DE10102760B4

DE10102760B4 - Safety systems with an impact-absorbing front hood on a vehicle

Info

Publication number: DE10102760B4
Application number: DE10102760.5A
Authority: DE
Inventors: Ruprecht Sinnhuber; Thomas Wohllebe
Original assignee: Volkswagen AG
Current assignee: Volkswagen AG
Priority date: 2001-01-23
Filing date: 2001-01-23
Publication date: 2019-07-18
Anticipated expiration: 2021-01-24
Also published as: DE10102760A1

Abstract

A safety system having an impact absorbing front bonnet on a vehicle having a top plate and a rigid substructure and capable of adjusting an impact position to a collision participant in the event of a collision, comprising at least one energy accumulator cooperating with the bonnet and a collision detection and activation device Energy release and with Kraftbegrenzungsmitteln, characterized in that the front hood (1) about a given at the front of the vehicle horizontal axis (A) is pivotable, that the energy storage (compression spring 5) arranged in the region of the rear front end and with an actuator (Schfießzapfen 7th / Support plate 8) is connected to the substructure (3) and supported on the rigid vehicle body (10) and coupled to the collision detection and activation device (12/13), and the actuator (lock pin 7 / support plate 8) unterstrukt urseitig with the piston (14) of a vehicle body (10) fixed piston-cylinder unit (15) is connected as a force limiting means for the return movement of the front hood (1).

