DE102012210943A1 - Cold gas generator for filling inflatable airbag in motor car, has closing device for opening or closing blow-out port of pressure tank, where closing element of closure valve is arranged within pressure chamber that is locked by tank - Google Patents

Abstract

The generator (1) has a pressure tank (20) filled with nitrogen and carbon dioxide, and a closing device (7) for opening or closing a blow-out port (25) of the tank over a pilot valve (10) and a closure valve (30). A closing element (32) of the closure valve is arranged within a pressure chamber (21) that is locked by the tank. The closing element seals pressure difference between the tank facing a front end (32.2) of the closing element and a control space (38) facing a front end (36.1) of a main piston valve (36). The closing element is connected with the piston valve over a plunger (34).

Description

State of the art

The invention relates to a cold gas generator according to the preamble of independent claim 1.

Today's passenger safety systems in automobiles include inflatable air bags which are triggered either by hot gases triggered by the ignition of small explosive charges or by a combination of cold gases stored in a gas storage and explosive charges. The hot gases require special precautions, such as an inner coating of the air bag, so that the occupants do not burn or fire in an accident is triggered.

Cold gas generators for filling airbags are known from the prior art, which have a pressure accumulator and a switching valve, wherein the sealing function of the switching valve via conventional seals in radial or in axial form. Furthermore, valve systems are known from the prior art, which can be constructed from a pilot valve and a main control valve, wherein the system main pressure can be used to boost the power at the main control valve. For this purpose, a surface difference is applied to the main control valve and the pressure on one side of the main control valve is influenced by an upstream pilot valve (pilot control valve). These force ratios can be enhanced if necessary by additional springs. The pilot valve can be controlled directly in a known manner electromagnetically. These known systems can have the fundamental disadvantage that by means of conventional seals hardly sufficient tightness over the life of about 15 years can be achieved. In addition, these seals must allow movement of the control piston in case of operation in order to implement fast switching functions, and thus can not have the required for long-term tightness bias.

Disclosure of the invention

The cold gas generator according to the invention with the features of independent claim 1 has the advantage that a closure device for a discharge opening with a pilot valve and a closure valve can be opened and closed several times, and thus a controllability of the gas volume and the rate of inflation is enabled in the case of activation. At the same time, the tightness of the cold gas generator or pressure vessel over the life of about 15 years can be realized by the arrangement of a closing element of the closure system within a closed pressure chamber from the pressure chamber. The arrangement of the closing element of the closure system within the pressure chamber, the high pressure in the pressure chamber of up to about 800 bar can be used advantageously to press the closing element of the closure valve in the corresponding first valve seat and the first valve seat to glue defined. The first valve seat of the closure valve is preferably formed on the inner edge of the discharge opening of the pressure vessel. As a result, the tightness of the closure system can advantageously be made possible over a period of approximately 15 years, which corresponds to the service life of the cold gas generator.

Due to the controllability of the gas volume and the speed of inflation, embodiments of the cold gas generator according to the invention allow an airbag or airbag to be inflated several times as required by a medium stored in the pressure vessel. Information from the accident can be used for this purpose. This means that the inflation of the airbag or airbag can be optimally adapted to the accident, so that the occupants can be protected not only in a first collision, but also in other collisions following the first collision. Furthermore, it is possible to individually adapt the inflation behavior of the cold gas generator to the corresponding occupant, so that not only heavy persons, for whom the airbag system is usually designed, but also lighter persons can be optimally protected, if a corresponding device for detecting the individual occupant data is present in the vehicle.

Another advantage of the cold gas generator according to the invention is the reusability after an accident. The pressure vessel can be refilled with a medium. As the medium, for example, nitrogen (N) or carbon dioxide (CO2) can be used. During vehicle disposal, only the gas pressure in the pressure vessel has to be reduced.

Embodiments of the present invention provide a cold gas generator that can be used for safety critical applications, such as a passive vehicle safety system, that includes at least one air bag. In addition, the cold gas generator according to the invention can be used by controllability of the gas volume and the inflation speed for construction machinery, aircraft and mining.

