WO2004053262A1

WO2004053262A1 - Motor vehicle hood lock for damping pedestrian impacts

Info

Publication number: WO2004053262A1
Application number: PCT/FR2003/003554
Authority: WO
Inventors: Kaci Boucherit; Chaène SEYRANIAN
Original assignee: Renault S.A.S
Priority date: 2002-12-03
Filing date: 2003-12-02
Publication date: 2004-06-24
Also published as: JP4431500B2; FR2847929B1; FR2847929A1; EP1567737A1; JP2006509132A

Abstract

The invention concerns a lock for motor vehicle hood (1), comprising first (2) and second (3) parts whereof one is integral with the hood (1) and the other is integral with a body component (4) whereon the hood (1) is selectively applied by a displacement mutually bringing the two lock parts closer together along a first direction (5), the first part essentially including a lock-bolt keeper (6), and the lock-bolt keeper (6) including at least one blank (7) and one lock-bolt keeper wire (9). The lock-bolt keeper shifts from an initial configuration to an extreme configuration by displacement of the hood in the first direction (5) beyond a relative position closing the two parts of the lock. The lock-bolt keeper wire (9), which is inserted in at least one elongated opening (10) of a blank (7) of the lock-bolt keeper (6) moves into said elongated opening and shifts from an initial position to an extreme position absorbing mechanical energy.

Description

LOCK FOR MOTOR VEHICLE HOOD ALLOWING

DAMPING PEDESTRIAN SHOCKS

The present invention relates, in general, to a lock for a motor vehicle hood making it possible to absorb part of the shocks or mechanical forces resulting in particular from a collision with a pedestrian.

More particularly, the invention relates to a lock for a motor vehicle hood, comprising first and second parts, one of which is secured to the hood and the other of which is secured to a bodywork element on which the hood is selectively applied by a movement of mutual approximation of the two lock parts in a first direction, the first part mainly comprising a keeper, and the keeper comprising at least one blank and a keeper wire.

During a front impact between a motor vehicle and a pedestrian, the head of the latter generally strikes the vehicle body, and mainly affects the front hood, the window posts or the windshield.

This is the reason why many automobile manufacturers have developed various solutions aimed at absorbing the impact suffered by a pedestrian struck by a motor vehicle, the impact being able, for example, to be absorbed by the hood lock. A lock of the type previously defined, allowing such damping, is for example described in the patent document JP 2002019641 by TOYOTA JIDOSHA KK. The method of attachment is achieved by three attachment points allowing movement of the plate in the event of a pedestrian impact or in the event of significant mechanical overload. This method of fixing constitutes a mechanical fuse intended to absorb part of the mechanical energy transmitted by the strike on the second part of the lock during an accident.

Despite its shock absorption function, the lock of this device of the prior art has many technical drawbacks. For example, the amount of energy absorbed in the event of an impact cannot be adjusted precisely because of the variable friction forces existing between the plate and the body element. In addition, the range of motion for shock absorption is very limited.

Furthermore, insofar as part of the absorption results from a deformation of an elastic stop integral with the bodywork element, the risk exists that a shock will result in a permanent deformation of this stop and make repair very difficult.

In this context, the present invention aims to provide a lock for a motor vehicle hood allowing the opening and closing of the hood, the maintenance of the hood, and provided with an effective, precise and low impact absorption function. expensive to produce.

To this end, the lock of the invention, which also conforms to the generic definition given in the preamble above, is essentially characterized in that the keeper selectively adopts an original configuration and an extreme configuration and passes from its original configuration to its extreme configuration by movement of the cover in the first direction beyond a relative position for closing the two parts of the lock ensuring closing of the cover, in that a first elongated opening in the first direction is made in the first blank of the keeper, in that the keeper wire is inserted in the first elongated opening, perpendicular to this opening and said blank, and in that the strike wire passes in the first opening from an original position to an extreme position by pressing on the second part of the lock and with absorption of mechanical energy when the strike passes from its original configuration to its extreme configuration.

During a pedestrian impact, a large force is exerted on the hood, which correlatively causes a movement of mutual approximation of the two parts of the lock in the first direction. The striker wire, which is an element of the first part, then abuts against a complementary part of the second part. Under the action of resistance to the advance of the strike wire exerted by the second part, the strike wire which was hitherto blocked in its original position, in a first portion of the elongated opening, emerges from this first portion and slides by translation in the elongated opening towards a second portion of the elongated opening until thus reaching an extreme position. The energy absorbed during the movement of the strike wire from its original position to its extreme position makes it possible to dampen the passage of the strike from its original configuration to its extreme configuration and correspondingly to dampen the intensity of the shock pedestrian.

The amount of mechanical energy absorbed during the transition of the strike from its original configuration to its extreme configuration can be increased. For example, at least a portion of the first elongated opening may be located between the original position and the extreme position and may have a minimum width less than the diameter of the strike wire.

