DE102005042364A1 - Pressure medium system e.g. pneumatic system, safety device for motor vehicle, has gas supply units activated individually or in combination, where gas volume is controlled, and gas expansion of unit is switched in controllable manner - Google Patents

Abstract

The device has gas supply units (7a-7c) provided for an emergency operation, where the gas supply units are formed in a common module. The units are activated individually or in combination using a control mechanism (5) with the determined conditions. The overall time unit of the gas supply unit is determined, and the gas volume is controlled or adjusted over time. The gas expansion of the unit is else switched in a controllable manner. An independent claim is also included for a method for operating a safety device.

Description

The The invention relates to a safety device for a pressure medium system according to the preamble of claim 1 and a method for its application.

Pressure fluid systems are in the form of hydraulic and / or pneumatic systems in various embodiments and for a big number of use cases in use for a long time. Especially for safety-critical applications It is known, the consequences of a pressure drop, for example by a failure of the pressure source, by special measures or counteract devices.

So can be provided as a pressure source about a second pressure medium pump be which for the case of failure of the first pressure medium pump assumes its function. However, this variant is on the one hand with high costs for a redundant Design of the pressure medium pump connected and offers the other hand often limited additional security, because the availability of pressure medium pumps as mechanical systems even when not in use decreases over time. To the availability of emergency pressure medium pumps to ensure, Therefore, a relatively high maintenance is necessary.

moreover it is basically also for the case of an over the actual pressure medium pump outgoing disorder, for example in case of a major leak of the printing system, desirable and for many safety-relevant applications are essential, if then one after Volume and pressure sufficient amount of pressure medium within a very short time to disposal stands to the overall system for a certain amount of time or number of activities operated by associated actuators continue and / or in a safe Condition to convict can. A redundant pressure medium pump would have to be quite large and dimensioned for this purpose They will also be able to get their rated output within the shortest possible time Time to reach.

to Avoiding these disadvantages, different approaches are already known: Thus, in particular in pneumatic systems usually one anyway existing pressure accumulator, which ensures a more even operation of the pressure medium pump allows and Should buffer demand peaks, be designed so large that a for one Emergency operation sufficient volume stored under operating pressure can be. Besides also here relevant disadvantages in relation to Space, weight and cost is in addition to consider that in pneumatic systems at a standstill often due to small leaks after some time a pressureless system state sets, so that this extra Pressure medium volume for the emergency operation when commissioning the system every time anew must be built. This not only worsens the energetic Efficiency of the whole plant, but also extends the time span of the Startup of the system considerably.

at Application of this approach to hydraulic systems is an additional one here Provide diaphragm or other seal, which under pressure located gas or a spring chamber of a mechanical spring of the hydraulic fluid separates. This membrane is exposed to high operating pressures and frequent movements and therefore prone to failure, maintenance-intensive and expensive. In case of damage The diaphragm can also control the hydraulic system by gas in Fail the hydraulic circuit.

Further It is known in place of spring accumulators in the form of mechanical Springs or gas springs, energy storage in the form of pyrotechni rule Provide gas generators. These have the advantage of being pronounced favorable relationship of weight and volume to the storable amount of energy. To exist until the moment of their release here only small claims with respect to a seal to the pressure medium, creating a seal of the gas generated by the pyrotechnic gas generator against a hydraulic fluid or Also, a pneumatic system is much cheaper to realize.

From the DE 44 33 212 C1 a device is known which can set a hydraulic fluid in a hydraulic tank and thus a hydraulic circuit under pressure with the aid of a pyrotechnic gas generator and a plunger. The publication deals with hydraulic circuits for emergency systems such as shutdown systems for high voltage circuits and opening systems for emergency doors, ie with systems that are not designed for normal operation by means of a pressure medium pump.

A similar system is in the DE 43 30 216 A1 which discloses pyrotechnically operated rescue and emergency equipment, which are operated by means of exchangeable pyrotechnic cartridges.