The cold gas generator according to the invention comprises a pressure vessel filled with a medium and a closure device which releases or closes an exhaust opening of the pressure vessel via a pilot valve and a closure valve. According to the invention, a first closing element of the closure valve is arranged within a pressure chamber closed off from the pressure vessel.

The measures and refinements recited in the dependent claims advantageous improvements of the independent claim 1 cold gas generator are possible.

It is particularly advantageous that the first closing element can seal against a pressure difference which rests between a pressure vessel facing first end face of the first closing element and a control chamber facing the second end face of a main control piston, which is coupled to the first closing element. The first closing element is connected to the main control piston, for example via a first plunger, which passes through the outlet opening. The main spool and the first closing member may be moved in the opening direction when a force difference between an opening force which can be generated by the pressure in the control space and an effective area of the second end face and a closing force which exceeds the pressure in the pressure vessel and an effective area the first end face can be generated, reaches or exceeds a predetermined threshold, wherein the effective area of the second end face is greater than the effective area of the first end face.

In an advantageous embodiment of the cold gas generator according to the invention, a first valve seat of the closure valve and / or a first sealing geometry of the first closure element can be coated with a sealing material. Preferably, the sealing material can be designed as a gas-tight film, which is glued to the first valve seat of the closure valve and / or the first sealing geometry of the first closing element. By coating with sealing material, the tightness of the pressure vessel can be further improved in an advantageous manner.

In a further advantageous embodiment of the cold gas generator according to the invention, at least one compensation channel can enable the pressure exchange between the pressure chamber and the control chamber. Advantageously, the pilot control valve regulates an opening cross section of a control opening arranged between the control chamber and a pressure chamber. The pilot valve releases the control port for pressure equalization via the at least one compensation channel or closes the control port. In addition, an outlet throttle is proposed, which performs a pressure equalization between the control room and the environment. The pilot valve is preferably designed as a normally closed switching valve with a drive and a second closing element which closes or releases the control opening between the at least one compensation channel and the control chamber. When opening the pilot valve, the medium flows through the at least one compensation channel and the control port into the control chamber and the pressure in the control chamber increases until the internal pressure in the pressure vessel is reached. The main control piston has a larger effective area than the first closing element of the closure valve. This results in a resultant force, which leads to the opening of the closure valve. Above the main control piston, the outlet throttle is arranged in the control room to the environment. Through the outlet throttle flows at a pressure difference between the control chamber and the environment, the medium. If the pilot valve is closed again, the pressure in the control chamber drops due to the pressure equalization via the outlet throttle, and the first closing element of the closure valve is pressed back into the first valve seat and thus terminates the outflow of the medium from the pressure vessel. A reopening of the pilot valve again leads to the opening of the closure valve, whereby the medium can flow out of the pressure vessel again. The dynamics of the entire system may be affected by the diameters chosen, the dynamics of the pilot valve and the outlet throttle.

In a further advantageous embodiment of the cold gas generator according to the invention, the drive of the pilot valve can be designed as an electromagnet, which moves the second closing element via an armature against the force of a return spring.

In a further advantageous embodiment of the cold gas generator according to the invention, the pressure vessel may have a mounting opening through which the first closing element of the closure valve can be introduced into the pressure chamber. Preferably, the mounting opening is arranged in the pressure vessel with respect to the discharge opening, wherein the discharge opening is preferably arranged in a cover of the pressure vessel, and wherein the mounting opening is preferably arranged in a bottom of the pressure vessel. For mounting the closure valve, the first closing element can be introduced, for example, with the plunger in the pressure vessel and the plunger are passed through the blow-out. The projecting out of the blow-out opening end of the plunger can then be connected for example by screwing or pressing with the main control piston become. After mounting the closure valve, the mounting opening can be closed by a closure element, in which preferably a safety valve is arranged.

An embodiment of the invention is illustrated in the drawings and will be explained in more detail in the following description. In the drawings, like reference numerals designate components that perform the same or analog functions.

Brief description of the drawings

1 shows a schematic sectional view of an embodiment of a cold gas generator according to the invention.

