3 . 4 Control accordingly so that the brake cylinder pressure at the work ports 18 . 19 according to the position of the treadle of the brake value transmitter 33 is "clocked up". When doing so, the pressure at the work connections 18 . 19 through the in 1 Pressure sensor shown in dashed lines 24 respectively. 25 is monitored, you get a closed pressure control circuit for monitoring the brake cylinder pressure.

The pressure is released - the brake is released - when the treadle of the brake value transmitter is released 33 for both pressure channels by controlling the 3/2 solenoid valve 9 through the electronics unit 2 in such a way that the solenoid valve 9 is moved from its spring-actuated basic position to its magnet-actuated working position, while at the same time the outside air connection 10 . 11 via the 2/2-way solenoid valves which are in their basic position again at this time 7 . 8th with the pneumatic control inputs 5 . 6 of the relay valves 3 respectively. 4 is connected, creating the control chamber of the relay valves 3 . 4 is vented, which has the consequence that the respectively connected brake cylinder (not shown) is vented via their reaction chambers.

In the event that the brake system works in ABS (anti-lock protection) mode or in ASR (traction control system) mode, the pressure is reduced via the 3/2 solenoid valve 9 , while the hold function and the pressure build-up function again via the two 2/2 solenoid valves 7 . 8th will be realized. It is through a phase-shifted control of these two 2/2 solenoid valves 7 . 8th easily possible to generate different brake pressures both in the pressure build-up and in the pressure reduction in the two regulated pressure channels.

At the in 1 shown configuration of the valve unit 1 However, it is not possible in one pressure channel to apply the brake pressure, ie the pressure at the relevant working connection 18 respectively. 19 build up for one pressure channel and simultaneously dismantle it for the other pressure channel.

At the in 2 the pressure control module shown in the drawing 100 according to the invention is omitted in the valve unit 1 which is otherwise constructed in the same way as the valve unit 1 of the embodiment according to

1 , the additional 3/2 solenoid valve provided there 12 , so that in this variant on the inlet side of the 3/2 solenoid valve 9 only the control pressure from the connection 13 arrives while the supply pressure from the port 17 constantly directly at the two relay valves 3 . 4 is available, as is also the case with the variants according to 1 . 2 and 2a the case is.

The application of the design according to 2 is preferably provided for conventional braked trailer vehicles in which only an ABS function has to be implemented.

For vehicles with drive axles, however, an ASR function (traction control system) is often required in addition to the ABS function. Unab Depending on whether this drive axle is braked conventionally or electronically, such an ASR function can be done in the simplest way with the valve unit 1 according to 1 with the help of the 3/2 solenoid valve available in this variant 12 will be realized. As soon as the electronics unit 1 recognizes different wheel speeds when driving on the drive axle via speed sensors, which cannot be traced back to a difference in wheel speeds caused by cornering, this is interpreted as undesirable slip, whereupon the electronics unit 2 the 3/2 solenoid valve 12 switches and via the corresponding 2/2 solenoid valve 7 respectively. 8th increases the brake pressure for the faster rotating wheel until both drive wheels have approximately the same wheel speed or speed. The build-up of a corresponding brake pressure for the brake cylinder of the slower rotating wheel is achieved by locking the 2/2 solenoid valve assigned to this wheel 7 respectively. 8th prevents the corresponding 2/2 solenoid valve 7 respectively. 8th is from the electronics unit 2 not clocked, but controlled in such a way that it supplies the compressed air to the pneumatic control input 5 respectively. 6 of the relevant relay valve 3 respectively. 4 prevented. The solenoid valve 12 is decisive for the traction control system or for the achievement of an electronic differential lock insofar as the brake signal transmitter when the drive wheels spin, especially when starting off 33 normally not actuated and consequently no control pressure at the connection 13 is available.

If, in the event of a fault, the 3/2 solenoid valve 12 is no longer electrically controlled, ie can be brought into its switched-on position, via the line connection that is open when the valve is not actuated 13 . 14 . 15 the full braking effect can still be achieved (back-up function). In this case, too, the full ABS function of the brake system is retained.

3 The drawing illustrates the use of two pressure control modules according to the invention on the basis of a highly schematic representation 100 . 100 ' in a complete braking system. It can be seen that the brake value transmitter 33 except its electrical part 33a two pneumatic parts 33b . 33c and a pressure relief point 33d having. About the two pneumatic parts 33b . 33c can the brake cylinder 40 . 41 . 42 . 43 pneumatically controlled for the four wheels of the vehicle in the usual way. The electrical part 33a of the brake value transmitter 33 delivers electrical signals which indicate the position of the tread plate 33e correspond to a central control unit 34 , which has the two pressure control modules via corresponding bus lines 100 . 100 ' controls the control of the associated brake cylinders in the manner described above for the brake system operating as an electronic brake system 40 . 41 . 42 . 43 take.

