DE102014108681B3 - Electro-pneumatic spring brake device of a motor vehicle with sudden pressure increase during brake release - Google Patents

Abstract

The invention relates to an electropneumatic spring brake device (1) of a motor vehicle, which means for generating electrical brake actuation signals, which at least represent the states "Brake tension" and "brake release", an electronic control device (8) receiving the brake actuation signals, one of the control electronics (8). depending on the actuating signals controlled electropneumatic valve device (10) and at least one pneumatically actuated spring brake cylinder, wherein the electropneumatic valve means (10) the at least one spring brake cylinder by connecting to a compressed air reservoir (12) vented or vented by connecting to a pressure sink (3), and wherein a maximum ventilation state of the electro-pneumatic valve device (10) that can be brought about by the electronic control device (8) exists, in which the electropneumatic valve device (10) has a maximum flow cross section between the compressed air reservoir (12) and the at least one spring brake cylinder releases. According to the invention, it is provided that the electronic control device (8) is designed such that the electromagnetic valve device (10) from the electronic control device (8) remains in the brake during a change of the state from "brake clamping" to "brake release" Maximum ventilation state is controlled until the pressure in the at least one spring brake cylinder starting from an initial pressure value below a first gradient is suddenly increased to a higher contrast first, but still below the spring brake cylinder completely dissolving brake release pressure pressure value and controlled after reaching the first pressure value in a state is in which the pressure in the at least one spring brake cylinder starting from the first pressure value under a second, compared to the first gradient small ren gradient for taking a partial release position or full release position au f is increased compared to the first pressure value higher second pressure value.

Description

State of the art

The invention relates to an electro-pneumatic spring brake device of a motor vehicle, which means for generating electrical brake actuation signals, which represent at least the states "Brake tension" and "brake release", an electronic control device receiving the brake actuation signals, one controlled by the control electronics depending on the actuation signals Electropneumatic valve means and at least one pneumatically actuated spring brake cylinder includes, wherein the electropneumatic valve means the at least one spring brake cylinder ventilated by connecting to a compressed air supply and vented by connecting to a pressure sink, and wherein a forth by the electronic control device forthable maximum ventilation state of the electropneumatic valve device exists in which the electropneumatic valve device a maximum flow cross section between en the compressed air supply and the at least one spring brake cylinder releases according to the preamble of claim 1.

Such electro-pneumatic spring brake device of a motor vehicle, in particular a heavy commercial vehicle is for example from the DE 10 2007 052 521 A1 or off DE 10 2008 007 877 B3 known, wherein the electropneumatic valve device together with the electronic control device forms a parking brake module which is connected between the compressed air reservoir and the at least one spring brake cylinder. Depending on the equipment with electromagnetic valves, such as inlet valve, exhaust valve, bistable valve, relay valve can be brought from such an electro-pneumatic spring brake device in addition to the parking brake function and the driving function in which the at least one spring brake cylinder at a stagnant vehicle in Bremszuspannstellung or in Bremslösestellung usually more functions are performed.

These additional functions include, for example, a test function in which the spring brake of the towing vehicle is tensioned and the service brake of a trailer is released when stationary, to test whether the braked towing vehicle can hold the unbraked trailer at a standstill. Furthermore, in the electro-pneumatic spring brake device also a stretch braking function may be provided in which when the towing vehicle-trailer combination only the brakes of the trailer are actuated to the towing vehicle-trailer combination, for. to stretch at an undesirable buckling.

Last but not least, a so-called auxiliary brake function is also important in which e.g. in the case of a defect in the electro-pneumatic or pneumatic service brake present in parallel, the spring-loaded brake is used as an emergency or auxiliary brake. The auxiliary or emergency brake can then also be regulated with regard to the pressure applied in the at least one spring brake cylinder.

For example, if the brake actuation signals from a driver-operable brake actuator, e.g. be generated in the form of an operating lever, this operating lever has a driving position, a parking position and an auxiliary brake position therebetween in which a certain pressure in the spring brake cylinders is generated depending on the rotation angle of the actuating lever and thus a certain auxiliary braking effect is caused. In the park position then the maximum auxiliary braking force is applied.

Such spring brake cylinders are so-called passive brake cylinders in which a spring brake piston is brought against the action of at least one accumulator spring in the brake release position and by venting the spring accumulator brake chamber into the brake set position by aerating a spring accumulator brake chamber. Most of these spring brake cylinders are arranged on the rear axle of heavy commercial vehicles and installed with pneumatic service brake cylinders service brake to combination cylinders.

The problem with such spring brake cylinders, however, that for brake release by aerating the spring brake chamber against the action of the storage springs due to friction first a certain breakout force must be overcome until the spring brake can move in brake release position, which causes an unfavorable dynamics in the context of an example pressure-controlled auxiliary braking ,

The present invention is based on the object to further develop an electro-pneumatic spring brake device of a motor vehicle method of the type mentioned in such a way that it has improved dynamics.

This object is achieved by the features of claim 1.

Disclosure of the invention

According to the invention, it is provided that the electronic control device is designed such that the electromagnetic valve device is controlled by the electronic control device into the maximum ventilation state during a change of the state from "brake clamping" to "brake release" during the travel of the vehicle until the pressure in the at least one spring brake cylinder starting from an initial pressure value under a first gradient is suddenly increased to a higher, but still below a spring brake cylinder completely dissolving brake release pressure pressure value is controlled and after reaching the first pressure value in a state in which the pressure in the at least a spring brake cylinder starting from the first pressure value under a second, compared to the first gradient smaller gradient for taking a partial release position or full release position against a is increased above the first pressure value higher second pressure value.

When, when changing or transitioning from the brake-apply state to the brake-release state, the maximum aeration state, i. the condition of maximum ventilation of the at least one spring brake cylinder is produced under a very large pressure gradient, the first pressure value acting on the spring brake piston of the at least one spring brake cylinder is abruptly or suddenly generated, resulting in a release force, preferably at least as large as the breakaway force of the spring brake within of the spring brake cylinder is. As a result, the hysteresis typical of such a spring brake cylinder is compensated for in a quick manner and the spring brake piston ruptures abruptly by overcoming the frictional forces. This results in placing the brake actuator of "Bremszuspannen" on "brake release" high dynamics, which is just when using the spring brake or parking brake as an auxiliary brake while driving a great advantage, because then a sensitive brake dosage is possible.