2 shows a schematic sectional view of an enlarged section of the cold gas generator according to the invention 1 ,

Embodiments of the invention

How out 1 and 2 can be seen, includes the illustrated embodiment of a cold gas generator according to the invention 1 a filled with a medium pressure vessel 20 and a closure device 7 , which has a blow-out opening 25 of the pressure vessel 20 via a pilot valve 10 and a shut-off valve 30 releases or closes. According to the invention, a first closing element 32 of the closure valve 30 within one of the pressure vessel 20 closed pressure chamber 21 arranged. In the illustrated embodiment, the exhaust port 25 with two outlet channels 5 connected via which in the pressure vessel 20 stored medium can flow out. The outlet channels 5 are preferably connected to an inlet of an airbag or airbag, not shown.

How out 1 or 2 is further apparent, is the first closing element 32 over a first pestle 34 which the exhaust opening 25 engages, with a main control spool 36 connected, which in a control room 38 is guided longitudinally movable. At rest, a first sealing geometry acts 32.2 of the first closing element 32 sealing with a respect to the pressure chamber 21 at the inner edge of the exhaust opening 25 arranged first valve seat 26 of the closure valve 30 together. The first valve seat 26 of the closure valve 30 and / or the first sealing geometry 32.2 of the first closing element 32 can be coated with a sealing material to the sealing effect of the closing valve 30 to increase or improve. The sealing material may for example be designed as a gas-tight film, which with the first valve seat 26 of the closure valve 30 and / or the first sealing geometry 32.2 of the first closing element 32 is glued.

How out 1 and 2 is further apparent, is the control room 38 in the illustrated embodiment as of a housing wall 17 the closure device 7 formed limited cavity, wherein the control room 38 a funnel-shaped bottom having an opening which also from the first plunger 34 is penetrated. At the main control piston 36 not shown seals can be arranged, which on the wall 39 of the control room 38 issue. Between the pressure room 21 and the control room 38 is at least one equalization channel 16 arranged, which a pressure equalization between the pressure space 21 and the control room 38 allows. Moreover, in the wall 39 of the control room 38 an outlet throttle 38.1 arranged, which via a drainage channel 38.2 a pressure equalization between the control room 38 and the environment. The pilot valve 10 regulates a cross section of one between the control room 38 and the pressure room 21 arranged control opening 19 , which in the illustrated embodiment at the upper end of the control room 38 is arranged. That means that the pilot valve 10 , Which for a pressure equalization over the at least one compensation channel 16 the tax opening 19 releases or closes.

How out 1 or 2 is further apparent, is the pilot valve 10 executed in the illustrated embodiment as a normally closed switching valve with ball seat, which as a drive 11 an electromagnet with a coil winding 11.1 which has an electrical connection 3 is energized. Will the coil winding 11.1 of the electromagnet via the electrical connection 3 energized, then the generated magnetic force moves an anchor 12 against the force 26 a return spring 12.1 moves, leaving a over a second pestle 13 with the anchor 12 connected second closing element 14 with a second sealing geometry 14.1 from a second valve seat 18 the pilot valve 10 is lifted. The second valve seat 18 is in relation to the control room 38 on the outer edge of the control opening 19 arranged. In addition, on the second ram 13 a seal 15 provided to the armature space against the at least one compensation channel 16 or to seal the control room. The armature space is also considered by the housing wall 17 the closure device 7 limited cavity formed.

How out 1 can be further seen, the pressure vessel 20 a mounting hole 27 on, through which the first closing element 32 of the closure valve 30 in the pressure room 21 can be introduced. After mounting the closing valve 30 becomes the mounting hole 27 through a closure element 28 closed, in which in the illustrated embodiment, designed as a pressure control valve safety valve 29 is arranged. The pressure vessel 20 can in particular in case of fire on the designed as a pressure control valve safety valve 29 Blow off the stored medium to prevent explosion. The gas pressure inside the pressure vessel 20 is about 800 bar. As the medium, for example, nitrogen (N) or carbon dioxide (CO2) can be used.