Description

The invention relates to two safety systems with an impact-absorbing front hood on a vehicle for absorbing impact energy, which is introduced by a pedestrian or other impact participants, in particular by an impactor simulating the impacting head of a pedestrian.
In order to reduce the severity of injuries, in particular head injuries to pedestrians or other impact participants whose head hits in the event of a collision on the front hood, liftable bonnets have become known DE 27 11 338 A1 and DE 28 14 107 A1 By raising the distance of the deformable and thereby energy-absorbing front hood is increased to underlying, non-deformable vehicle parts, in particular the internal combustion engine, so that a larger deformation path is available. For this purpose, the front hood is either raised only in the rear front area of the car and thereby pivoted about a horizontal axis of rotation in the front area, or the front hood is raised in the front and rear front end of the vehicle. Actuators are proposed by a sensor device triggerable airbag devices and pyrotechnic propellant charges. In further development of DE 28 14 107 A1 is in the DE 28 41 315 A1 have been proposed to form the devices for lifting the bonnet by reciprocating cylinder units, which are driven by energy-saving means activated by the sensor device for releasing energy. As an energy-storing and acting on the reciprocating means is also intended to a preloaded spring. The reciprocating cylinder units may be associated with force limiting devices, is defined by the energy defined in the return movement of the front hood destroyed. By this force limiting devices targeted energy reduction is achieved in a collision of a pedestrian on the front hood, which is given by the enlarged deformation path of the bonnet and by a force-limiting return movement of the piston-cylinder unit. The force limiting devices may be formed by means which jam the reciprocating piston in the return movement relative to the cylinder, for example a ramp arranged in the cylinder, on which the piston runs with arranged on this clamping bodies.
A liftable front hood is also the subject of DE 197 21 565 A1 , In this, the triggerable by the sensor actuator actuator is a controllable unlocking device for the front hood lock, wherein after a release by the sensor device, the front hood opening is released by means of at least one bonnet Aufstellfeder. In addition, a limiting device for determining a certain opening path of the front hood and thus provided for fixing the raised impact position. In principle, the described opening mechanism can also be used in front hoods, which can be pivoted open about a front horizontal axis of rotation, ie counter to the direction of travel.
Furthermore, it is from the DE 196 15 744 C1 It is known to assign a gas bag device to a predetermined outer wall region of a body part formed from an inner wall and an outer wall, by means of which the outer wall area can be displaced counter to an impact element. In a detected collision and impact load, the outer wall area bulges outwards under the pressure of the released gas, whereby a timely, energy-consuming contact of the collision participant is achieved with the body part. With the DE application, file number 100 14 832.8, a front hood formed from an inner and an outer panel has been proposed, between which airbag hoses are arranged, which raise the entire outer panel relative to the inner panel in the event of a collision to the hardness of the impact of a To reduce impact participants. This solution has the advantage that not only provided a larger deformation path for the outer panel, but also provided gas cushion for energy absorption.
From the DE 197 21 565 A1 is a safety system with an impact-damping front hood on a vehicle known. The pivot axis of the front hood is located in the area of the rear front end. The safety system disclosed therein has an energy store interacting with the front hood, which is arranged on the vehicle front side.
It is an object of the invention to provide a safety system with an impact-damping front hood according to the preamble of claim 1 or 2 so that with the front hood in no time free space for deformation of the front hood to reduce the head injury criterion HIC (Head Injury Criterion) is created.
This object is achieved in a security system according to the preamble of claim 1 or 2 alternatively in each case by their characterizing features. Advantageous embodiments are listed in the subclaims.
The invention consists in the fact that in a safety system with an impact damping front hood formed from a top sheet and a rigid substructure, with the If a collision with at least one energy store and a trigger device for this one impact position with an enlarged deformation path is adjustable, the front hood or alternatively only the upper metal sheet can be raised about a horizontal axis provided on the front side of the vehicle and raised in the region of the rear front carriage. For this purpose, the energy storage between the fixed vehicle body and the substructure and between the substructure and the upper plate in the region of the rear front end is arranged and connected to an actuator with the substructure or the upper plate and coupled to a device for detecting the collision and activation of energy release , The respective actuator is also in operative connection with the piston of a piston-cylinder unit fastened to the vehicle body as force-limiting means for the return movement of the front hood or of the upper plate by the impact member.
In the event of an impact, the energy store, in particular a spring supported on the substructure and supported on the substructure and supported on the upper plate, or a pyrotechnic propellant, activates and presses the bonnet or the upper plate substantially in the area of the rear front carriage unattenuated and abrupt, but limited by the limited stroke of the piston of the connected piston-cylinder unit, upwards. Deformation space for the bonnet between this and the vehicle body or for the upper plate between the latter and the substructure is thus created in a very short time, so that a larger energy absorbing deformation can take place, for which the mass and the stiffness of the bonnet or the upper plate are mitbestimmend , Moreover, by the force-limiting return movement of the front hood and the upper sheet. additionally dissipates energy by connected to the actuator and damped in its return movement piston piston-cylinder unit.
The spring can also be designed and releasably supported on the vehicle body or the substructure that this accelerates the bonnet or the upper plate in their activation, is taken from the accelerated front hood or the upper plate and dissolves the vehicle body or the substructure and moves against a stop arranged separately and thus no longer supports the front hood. During the return movement, initially only the piston-cylinder unit acts as a damper until the spring has reached the stop again and is then coupled back to the vehicle body or the substructure. In this embodiment, the (acceleration) compression spring may be made shorter.
The advantage of the alternative solution, in which only the upper plate of the bonnet is raised, lies in the lower mass to be set up and the lower mass inertia. However, the energy absorption capacity is reduced.
The prestressed compression spring used as energy storage and held on the substructure or the upper metal sheet is held in the pretensioned state on the lower side or on the upper side by a locking element arranged on the rigid vehicle body or substructure. This locking member is in direct communication with the device for detecting the collision and activating the energy release. The actuator for the front cover and the upper plate is the structure side or the oberblechseitige spring bearing against which presses the unlocked compression spring with its entire spring force. The advantage is that for actuating the locking member and triggering the energy release, a mechanical transmission member, preferably a Bowden cable, can be used and that the unlocking is characterized reversible, so that a raised and not deformed or damaged front hood, for example, in a false trip, can be brought back to its closed position. Instead of the mechanical release device, preferably with a Bowden cable, however, a sensor device with an electrically controlled release can be used. In the alternative solution, in which only the upper sheet can be raised and which is irreversible, since the connection between the latter and the lower structure is irreversibly released when the upper sheet is lifted relative to the lower structure, an electromagnetic unlocking device is also possible.
In both solutions, the sensors or mechanical release elements for the device for detecting the collision and activating the energy release on the front side in the front hood and / or in the bumper area are integrated. Upon contact of a collision with the bumper or the front hood, the energy release is triggered, and the front cover and the upper plate is raised. In a subsequent impact of the impact on the front bonnet or the upper sheet deforms this energy absorbing and is pressed against the compression spring and acting as a damper piston-cylinder unit, which in addition energy is consumed.
In the solution in which the compression spring between the fixed vehicle body and the substructure of the front hood is arranged, it may be coupled to the hood lock, wherein the locking pin is also used as an actuator for the front hood. The lifting of the bonnet can be optimized if the lock pin or the lock on activation of the compression spring over a particular mechanical, electronic or hydraulic sensor is partially unlocked.
To achieve that the preferred pneumatic piston-cylinder unit used as Kraftbegrenzungsmittel is effective only in the direction of the return movement of the front cover or the upper sheet, the unit may be provided with a pressure compensation system that when lifting the bonnet by the piston is effective and is ineffective in the return movement of the piston.
The invention will be explained below with reference to two embodiments. In the accompanying drawings show schematically:

1 a safety system with a front hood which can be lifted by a compression spring,
2 a safety system with a top plate of a front hood, which can be raised by a compression spring,
3 : the compression spring assembly in the front hood closing position, enlarged, and
4 : the arrangement in the installation position of the front hood.