The first pressure value, i. the pressure, which is preferably necessary to overcome the breakaway force, can be readily determined by the skilled person at the end of the production of the spring brake cylinder or by experiments.

If then the first pressure value is reached in the at least one spring brake cylinder, which is detectable for example by a pressure sensor cooperating with the electronic control device, the further release of the at least one spring brake cylinder with a second gradient, which is lower than the first gradient, takes place, for example, by the electropneumatic valve device is controlled by the control device in a ventilation state in which the ventilation of the at least one spring brake cylinder is below the maximum ventilation state and thus a slower release of the at least one spring brake cylinder takes place. The first and second gradients can be determined by the person skilled in the art and adapted as needed.

If the brake actuation signals are generated by a driver-operable brake actuator, the change takes place from the state "Brake release" in the state "brake release" by a place of the vehicle while this vehicle body of this actuator from a position "Bremszuspannen" in the position "Brake release" ,

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

Particularly preferably, the means for generating electrical brake actuation signals includes a driver-actuatable brake actuator such as a rocker switch, a lever or a push button with two positions "Zuspannen" and "brake release" or each with three positions "Brake", "Neutral" and "brake release ".

Alternatively or additionally, the brake actuation signals can also be generated automatically by a further electronic control device and without the driver's intervention, for example by a control device of a driver assistance system, such as a driver assistance system. a Hill Holder system.

As already mentioned above, the first pressure value is at least as great and particularly preferably the same as the pressure value which generates a pressure force on a spring brake piston of the at least one spring brake cylinder, which corresponds precisely to the breakaway force of the spring brake piston with respect to the spring brake cylinder. Then, in the first phase of the brake release just the breakaway force of the spring brake piston is compensated.

According to a further development, the electromagnetic valve device is further controlled by the electronic control device such that the longer the signal duration of the brake actuation signal representing the "brake release" state, the greater the second pressure value, and maximum corresponds to a brake release pressure at which the at least one spring brake cylinder is in the full release position. Thus, the release pressure value for the case that the brake actuation signals are generated by the brake actuator actuated by the driver depends on the holding period of the brake actuator in the position "brake release", so that the brake release can be dosed by the driver.

Alternatively, after reaching the first pressure value representing the overcoming of the hysteresis, the brake release could be done without further driver intervention or by an automatically acting system, by then reducing the brake pressure below the second gradient to the full release pressure, i. is increased to the pressure required for the full release state. In other words, the described full release operation is then caused only by the change from the state "Brake release" in the state "brake release", without the signal duration of the "brake release" representing brake actuation signal to the height of the release pressure value would influence, for example, that the driver keeps the brake actuator in the "brake release" position for a certain period of time.

For the general realization of the brake release, the electromagnetic valve device can have at least one passage position providing a connection between the compressed air reservoir and the at least one spring brake cylinder and a solenoid valve having this locking position. is controlled by the electronic control device alternately or pulsed between the passage position and the blocking position when taking or holding the state "brake release". This creates an approximately ramp-shaped pressure curve of the brake release pressure.

Alternatively or additionally, the electromagnetic valve device may include at least one proportional solenoid valve, with which a variable flow cross section between the compressed air reservoir and the at least one spring brake cylinder is adjustable. The flow cross section can preferably be increased depending on the signal duration of the brake actuation signal representing the "brake release" state.

Even when the brake is engaged, it can preferably be provided that the electromagnetic valve device is controlled by the electronic control device in such a way that the pressure value set in the at least one spring-loaded brake cylinder is smaller, the longer the signal duration of the actuating signal representing the "brake-engaged" state is minimal and a brake application pressure corresponds, in which the at least one spring brake cylinder is in the Vollzuspannstellung. The signal duration of the actuating signal representing the "brake-engaged" state is then the longer the longer the brake actuating element is held in the "brake-engaged" position.

For the general realization of the brake release, the electromagnetic valve device may have at least one connection establishing a connection between the pressure sink and the at least one spring brake cylinder passage position and a locking blocking position exhibiting this solenoid valve, which alternately or pulsed when taking or holding the state "brake tensioning" of the electronic control device between the passage position and the blocking position is controlled.

Alternatively or additionally, the electromagnetic valve device may also include at least one proportional solenoid valve with which a variable flow cross-section between the pressure sink and the at least one spring brake cylinder is adjustable.

If a state "neutral" is provided, the position "neutral" is preferably passed during a change of the vehicle during the drive from the state "brake clamping" to the state "brake release". Therefore, if a brake actuator is provided with a position "neutral", then the position "neutral" is passed in the made during the driving of the vehicle bodies of the actuator from the position "Brake tension" in the position "brake release".

The electromagnetic valve device is then controlled by the electronic control device in the maximum ventilation state until the pressure in the at least one spring brake cylinder, starting from an initial pressure value below the first gradient even with ingestion of the state "neutral" or only when assuming the state "brake release" is increased suddenly to the first pressure value. Transferred to an operable by the driver brake actuator means that already on reaching the position "Neutral" or until the position "brake release" the electromagnetic valve device is controlled by the electronic control device as long as in the maximum ventilation state until the pressure in the at least one spring brake cylinder is increased abruptly from an initial pressure value below the first gradient to the first pressure value.

In the first case (maximum ventilation state already ingesting the state "neutral") at so the hysteresis of the at least one spring brake piston is compensated relatively early, but preferably then already carried out a brake release movement of the spring brake piston, because the first pressure value is not sufficient for this. Thus, the at least one spring brake piston is already prepared when taking the state "neutral" for the subsequent brake release, by then already the breakout force is just compensated.

Then, furthermore, the electromagnetic valve device can be controlled by the electronic control device such that the pressure in the at least one spring-loaded brake cylinder is increased starting from the first pressure value below a third gradient. This already results in the state "neutral" in a slow brake release phase, because after the compensation of the hysteresis also a brake release movement of the spring brake piston is initiated.

