• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The pyrotechnic actuator has a housing (1) in the interior of which a piston (3) and a pyrotechnic propellant (12) are arranged. According to the invention, an air gap is provided as thermal insulation in the region of the propellant (12) between the housing (1) and the piston (3). In this way, the housing (1) loses its strength in case of fire, before the propellant (12) ignites, even if the softening temperature of the housing (1) is far above the autoignition temperature. The housing (1) is preferably made of aluminum, the autoignition temperature of the propellant (12) is preferably above 260 ° C. The propellant (12) is preferably located in a piston bore (11) and the base (9) of the igniter (10) is produced by a plastic extrusion with a melting temperature below 260 ° C. and abuts against the inside of the piston tulip (8). so that it must first melt before the propellant (12) reaches the ignition temperature. In order to delay heating of the propellant (12) from the piston tip, the piston (3) at its end facing away from the propellant charge (12) may be solid over at least 30% of its length.
    公开号:AT518680A1
    申请号:T50506/2016
    申请日:2016-06-02
    公开日:2017-12-15
    发明作者:
    申请人:Hirtenberger Automotive Safety Gmbh & Co Kg；
    IPC主号:
    专利说明:

    The present invention relates to a pyrotechnic actuator, in particular for lifting a hood of a vehicle for pedestrian protection, with a housing in the interior of which a piston and a pyrotechnic propellant are arranged, so that shifts in ignition of the propellant, the piston in the housing.
    Pyrotechnic actuators find in the automotive safety technology in the field of passive safety various uses, except in pedestrian protection systems in the known applications safety belt tensioners, active headrests, etc.
    In active pedestrian protection systems, when the pedestrian strikes the bumper, the bonnet is raised to create a head impact deformation space and avoid contact with the hard structures in the engine compartment. As a rule, the adjustment is done on the hinge side, with insufficient deformation area in the front area of the hood and by additional increase in the lock area. The forces required for setting are in the range between about 1 and 10 kN, due to the high dynamic forces and the high safety requirements, the actuators are usually made with a steel housing. An actuator of this type is shown for example in AT 12351 U.
    Another reason for the use of steel as a housing material is the high melting point, which is much higher than the ignition temperature of the pyrotechnics, which takes place in case of fire, the ignition of the pyrotechnics before the softening of the housing. Otherwise, there is a risk that the housing breaks when the pyrotechnics are ignited, parts of the housing are thrown out and rescue personnel are endangered.
    Often, the early ignition of the propellant charge is additionally secured by means of autoignitor. A disadvantage is the high weight of the steel housing and of course the price, since steel housing must be made either stainless or with a corresponding corrosion-inhibiting coating.
    On the other hand, it is also known to provide for fire protection particularly low melting elements, see, e.g. WO 2015/120478 Al. It is shown there an opening which is closed, for example by HDPE. HDPE melts at about 135 ° C, and when the propellant charge a
    Auto-ignition temperature of more than 135 ° C, the opening is melted free, before the propellant ignites, so that the resulting gases are derived to a considerable extent over the opening and thus can not burden the housing or the hood can be adjusted with great force.
    A disadvantage of this solution is the additional production cost. In addition, there is a risk that the HDPE will not ensure tight closure throughout the life of the actuator.
    It is an object of the present invention to provide an actuator which is less expensive to produce and yet has a safe behavior in case of fire.
    This object is achieved by an actuator of the type mentioned in the present invention, that between the housing and the propellant an air gap is provided as a thermal insulation.
    The essence of the present invention can be seen in the realization that in the event of a fire, the temperature on the outside of the actuator increases extremely rapidly. When the propellant is thermally isolated from the housing, the housing softens before the propellant ignites, even if its melting point is well above the autoignition temperature, simply because the temperature of the housing rises significantly faster than the temperature of the body in the event of sudden extreme heat driving element.
    When a flame from the outside is applied to the housing, the ignition is delayed until the strength of the housing has been almost completely lost. When igniting the propellant charge, the back pressure required for the high burnup rate can no longer build up because the housing is destabilized. In the best case, the housing is melted through.
    In the event of a fire, therefore, the housing first loses its strength (for example, the bursting pressure of the housing is only less than 10 bar), and thereafter the blowing agent burns off largely undamaged (and thus slowly). The melting temperature should thus be low, but it may well be well above the autoignition temperature of the propellant.
    It is thus expedient for the melting temperature of the housing to be less than 700 ° C., preferably not more than 630 ° C., but higher than the self-ignition temperature of the blowing agent.
