EP2872785A1 - Verin a course declenchee a retour arriere amorti - Google Patents
Verin a course declenchee a retour arriere amortiInfo
- Publication number
- EP2872785A1 EP2872785A1 EP13747439.1A EP13747439A EP2872785A1 EP 2872785 A1 EP2872785 A1 EP 2872785A1 EP 13747439 A EP13747439 A EP 13747439A EP 2872785 A1 EP2872785 A1 EP 2872785A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- cylinder according
- expansion chamber
- charge
- pyrotechnic charge
- rod
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
- B60R21/00—Arrangements or fittings on vehicles for protecting or preventing injuries to occupants or pedestrians in case of accidents or other traffic risks
- B60R21/34—Protecting non-occupants of a vehicle, e.g. pedestrians
- B60R21/38—Protecting non-occupants of a vehicle, e.g. pedestrians using means for lifting bonnets
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
- F15B15/19—Pyrotechnical actuators
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
- B60R21/00—Arrangements or fittings on vehicles for protecting or preventing injuries to occupants or pedestrians in case of accidents or other traffic risks
- B60R2021/003—Arrangements or fittings on vehicles for protecting or preventing injuries to occupants or pedestrians in case of accidents or other traffic risks characterised by occupant or pedestian
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
- F15B15/08—Characterised by the construction of the motor unit
- F15B15/14—Characterised by the construction of the motor unit of the straight-cylinder type
- F15B15/1423—Component parts; Constructional details
- F15B15/1447—Pistons; Piston to piston rod assemblies
- F15B15/1452—Piston sealings
Definitions
- the invention relates to an actuator with triggered stroke allowing a cushioned return back of the rod of this cylinder, under the effect of a force applied to this rod.
- the invention relates more particularly to an improvement of this type of cylinder remarkable in that the damping resistance in return is adapted to the evolution over time of the force applied to the rod of the cylinder.
- the invention is particularly adapted to a jack constituting the driving element of a safety system fitted to a motor vehicle and having the function of quickly raising the hood of the vehicle in the event of collision with a pedestrian.
- Cylinders designed for the lifting of an automobile hood are known. Such a cylinder is triggered by a pyrotechnic charge when a collision is imminent, so as to prevent the pedestrian and in particular his head, hit the engine block after a deformation of the hood. The lifting of the hood is performed at the rear of it, in the vicinity of the windshield. The hood remains attached to the front of the motor vehicle. The jack is arranged so that, after raising the hood, a cushioned return thereof is possible to accompany the impact on the hood and lessen the impact on the pedestrian. This feedback damping system is advantageously combined with the cylinder having raised the hood.
- the assembly consists of the hood, the lifting mechanism and the piston of the cylinder which retracts under the impact (after initial lifting and deformation of the hood under impact) while being braked and then blocked.
- the damping device is arranged in the cylinder body. It uses mechanical means as described for example in patent FR 2 878 212. In this case, these mechanical means hold the hood in the deployed position until the impact of the pedestrian and then retract under the effect of shock of it, while absorbing energy.
- a non-return damping effect is obtained by keeping the pressurizing chamber of the jack under a sufficiently high pressure to oppose its return movement.
- the use of a high mass pyrotechnic charge ensuring both the pressurization of the piston for the rapid deployment of the cylinder and then maintaining the pressure of the piston chamber has disadvantages.
- a pyrotechnic charge of this type would imply a too sudden deployment of the cylinder likely to damage the deployment mechanism and the hood.
- Patent FR 2 938 884 proposes to use an additional pyrotechnic charge with a slower combustion than that used to cause rapid initial deployment. This slow additional pyrotechnic charge is incorporated in the jack and is advantageously ignited by the fast combustion charge already present in the gas generator of the jack.
- the gas generator itself, or in a location communicating with the pressurizing chamber of the jack, for example in a piston cavity opening into the combustion chamber of the jack.
- the additional slow-burning charge takes over from the one that caused the hood to lift quickly and no longer provides enough gas.