If then the state "brake release" is taken, for example, with further actuation of the brake actuator in this position, the electromagnetic valve device is preferably controlled by the electronic control device such that the pressure in the at least one spring brake cylinder under a fourth, compared to the third gradient larger Gradients is increased until the second pressure value is reached. This then corresponds to a faster brake release phase in the "brake release" state subsequent to the slow brake release phase present in the "neutral" state.

In the second case (maximum ventilation state only at revenue of the position "brake release"), the compensation of the hysteresis takes place later, namely shortly before the brake release movement of the spring brake piston in the state "brake release".

In this case, when the state "neutral" is assumed, the electromagnetic valve device can be controlled within the scope of a pressure-holding phase by the electronic control device in such a way that the pressure value last set or assumed in the "brake-engaged" state is kept constant in the at least one spring-loaded brake cylinder.

In order to prevent the spring brake from being unintentionally or only partially released for an extended period of time resulting in overheating and wear of the brake actuator, e.g. a disc brake, it may be preferably provided that the electronic control device has an accelerator pedal signal input from an accelerator pedal of the vehicle accelerator pedal signals and is designed so that when pending on the accelerator pedal signal input, an accelerator pedal representing accelerator pedal signal, the electronic control device, the electro-pneumatic valve device in the maximum ventilation state controls to cancel the pressure holding phase or the slow brake release phase and to bring the at least one spring brake cylinder in the full release position.

Alternatively or additionally, for the same purpose, the electronic control device may comprise or be connected to a time measuring device such that the electronic control device switches the electropneumatic valve device into the maximum ventilation state in the "neutral" state detected by the electronic control device for a predetermined period of time controls to cancel the pressure holding phase or the slow brake release phase and to bring the at least one spring brake cylinder in the full release position.

According to a particularly particularly preferred measure may be provided together with the electronic control device acting means for detecting brake slip in the state "Bremszuspannen", wherein the electronic control device controls the electromagnetic valve device such that at a detected, a tolerable brake slip exceeding the brake in the pressure the at least one spring brake cylinder in cycles initially reduced so suddenly and then gradually increased again until the tolerable brake slip is reached. By "sudden reduction" is meant a brake pressure reduction under a very large pressure gradient, while "gradual increase" is understood to mean a change in pressure with a lower gradient. In order for a brake slip control is realized in particular in the position "Bremszuspannen" of the brake actuator. According to a development of this measure, the reduction of the brake pressure decreases with each cycle.

The invention also relates to a motor vehicle, in particular a road-bound motor vehicle comprising a spring-loaded brake device described above.

drawing

Embodiments of the invention are illustrated in the drawings and explained in more detail in the following description. In the drawing shows

1 A preferred embodiment of an electropneumatic spring-loaded brake device of a road-bound motor vehicle;

2 a brake pressure-time diagram of prevailing in a spring brake cylinder of the preferred embodiment of the electropneumatic spring brake device braking pressure;

3 a braking force-time diagram resulting from the brake pressure-time diagram of 2 resulting braking force, as generated by the spring brake cylinder;

4 a brake pressure-time diagram of prevailing in a spring brake cylinder of a further embodiment of the electropneumatic spring brake device braking pressure;

5 a braking force-time diagram resulting from the brake pressure-time diagram of 4 resulting braking force, as generated by the spring brake cylinder;

6 a brake pressure-time diagram of prevailing in a spring brake cylinder of a further embodiment of the electropneumatic spring brake device braking pressure;

7 a braking force-time diagram resulting from the brake pressure-time diagram of 6 resulting braking force, as generated by the spring brake cylinder;

8th a brake pressure-time diagram of prevailing in a spring brake cylinder of a further embodiment of the electropneumatic spring brake device braking pressure;

9 a braking force-time diagram resulting from the brake pressure-time diagram of 8th resulting braking force, as generated by the spring brake cylinder.

Description of the embodiments

In the 1 shown preferred embodiment of an electropneumatic parking brake device 100 is part of a pressure medium-actuated, for example, electropneumatically actuated braking device of a tractor-trailer combination and is arranged in the towing vehicle. In particular, it is an electronically controlled braking system (EBS).

The electropneumatic parking brake device 100 includes a parking brake module symbolized by the frame 1 and one, for example, manually via a brake actuator, here, for example, a control lever 2 adjustable parking brake signal transmitter 4 , which via an electrical signal line 6 by electrical actuation signals an electronic control device 8th the parking brake module 1 controls.

The electronic control device 8th is preferred in the parking brake module 1 integrated. In the parking brake module 1 is still one of the controller 8th controllable electromagnetic valve device 10 integrated, which via a supply connection 12 is supplied with compressed air from a supply air reservoir, not shown here.

From the supply connection 12 the parking brake module 1 extends a supply pressure line 14 to a connection 16 a clocked controllable first valve MV2, as by the electronic control device 8th electrically controllable 3/2-way solenoid valve two switching states for a stepped venting of a connection 18 having, which via a pressure line 20 with a pressure sensor 24 communicating, which depends on that in the pressure line 20 prevailing pressure an electrical pressure signal for the electronic control device 8th generated.

Furthermore, there is the pressure line 20 also with a connection 26 a bistable second valve MV1 and with a connection 22a for a subordinate, not shown here trailer control valve device of a trailer in conjunction.

In a first switching state, the cyclically controllable first valve MV2 supplies compressed air under supply pressure from the supply connection 12 the connection 26 the bistable, second valve MV1 and the pressure line 20 one connection 22a for the trailer control valve device of the trailer. In general, a trailer control valve device controls the service brake device of a trailer, which comprises service brake cylinders described in the introduction, which apply in the ventilated state and release in the vented state. Furthermore, such trailer control valve devices invert the pressure introduced into them, ie they invert a pressure corresponding to aeration into a pressure corresponding to a vent and vice versa.

