SE1550691A1

SE1550691A1 - Pedestrian safety arrangement for a vehicle

Info

Publication number: SE1550691A1
Application number: SE1550691A
Authority: SE
Inventors: Svensson Christian; Fredriksson Rikard; Östling Martin; Berner Magnus; Rosen Erik; Sander Ulrich
Original assignee: Autoliv Dev
Priority date: 2015-05-28
Filing date: 2015-05-28
Publication date: 2016-10-25
Also published as: SE538715C2; WO2016189140A1

Abstract

ABSTRACT The present invention relates to a safety arrangement configured to bemounted in a vehicle (1) having a front-end member (7) and a vehiclestructure member (5) to which the front-end member (7) is releasablyconnected. The safety arrangement comprises an energy absorbing device (15), arelease device arranged to, upon heavy braking, release said front-endmember (7) to allow the front-end member (7) to be moved forvvardly in avehicle forward direction by inertia forces during the heavy braking, and alocking device capable of locking the front-end member in a forward position,wherein a pedestrian or a cyclist (13) that is impacted by the front-endmember (7) deforms the energy absorbing device (15). Elected for publication: Figure 1c.

Description

SAFETY ARRANGEMENT Technical Field of the lnvention The present invention relates to a safety arrangement configured to bemounted in a vehicle having a front-end member and a vehicle structuremember to which the front-end member is releasably connected.

Background Artln order to try to minimize injury to a pedestrian hit by a vehicle, it has been proposed previously to raise a part of the hood before the pedestrianlands on the hood. Such a hood hood-lifting arrangement can work effectivelywhen installed in a medium size vehicle which has a standard length hood.

However, it is less effective when used in a vehicle which has a shorterthan average hood, such as a small car or a light truck.

Summary of the lnvention lt is an object of the present invention to provide improved protection ofpedestrians hit by a vehicle.

These and other objects that will be apparent from the followingsummary and description are achieved by a safety arrangement according tothe appended claims.

According to an aspect of the present disclosure there is provided asafety arrangement configured to be mounted in a vehicle having a front-endmember and a vehicle structure member to which the front-end member isreleasably connected, wherein the safety arrangement comprises an energyabsorbing device arranged between said front-end member and said vehiclestructure member as seen in a vehicle forward direction, a release devicearranged to, upon heavy braking, release said front-end member to allow thefront-end member to be moved forwardly in a vehicle forward direction byinertia forces during the heavy braking, and a locking device capable oflocking the front-end member in a forward position, wherein a pedestrian or a cyclist that is impacted by the front-end member deforms the energyabsorbing device.

The front-end member, e.g. a bumper, windscreen or bumperwindscreen combination, is thus, when the vehicle deceleration exceeds apredetermined level in a sudden braking event, released from the vehiclestructure member to which it is normally secured.

Due to its mass the front-end member has a certain inertia and will,once released, move in response to the vehicle deceleration during the heavybraking. The forward movement of the front-end member relative to thevehicle structure member is thus energized by vehicle deceleration. This hasthe advantage that no external force is needed to move the front-end memberfon/vardly to the forward position during heavy braking. There is thus no needfor a driving means driving the front-end member to the fon/vard position.

By moving the front-end member forwardly relative to the vehiclestructure member the safety arrangement is able to increase the roof edgewrap around distance of a vehicle having a shorter than average hoodsignificantly. Furthermore, the safety arrangement is able to absorb energyduring impact with a pedestrian. As the energy absorbing device deforms, theenergy absorbing device absorbs energy from the pedestrian, decreasing therelative speed of the pedestrian down gradually and thus minimizing injury tothe pedestrian. Furthermore, the front-end member, or a member connectedthereto, may act as a shield which may shield a pedestrian from part of thewindscreen and from rigid parts, such as the cowl or roof, of the vehicle.

Hence, the safety arrangement minimises injury to a person hit by avehicle equipped with the safety arrangement. An efficient safetyarrangement for protection of pedestrians hit by a vehicle is thus achieved.Especially, an improved safety arrangement for protection of pedestrians hitby a small vehicle, such as a small car, is achieved.

When released the front-end member thus moves forwardly by inertiaforce, which enables a very cost-efficient solution. Furthermore, a robust andreliable solution may be achieved.

According to one embodiment said energy absorbing device isextendible. This has the advantage that an additional deformation distancemay be created.

According to one embodiment the energy absorbing device comprisesat least one telescopic structure.

According to one embodiment the energy absorbing device comprisesa self-locking telescopic device.

According to one embodiment said at least one telescopic structurecomprises an outer tube and an inner tube telescoped into the outer tube.