- the combustion of the slow charge maintains a pressure level in the cylinder expansion chamber, sufficient and long enough to allow the damped return of the hood during the impact.
- the evolution of the pressure observed in the pressurizing chamber of this type of cylinder then has a rapid rise generated by the pyrotechnic fast combustion charge to provide the energy required for the deployment of the system in a very short period of time, typically less than at 30 ms for the pedestrian protection application.
- a lower pressure is established in the chamber, at a level dependent on the combustion of the slow load, for a period of about 300 ms for pedestrian protection application.
- the times of 30 ms and 300 ms can be modified and adapted according to the application.
- a trigger stroke cylinder comprising a body housing a piston connected to a rod projecting from an end of said body, said rod being adapted to be coupled to a mechanism capable of exerting on it a variable return force and a controlled gas generator mounted in said cops facing said piston and at a predetermined distance from an initial position before triggering thereof, an expansion chamber being thus defined between said gas generator and said piston, said gas generator comprising a pyrotechnic charge of initial activation of the jack, communicating with said expansion chamber, characterized in that it further comprises at least one additional pyrotechnic charge, located in a housing communicating with said chamber expansion to exert on the piston a non-return resistance adapted to the evolution over time of said force in return varia ble being exerted on said rod.
- the evolution over time of the return damping resistor is adapted to a shock or a series of successive shocks, possibly after a certain delay following the detection of an imminent collision. and / or in response to a series of shocks.
- the force exerted in return on the rod may be consecutive to the deployment of the jack; it can possibly take birth after a certain delay.
- damping resistance back is related to the evolution of the pressurization of the expansion chamber, during the succession or shock (s).
- the additional pyrotechnic charge has a longer burning time than that of the initial pyrotechnic activation charge.
- This additional pyrotechnic charge can be housed in the cylinder body, in communication with the expansion chamber.
- the additional pyrotechnic charge is housed in a cavity of the piston opening into the expansion chamber, opposite the controlled gas generator.
- the additional pyrotechnic charge can be ignited automatically, with a certain delay controllable by construction, by the initial pyrotechnic activation charge.
- the expansion chamber with which the gas generator communicates is located on the side of the piston opposite the rod.
- the additional pyrotechnic charge has a shape and / or a composition adapted (s) for its combustion generates, in the expansion chamber, a variable gas flow over time and, at least over a period of given time, a rising gas flow.
- the pyrotechnic charge can be arranged so that its useful combustion area is variable during its combustion, and in particular that this useful surface increases during at least one phase of the combustion.
- the additional pyrotechnic charge may have a variable section, and in particular an increasing section, over at least a portion of its length generally taken along an axis extending from the end of the charge located in the vicinity of the chamber of gas expansion to its opposite end.
- This axis may be, for example, coincident with or substantially parallel to the axis of the rod.
- the additional pyrotechnic charge may thus have a flared shape, in particular frustoconical or pyramidal (or the like), whose end of smaller section is in the vicinity of said expansion chamber, in particular whose axis coincides with or substantially parallel to that of the stem.
- the additional pyrotechnic charge consists of several fuel blocks of different characteristics, aligned in the direction of said rod.
- the additional pyrotechnic charge may comprise several fuel blocks of different characteristics coupled to each other, in other words arranged in such a way that each block is initiated following the directly adjacent block.
- the pyrotechnic blocks constituting the additional pyrotechnic charge are preferably in contact with each other, to form a one-piece assembly.
- These fuel blocks may have different sections and / or lengths along said axis. They can also be made of materials having different rates of combustion.
- the additional pyrotechnic charge has a part of its surface covered by an anti-combustion coating (also called combustion inhibitor coating) to favor a direction of propagation of the combustion front, over time.
- an anti-combustion coating also called combustion inhibitor coating
- the additional pyrotechnic charge is illuminated by one end and the combustion propagates in an almost rectilinear manner along an axis, this axis coinciding with that of the cylinder rod.