    Due to this, it is possible to manufacture the housing from an aluminum alloy. Aluminum is not only favorable in terms of the melting point, but also in terms of manufacturing costs, because a housing made of aluminum or an aluminum alloy can be produced inexpensively by extrusion or by extrusion.
    The actuator can therefore have a housing made of an aluminum material with a solidus temperature of <630 ° C. The propellant is thermally isolated through the air gap to the housing.
    The second aspect of the invention is the use of a propellant with a high ignition point above 200 ° C, preferably above 260 ° C, and as low a burn rate as possible at low pressure. In contrast to the traditional concept, no autoignitor is required here, it would even be harmful.
    Experience has shown that propellants with a combustion rate at normal pressure (or at a pressure below 2 bar) and room temperature below 10 mm / s are suitable for this principle. The inventive combination of the boundary conditions described above, the external effect of the actuator is reduced in the event of fire to non-hazardous levels.
    It is favorable if the blowing agent adjacent a substance whose melting point is below the autoignition temperature of the propellant. In this way, first this substance must melt before the propellant burns due to auto-ignition, so that more time is gained in which the housing loses its strength. The substance adjacent to the blowing agent may be wax. However, it is particularly simple if an igniter is provided whose base is formed by a plastic extrusion, because then the substance adjacent to the blowing agent is formed by the material of the plastic extrusion. If an igniter coating is used, for example, made of polyamide 66, above 260 ° C, a slowing of the heating occurs with heat input, because the encapsulation begins to melt, which delays further heating. Alternative materials for the encapsulation are polyethylene, polypropylene and polyketone.
    It is further favorable if the plastic extrusion has at least one cavity. In the case of normal ignition, the ignition unit holds with cavity or keep the cavities the resulting pressure in case of fire - when the plastic softens - this is not the case, so that the gases can escape through the plastic extrusion.
    To ensure adequate thermal insulation through the air gap, its thickness should be at least 1 mm.
    Since thus the diameter of the propellant container or the piston rod is 2 mm lower than usual (where it almost touches the housing), it must be correspondingly longer for the same amount. Thus, the length of the actuator does not need to be increased is provided according to a further feature of the invention that the propellant is in a piston bore, ie in a recess of the piston, and the air gap is at least in the region of the propellant between the piston and housing.
    The piston must, of course, at least partially contact the housing at its two ends, so that it is stably guided. Heat is inevitably transferred to the piston through these points of contact. Advantageously, the piston below the propellant charge has a widening in which the igniter is located. As a result, heat flow into the piston via the direct contact points with the housing takes place only in the region of the igniter at this end, where - as described above - the heat input is delayed by its encapsulation.
    In order to slow down the heating at the opposite end of the piston, ie at the end facing away from the propellant, it is provided according to one embodiment that the piston is solid there over at least 20%, preferably at least 30%, of its length. It is therefore slowed down on the side of the piston tip, the temperature increase by the piston is made massive in its upper region, for example, at least 20% of the length of the piston. The heat transfer from the outside is significantly slowed down by the structural details described, resulting in a delay of the ignition and a strong thermal load of the housing. Additionally or alternatively, the tip may be within the housing.
    Since the piston according to the invention over a majority of its length has a distance from the housing, the seal between the housing and the piston at the opposite end of the propellant means of the piston by means of a sealing element, wherein the sealing element is secured by a bead in the housing against displacement.
    To limit the force peaks occurring, it is necessary to connect the actuator to the body with defined compliance (path-force characteristic). It is therefore expedient to fix a fastener by means of double-sided circumferential crimping on the housing, wherein preferably the fixation of the fastener is reinforced by a diameter jump of the housing. In this way, a damping of force peaks can take place via a defined flexibility between the fastening element and the housing.
    The connection fastener housing can therefore be done via a crimping to dampen force peaks. Alternatively or additionally, an attenuation of force peaks over a defined compliance of the piston, in particular by the fact that upon reaching a defined force level, a targeted deformation of the piston tip occurs and thereby force peaks are limited when hitting the piston tip on the hinge or hood.
    With reference to the accompanying drawings, the present invention will be explained in more detail. 1 shows an actuator according to the invention in side elevation, partly in section; Fig. 2 the same in a perspective view;
    3 shows a detail in the region of the fastening element; and FIG. 4 shows a detail of the piston rod side seal.
    The actuator has a housing 1, which can be fastened by means of a fastening element 2 to a body (not shown). In the housing 1 with the housing bottom 4 is a piston 3, which has a piston tulip 8 and a piston rod 7. The piston rod 7 is guided linearly through the housing bottom 4. Since this contact point is one of the two thermal bridges between the piston 3 and housing 1, this is designed only as long as necessary. As described above, the piston 3, more precisely the piston rod 7, made massive in the tip region, which also allows a cheaper production.