According to one embodiment the front-end member is arranged to,upon activation of the safety arrangement, move linearly in the vehicleforward direction.

According to one embodiment the energy absorbing device comprisesfour telescopic structures, which provides for a very robust solution.Furthermore, with four telescopic structures the energy absorbing during animpact with a pedestrian may be distributed which may further reduce the riskof injury to the impacted pedestrian.

According to one embodiment the front-end member is pivotallyconnected to the vehicle structure member. This embodiment has theadvantage that a cost-efficient solution comprising only two telescopicstructures may be achieved.

According to one embodiment said release device is active andcomprises an actuator arranged to operate an engaging element of therelease device.

The active release device may be arranged to move an engagingelement in order to release the front-end member. Release of the front-endmember may thus be carried out in a very controllable and reliable manner.When the the active release device is activated the front-end member is freeto move relative to the vehicle structure member, which enables an exendibleenergy absorbing element to be extended and prepared for maximum energyabsorbing when a pedestrian is hit by the vehicle.

According to one embodiment the release device comprises anactuator in the form of a pyrotechnical actuator or an electrical actuator. Theuse of such an actuator provides for a very controllable and reliable solution.

According to one embodiment said active release device comprises apyrotechnic actuator, which provides for very fast actuation and thus enablesvery fast release of the front-end member.

According to one embodiment said pyrotechnic actuator is arranged tooperate an engaging element of the active release device.

According to one embodiment the release device comprises an electric actuator in the form of an servo motor provided with a linearly displacable rod.

According to one embodiment the release device comprises apyrotechnic actuator in the form of a linear pyrotechnic piston actuator.

According to one embodiment said active release device comprises anelectric, pneumatic or hydraulic actuator, which provides for a robust andreliable release device that may be reset, automatically or manually, in aneasy manner.

According to one embodiment the active release device is resettable,which enables the release device to be reset after activation. The activerelease device may thus be activated repeatedly. The active release devicemay be resetted manually or automatically. Hence, a reversible safetyarrangement may be achieved.

According to one embodiment the release device comprises abreakable element, such as a breakable pin, which provides for a very cost-efficient solution.

The breakable element may be configured to break when subjected toa load that corresponds to a predetermined deceleration level of the vehicle.

According to one embodiment the predetermined deceleration level, atwhich the breakable element is configured to break, is 1,5 and morepreferably 2g.

Hence, according to one embodiment the breakable element is thusconfigured to break when the vehicle deceleration exceeds 1,5g during aheavy braking event.

According to one embodiment the safety arrangement comprises apre-crash sensor system capable of sensing a pedestrian in front of thevehicle, i.e. that is capable of predicting an impact with a pedestrian in front ofthe vehicle.

These and other aspects of the invention will be apparent from andelucidated with reference to the claims and the embodiments describedhereinafter.

Brief Description of the Drawinqs The invention will hereafter be described in more detail and withreference to the appended schematic drawings.

Fig. 1a is a side view of a vehicle provided with a safety arrangementaccording to an embodiment of the present disclosure.

Fig. 1b is a side view and illustrates the vehicle in Fig. 1a in a suddenbraking event.

Fig. 1c is a side view and illustrates the vehicle in Fig. 1a in a collisionwith a pedestrian.

Fig. 2a-b illustrates a release device of the safety arrangementillustrated in Figs.1a-c.

Fig. 3a-c illustrates a release device of a safety arrangement accordingto a second embodiment of the present disclosure.

Fig. 4a-c illustrates a release device of a safety arrangement accordingto a third embodiment of the present disclosure.

Fig. 5a is a side view of a vehicle provided with a safety arrangementaccording to a fourth embodiment of the present disclosure.

Fig. 5b is a side view and illustrates the vehicle in Fig. 5a in a suddenbraking event.

Fig. 5c is a side view and illustrates the vehicle in Fig. 5a in a collisionwith a pedestrian.

Detailed Description of Preferred Embodiments of the lnvention Fig. 1a shows a motor vehicle 1 provided with a safety arrangement 3according to an embodiment of the present disclosure. The vehicle 1comprises a vehicle structure member 5 and a front-end member 7. The front- end member 7 comprises a windscreen 9, a bumper 11 and a roof extender 12 and is connected to the vehicle structure member 5. A pedestrian 13 isstanding in front of the vehicle 1 as seen in a vehicle forward direction.

The front-end member 7 is releasably connected to the vehiclestructure member 5. To this end the safety arrangement 3 comprises arelease device 6, which is illustrated in Figs. 2a-b. Upon activation of thesafety arrangement 3 the front-end structure 7 is released to allow movementof the front-end member 7 relative to the vehicle structure member 5. Undernormal conditions the front-end member 7 is secured to the front-end member7 by a breakable engaging element 23, illustrated in Fig. 2a.