This in 1 illustrated safety system has an impact-damping front hood 1 with a top sheet 2 and a rigid substructure 3 , one at the substructure 3 in the area of the rear front end in aggregation with a bonnet lock 4 retained pressure spring 5 on, by one with the substructure 3 connected locking member 6 is biased. The compression spring 5 is with the locking pin 7 of the front hood lock 4 over a Hatterungsplatte 8th and a locking mechanism 9 connected, wherein on the support plate 8th Front hood also the locking member 6 attacks and the compression spring 5 against the stiff vehicle body 10 as an abutment for this (5) presses. The front hood 1 is hinged to the front of the vehicle (front end) and after unlocking the bonnet lock 4 in a known manner about the horizontal axis A pivotable in an opening position. At the front end is in the bumper 11 a sensor plate 12 as a device for detecting a collision and actuation of one with the locking member 6 coupled Bowden cable 13 for unlocking the compression spring 5 arranged. At the one with the front hood lock 4 and the compression spring 5 connected mounting plate 8th is also the piston 14 one with the vehicle body 10 firmly connected pneumatic piston-cylinder unit 15 arranged with a damping system as a force limiting means.
In a collision with a collision participant, for example, with the leg of a pedestrian, in which the sensor plate 12 on the Bowden cable 13 acts and on this the locking member 6 from the mounting plate 8th pulls, the compression spring relaxes 5 and push the front hood 1 from the stiff Fahrzeugaufbäu 10 from. This is also the piston 14 in the cylinder of the piston-cylinder unit 15 moved to top dead center. The top dead center limits the relaxation of the compression spring 5 and the movement of the bonnet 1 and thus defines the installation position of the front hood 1 (shown in dashed lines). If in this position, the pedestrian, especially with his head, on the front hood 1 This is deformed, whereby the deployment position an extended deformation path is available as in the front cover in its normal closed position 1 , and pushed back again.
The 3 shows the in 1 illustrated locking position of the front hood 1 before a collision. On the piston 14 and the cylinder of the piston-cylinder unit 15 are openings 16 and butterfly valves 17 to recognize that form a damping system, the case of an upward movement of the piston 14 is essentially ineffective. Will the piston 14 through the unlocked compression spring 5 Moves upwards, this presses the air in the cylinder through the openings 16 and the flapped valve flaps 17 out of the cylinder. In addition, there is an air balance within the cylinder through the piston 14 located openings 16 and butterfly valves 17 instead, during the upward movement of the piston 14 are also open. In its downward movement, however, close the valve flaps 17 both on the piston 14 due to the build-up of this pressure as well as on the cylinder by the resulting negative pressure. By further energy-consuming compression of the air under the piston 14 its movement is increasingly slowed or damped, which converts additional impact energy and reduces the risk of injury. 4 shows the arrangement at top dead center of the piston 14 in which the front hood 1 the with the dashed line in 1 marked, compared to the rigid vehicle body 10 has raised impact position.
In 2 an alternative security system is shown. In this only the top sheet 18 a front hood 19 opposite to this co-forming substructure 20 raised in the area of the rear front end, with the upper plate 18 via a predetermined breaking connection S (adhesive strip) with the understrut 20 connected, and the front hood 19 in this area in a known manner about Schamierhalterungen 21 on the stiff vehicle body 10 hinged and at the front end with a front hood lock 22 is closed, so that the front hood 19 open in a conventional manner. A compression spring 23 is in common with the piston 24 a pneumatic piston-cylinder unit 25 with a damping system equal to that of the 1 described (in 2 not shown) on one of the upper sheet 18 arranged Hafterungsplatte 26 supported. This is by a locking member 27 against the substructure 20 pressed and biased, with the locking member 27 over a Bowden cable 28 with a sensor plate arranged at the front end 29 connected is. Will the sensor plate 29 impacted by a collision participant, is via the Bowden cable 28 the locking song 27 from the mounting plate 26 pulled, and this is released. The compression spring 23 relaxes, releases the top sheet 18 at the predetermined breaking connection S of the substructure 20 and puts the top sheet 18 opposite to this, with the support plate 26 connected pistons 24 in the cylinder is also moved upward. Toward the security system 1 In this solution, the inertia of the compression spring 23 lower to moving mass, so that the upper sheet 18 is lifted faster at the same spring force. An impact participant and the head impactor also have less inertial mass to accelerate.
LIST OF REFERENCE NUMBERS