These emergency systems for exclusive operation by means of pyrotechnic gas generators or interchangeable Druckgaspatronen make in practice entirely different requirements and therefore form a completely different application than pressure fluid systems that are designed for continuous operation by means of a pump and only in addition to have an emergency pressure supply.

From the DE 101 11 233 A1 an energy storage device for hydraulic systems is known in which when lowering the pressure in a hydraulic circuit automatically a gas generating cartridge is activated, which can be a Gasdruckbehäl ter or a pyrotechnic gas generating cartridge. In this case, to prevent a reaction of the gas of the gas generating cartridge with the hydraulic medium is either provided with an inert gas filled gas generating cartridge or the gas space from the hydraulic medium separating membrane. Although this membrane is exposed to the activation of the gas generating cartridge only comparatively low mechanical loads, but still causes effort and expense in the production and is also difficult to control or maintain in the context of an inspection. To increase the reliability of the device, according to one embodiment, a plurality of gas generating cartridges can be used in particular as redundant systems. This significantly improves the overall availability of the system.

Indeed In practice, numerous disturbances are conceivable in the operation of printing systems, to which such a system does not respond in an ideal way can. Thus, the pyrotechnic known in the art Gas generators in any way regulated in their gas production, which e.g. at a relatively slow pressure drop of the pressure medium system first no measures are taken until a threshold is reached, and subsequently upon reaching the threshold, the pyrotechnic gas generating cartridge ignited and in a very short time a considerable system pressure is built up. Before the ignition Depending on the design, the pyrotechnic gas generating cartridge can do this of the system to a system pressure drop come the special requirements may no longer be fair. In addition, there is a risk that at a mechanical damage of the system by the generated pressure surge of the pyrotechnic gas generator the system is damaged even further and in the worst case, for example, by tearing or bursting a previously only damaged Connection or fluid line, completely fails.

Finally is it always provided by the prior art, only by activation a gas generating cartridge to ensure the required system pressure, for example, to bring the system into a safe state can. In many cases would it be however desirable one about it to allow operation beyond for example, to continue the system for a while to be able to operate or after a standstill phase again in an emergency operating mode to be able to bring.

So it is with a hydraulically or pneumatically switchable transmission of a motor vehicle is very desirable, in case of failure of the operating pressure source with the help of a pyrotechnic gas generator a short-term To enable further operation, to safely stop the vehicle outside the traffic flow to ensure. The possibilities the known solutions but exhausted. However, it makes sense to keep the system after a certain amount of time to operate again briefly, for example, from own power to drive on a tow truck, or at least for a towing process to be capable of any Switching position of the transmission in the idle position and / or to open a pressure-medium-controlled drive clutch.

In front In this background, the invention is based on the object Device to present the problems described with Help one as possible inexpensive, space-saving, reliable and low-maintenance device solves.

The solution This object is apparent from the features of the main claim, while advantageous embodiments and developments of the invention the dependent claims are removable.

Of the Invention is based on the finding that an extended or intermittent emergency operation at a pressure drop enable in a pressure medium system and reduce the burden on the entire system by pressure fluctuations leaves, if it succeeds, the type of gas generation after pressure and volume over time to regulate or control. Therefor may instead of the prior art provided a gas generating cartridge - or more Gas generating cartridges, merely as redundant systems for increasing the reliability provided gas generating cartridges - be provided, several gas generators either individually and / or in combination to activate or the gas evolution of one or more gas generators controllable too shape.

Therefore The invention relates to a safety device for a pressure medium system out, which next to a for a normal operation provided pressure source at least one gas supply device which, in the presence of certain conditions by means of a Activation device is activated.

In this case, a normal operation is understood to mean operation with a trouble-free pressure medium system, in which all the usual system functions NEN be executed without activation of a gas supply device of the safety device. The mentioned specific conditions mostly relate to system states of the pressure medium system in which the system pressure due to a malfunction and / or due to a rarely occurring event is not sufficient to fulfill the intended task or where such a condition is expected in the near future. Examples include the failure of the intended for normal operation pressure source, the occurrence of major leaks and consequent pressure drop.