Upon heavy braking of the vehicle 1, e.g. when a pedestrian 13 in frontof the vehicle 1 has been observed or detected, the safety arrangement 3 isactivated, which allows the front-end member 7 to move, under the action ofinertia forces during the vehicle deceleration following the heavy breaking,forvvardly relative to the vehicle structure member 5, as illustrated by arrow Ain Fig. 1b.

When the safety arrangement 3 is activated the front-end member 7 isthus moved fon/vardly in the vehicle forward direction to a forward position,illustrated in Fig. 1b, by inertia forces. The safety arrangement is activated if apredetermined vehicle deceleration, such as, e.g., 1g, is exceeded. Typically,such a vehicle deceleration is reached during heavy braking when apedestrian has been observed or detected in front of the vehicle 1. Hence, thesafety arrangement 3 is not activated during a normal braking event, in whicha vehicle decelarion of about 0,4g is typically reached. ln this embodiment the front-end member 7 is arranged to, when thesafety arrangement 3 is activated, move linearly to the forward position. Thefront-end member 7 is thus, when released, linearly displaceably relative tothe vehicle structure member 5. To this end the safety arrangement 3comprises four telescopic structures 17, two of which are schematicallyillustrated in Fig, 1b.

Now referring to Fig. 1b the safety arrangement 3 comprises an energyabsorbing device 15 that is arranged between the vehicle structure member 5and the front-end member 7. The energy absorbing device 15 comprises thefour telescopic structures 17. Each telescopic structure 17 is at one end 17a connected to the vehicle structure member 5 and at another end 17bconnected to the front-end member 7, as illustrated schematically in Fig. 2a.

When the front-end member 7 is moved forvvardly to the forwardposition each of the telescopic structures 17 of the energy absorbing device15 is moved to an extended position, as illustrated by arrow B in Fig. 2b. Theenergy absorbing device 15 is thus movable to an extended state, illustratedin Fig. 1b and in Fig. 2b, in which it is able to deform plastically and absorbenergy by the plastic deformation. ln the extended state the energy absorbingdevice 15 may thus absorb energy during an impact with, e.g, a pedestrian 13or a cyc|ist.

Fig. 1c i||ustrates an impact with a pedestrian 13. At the moment whenthe pedestrian 13 is hit by the vehicle 1 the front-end member 7 has beenmoved to the forward position and the energy absorbing device 15 has beenextended to the extended state. The front-end member 7, which is fixed to aportion of each of the telescopic structures 17, is locked in the forwardposition. To this end the safety arrangement 3 comprises a locking device(not shown) capable of locking the front-end member in a fon/vard position.The front-end member 7 is thus locked in the forward position creating aenergy absorbing distance. As one or more of the telescopic structures 17 ofthe energy absorbing device 15 deforms, the energy absorbing device 15absorbs energy from the pedestrian 13, slowing the pedestrian 13 downgradually and thus minimizing injury to the pedestrian 13.

Now referring to Figs. 2a and Fig. 2b, which schematically illustratrateone of the telescopic structures 17, the energy absorbing device 15 will befurther described.

Each telescopic structure 17 comprises an outer tube 19, which isattached to the vehicle structure member 5, and an inner tube 21 telescopedinto the outer tube 19. As schematically illustrated in Fig. 2a the front-endmember 7 is secured to the inner tube 21. The release device 6 comprises abreakable engaging element, in the form of a breakable engagement pin 23,which is arranged to, under normal conditions, prevent the telescopicstructure 17 from assuming the extended state by locking the inner tube 21 tothe outer tube 19.

Under normal conditions the breakable pin 23 thus locks the inner tube21 to the outer tube 19 and prevents relative movement between them. Uponheavy braking of the vehicle 1 the inner tube 21 applies, due to inertia forces,a force on the breakable pin 23. Since the outer tube 19 of the telescopicstructure 17 is fixed to the vehicle structure member 5, the breakable pin 23 isthen subjected to a shear force that will break the pin 23 when apredetermined force, corresponding to a predermined deceleration of thevehicle, is esxceeded. ln this case the breakable pin 23 has a weakenedportion 23a which is configured to break when a predetermined force isexceeded. The release device 6, 23 is thus designed to release the inner tube21, and the front-end member 7 which is attached thereto, when the vehicledeceleration exceeds a predetermined level, such as, e.g., 1g.

Each telescopic structure 17 is provided with such a breakableengaging element 23.