- the jack comprises or is associated with a secondary expansion chamber communicating with said first mentioned expansion chamber and housing several additional pyrotechnic charges connected to respective actuating means.
- these actuating means comprise igniters respectively coupled to said additional pyrotechnic charges and these igniters are connected to firing means arranged to control said charges in a predetermined order.
- the magnitude and duration of the additional pyrotechnic charges may be predetermined depending on the foreseeable shocks mentioned below.
- the firing means can be controlled by a displacement sensor of the rod of the jack. During the movement of back of the rod, the sensor controls the firing means (microprocessor), which successively trigger additional pyrotechnic charges to raise the pressure level in the expansion chamber.
- the firing means microprocessor
- the compounds constituting the initial pyrotechnic activation charge and the additional pyrotechnic charge (s) may be chosen from those which are generally selected for gas generators in the field of automobile safety for air bags, safety pretenters, extinguishers and lift cylinders.
- WO 2006/134 311 and WO 2007/042 735 and in particular those which consist essentially of guanidine nitrate and basic copper nitrate are well suited for the invention.
- Those skilled in the art can easily adjust the combustion rate of these compounds and size the pyrotechnic charges so as to obtain the pressurization sequences of said expansion chamber in accordance with what is desirable to better damp the shocks resulting from a impact with the pedestrian.
- FIG. 1 shows schematically a stroke cylinder triggered according to a first embodiment of the invention
- FIG. 2 is a graph illustrating the behavior of the jack during the damping period following the release of the jack.
- FIGS. 3a, 3b are partial views of two variants of the cylinder.
- a cylinder 11 with triggered stroke having a generally cylindrical body 12 housing a piston 13 connected to a rod 14 projecting from one end of this body.
- the rod 14 is adapted to be coupled to a mechanism 15 able to exert on it a variable return force.
- a mechanism 15 able to exert on it a variable return force.
- it is a cowl mechanism intended, as we know, to protect a pedestrian during a collision.
- the cylinder comprises a controlled gas generator 18. It consists of a pyrotechnic initial activation charge 17, fast combustion and a firing device 16, associated with this load, electrically controlled.
- the arrangement is such that an expansion chamber 24 is defined between the gas generator 18 and the piston 13.
- the pyrotechnic initial activation charge 17 of the cylinder is here in the rear axial extension of the rod 14.
- an orifice 19 is made through the wall of this expansion chamber 24 to create a gas leakage flow towards the outside thereof.
- the pressure that is generated in the expansion chamber tends to decrease after the bonnet is lifted, that is to say after a certain time following the firing and combustion of the pyrotechnic charge. initial activation 17.
- a pyrotechnic gas leak can be arranged between the piston and the cylinder body as described in particular in FR 2 961 274.
- the jack comprises or is associated with at least one additional pyrotechnic charge 21a, 21b, 21c, for example with delayed actuation, located in a housing 23 communicating with the expansion chamber, to exert on the piston a non-return resistance (pressure) adapted to the evolution over time of the variable return force exerted on the rod of the jack 14.
- the additional pyrotechnic charge has a longer burning time than that of said initial pyrotechnic activation charge 17.
- the housing 23 forms a secondary expansion chamber communicating with the expansion chamber 24, through a conduit 22.
- This secondary expansion chamber houses several additional pyrotechnic charges 21a, 21b, 21c connected to respective actuating means, controlled.
- these actuating means comprise igniters 25a, 25b, 25c respectively coupled to said additional pyrotechnic charges, and these igniters are connected to firing means 26, 27, arranged to control the ignition of said charges in a predetermined order.
- the actuating means comprise a control circuit 26, microprocessor or the like, generating electrical signals applied to the igniters in a predetermined order.
- the control circuit is controlled by a sensor 27 detecting the displacement of the rod 14.
- the operation of the jack according to the invention is explained by the graph of FIG. 2.
- the time is indicated on the abscissa
- the curve in bold line illustrates the evolution over time of the pressure in the expansion chamber. 24
- the curve in broken line illustrates the evolution over time of the position of the rod 14 of the cylinder.