It but they are also cases conceivable in which the for the normal operation provided and fully functional pressure medium source is unable to sufficiently fast enough system pressure build. So it is possible, for example, in one by the Actuated pressure medium system, clamped actuator by activating the gas supply device and the thus generated pressure surge a Try to solve this bound actuator.

To achieve the object, a safety device for a pressure medium system with at least one provided for emergency operation gas supply device is provided which can be activated in the presence of certain conditions by means of an activation device. It is crucial that the pressure medium system has at least one intended for normal operation pressure source. Such a generic device is from the DE 101 11 233 A1 known.

The Asked task is now solved by the total and / or provided per unit time by the at least one gas supply device and controllable on the pressure fluid system becoming effective amount of gas and / or is controllable.

hereby is it possible, on the one hand, even at a relatively minor Decrease in the pressure medium pressure a gas supply device to activate and as possible harmonic transition to get from normal operation to emergency operation without this to a critical increase in fluid pressure and possibly to a surge-related further damage of the system leads.

moreover can the system pressure generated by means of the gas supply device the pressure fluid system of the respective task and the respec conditions System state can be adjusted. This allows a reduction of Total effort and / or a reduction in the system load of the Pressure fluid system. Through a more economical use of through Gas supply device to be provided gas results the possibility an extension Emergency operation with or without time interruptions. Hereinafter the concept of regulation is intended for reasons of linguistic simplification each also include controls.

According to a first embodiment of the safety device according to the invention, the gas supply device is a container under high gas pressure, for example a compressed gas cylinder with CO ₂ gas. Such containers offer the advantage that they are relatively inexpensive and reliable at a suitable connection to the pressure medium system over a comparatively long time without pressure loss. You can be filled with a non-reactive with the fluid of the pressure fluid system gas high purity and thus avoid unwanted reactions with, for example, a hydraulic fluid. It does not matter in which state of aggregation the gas is present in the container. In highly compressed and thereby liquefied gases, it is also conceivable to provide for at least partial compensation of the resulting on activation evaporative cooling special heaters, which may for example be electrically or based on a chemical reaction.

Indeed he falls providable pressure of such a compressed gas cylinder with increasing Emptying off, so that especially in operations, the high system pressures and relatively large Require pressure medium volume, only a part of the gas filling of the compressed gas cylinder can be used meaningfully. In addition, such high pressure resistant Gas cylinders in comparison to the pyrotechnic described in more detail below Gas supply facilities quite bulky and heavy.

In a preferred embodiment According to the invention, the gas supply device is therefore a pyrotechnic Gas supply equipment. Such gas supply facilities have long been known, offer an extremely good ratio of Weight and volume of gas volume to be generated and gas pressure that can be generated. They are almost complete maintenance-free and offer an excellent even after more than 10 years Availability.

According to an advantageous variant, a plurality of gas supply devices can be provided, which can be activated individually. This makes it possible either to extend the total operating time of the pressure medium system in the event of, for example, a leak and / or even after a shutdown of the system to make a short-term reactivation to the pressure fluid system, for example, from an intrinsically safe operation taken during an emergency shutdown condition into a suitable for a repair or towing a vehicle operating condition.

If several gas supply facilities in a common module are summarized, this results in advantages in terms of the connection of the gas supply devices to the pressure medium system as well as on the effort for the assembly and any maintenance or replacement.