When the breakable pin 23 is broken movement of the telescopicstructure 17 to an extended state is enabled. Hence, the inner tube 21 of thetelescopic structure 17 is then free to move forvvardly in the vehicle forwarddirection relative to the outer tube 19, as illustrated by arrow B in Fig. 2b. Theinner tube 21, which is moved forvvardly in the vehicle forward direction byinertia forces during the braking event, is moved to an extended position,illustrated in Fig. 2b, in which it is locked by a tube locking mechanism (notshown). The tube locking mechanism, which, e.g., may be of the typedescribed in US 6,302,458, is capable of locking the inner tube 21 to the outertube 19 in the extended position and is thus configured to prevent relativemovement between the inner and the outer tube in the extended state, i.e.when the inner tube 21 is situated in the extended position. ln the extendedstate, illustrated in Fig. 2b, the self-locking telescopic structure 17 forms anenergy absorbing element which is configured for absorbing energy during acollision with a pedestrian 13 in order to minimise injury to the pedestrian.

Each telescopic structure 17 is provided with a tube lockingmechanism capable of locking the inner tube 21 to the outer tube 19 in theextended position. The tube locking mechansims together form the lockingdevice of the safety arrangement 3.

Figs. 3a-c illustrates a release device 122 of a safety arrangementaccording to a second embodiment of the present disclosure. Essentially allfeatures disclosed in the first embodiment are also present in the secondembodiment with reference numerals identifying similar or same features.Having mentioned this, the description will focus on explaining the differingfeatures.

A pedestrian in front of a vehicle may be detected by a pre-crashsensor based detection system. ln this embodiment the vehicle provided withthe safety arrangement comprises a pre-crash sensor which is connected to acontrol unit of the vehicle. The pre-crash sensor may be mounted at the frontof the vehicle and configured to sense when the vehicle is expected to crashinto a pedestrian.

The safety arrangement according to this embodiment differs in that itcomprises an active release device 122. The active release device 122comprises a pivotally arranged engaging element 123 which is arranged to,under normal conditions, prevent a telescopic structure 17 of the energyabsorbing device 115 from assuming the extended state by engaging each ofthe outer tube 19 and the inner tube 21, as illustrated in Fig. 3a. The activerelease device 122 further comprises an actuator, in the form of a servomotor124 having a rod 126. The motor rod 126 is arranged to hold the engagingelement 123, to keep the engagement with each of the outer tube 19 and theinner tube 21, i.e. to maintain the engaging element 123 in a locking position.Hence, in the locking position, illustrated in Fig. 3a, the engaging element 123locks the inner tube 21 to the outer tube 19, thereby preventing relativedisplacement between the tubes 19, 21 of the telescopic structure 17. Uponactivation of the release device 122 the motor rod 126 is retracted, asillustrated by arrow C in Fig. 3b, which enables the engaging element 123 topivot away from the engagement with the tubes 19, 21, as illustrated by arrowD in Fig. 3b, as the inner tube 21 is moved toward an extended position, asillustrated by arrow E in Fig. 3b and Fig. 3c.

Each telescopic structure 17 of the energy absorbing device 115 isprovided with such a engaging element 123.

As long as no collision is sensed by the pre-crash sensor system theengaging elements 123 of the active release device 122 prevents the energyabsorbing device 115 from extending to an extended state.

When a collision with a pedestrian is sensed by the sensor system anactivation signal is generated and transmitted to the active release device 122to activate the same.

Upon activation of the active release device 122, each engagingelement 123 is released from the locking position by a respective actuator124. Then, the energy absorbing device is free to move to the extended stateby inertia forces during the braking event.

Each actuator 124, 126 is thus adapted to maintain an engagingelement 123 in a locking position, in which it locks an inner tube 21 to anouter tube 19, and, in response to an activation signal, release the engagingelement 123 from the locking position. The active release device 122 is thusarranged to, upon a signal indicative of a collision with a pedestrian, releasethe energy absorbing device 115 from a locked state.

Figs. 4a-c illustrate a release device 222 of a safety arrangementaccording to a third embodiment of the present disclosure. Essentially allfeatures disclosed in the second embodiment are also present in the secondembodiment with reference numerals identifying similar or same features.Having mentioned this, the description will focus on explaining the differingfeatures.

The safety arrangement according to the third embodiment differs inthat the active release device 222 comprises a linear pyrotechnical actuator224 instead of an electric servo motor and in that the engaging element 223,which has the shape of a truncated cone, is arranged for linear displacementfrom a locking position, illustrated in Fig. 4a. The linear pyrotechnical actuator224 comprises a piston 226 which is arranged to, upon activation of thepyrotechnical actuator 224, push the engaging element 223 away from thelocking position, as illustrated by arrows F in Fig. 4b, thereby allowing thetelescopic structure 17 to assume an extended state, as illustrated by arrow Gin Fig. 4c. 11 Figs. 5a-c illustrate a safety arrangement 303 according to a fourthembodiment of the present disclosure. Essentially all features disclosed in thefirst embodiment are also present in the fourth embodiment with referencenumerals identifying similar or same features. Having mentioned this, thedescription will focus on explaining the differing features.