    The seal of the piston 3 relative to the housing 1 via an O-ring 6 between the inner surface of the housing 1 and the piston rod 7, as shown, or alternatively via a 0-ring between the piston cup 8 and housing 1. In the piston 3, more precisely in the Kolbentulpe 8, there is a base 9 of a fuze 10. The powder space in the piston 3 forms a piston bore 11, the propellant 12 from the second thermal bridge between the housing 1 and piston 3 (di the contact surface between piston tulip 8 and
    Housing 1) distanced. From the housing 1, the propellant 12 is separated by an air gap.
    The attachment of the base 9 takes place directly through the housing 1, here represented by a crimping 13. The crimping 13 further allows at least one liquid seal for the actuator interior.
    The housing 1 is protected at the bottom of the housing 4 with a closure 14 from splash water and environmental influences. The closure 14 also serves to secure the initial position of the piston 3 and is broken when triggered.
    The connection between the housing 1 and fastener 2 via a pinch 15 on the fastener 2 against the housing. 1
    权利要求:
    Claims (18)
    [1]
    Claims:
    1. Pyrotechnic actuator, in particular for lifting a hood of a vehicle for pedestrian protection, with a housing (1), in the interior of which a piston (3) and a pyrotechnic propellant (12) are arranged so that upon ignition of the propellant (12) the piston (3) in the housing (1) shifts, characterized in that between the housing (1) and the propellant (12) an air gap is provided as a thermal insulation.
    [2]
    2. Pyrotechnic actuator according to claim 1, characterized in that the melting temperature of the housing (1) is less than 700 ° C, preferably at most 630 ° C, but higher than the autoignition temperature of the propellant (12).
    [3]
    3. Pyrotechnic actuator according to claim 2, characterized in that the housing (1) is made of an aluminum alloy.
    [4]
    4. Pyrotechnic actuator according to claim 3, characterized in that the housing (1) is produced by extrusion or by extrusion.
    [5]
    5. Pyrotechnic actuator according to one of claims 1 to 4, characterized in that the autoignition temperature of the propellant (12) is at least 200 ° C, preferably at least 260 ° C.
    [6]
    6. Pyrotechnic actuator according to one of claims 1 to 5, characterized in that the blowing agent (12) at pressures below 2 bar has a burning rate below 10 mm / s.
    [7]
    7. Pyrotechnic actuator according to one of claims 1 to 6, characterized in that the blowing agent (12) adjacent to a substance whose melting point is below the autoignition temperature of the propellant (12).
    [8]
    8. Pyrotechnic actuator according to claim 7, characterized in that the blowing agent (12) adjacent substance is wax.
    [9]
    9. Pyrotechnic actuator according to claim 7 with an igniter (10) whose base (9) is formed by a plastic extrusion, characterized in that the blowing agent (12) adjacent substance is the material of the plastic extrusion.
    [10]
    10. Pyrotechnic actuator according to claim 9, characterized in that the material of the plastic extrusion is selected from the group polyamide, polyethylene, polypropylene and polyketone.
    [11]
    11. Pyrotechnic actuator according to claim 9 or 10, characterized in that the plastic extrusion has at least one cavity.
    [12]
    12. Pyrotechnic actuator according to one of claims 1 to 11, characterized in that the thickness of the air gap is at least 1 mm.
    [13]
    13. Pyrotechnic actuator according to one of claims 1 to 12, characterized in that the propellant (12) in a piston bore (11) of the piston (3) and the air gap, at least in the region of the propellant (12) between the piston (3 ) and housing (1) is located.
    [14]
    14. Pyrotechnic actuator according to claim 13, characterized in that the piston (3) at its the propellant charge (12) facing away from the end of at least 20%, preferably at least 30%, its length is solid.
    [15]
    15. Pyrotechnic actuator according to claim 13 or 14, characterized in that the piston (3) at its the blowing agent (12) opposite end by means of a sealing element (6) relative to the housing (1) is sealed, and that the sealing element (6) is secured by a bead (16) in the housing (1) against displacement.
    [16]
    16. Pyrotechnic actuator according to one of claims 1 to 15, characterized in that a fastening element (2) by means of double-sided circumferential crimping (15) on the housing (1) is fixed, wherein preferably the fixation of the fastener (2) by a diameter jump of the housing (1) is reinforced.
    [17]
    17. Pyrotechnic actuator according to one of claims 1 to 16, characterized in that via a defined flexibility between the fastening element (2) and housing (1) there is an attenuation of force peaks.
    [18]
    18. Pyrotechnic actuator according to one of claims 1 to 17, characterized in that via a defined compliance of the piston (3) takes place an attenuation of force peaks.