According to one another variant of this embodiment can be provided that a plurality of gas supply facilities are provided, which in terms of the total and / or amount of gas provided per unit of time and / or with regard to differentiate between the available pressure. This can be achieved by a corresponding activation of one or more gas supply facilities easily a variety of different characteristics in relation to the total amount of gas provided and the timed course of the volume and pressure provided without being able to regulate the individual gas supply device individually would have to be. This is especially true if the possibility of a staggered Activation of different gas supply facilities provided becomes.

alternative However, it can also be provided that a plurality of Gas supply facilities with regard to the total and / or amount of gas provided per unit of time and / or with regard to just do not distinguish the available pressure just. If some or all of the gas supply facilities at least largely have the same properties, the structure and the Control the gas supply device simplify and still by a clever control of the safety device by far Scope affects the total amount of gas provided as well take its temporal distribution. In the simplest case, this can be the individual Gas supply facilities delayed or activated simultaneously become.

Basically it is possible the gas supply facilities depending on the available space and other Requirements at almost any point of the pressure fluid system to arrange. However, it makes sense if at least one gas supply device is arranged so that it is at a central location or a central region of the pressure medium system can act. Under a central In this case, for example, an area is understood to be an area which spatial near several branches of pressurized lines is to preferably supply many system parts with low line losses with pressure to be able to.

Especially However, it is useful if the central office or the central Area of the pressure fluid system, a large-volume accumulator element and / or a storage container for pressure medium is, being bulky in relation to to understand the volume of other elements or modules of the printing system is. By the buffer effect of the pressure accumulator element or the reservoir for pressure medium Is it possible, also a relatively large gas volume feed into the pressure medium system within a short time, without overloading individual parts of the pressure medium system. In addition, pressure accumulator elements and reservoirs for pressure medium often also in hydraulic systems the possibility of a larger amount of gas without introducing a separating membrane without the gas in the Pressure lines and actuators penetrates and impairs their effectiveness.

alternative or additionally For this purpose, at least one gas supply device arranged so be that they point to a location or area of the fluid system can act, the spatially close in one or more operable by the pressure medium system Actuators is arranged. This is especially useful if within a larger fluid system one or a few actuators are particularly safety-relevant and / or Supply lines to individual actuators or specific system parts the pressure fluid system exposed to a particular risk of damage are. In the case of such damage could also be a large amount generated gas remain ineffective, for example, if a line between the point of introduction of the gas and the corresponding actuator severed or severely damaged, for example, squeezed together. By an arrangement of a Gas supply device close to the site of action of the generated System pressure leaves largely circumvent this problem.

If In addition, at least one gas supply device so arranged is that they are on at least one pressure medium line directly or can act indirectly so that this at least largely can be closed, for example, a safety-critical Actuator can still be actuated, when the connecting lines to the pressure medium system completely torn off are. Under a pressure medium line is in this case not just one flexible pipe or a rigid connecting pipe but any type understood by fluid communication, which in normal operation at least temporarily for used the transport of fluid or the transmission of pressure and, in the event of damage, constitute a safety-critical leak can.

The simplest in this regard concrete embodiment consists of at least one check valve, which in normal operation an access of a pressure medium flow allowed, but in response of a gas generating device, an outflow of the prevented generated gas. However, the system can also do that be designed so that, for example, by the ignition of a pyrotechnic gas generator and the onset of gas initially slide or valves are closed or line connections squeezed.

Especially, but not exclusively, in such cases, in which a gas supply device close to one actuated Actuator is arranged, it may be particularly advantageous if the at least one gas delivery device also so is arranged that the provided gas directly on an actuator and in particular can act on a piston of an actuator, which acted upon in normal operation by the pressure medium of the pressure medium system can be. For pneumatic Systems this is usually possible without special additional measures and requires at best an optional cooling device and / or a filter device for the combustion gas.

It but it is also possible one for a hydraulic actuation exceptionally provided with an intended and designed actuator for an emergency operation To pressurize gas. This has an advantageous effect that the Actuator initially filled with hydraulic fluid or at least moistened, resulting in a one-off or short-term activity usually no major sealing problems result. It is important to achieve the required pressures, however, that the under Pressure to be set total volume in relation to the amount of gas generated not is too big which in particular by the above-described arrangement of Gas supply device next to a to be operated Actuator and optionally a seal of pressure medium lines guaranteed can be.

following is a method for using a security device according to the invention described.