In a second switching state of the clocked controllable first valve MV2 pressure medium from the terminal 26 of the bistable second valve MV1 and from the one terminal 22a for the trailer control valve device of a trailer of the one type to a pressure medium sink, which, for example, by a vent port 28 the clocked controllable first valve MV2 is formed.

The bistable second valve MV1, which is designed, for example, as an electromagnetic valve actuated by two electromagnets, of which one solenoid switches the bistable valve MV1 when energized in one switching state and the other electromagnet switches the bistable valve MV1 when energized into the other switching state Property to take in the de-energized state no preferred switching position, but to maintain the resulting by corresponding previous energization switching position.

The bistable second valve MV1 of the valve device, which preferably also as one of the electronic control device 8th electrically controllable 3/2-way solenoid valve is formed, has two switching states, wherein compressed air via the located in the first switching state first valve MV2 via a connection 30 and a pressure line 32 another connection 22b for a trailer control valve device of a trailer and a third valve MV3 can be supplied and in a second switching state compressed air from the other terminal 22b as well as from a connection 34 of the third valve MV3 can be discharged to a pressure medium sink, which, for example, by a vent port 36 of the bistable second valve MV1 is formed. This is the connection 30 of the bistable second valve MV1 via the pressure line 32 with the connection 34 of the third valve MV3 and with the connection 22b connected.

This further connection 22b is provided for a different control of the service brake of a trailer in the event that the tractor-trailer combination is parked or parked with braked or applied parking brake of the towing vehicle. This situation will be described later in detail.

The third valve MV3 of the valve device, which is preferably a 2/2-way solenoid valve, has two switching states, wherein in a first switching state compressed air via the located in the first switching state first valve MV2 and located in the first switching state bistable second valve MV1 via the connection 34 , a connection 38 and a control pressure line 40 a control connection 42 a relay valve 44 the valve device can be fed and in a second switching state of this control terminal 42 from the pressure line 32 is locked.

A connection 46 of the relay valve 44 is still on the pressure line 14 with the supply connection 12 and via another pressure line 48 with a vent connection 3 the parking brake module 1 connected. The relay valve 44 modulated in a known manner depending on the at its control terminal 42 Pending pressure from the at the supply connection 12 pending supply pressure of the reservoir pressure a pressure for a connection 21 the parking brake module 1 for example, two, in 1 not shown spring brake cylinder on the rear axle as parking brake device of the towing vehicle. These spring brake cylinders release in a ventilated state and tighten in a vented state. A check valve 50 ensures that no compressed air from the pressure line 14 can flow back into the reservoir pressure vessel.

The pressure sensor 24 reports the pressure level at the connections 22a and 22b , which drive the service brakes of the trailer to the electronic control device 8th which via the control lever 2 of the parking brake signal generator 4 may receive, for example, a stepped brake request signal, for example, by clocking the first valve MV2 the pressure at the terminals 22a and 22b respectively. 21 to regulate to a target pressure.

Furthermore, stands with the connection 21 output connected to the parking brake device of the towing vehicle 53 of the relay valve 44 via a pressure line 54 with a pressure sensor 56 in communication, which sends a signal to the electronic control device 8th einsteuert, which at the connection 21 represents prevailing actual brake pressure in the spring brake cylinders.

The electromagnetic valve device 10 As solenoid valves, therefore, it includes the valves MV1, MV2 and MV3, which are the relay valve 44 pneumatically controlled.

Against this background, the operation of the spring brake device 100 as follows:

In 1 is the switching state of the valves MV1, MV2 and MV3 shown in the operating mode "driving" or "brake release", which the driver on the operating lever 2 of the parking brake signal generator 4 can adjust. Then the clocked controllable first valve MV2, the bistable second valve MV1 and the third valve MV3 are each in their first switching states, whereby supply pressure from the supply terminal 12 to the two connections 22a . 22b is controlled for the downstream trailer control valve device to ventilate them. In practice, however, only one of these connections 22a or 22b occupied because only one trailer is pulled by the towing vehicle. The inversion by the trailer control valve device in question leads to a ventilation of the service brake of the trailer, whereby this is solved or remains. Farther These switching states of the valves MV1, MV2 and MV3 also lead to a pressure drop of the control port 42 the relay valve 44 , making this the connection 21 for the spring brake of the towing vehicle modulated ventilated, resulting in a loosening or loosening of the corresponding spring brake cylinder.

If the towing vehicle / trailer combination buckles in the operating mode "Drive" or "Brake release", the driver can straighten it again by manual operation of the stretch brake, this being done by the driver actuating the control lever 2 of the parking brake signal generator 4 in a designated position brings and, if necessary, between the position "driving" and "brakes" back and forth until the straightening is done. Because only the service brakes of the trailer are used for bracing, the brakes of the towing vehicle but not. The by the control lever 2 correspondingly actuated parking brake signal transmitter 4 provides an electrical signal to the electronic controller 8th the parking brake module 1 , whereupon the third valve MV3 is switched to its second switching state, the blocking state. This will be a control chamber of the relay valve 44 disconnected from the compressed air supply and keeps the previously produced by the operating mode "driving" high pressure level, which leaves the spring brake cylinders of the towing vehicle dissolved in the result.

For plug braking, the driver can therefore the first valve MV2 by the operating lever 2 control clocked, ie it is repeatedly switched from its first switching state to the second switching state to a mutual ventilation and ventilation of the terminals 22a . 22b to achieve, so that at the two connections 22a and 22b Compressed air with time-stepped pressure is pending to alternately tighten and release the service brakes of the trailer until the towing vehicle-trailer combination is straight again. The bistable second valve MV1 remains in its first switching state, in which it the clocked by the first valve MV2 pressure to the terminal 22b can control. About the pressure sensor 24 and the electronic control device 8th is a pressure control at the ports 22a and 22b possible.