    类似技术:
    公开号 | 公开日 | 专利标题
    DE102017112054A1|2017-12-07|Pyrotechnic actuator
    DE3901449C1|1990-02-01|
    EP2193053B1|2011-09-28|Gas generator and method for influencing a flow of gas in a gas generator
    EP2195205B1|2012-10-10|Gas generator for an air bag module
    EP0884227B1|2002-04-24|Linear drive for a vehicle occupant restraint system
    DE112014003721T5|2016-04-28|Pressurized actuator
    DE112014004496T5|2016-07-21|Pyrotechnic actuator
    WO1998057828A1|1998-12-23|Gas generator
    EP0960634A2|1999-12-01|Temperature responsive safety device for pressure vessel
    DE102013000142B4|2020-08-06|Airbag unit with influencing device
    DE102012213169B4|2015-06-11|Hydraulic monotube shock absorber
    EP2547950B1|2014-04-23|Safety device against excess temperature
    EP2537561B1|2016-06-08|Blocking element for closing an opening
    DE60013076T2|2004-12-30|PRESSURE RELIEF VALVE
    AT516050B1|2016-02-15|Pyrotechnic actuator
    WO2018153649A1|2018-08-30|Closure package, vibration damper, and use of a seal holder
    EP1113955B1|2005-11-02|Steering shaft
    AT522245B1|2020-09-15|Actuator, in particular for raising hoods
    DE102012209254A1|2013-12-05|Vehicle safety release device for use in vehicle safety system, has destroying device partly formed to destroy victim element in response to trigger signal, where destroyed victim element is not partly fixed to trigger element
    AT9827U1|2008-04-15|ACTUATING DEVICE WITH A CYLINDER PISTON DEVICE
    DE1428672A1|1971-03-04|Anti-tank mine
    EP2993441A1|2016-03-09|Container for storing an explosive substance
    DE202004008312U1|2004-09-30|Igniter for a gas generator for a motor vehicle safety device has early ignition material in spark device adjacent to a contact rod
    AT515658B1|2015-11-15|Rollover body for vehicles
    DE2010880C3|1978-04-13|Hand grenade detonator
    同族专利:
    公开号 | 公开日
    DE102017112054A1|2017-12-07|
    AT518680B1|2018-10-15|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    DE2747977A1|1977-10-26|1979-05-03|Dynamit Nobel Ag|Electrically-triggered gas-driven piston - esp. for activating military battery, has gas generating capsule contained within pot shaped piston|
    EP0685370A1|1994-05-31|1995-12-06|Morton International, Inc.|Autoignition of a fluid fuelled inflator|
    DE60206835T2|2001-06-08|2006-04-20|Etienne Lacroix Tous Artifices S.A.|Thermally controlled release mechanism|
    JP2008075739A|2006-09-21|2008-04-03|Takata Corp|Safety valve for vehicle safety device|
    WO2011138553A1|2010-05-04|2011-11-10|Sme|Triggered-stroke actuator comprising sealing means and means for blocking the rod|
    DE102012105518A1|2012-06-25|2014-01-16|Benteler Automobiltechnik Gmbh|Releasable holding device for force-operated devices in motor car, has active unit that is equipped in actuator device and is operated to release the component or pawl from locking position|
    WO2015072293A1|2013-11-18|2015-05-21|タカタ株式会社|Gas-pressure-type actuator|
    SE9802291D0|1998-06-26|1998-06-26|Martin Svensson|Plant Protection|
    AT12351U1|2010-12-22|2012-04-15|Hirtenberger Automotive Safety Gmbh & Co Kg|CONTROL DEVICE|FR3085917B1|2018-09-14|2021-04-09|Autoliv Dev|VEHICLE SAFETY DEVICE TO PROVIDE PEDESTRIAN PROTECTION|
    AT522513B1|2019-05-07|2021-02-15|Hirtenberger Automotive Safety Gmbh & Co Kg|Pyrotechnic actuator|
    DE102020118957A1|2020-07-17|2022-01-20|Bayerische Motoren Werke Aktiengesellschaft|ACTUATOR FOR ADJUSTING A FRONT HOOD FROM A NORMAL POSITION TO A PROTECTIVE POSITION|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    ATA50506/2016A|AT518680B1|2016-06-02|2016-06-02|Pyrotechnic actuator|ATA50506/2016A| AT518680B1|2016-06-02|2016-06-02|Pyrotechnic actuator|
    DE102017112054.8A| DE102017112054A1|2016-06-02|2017-06-01|Pyrotechnic actuator|
    [返回顶部]