The safety arrangement 303 differs in that the front-end structure 307is pivotally connected to a vehicle structure member 305. To this end thesafety arrangement 303 comprises a pivotal joint 308, illustrated in Fig. 5b. Anenergy absorbing device 315, which comprises two telescopic structures 17,is arranged between the front-end member 307 and the vehicle structuremember 305, as illustrated in Fig. 5b. ln this embodiment the front-endmember 307 is thus arranged to, when the safety arrangement 303 isactivated, pivot to a forward position, as illustrated by arrow H in Fig. 5b. Thefront-end member 307 is thus, when released by the release device, pivotablewith respect to the vehicle structure member 5. ln this embodiment the energyabsorbing device 315 comprises two telescopic structures 117 instead of four,as described hereinbefore with reference to Figs. 1a-b.

The two telescopic structures 17 of the energy absorbing device maybe of the type described hereinbefore with reference to Fig. 2a-b or of a typedescribed hereinbefore with reference to Figs. 3a-c or of a type describedhereinbefore with reference to Figs. 4a-c. lt is realized by a person skilled in the art that features from variousembodiments disclosed herein may be combined with one another in order toprovide further alternative embodiments.

As described hereinbefore with reference to Figs. 3a-c, the activerelease device of the safety arrangement comprises an actuator in the form ofan electrical actuator which is arranged to operate an engaging element. lt ishowever appreciated that the active release device may comprise anothertype of electric actuator, such as, e.g, an electric rotary actuator or a solenoid,or another type of actuator, such as a pneumatic actuator in the form of a gasspring, a hydraulic actuator, or a mechanical actuator, such as a preloadedspring, for operation of an engaging element. 12 As described hereinbefore with reference to Figs. 4a-c an activerelease device may comprise a pyrotechnic actuator. Such a pyrotechnicactuator may be arranged to push out, as in the described embodiment, orpull out an engaging element from engagement. The pyrotechnic actuatormay be activated by an electrical signal.

Claims

1. A safety arrangement configured to be mounted in a vehicle (1) having afront-end member (7) and a vehicle structure member (5) to which the front-end member (7) is releasably connected, characterized in comprising an energy absorbing device (15) arranged between said front-endmember (7) and said vehicle structure member (5) as seen in a vehicleforward direction, a release device (6; 122; 222) arranged to, upon heavy braking,release said front-end member (7) to allow the front-end member (7) to bemoved forvvardly in the vehicle fon/vard direction by inertia forces during theheavy braking, and a locking device capable of locking the front-end member in a forwardposition, wherein a pedestrian or a cyclist (13) that is impacted by the front-end member (7) deforms the energy absorbing device (15; 115; 215).

2. Safety arrangement according to claim 1, wherein said energy absorbingdevice (15; 115; 215) is extendible.

3. Safety arrangement according to claim 2, wherein said energy absorbingdevice (15; 115; 215) comprises at least one telescopic structure (17).

4. Safety arrangement according to claim 3, wherein said at least onetelescopic structure (17) comprises an outer tube (19) and an inner tube (21)telescoped into the outer tube (19).

5. Safety arrangement according to any of the preceding claims, wherein thefront-end member (7) is arranged to move linearly in the vehicle forwarddirection. 14

6. Safety arrangement according to claim 5, wherein the energy absorbingdevice (15; 115; 215) comprises four telescopic structures (17).

7. Safety arrangement according to any of the claims 1-4, wherein the front-end member (7) is pivotally connected to the vehicle structure member (5).

8. Safety arrangement according to any of the preceding claims, wherein saidrelease device is active and comprises an actuator (124, 224) arranged tooperate an engaging element (123; 223).

9. Safety arrangement according to any of the preceding claims, wherein therelease device (122; 222) comprises an actuator, preferably in the form of anelectrical actuator (124, 126) or in the form of a pyrotechnical actuator (224,226).

10. Safety arrangement according to claim 9, wherein said release device(122) is resettable.

11. Safety arrangement according to any of the preceding claims, wherein therelease device (6) comprises a breakable element (23).

12. Safety arrangement according to any of the preceding claims, wherein thesafety arrangement (3) comprises a pre-crash sensor system capable ofsensing a pedestrian in front of the vehicle (1).