In the illustrated embodiment, the pressure vessel comprises 20 for limiting the pressure chamber 21 a container wall 22 , a lid 23 in which the exhaust opening 25 is introduced, and a floor 24 in which the mounting opening 27 is introduced. Thus, the mounting hole 27 in the pressure vessel 20 opposite the exhaust opening 25 is arranged, whereby the assembly process of the closure valve 30 is relieved.

The following is with reference to 1 and 2 the function of the cold gas generator according to the invention 1 described.

How out 1 can be seen seals the first closing element 32 against a pressure difference, which between a pressure vessel 20 facing first end face 32.2 of the first closing element 32 and one to the control room 38 facing the second end face 36.1 of the main control piston 36 is present, which with the first closing element 32 is coupled. The main control piston 36 and the first closing element 32 are moved in the opening direction when a force difference between an opening force, which exceeds the pressure in the control room 38 and an effective area of the second end face 36.1 is generated, and a closing force which exceeds the pressure in the pressure vessel 20 and an effective area of the first end face 32.1 can be generated, reaches or exceeds a predetermined threshold. Here, the effective area of the second end face 36.1 larger than the effective area of the first end face 32.1 ,

In the illustrated idle state corresponds to the pressure in the control room 38 the ambient pressure, since the outlet throttle 38.1 over the drainage channel 38.2 a pressure equalization between the control room 38 and the environment performs and the control opening 19 from the pilot valve 10 is closed while the internal pressure in the pressure vessel 20 from about 800 bar only to the effective area of the first face 32.1 of the first closing element 32 acts. Thus, in the illustrated idle state, the maximum differential force acting on the closure valve of about 5200 N. The excess of force can be used to the first sealing geometry 32.2 of the first closing element 32 of the closure valve 30 defined in the first valve seat 26 of the closure valve 30 to glue to allow the tightness over a period of about 15 years.

To open the shut-off valve 30 becomes the pilot valve 10 by energizing the coil winding 11.1 of the drive designed as an electromagnet 11 activated and opened. In the illustrated embodiment, an opening force of about 90 N is required to the second closing element 14 with the second sealing geometry 14.1 from the second valve seat 18 take off and the tax opening 19 to open. In the open state of the pilot valve 10 the medium flows over the at least one compensation channel 16 and the open control port 19 in the control room 38 , in which the pressure up to the storage pressure in the pressure vessel 20 increases. Because the second front side 36.1 of the main control piston 36 a larger effective area than the first face 32.1 of the first closing element 32 has, resulting in a resultant force, which is the main control piston 36 and the first closing element 32 moved in the opening direction and to the opening of the closure valve 30 leads. In the opened state of the closing valve 30 can the medium through the exhaust opening 25 and the outlet channels 5 flow out and fill, for example, an airbag or airbag, not shown.

Will the pilot valve 10 closed again, so the pressure in the control room decreases 38 , because the outlet throttle 38.1 over the drainage channel 38.2 a slow pressure equalization between the control room 38 and the environment performs, and the first closing element 32 of the closure valve 30 will be back in the first valve seat 26 pressed and thus stops the outflow of the medium through the exhaust port 25 and the outlet channels 5 , By re-energizing the coil winding 11.1 of the drive designed as an electromagnet 11 becomes the pilot valve 10 reopened, causing a reopening of the shutter valve 30 leads, causing the medium again through the exhaust port 25 and the outlet channels 5 flow out and can fill the airbag or airbag, not shown on or refill. The dynamics of the entire system is determined by the selected dimensions of the effective areas, the dynamics of the pilot valve 10 and the outlet throttle 38.1 affected. In the illustrated embodiment, the effective area of the main control piston 36 for example, a diameter of about 11 mm. The effective area of the first closing element 32 For example, has a diameter of about 10 mm, and the second closing element has a diameter of about 1.2 mm. The numerical values chosen here are only orientations.

Embodiments of the present invention provide a cold gas generator, which advantageously realizes the tightness of the cold gas generator over the service life via the arrangement of the closing element of the closure valve within the pressure vessel.