In the event that the tractor-trailer combination is parked or parked, the operating lever 2 of the parking brake signal generator 4 brought into the position "parking" or "Brake Locking", which results in that the bistable second valve MV1 is transferred to its second switching state, in which the further connection 22b via the vent connection 36 the second valve MV1 is vented, as well as compressed air from the control port 42 of the relay valve 44 via the remaining in its first switching position third valve MV3 through the vent port 36 is vented, which ultimately has a vent of the spring brake cylinder of the towing vehicle and thus their application result. On the other hand, via the first valve MV2, which remains in its first switching position, compressed air is under reservoir pressure at the one connection 22a for the trailer control valve device of the trailer, which is thereby ventilated. In this position of the operating lever 2 Therefore, an opposite ventilation of the connections 22a and 22b , This has the consequence that with the parking brake module 1 the towing vehicle can be used to service various functions of trailers with regard to parked or parked behavior. If the trailer control valve device of the trailer to the one port 22a the parking brake module 1 is connected, the service brake of the trailer remains in the parked or parked state of towing vehicle trailer combination solved. In contrast, when the trailer control valve device of the trailer with the connection 22b is connected, the service brake of the trailer is parked in the parked or parked state of towing vehicle-trailer combination. As a result of the inversion by the trailer control valve device takes place in the parked state ventilation or pressurization of a connection 22a in a ventilation of the service brake cylinder of the trailer and the venting or pressure reduction at the connection 22b converted into a ventilation of the service brake cylinder of the trailer, which solve the service brakes of the trailer.

When starting from "parking" by an appropriate adjustment of the operating lever 2 the test function is selected, in which it is checked whether the braked with the parking brake vehicle can hold the unbraked trailer in the state, so only the third valve MV3 is transferred to its second switching state, in which it the control terminal 42 of the relay valve 44 decoupled and so vented the spring brake cylinder of the towing vehicle and keeps it clamped. In contrast, the bistable second valve MV1 is converted into its first switching state, in which it is located in the first switching state located first valve MV2 the further connection 22b with the supply connection 12 connects to this port 22b to ventilate what due to the inversion function of the trailer control valve device in a vent of the service brake cylinder of the trailer and thus leads to brake release. On the other hand, this will also be the one connection 22a ventilated, which leads to the same consequence. Overall, therefore, the service brakes of the trailer are solved for the purpose of the test function described above.

In the embodiment of 1 becomes the parking brake signal generator 4 via a manually adjustable brake actuator 2 controlled. Likewise, the electric parking brake signals for the controller 8th However, also come from an external unit, such as a Hillholder, which generates these signals automatically.

It is further understood that if to one port 22a or to the other terminal 22b a trailer control valve device of a trailer is connected, each having a different connection 22b respectively. 22a is sealed pressure-tight.

If the service brakes of the towing vehicle fail or if the driver wishes to support the operational service brake by the spring-loaded brake, the driver has the option of braking the towing vehicle-trailer combination using the "auxiliary brake" operating mode by actuating the operating lever 2 from the "Drive" or "Brake release" position in the "Parking" or "Brake-engaged" position, braking with the spring-loaded brake of the towing vehicle and with the service brake of the trailer.

Depending on the deflection of the operating lever 2 from the "Drive" position towards the "Park" position, the parking brake signal transmitter transmits 4 a corresponding electrical signal to the electronic control device 8th the parking brake module 1 to correspondingly clock the second valve MV1, that is to repeatedly switch it from its first switching state to the second switching state, to alternately vent and bleed the connections 21 such as 22a . 22b to achieve. The resulting cyclic application and release of the service brakes of the trailer or the spring brakes of the towing vehicle is equal to a comfort braking with a certain anti-lock function.

Instead of an operating lever 2 can be used as a brake actuator of course, a rocker switch, a push button or the like. The decisive factor is that the brake actuator 2 distinguishable positions, which represent at least the operating modes "driving (brake release)", "parking (Brake release)" and "auxiliary brakes".

As described above, in the operating mode "auxiliary brake", the spring-loaded brake of the towing vehicle can be used in the event of a malfunctioning service brake or in addition to a functional service brake for braking while driving. In the following, the variant is considered, in which in the brake actuation signals from a driver-operable brake actuator as in 1 be generated for the operating mode "auxiliary brake".

It should be noted, however, that in the context of the invention, a braking of the towing vehicle or towing vehicle-trailer combination while driving can be triggered either automatically or without driver intervention, for example by a driver assistance system such as a Hill Holder system.

Furthermore, the embodiment described above, in which the second valve MV1 is actuated in a clocked manner, merely represents a variant of a number of variants, if necessary, with the service brakes of the trailer, while the vehicle is driving, metering or dosing the spring-loaded brakes of the towing vehicle together with the service brakes of the trailer.

In the 2 to 9 the course of the brake pressure p at the port 21 or in the spring brake cylinders and the braking force F generated therefrom by the spring brake cylinders during the activation of the spring-loaded brake during travel, where the pressure curve of the brake pressure p or of the braking force over time is respectively indicated by a dashed line and the position of the brake brake actuator 2 is characterized by a solid line over the time t, wherein the vertical level of the respective solid line indicates the right next to it specified position "Zuspannen", "Neutral" or "Solve".

In all embodiments, when Bremszuspannen preferred that the electromagnetic valve device 10 from the electronic control device 8th is controlled such that the brake pressure p for the spring brake cylinders is smaller, the longer the holding period of the brake actuator 2 in the position is "Bremszuspannen" and minimal _to correspond to the Vollzuspanndruck p, wherein the spring brake cylinder are located in the Vollzuspannstellung.

In an analogous manner, the electromagnetic valve device 10 from the electronic control device 8th when brake release preferably controlled such that the target brake pressure is greater, the longer the holding duration of the brake actuator 2 is in the "brake release", whereby a maximum of the full-release pressure p can be achieved _lös, in which the spring brake cylinder are located in the full release position. Thus, the target release pressure depends preferably on the holding duration of the brake actuator 2 in the "brake release" position, so that the brake release can also be dosed by the driver.

In the embodiment of 2 and 3 becomes the brake actuator 2 For example, in the context of the auxiliary brake function while driving at time t ₀ of the position "ride (brake release)" in the position "Bremszuspannen" set, whereby by means of a corresponding control of the valve device 10 the brake pressure p here, for example, linearly from a maximum brake release pressure p _lös which the full release state (drive) represents the spring brake cylinder, to a Vollzuspanndruck p _to the time t ₁ is reduced, in which the spring brake cylinder are maximum applied biases (Bremszuspannen).