1: bonnet
2: upper sheet
3: substructure
4: Front hood lock
5: compression spring
6: locking member
7: locking pin
8th: support plate
9: closing mechanism
10: vehicle body
11: bumper
12: sensor plate
13: Bowden
14: piston
15: Piston-cylinder unit
16: opening
17: valve flap
18: upper sheet
19: bonnet
20: substructure
21: hinge bracket
22: Front hood lock
23: compression spring
24: piston
25: Piston-cylinder unit
26: support plate
27: locking member
28: Bowden
29: sensor plate

Claims

A safety system having an impact absorbing front bonnet on a vehicle having a top plate and a rigid substructure and capable of adjusting an impact position to a collision participant in the event of a collision, comprising at least one energy accumulator cooperating with the bonnet and a collision detection and activation device Energy release and with Kraftbegrenzungsmitteln, characterized in that the front hood (1) about a given at the front of the vehicle horizontal axis (A) is pivotable, that the energy storage (compression spring 5) arranged in the region of the rear front end and with an actuator (Schfießzapfen 7th / Support plate 8) is connected to the substructure (3) and supported on the rigid vehicle body (10) and coupled to the collision detection and activation device (12/13), and the actuator (lock pin 7 / support plate 8) under constructive tursitig with the piston (14) of a vehicle body (10) fixed piston-cylinder unit (15) is connected as a force limiting means for the return movement of the front hood (1).
A safety system having an impact absorbing front bonnet on a vehicle having a top plate and a rigid substructure and capable of adjusting an impact position to a collision participant in the event of a collision, comprising at least one energy accumulator cooperating with the bonnet and a collision detection and activation device Energy release and with power limiting means, characterized in that the upper plate (18) in the region of the rear front end of the vehicle with the substructure (20) is releasably connected and with respect to this (20) in a collision after release of the connection to a given at the front of the vehicle pivotable horizontal axis, that the energy storage (compression spring 23) in the region of the rear front end between the substructure (20) and the upper plate (18) and arranged with an actuator (support plate 26) with the latter (18) and connected to the substructure (20 ) supported and is coupled to the device for detecting the collision and activating the energy release (29/28), and in that the actuator (support plate 26) is connected to the piston (24) of a piston-cylinder unit (25) fixed to the vehicle body (10) as force-limiting means for the return movement of the upper plate (18).
Security system after Claim 1 or 2 , characterized in that the energy store is a pyrotechnic propellant and the actuator is the piston rod of a piston acted upon by this.
Security system after Claim 1 , characterized in that as an energy store on the substructure (3) held prestressed compression spring (5) is inserted, the structure side is held by a locking member (6) in the prestressed state, this (6) with the device for detecting the collision and Activation of the energy release (12/13) is coupled, and that the actuator is the substructure-side spring bearing (support plate 8 / locking pin 7).
Security system after Claim 2 , characterized in that a prestressed compression spring (23) held on the upper sheet (18) is used as the energy store, which is held in the prestressed state on the upper sheet side by a locking member (27) supported on the lower structure (20), this (27) being held in contact with the Device for detecting the collision and activation of the energy release (29/28) is coupled, and that the actuator is the shroud-side spring bearing (support plate 26).
Security system after Claim 1 or 4, characterized in that the device for detecting the collision and activating the energy release is an electrical sensor device or a mechanical bowden cable device (sensor plate 12/13).
Security system after Claim 2 or 5 , characterized in that the device for detecting the collision and activating the energy intake is an electromagnetic device with a trigger member, a sensor device or a mechanical Bowden cable device (sensor plate 29/28).
Security system after Claim 4 , characterized in that the compression spring (5) coupled to a front cover lock (4) and the actuator of the locking pin (7) is the same.
Security system after Claim 1 or 2 , characterized in that the piston-cylinder unit (15/25) a pneumatic system with a lifting the bonnet (1) or the upper plate (18) effective and in the return movement of the piston (14/24) inoperative pressure equalization system ( Openings 16 / valve flaps 17).