Claims (15)

Cold gas generator with a pressure vessel filled with a medium ( 20 ) and a closure device ( 7 ), which an exhaust opening ( 25 ) of the pressure vessel ( 20 ) via a pilot valve ( 10 ) and a closure valve ( 30 ) releases or closes, characterized in that a first closing element ( 32 ) of the closure valve ( 30 ) within one of the pressure vessel ( 20 ) closed pressure chamber ( 21 ) is arranged. Cold gas generator according to claim 1, characterized in that the first closing element ( 32 ) is sealed against a pressure difference which exists between a pressure vessel ( 20 ) facing the first end face ( 32.2 ) of the first closing element ( 32 ) and a control room ( 38 ) facing the second end face ( 36.1 ) of a main control piston ( 36 ) is applied, which with the first closing element ( 32 ) is coupled. Cold gas generator according to claim 2, characterized in that the first closing element ( 32 ) via a first plunger ( 34 ), which the exhaust opening ( 25 ), with the main control piston ( 36 ) is connected and / or coupled. Cold gas generator according to claim 2 or 3, characterized in that the main control piston ( 36 ) and the first closing element ( 32 ) are movable in the opening direction when a force difference between an opening force, which on the pressure in the control room ( 38 ) and an effective area of the second end face ( 36.1 ) and a closing force which exceeds the pressure in the pressure vessel ( 20 ) and an effective area of the first end face ( 32.1 ), reaches or exceeds a predetermined threshold, the effective area of the second end face ( 36.1 ) greater than the effective area of the first end face ( 32.1 ). Cold gas generator according to one of claims 1 to 4, characterized in that a first valve seat ( 26 ) of the closure valve ( 30 ) and / or a first sealing geometry ( 32.2 ) of the first closing element ( 32 ) are coated with a sealing material. Cold gas generator according to claim 5, characterized in that the sealing material is designed as a gas-tight film, which with the first valve seat ( 26 ) of the closure valve ( 30 ) and / or the first sealing geometry ( 32.2 ) of the first closing element ( 32 ) is glued. Cold gas generator according to claim 5 or 6, characterized in that the first valve seat ( 26 ) of the closure valve ( 30 ) at an inner edge of the exhaust opening ( 25 ) of the pressure vessel ( 20 ) is trained. Cold gas generator according to one of claims 1 to 7, characterized in that at least one compensation channel ( 16 ) the pressure balance between the pressure chamber ( 21 ) and the control room ( 38 ). Cold gas generator according to claim 8, characterized in that the pilot valve ( 10 ) one between the control room ( 23 ) and a pressure chamber ( 38 ) arranged control opening ( 19 ) for pressure equalization via the at least one compensation channel ( 16 ) releases or closes. Cold gas generator according to one of claims 2 to 9, characterized in that an outlet throttle ( 38.1 ) a pressure equalization between the control room ( 38 ) and the environment. Cold gas generator according to one of claims 1 to 10, characterized in that the pilot valve ( 10 ) as a normally closed switching valve with a drive ( 11 ) and a second closing element ( 14 ) is executed. Cold gas generator according to claim 11, characterized in that the drive ( 11 ) is designed as an electromagnet, which the second closing element ( 14 ) via an anchor ( 12 ) against the force ( 26 ) a return spring ( 12.1 ) emotional. Cold gas generator according to one of claims 1 to 12, characterized in that the pressure vessel ( 20 ) a mounting opening ( 27 ), by which the first closing element ( 32 ) of the closure valve ( 30 ) into the pressure chamber ( 21 ) can be introduced. Cold gas generator according to claim 13, characterized in that the mounting opening ( 27 ) in the pressure vessel ( 20 ) opposite the exhaust opening ( 25 ) is arranged, wherein the exhaust opening ( 25 ) preferably in a lid ( 23 ) of the pressure vessel ( 20 ), and wherein the mounting opening is preferably in a floor ( 24 ) of the pressure vessel ( 20 ) is arranged. Cold gas generator according to claim 13 or 14, characterized in that the mounting opening ( 27 ) after mounting the closing valve ( 30 ) by a closure element ( 28 ), in which a safety valve ( 29 ) is arranged.

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