- the curve in broken line is therefore representative of the return force exerted on the rod after release of the cylinder.
- the gas generator 18 is triggered and the initial pyrotechnic activation charge is fired at time A.
- the pressure in the expansion chamber 24 increases very rapidly, which causes the lifting of the hood. Then, because of the calibrated leakage 19 and / or the end of the combustion of the charge, and / or the cooling of the pyrotechnic gases, the pressure begins to decrease. If the shock is avoided in extremis, the additional pyrotechnic charges 21a - 21c are not fired and the cover, intact, can be put back into position.
- a first shock causes a withdrawal of the rod 14 inside the body of the cylinder, this movement is detected by the sensor 27 which controls the firing of a first additional pyrotechnic charge 21a which refills the expansion chamber 24.
- the firing of this first additional charge takes place in point B.
- This results in a rise in pressure which results in an increase in the resistance to the return of the rod followed by a new Decrease of the pressure in the expansion chamber.
- a second shock shock 2 occurs, the sensor controls the firing of the second additional pyrotechnic charge 21b which is at point C. The pressure in the expansion chamber increases again and then decreases.
- FIGS. 3a and 3b describe variants in which said at least one additional pyrotechnic charge is ignited directly by the pyrotechnic initial activation charge 17 of the jack. It is therefore the shape and / or the constitution of this additional pyrotechnic charge which conditions the return damping which is exerted on the rod.
- the at least one additional pyrotechnic charge 28 or 29 is here housed in the cylinder body in communication with the expansion chamber itself. More particularly, in these two examples, this additional pyrotechnic charge is housed in a cavity of the piston 13 opening into the expansion chamber opposite the controlled gas generator 18.
- the additional pyrotechnic charge 28 has a frustoconical shape of axis coincides with that of the rod. The smaller section end of the load is in the vicinity of the expansion chamber. The additional pyrotechnic charge is therefore ignited for a certain time after ignition of the pyrotechnic initial activation charge 17 of the jack, by the same flame that emerges from it.
- the protective coating extends on the surface frustoconical load. The shape of the additional pyrotechnic charge is such that the quantity of gas evolved increases over time because of the combustion surface of larger and larger since the combustion is propagated in a substantially longitudinal direction parallel to the axis of the rod 14.
- the additional pyrotechnic charge 29 consists of several fuel blocks of different characteristics contiguous to each other and aligned in the longitudinal direction of the rod 14.
- five blocks can be distinguished. , two small-sized blocks (2, 4) being arranged between three blocks of larger size (1, 3, 5). It is therefore conceivable that under these conditions, the pressure curve in the expansion chamber, will be close to that shown in Figure 2.
- the surface of all of these blocks, not included the surface of the first adjacent the expansion chamber is covered with a protective coating 30 favoring an axial direction of combustion.
- the contiguous fuel blocks may consist of materials having different rates of combustion.
- the fuel blocks may be arranged to favor a radial combustion whose combustion rate is progressive in concentric layers.