In 4 is the possibility of using a pressure control module based on a likewise highly schematic representation 100 according to 2 for a three-axle trailer vehicle with a conventional brake system.

With regard to the function of the pressure control module explained above 100 according to 2 only one ABS function is possible for the application under consideration. The control of the various solenoid valves 7 . 8th . 9 the valve unit 1 of the pressure control module 100 takes place in the manner already explained above. Thereby, the pressure control module 100 in this application four wheel sensors in the form of speed sensors 101 connected, whose output signals from the pressure control module 100 are processed individually, for example in such a way that the speed signals from two wheels, which are preferably arranged side by side, provide individual pressure control for the brake cylinders in question 102 takes place, in particular on the principle that the speed of the slower rotating wheel is function-determining. Additional central electronics or, generally speaking, another electronic system unit is not required in this case.

Also in the case of using an electronic brake system in a trailer vehicle, except for the variants of a pressure control module according to the invention 1 or 2 No additional central electronics required, since the 2-channel pressure control module can receive the information from the towing vehicle directly via its own interface (possibly several interfaces) and process it internally. Also other signal values, such as the output signals of a load transmitter 35 , can be received and processed directly to generate the braking force suitable for the individual case.

It is clear from the above description that considerable advantages can be achieved with the pressure control module according to the invention compared to the prior art. One of these advantages is first of all that two solenoid valves - in the embodiment according to 1 - can be saved. Above all, however, when using a pressure control module according to the invention, there is the advantage that, in particular compared to the prior art EP-AO 467 112 A2 , a wheel module electronics can be saved almost completely. In addition, there are considerable savings in electrical and pneumatic lines and line connectors, such as connector components, fittings and the like. Finally, according to the invention, there is also a higher level of security since assemblies and connecting elements are less prone to malfunction.

Claims (9)

Pressure control module ( 100 ) a compressed air vehicle brake system for regulating the pressure in the brake cylinders, especially for commercial vehicles, with a two-channel valve unit ( 1 ) with a relay valve ( 3 ; 4 ) and a solenoid valve assigned to this on the input side ( 7 ; 8th ) per channel and with one electronic unit ( 2 ) with a microcomputer to control the valve unit ( 1 ), the solenoid valves ( 7 ; 8th ) common on the input side. a single one, on the one hand for the supply of control compressed air to control chambers of the relay valves ( 3 ; 4 ) and on the other hand 3/2-way solenoid valve for venting these control chambers ( 9 ) is connected upstream. Pressure control module according to claim 1, characterized in that the 3/2-way solenoid valve ( 9 ) is designed in such a way that the control compressed air to the solenoid valves ( 7 ; 8th ) switches through and the latter is energized with a vent ( 11 ) connects. Pressure control module according to claim 1 or 2, characterized in that the solenoid valves ( 7 ; 8th ) 2/2-way high-cycle valves and through the electronics unit ( 2 ) clocked switchable. Pressure control module according to one of claims 1 to 3, characterized in that the two relay valves ( 3 ; 4 ) are directly supplied with compressed air supply. Pressure control module according to claim 1 or 2, characterized in that the 3/2-way solenoid valve ( 9 ) another 3/2-way solenoid valve ( 12 ) is connected upstream, which depending on its switching position control compressed air or compressed air supply to an input of the 3/2-way solenoid valve ( 9 ) leads. Pressure control module according to claim 5, characterized in that the further 3/2-way solenoid valve ( 12 ) is designed in such a way that the control compressed air is in the de-energized state and the supply compressed air in the energized state to the 3/2-way solenoid valve ( 9 ) switches through. Pressure control module according to claim 6, characterized in that the further 3/2-way solenoid valve ( 12 ) and the solenoid valves ( 7 . 8th ) can be switched as part of a traction control system depending on a wheel slip. Pressure control module according to at least one of claims 1 to 7, characterized in that the pressure at work connections ( 18 ; 19 ) of the relay valves ( 3 ; 4 ) with the help of the electronic unit ( 2 ) signal transmitters in signal connection ( 24 ; 25 ) is detectable. Vehicle brake system with at least one pressure control module according to one of the claims 1 to 8.