In 3 the course of the braking force F generated by the spring brake cylinders is shown, which from the course of the brake pressure p in 2 results. Consequently, in the period between t ₀ and t _1, the braking force increases from zero to a maximum spring brake force F _max . If then the driver wants to reduce the brake pressure while running braking again while driving, so he puts the brake actuator 2 in the course of the auxiliary braking back into position "ride (brake release)", here, for example, at time t ₁ , whereupon the braking force F is reduced to zero again at time t ₂ .

The electronic control device is then designed such that, in such a position of the operating lever that has taken place during the travel of the vehicle 2 from the position "Parking (brakes)" in the position "drive" (brake release) "the electromagnetic valve device 10 from the electronic control device 8th as long as in a maximum ventilation state is controlled until the pressure in the at the port 21 completely dissolving the connected spring-loaded brake cylinders, starting from the Vollzuspanndruck p _to the time t ₁ at a first, very large gradient abruptly to a contrast higher first, but still below a spring-loaded brake cylinder, maximum brake release pressure p _lös lying pressure value P is increased. ₁

The maximum ventilation state of the electropneumatic valve device is understood to be a ventilation state in which the electropneumatic valve device has a maximum or maximum possible flow cross section between the supply connection 12 or the compressed air supply and the connection 21 or releases the spring brake cylinder.

This maximum ventilation state becomes in the embodiment of a spring brake device 100 to 1 for example, by the local positions of the valves MV1, MV2 and MV3 of the valve device 8th represents, in which the clocked controllable first valve MV2, the bistable second valve MV1 and the third valve MV3 are each in their first switching states, whereby supply pressure from the supply terminal 12 to the connection 21 and the two connectors 22a . 22b is controlled for the downstream trailer control valve device to ventilate them.

By immediately setting the maximum ventilation state, ie the state of maximum ventilation of the spring brake cylinder under a first, very large pressure gradient is established when the actuator of the position "Brake tension" in the position "brake release" is suddenly or suddenly acting on the spring brake piston of the spring brake cylinder first Pressure value generated p ₁ , from which a release force results, which is preferably at least as large as the breakaway force of the spring brake piston within the spring brake cylinder. As a result, the hysteresis typical of such spring brake cylinders is compensated in a rapid manner and the spring brake pistons suddenly break loose, overcoming the frictional forces. The size of the first pressure value p ₁ can be determined for example by experiments and in the context of an end-of-line programming in a memory of the control device 8th be filed.

After reaching the first pressure value p ₁ , which, for example, from the pressure sensor 56 measured and sent to the controller 8th is reported, the valve device 10 then from the controller 8th controlled in a state in which the brake pressure p in the spring brake cylinders starting from the first pressure value p ₁ under a second, compared to the first gradient smaller gradient for taking a partial release position or full release position at time t ₂ to a higher than the first pressure value p ₁ second Pressure value is increased. In the illustrated embodiment, the driver holds the operating lever 2 For example, while in the position "drive (brake release)" until the full-release pressure p _lös at time t ₂ is reached, in which according to 3 the braking force F is equal to zero.

In 2 For example, the first gradient is shown in idealized form by a vertical pressure curve at time t ₁ , also in order to clarify the difference to the smaller second gradient in the period between t ₁ and t ₂ . In reality, however, some time is needed to reach the first pressure value p ₁ .

In the embodiments of 4 and 5 . 6 and 7 such as 8th and 9 has the brake actuator 2 as another position the position "neutral". This can be achieved, for example, by a rocker switch with three positions "Brake Locking", "Neutral", "Brake Release" be realized, wherein the brake pressure p is varied in the manner described above depending on the holding period of the rocker switch in the positions "Bremszuspannen" or "brake release". Furthermore, the position "neutral" is preferably arranged between the positions "Brake tensioning" and "brake release", so that at a place made during the drive of the vehicle bodies of the brake actuator 2 from the "brake-to-brake" position to the "brake-release" position or, in the reverse direction, to the "neutral" position.

In the embodiment of 4 and 5 is by placing the brake actuator 2 from the "brake release" at time t ₀ and holding in position "Bremszuspannen" between the times t ₀ and t _1, the brake pressure p from the full-release pressure p _lös on a opposite the Vollzuspanndruck p _to, for example, slightly larger target braking pressure p ₂ reduced.

When taking the position "neutral" between the times t ₁ and t ₂ by the brake actuator 2 then becomes the electromagnetic valve device 10 in the context of a pressure maintenance phase of the electronic control device 8th Preferably controlled such that the last set or taken in the position "Bremszuspannen" of the brake actuator and at times t ₁ pressure value p _{2 is} kept constant in the spring brake cylinders until time t ₂ .

If then at a further locations of the brake actuator 2 At time t _2, the position "brake release" is reached, then the electromagnetic valve device 10 from the electronic control device 8th in turn controlled as long as in the maximum ventilation state until the brake pressure p in the spring brake cylinders starting from the held in the previous position "Neutral" nominal brake pressure value p _2, for example, again under the first gradient increases abruptly to the first pressure value p ₁ .

Since the maximum ventilation state is set only when reaching the position "brake release" at time t ₂ , the compensation of the hysteresis takes place only in the position "brake release" at time t ₂ . By holding the brake actuator in the position "brake release" is then analogous to 2 an increase of the braking pressure p in the second, opposite the first gradient smaller gradient preferred to full release pressure p _lös at the time _T3. This results in the in 5 shown braking force curve of the braking force F.

In the embodiment of 6 and 7 is when placing the brake actuator 2 from "Brake Clamping" to "Brake Release" via "Neutral", the valve device already reaches the "Neutral" position 10 controlled in the maximum ventilation state until the brake pressure p in the spring brake cylinders, starting from the brake pressure p ₂ , which was last set in the context of "Bremszuspannen" under the first gradient abruptly to the first pressure value p _{1 is} increased.