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- General Engineering & Computer Science (AREA)
- Actuator (AREA)
- Superstructure Of Vehicle (AREA)
- Lock And Its Accessories (AREA)
Abstract
Description
Claims
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR1256805A FR2993326B1 (fr) | 2012-07-13 | 2012-07-13 | Verin a course declenchee a retour arriere amorti |
PCT/FR2013/051676 WO2014009670A1 (fr) | 2012-07-13 | 2013-07-12 | Verin a course declenchee a retour arriere amorti |
Publications (1)
Publication Number | Publication Date |
---|---|
EP2872785A1 true EP2872785A1 (fr) | 2015-05-20 |
Family
ID=47351798
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP13747439.1A Withdrawn EP2872785A1 (fr) | 2012-07-13 | 2013-07-12 | Verin a course declenchee a retour arriere amorti |
Country Status (10)
Country | Link |
---|---|
US (1) | US20150167701A1 (fr) |
EP (1) | EP2872785A1 (fr) |
JP (1) | JP2015522145A (fr) |
KR (1) | KR20150036420A (fr) |
CN (1) | CN104603470A (fr) |
BR (1) | BR112015000667A2 (fr) |
CA (1) | CA2878879A1 (fr) |
FR (1) | FR2993326B1 (fr) |
MX (1) | MX2015000480A (fr) |
WO (1) | WO2014009670A1 (fr) |
Family Cites Families (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3439408A (en) * | 1967-06-29 | 1969-04-22 | Du Pont | Process for initiating explosive and charge therefor |
US4547235A (en) * | 1984-06-14 | 1985-10-15 | Morton Thiokol, Inc. | Gas generant for air bag inflators |
US5959237A (en) * | 1995-08-31 | 1999-09-28 | The Ensign-Bickford Company | Explosive charge with assembled segments and method of manufacturing same |
US6007022A (en) * | 1996-11-08 | 1999-12-28 | Newport News Shipbuilding | Internal combustion catapult |
NO308717B1 (no) * | 1999-06-04 | 2000-10-16 | Nammo Raufoss As | Fremdriftsanordning for et prosjektil i et missil |
FR2856125B1 (fr) * | 2003-06-13 | 2005-07-22 | Pyroalliance | Amortisseur modulable a gaz pyrotechniques |
SE526922C2 (sv) * | 2003-12-09 | 2005-11-22 | Nexplo Bofors Ab | Progressiv drivkrutladdning med hög laddensitet |
EP2076410A2 (fr) * | 2006-10-09 | 2009-07-08 | SNPE Matériaux Energétiques | Procédé pyrotechnique de génération de gaz a deux régimes - générateur pyrotechnique associé |
EP2070870A1 (fr) * | 2007-12-14 | 2009-06-17 | Nederlandse Organisatie voor toegepast- natuurwetenschappelijk onderzoek TNO | Formulation pour la génération de gaz azote |
FR2938884B1 (fr) * | 2008-11-26 | 2013-02-08 | Snpe Materiaux Energetiques | Verin a course declenchee pour dispositif de securite integre a un vehicule automobile, pour la protection d'un pieton en cas de choc frontal |
-
2012
- 2012-07-13 FR FR1256805A patent/FR2993326B1/fr not_active Expired - Fee Related
-
2013
- 2013-07-12 KR KR1020157003182A patent/KR20150036420A/ko not_active Application Discontinuation
- 2013-07-12 BR BR112015000667A patent/BR112015000667A2/pt not_active Application Discontinuation
- 2013-07-12 CA CA2878879A patent/CA2878879A1/fr not_active Abandoned
- 2013-07-12 WO PCT/FR2013/051676 patent/WO2014009670A1/fr active Application Filing
- 2013-07-12 JP JP2015521052A patent/JP2015522145A/ja active Pending
- 2013-07-12 EP EP13747439.1A patent/EP2872785A1/fr not_active Withdrawn
- 2013-07-12 US US14/414,558 patent/US20150167701A1/en not_active Abandoned
- 2013-07-12 MX MX2015000480A patent/MX2015000480A/es unknown
- 2013-07-12 CN CN201380045768.4A patent/CN104603470A/zh active Pending
Non-Patent Citations (2)
Title |
---|
None * |
See also references of WO2014009670A1 * |
Also Published As
Publication number | Publication date |
---|---|
CA2878879A1 (fr) | 2014-01-16 |
US20150167701A1 (en) | 2015-06-18 |
JP2015522145A (ja) | 2015-08-03 |
MX2015000480A (es) | 2015-06-05 |
WO2014009670A1 (fr) | 2014-01-16 |
BR112015000667A2 (pt) | 2017-06-27 |
FR2993326A1 (fr) | 2014-01-17 |
KR20150036420A (ko) | 2015-04-07 |
CN104603470A (zh) | 2015-05-06 |
FR2993326B1 (fr) | 2014-08-01 |
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Legal Events
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RIN1 | Information on inventor provided before grant (corrected) |
Inventor name: BORG, EVRARD |
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