For this is one Control device provided, which characteristic values on system states of the pressure medium system from this Read in sensors, based on given decision rules on a Activation of the safety device decides and in the activation case at least one activation device of the safety device controls. The system states are primarily pressure values. However, pressure differences, Flow rates, capacities or levels of the Pressure fluid system and operating conditions of other units meaningfully evaluated become.

there it is particularly advantageous if the control device with Help of read system states and / or their temporal Course setpoints for the generating total and / or the per unit time to be generated Amount of by the at least one gas supply device determined gas to be generated, and a function of these setpoints or more gas generating devices at the same time and / or delayed activated.

This allows one on the respective pressure fluid system and the present claim adapted use of the safety device, and allows excessive system stresses to avoid that could lead to avoidable further damage to the pressure fluid system. In addition, this allows Method activation of each required gas supply facilities without unnecessary to activate additional gas supply facilities. These are standing with it for a time extension an emergency operation and / or for a Reactivation of the system available.

there It is particularly advantageous if the control device has information about the total and / or per unit of time producible amount of gas and / or the producible Gas pressure of several or all Gas generating facilities has or at least read it. This information can be, for example be stored in the form of a table and are from the controller used to activate the gas generating facilities and if necessary, the order and time delay of their Set activation.

The invention will be further explained with reference to an embodiment. For this purpose, the description is accompanied by a drawing. This shows in a highly simplified form part of a hydraulic system of a vehicle, which in normal operation by a pressure medium pump 1 is supplied with operating pressure, and inter alia via the hydraulic control line 2 an actuator 3 can control which a clutch 4 can operate.

In the event of a malfunction, such as a failure of the pressure medium pump 1 or significant damage to the hydraulic control line 2 , is a control device 5 provided, which of a plurality of sensors 6 Read in system values of the pressure medium system.

If, for example, a demolition of the hydraulic control line occurs 2 immediately next to the pressure medium pump 1 so this is done by the sensors 6 detected and the information from the controller 5 processed. Is according to the in the electronic control device 5 the activation of one or more gas supply facilities 7a . 7b . 7c attached, which in this example in a cartridge to be changed together 9 in close proximity to the actuator 3 the driving clutch 4 are arranged, the controller selects 5 with the help of in a table 8th stored characteristic values of the gas supply facilities 7a . 7b . 7c one or more gas delivery facilities 7a . 7b . 7c for activation, for example, and determines the order and the time interval of the activation.

At a demolition of the hydraulic control line 2 near the pressure medium pump 1 activates the controller 5 with the help of the activation device 10a first the pyrotechnic gas supply device 7a , which via the pressure line 12a first on a shut-off 11a acts and the hydraulic line 2 by squeezing seals and then the gas of the pyrotechnic gas supply device 7a over the intact part of the hydraulic control line 2 towards the actuator 3 passes.

This actuator 3 Now depending on its position, filling level and action volume and depending on the still in the hydraulic control line 2 located amount of hydraulic fluid either directly or indirectly pressurized and thus the drive clutch 4 open. The vehicle can roll out and reach a safe place to park.

Should the pressure on the actuator 3 fall below the required operating pressure or not reach this, this is done by the sensors 6 registered and the controller 5 For example, the gas supply device consisting of a compressed gas cylinder with a pyrotechnic opening actuator can be displaced in time 7b activate via the pressure line 12b directly on the piston of the actuator 3 acts. However, this can also be done at a later time to bring the vehicle, for example, in a towable state. For this purpose, it may also be useful if the control device 5 before or in place of the gas delivery facility 7b the gas supply facility 7c Activated to drain the in the actuator 3 guided pressure by pinching the hydraulic line 2 in the area of the shut-off element 11c to prevent.