Then, when the first pressure value p _{1 is reached} at time t ₁ , the electromagnetic valve device 10 from the electronic control device 8th is further controlled such that the target braking pressure p, starting from the first pressure value ₁ at a third gradient in a brake pressure ₃ at time t ₂ is increased p, which again is smaller than the full-release pressure p _lös. Thus, the third gradient exists between the times t ₁ (reaching or taking in "neutral") and t ₂ (reaching or taking in "brake release"). This already results in holding or taking the position "neutral" by the brake actuator 2 in a compensation of the hysteresis and in a slow brake release phase under the relatively low third gradient.

If then under further actuation of the brake actuator 2 is taken at the time t _2, the position "brake release" and held for a period between t ₂ and t ₃ , then the electromagnetic valve device 10 preferably controlled such that the desired brake pressure is increased under a fourth, opposite the third gradient larger gradient until, for example, at time t _3, the full-release pressure p _lös is reached. This then corresponds to a faster brake release phase in the "brake release" position subsequent to the slow brake release phase present in the "neutral" position.

In order to prevent the spring brake from being unintentionally or only partially released over a relatively long period of time, which leads to overheating and increased wear of the brake actuator, eg a disc brake, it can preferably be provided that the electronic control device 8th an accelerator pedal signal input 58 for of an accelerator 60 having the vehicle derived accelerator pedal signals and is formed that at at the accelerator pedal signal input 58 pending, an operation of the accelerator pedal 60 representative accelerator pedal signal, the electronic control device 8th the electropneumatic valve device 10 in the maximum ventilation state controls to those in the embodiment of 4 and 5 above described pressure holding phase or in the embodiment of 6 and 7 abort above described slow brake release phase and the Spring brake cylinder to bring to the full release position.

Alternatively or additionally, for the same purpose, the electronic control device 8th have a time measuring device or be connected to such and formed that at one of the electronic control device 8th detected, holding a predetermined time duration holding the brake actuator 2 in the "Neutral" position, the electronic control device 8th the electropneumatic valve device 10 in the maximum ventilation state controls to cancel the pressure maintenance phase or the slow brake release phase and bring the spring brake cylinder in full release position.

According to another, in 8th and 9 illustrated embodiment can with the electronic control device 8th be provided together acting means for detecting brake slip, for example in the form of wheel speed sensors 64 and an ABS logic, preferably in the control device 8th is implemented. The controller after 1 Accordingly, for example, has wheel speed signal inputs 62 that with wheel speed sensors 64 keep in touch. Alternatively, those of the wheel speed sensors 64 controlled wheel speed signals are also controlled via a vehicle data bus in the control device.

The ABS logic then determines from the wheel speeds whether the actual brake slip deviates from or exceeds a tolerable or optimal brake slip.

The electronic control device 8th controls the electromagnetic valve device 10 then in such a way that at a detected, the tolerable brake slip exceeding actual brake slip of the brake pressure p in the spring brake cylinders according to 8th while holding the brake actuator 2 in the position "Brake Tensioning" in cycles as long as initially reduced abruptly and then gradually increased again until the tolerable brake slip is reached. By "sudden reduction" is meant a brake pressure reduction under a very large pressure gradient, while "gradual increase" is understood to mean a change in pressure with a lower gradient. In order for a brake slip control is realized in particular in the position "Bremszuspannen" of the brake actuator. In this case, the reduction of the target brake pressure decreases with each cycle, as is the case 8th evident. This results in a sawtooth-like course of the brake pressure p or the braking force F ( 9 ) over time t while holding the brake actuator in the brake-apply position.

In all the embodiments described above, the valve device 10 from the controller 8th controlled that of the respective via the brake actuator 2 desired target brake pressure is generated, wherein preferably by means of a in the control device 8th implemented brake pressure control algorithm of the connection 21 or at the connections 22a and 22b Pending actual brake pressure is adjusted within an allowable tolerance to the setpoint brake pressure p shown in the figures over time.

The embodiment of a valve device 10 from 1 In contrast, any valve device with which the brake pressure curves or braking force curves shown or claimed in the figures can be implemented over time falls within the scope of the invention.

LIST OF REFERENCE NUMBERS

1

 The parking brake module

2

 operating lever

3

 exhaust port

4

 Parking brake signal transmitter

6

 signal line

8th

 control device

10

 valve means

12

 supply port

14

 Supply pressure line

16

 connection

18

 connection

20

 pressure line

21

 connection

22a / b

 connections

24

 pressure sensor

26

 connection

28

 exhaust port

30

 connection

32

 pressure line

34

 connection

36

 exhaust port

38

 connection

40

 Control pressure line

42

 control connection

44

 relay valve

46

 connection

48

 pressure line

50

 check valve

52

 output

53

 output

54

 pressure line

56

 pressure sensor

58

 Accelerator signal input

60

 accelerator

62

 Raddrehzahlsignaleingang

64

 wheel speed sensors

100

 Spring brake device

Claims (18)

Electro-pneumatic spring brake device ( 1 ) of a motor vehicle, which a) means ( 2 ) for generating electrical brake actuation signals which at least represent the states "brake application" and "brake release", b) an electronic control device which receives the brake actuation signals ( 8th ), c) one of the control electronics ( 8th ) dependent on the actuating signals controlled electropneumatic valve device ( 10 ) and d) at least one pneumatically actuated spring brake cylinder, wherein e) the electropneumatic valve device ( 10 ) the at least one spring brake cylinder by connecting to a compressed air reservoir ( 12 ) or by connecting to a pressure sink ( 3 ) and wherein f) a through the electronic control device ( 8th ) achievable maximum ventilation state of the electropneumatic valve device ( 10 ) exists in which the electropneumatic valve device ( 10 ) a maximum flow cross-section between the compressed air supply ( 12 ) and the at least one spring brake cylinder, characterized in that g) the electronic control device ( 8th in that, during a change of the state from "brake clamping" to "brake release" during the travel of the vehicle, the electromagnetic valve device ( 10 ) from the electronic control device ( 8th ) is controlled as long as in the maximum ventilation state until the pressure in the at least one spring brake cylinder is increased starting from an initial pressure value below a first gradient abruptly to a higher contrast first, but still below the spring brake cylinder completely dissolving brake release pressure pressure value and after reaching the first pressure value is controlled in a state in which the pressure in the at least one spring brake cylinder, starting from the first pressure value under a second, compared to the first gradient gradient for taking a partial release position or full release position is increased to a relation to the first pressure value higher second pressure value. Spring brake device according to claim 1, characterized in that the first pressure value is at least as large as the pressure value which generates a compressive force on a spring brake piston of the at least one spring brake cylinder, which corresponds to the breakaway force of the spring brake piston with respect to the spring brake cylinder. Spring brake device according to claim 1 or 2, characterized in that the electromagnetic valve device ( 10 ) from the electronic control device ( 8th ) is further controlled so that the second pressure value is greater, the longer the signal duration of the braking operation signal representing the "brake release" condition and corresponds at most to a brake release pressure at which the at least one spring brake cylinder is in the full release position. Spring brake device according to one of the preceding claims, characterized in that the electromagnetic valve device ( 10 ) at least one connection between the compressed air supply ( 12 ) and the at least one spring brake cylinder creating passage position and a connection blocking this locking position exhibiting magnetic valve, which in the state "brake release" of the electronic control device ( 8th ) is controlled alternately or pulsed between the passage position and the blocking position. Spring brake device according to one of claims 1 to 3, characterized in that the electromagnetic valve device includes at least one proportional solenoid valve, with which a variable flow cross section between the compressed air reservoir and the at least one spring brake cylinder is adjustable. Spring brake device according to one of the preceding claims, characterized in that by the means ( 2 ) for generating electrical brake actuation signals in addition to a state of "neutral" representing brake actuation signal is generated and that in the case of the vehicle during the change from the state "Brake" in the state "brake release" the state "Neutral" is passed, already at Ingestion of the "neutral" state or only when the "brake release" state is assumed, the electromagnetic valve device ( 10 ) from the electronic control device ( 8th ) is controlled in the maximum ventilation state until the pressure in the at least one spring brake cylinder is increased abruptly from an initial pressure value below the first gradient to the first pressure value. Spring brake device according to claim 6, characterized in that when ingesting the state "neutral" the electromagnetic Valve device ( 10 ) in the context of a pressure maintenance phase of the electronic control device ( 8th ) is controlled in such a way that the pressure value last set or assumed in the "brake-engaged" state is kept constant in the at least one spring-loaded brake cylinder. Spring brake device according to claim 6, characterized in that when ingesting the state "neutral", the electromagnetic valve device ( 10 ) in the context of a slow brake release phase of the electronic control device ( 8th ) is controlled such that the pressure in the at least one spring brake cylinder is increased starting from the first pressure value below a third gradient. Spring brake device according to claim 8, characterized in that when ingesting the state "brake release" the electromagnetic valve device ( 10 ) from the electronic control device ( 8th ) is controlled such that the pressure in the at least one spring brake cylinder is increased as long as a fourth, compared to the third gradient gradient until the second pressure value is reached. Spring brake device according to one of claims 7 to 9, characterized in that the electronic control device ( 10 ) an accelerator pedal signal input ( 58 ) for a gas pedal ( 60 ) of the vehicle and that is formed at the accelerator pedal signal input ( 58 ), pressing the accelerator pedal ( 60 ) representing the accelerator pedal signal the electronic control device ( 8th ) the electropneumatic valve device ( 10 ) in the maximum ventilation state controls to cancel the pressure holding phase or the slow brake release phase and bring the at least one spring brake cylinder in the full release position. Spring brake device according to one of claims 7 to 10, characterized in that the electronic control device ( 8th ) has a time measuring device or is connected to such and is formed such that at one of the electronic control device ( 8th ), a predetermined time exceeding the state of "neutral" detected the electronic control device ( 8th ) the electropneumatic valve device ( 10 ) in the maximum ventilation state controls to cancel the pressure holding phase or the slow brake release phase and bring the at least one spring brake cylinder in the full release position. Spring brake device according to one of the preceding claims, characterized in that the means ( 2 ) for generating electrical brake actuation signals includes a driver operable brake actuator such as a rocker switch, a lever or a push button with two positions "Zuspannen" and "brake release" or each with three positions "Brake,""neutral" and "brake release" includes, and / or another electronic control device which automatically generates the electric brake actuation signals without the driver's intervention. Spring brake device according to one of the preceding claims, characterized in that with the electronic control device ( 8th ) co-operative agents ( 64 ) are provided for detecting brake slip, wherein the electronic control device ( 8th ) the electromagnetic valve device ( 10 ) controls such that at a detected, a tolerable brake slip excess brake slip, the pressure in the at least one spring brake cylinder in cycles initially reduced so suddenly and then gradually increased again until the tolerable brake slip is reached. Spring brake device according to claim 13, characterized in that the reduction of the brake pressure with each cycle is reduced. Spring brake device according to one of the preceding claims, characterized in that the electromagnetic valve device ( 10 ) from the electronic control device ( 8th ) is controlled such that the set in the at least one spring brake cylinder pressure value is the smaller, the longer the signal duration of the state "Bremszuspannen" representing brake actuation signal and minimally corresponds to a Bremszuspanndruck, wherein the at least one spring brake cylinder is in the Vollzuspannstellung. Spring brake device according to one of the preceding claims, characterized in that the electromagnetic valve device ( 10 ) at least one connection between the pressure sink ( 3 ) and the at least one spring brake cylinder creating passage position and this connection blocking blocking position exhibiting magnetic valve, which is controlled in the presence of the state "Bremszuspannen" representing brake actuation signal from the electronic control device alternately or pulsed between the passage position and the blocking position. Spring brake device according to claim 15, characterized in that the electromagnetic valve device at least one Proportional solenoid valve includes, with which a variable flow area between the pressure sink and the at least one spring brake cylinder is adjustable. Motor vehicle, in particular road-bound motor vehicle comprising a spring brake device according to one of the preceding claims.

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