1

Hydraulic pump

2

hydraulic control line

3

actuator

4

clutch

5

control device

6

sensors

7a, 7b, 7c

Gas supply facilities

8th

table

9

cartridge

10a, 10b, 10c

activation devices

11a, 11c

shutoff

12a, 12b, 12c

pressure lines

Claims (15)

Safety device for a pressure medium system with at least one gas supply device provided for an emergency operation ( 7a . 7b . 7c ), which in the presence of certain conditions by means of an activation device ( 10a . 10b . 10c ) is activated, wherein the pressure medium system at least one intended for normal operation pressure source ( 1 ), Characterized in that the overall and / or per unit of time of at least (a gas supply device 7a . 7b . 7c ) and controllable on the pressure medium system becomes effective amount of gas controllable and / or regulated. Safety device according to claim 1, characterized in that the gas supply device ( 7a . 7b . 7c ) is a container under high gas pressure. Safety device according to claim 1, characterized in that the gas supply device ( 7a . 7b . 7c ) is a pyrotechnic gas supply device. Safety device according to at least one of the preceding claims, characterized in that a plurality of gas supply devices ( 7a . 7b . 7c ) is provided, which are individually activated. Safety device according to at least one of the preceding claims, characterized in that a plurality of gas supply devices ( 7a . 7b . 7c ) in a common module ( 9 ) is summarized. Safety device according to at least one of the preceding claims, characterized in that a plurality of gas supply devices ( 7a . 7b . 7c ) is provided, which differ in terms of the total amount of gas and / or per unit time provided gas quantity and / or in terms of the pressure available. Safety device according to at least one of claims 1 to 5, characterized in that a plurality of gas supply devices ( 7a . 7b . 7c ) is provided, which do not differ in terms of the total amount of gas and / or per unit of time provided and / or in terms of the pressure available. Safety device according to at least one of the preceding claims, characterized in that at least one gas supply device ( 7a . 7b . 7c ) is arranged so that it can act on a central location or a central region of the pressure medium system. Safety device according to claim 8, characterized in that that the central location or the central area of the pressure medium system a large volume Pressure accumulator element and / or a reservoir for pressure medium is. Safety device according to at least one of the preceding claims, characterized in that at least one gas supply device ( 7a . 7b . 7c ) is arranged so that it can act on a location or a region of the pressure medium system, which is spatially close to one or more actuatable by the pressure medium system actuators ( 3 ) is arranged. Safety device according to at least one of the preceding claims, characterized in that at least one gas supply device ( 7a . 7b . 7c ) is arranged so that it on at least one pressure medium line ( 2 ) can act directly or indirectly so that it is at least largely closed. Safety device according to at least one of the preceding claims, characterized in that at least one gas supply device ( 7a . 7b . 7c ) is arranged so that the supplied gas directly to an actuator ( 3 ), which can be acted upon by the pressure medium in normal operation. Method for operating a safety device according to at least one of the preceding claims, characterized in that a control device ( 5 ) which reads in characteristic values about system states of the pressure medium system and decides on the basis of predetermined decision rules to activate the safety device, and in the activation case at least one activation device ( 10a . 10b . 10c ) of the security device. Method according to claim 13, characterized in that the control device ( 5 ) with the aid of the read-in system states and / or their chronological progression, target quantities for the total quantity to be generated and / or the quantity of the quantity to be generated per unit of time, by the at least one gas supply device ( 7a . 7b . 7c ) to be generated gas and depending on these setpoints one or more gas generating devices ( 7a . 7b . 7c ) activated at the same time and / or with a time delay. Method according to claim 14, characterized in that the control device ( 5 ) information about the total and / or per unit of time producible amount of gas and / or the producible gas pressure of several or all gas generating devices ( 7a . 7b . 7c ), and with the aid of this information, the gas generators to be activated ( 7a . 7b . 7c ) and, where appropriate, the order and time delay of their activation.