When the striker wire passes from its original position to its extreme position, it exerts a significant mechanical stress against the edges of the first elongated opening whose width is less than its diameter. It may result from this situation either a deformation of the opening by rolling the edges, or a deformation of the striker wire, or a mutual deformation of the striker wire and of the first elongated opening, thus allowing absorption of a large quantity of 'mechanical energy .

Other characteristics and advantages of the invention will emerge clearly from the description given below, by way of indication and in no way limitative, with reference to the appended drawings, in which: FIG. 1 represents a schematic view of a front part of a vehicle provided with the lock according to the invention; FIG. 2 represents a perspective view of the keeper according to the invention; Figure 3 shows a side view of the strike before the pedestrian impact in the original configuration; Figure 4 shows a side view of the striker after the pedestrian impact in the extreme configuration.

As previously announced, the invention relates to a lock composed of two parts. In the embodiment of Figure 1, the first part 2 is fixed to the cover 1 by a fixing base 22, and the second part 3 is fixed to a body element 4 of the vehicle.

The first and second parts, 2 and 3, of the lock can be selectively moved towards one another in a first direction 5, in order to close the cover 1, or be selectively distant from each other according to a second direction 14, reverse of the first, in a movement of opening the cover 1. When the cover is closed, the lock is in the closed configuration, while it is in the open configuration when the cover is open. In this FIG. 1, the lock is in the opening configuration, the first part 2 of the lock being slightly distant from the second part 3. The keeper 6 is integral with the cover 1 and has a first blank 7 and a second blank 8. The blanks 7 and 8 are substantially parallel to the first direction 5, and substantially parallel to each other. Blanks 7 and 8 are placed laterally on each side of the keeper 6 and are interconnected by the fixing base 22 allowing the blanks 7 and 8 to be assembled with the cover 1. The fixing base 22 can be fixed to the cover by any conventional means, and more particularly by welding or screwing. The spacing between the blanks 7 and 8 is provided so that these can come in a yoke on the sides of the second part 3 of the lock when the cover 1 is closed. The first blank 7 is pierced with a first elongated opening 10, and the second blank 8 is pierced with a second elongated opening 15. The elongated openings are substantially parallel to each other, and are oriented parallel to the first direction 5. A wire strike 9 is inserted into the elongated openings 10 and 15, and positioned substantially perpendicular both to the planes of the blanks 7 and 8, and to the first direction 5. The strike wire 9 is provided to be housed in an opening of passage of the strike wire 23 made in the second part 3 of the lock. When the cover is in the closed position, the strike wire 9 is positioned at the bottom of the opening for passage of the strike wire 23, and generally comes into abutment against the edge thereof. The second part 3 of the lock is provided with a conventional device for gripping the striker wire 9, not shown in FIG. 1 for reasons of clarity. For example, a conventional striker wire gripping device may be composed of a sliding or rotary bolt, at least part of which obstructs the movement of the striker wire 9 in the passage opening 23 according to the second direction 14. Such a conventional device must allow the keeper wire 9 to be held at the bottom of the passage opening 23 when the lock is in the closed configuration and must also allow the release of the keeper wire when the lock changes from its configuration closing to its opening configuration.

A safety hook 13 is movably mounted on the first blank 7. Preferably, the safety hook 13 is pivotally mounted about an axis of rotation perpendicular to said first blank 7. A safety stop 25 is integral with the one element body 4. In the opening configuration of the lock, the keeper 6, which is no longer held in position at the bottom of the passage opening 23 of the keeper wire by the keeper wire grip device, is free to move in the second direction 14. The first part 2 of the lock can thus be freely moved from the second part 3 of the lock. In this configuration, when opening the safety hook 13 secured to the cover 1 comes into abutment against the safety stop 25 secured to the body element 4, thus limiting the amplitude of separation of the first part 2 relative to the second part 3 and avoiding the risk of involuntary opening of the cover beyond the secure opening position. The safety hook 13 is movable between an angular safety position where the hook is engaged in abutment against the safety stop 25 and an out of safety angular position where the hook 13 is pivoted around its axis so as to disengage from the safety stop 25. When the lock is in the secure opening position and the safety hook is engaged against the safety stop, the hook can be operated manually in its angular position out of security, thus allowing the complete opening of the cover 2 beyond the secure opening position.

Preferably, the safety hook 13 is subjected to a first return torque forcing it into its angular safety position. An opening pallet 24 integral with the safety hook 13 makes it possible to apply to the hook 13 a second torque opposite to the first in order to manually pivot it from its angular position of safety towards its angular position out of safety.

The detail of the assembly of the blanks 7 and 8 with the striker wire 9 is shown in FIGS. 2 to 4.

Figures 2 and 3 show views of the keeper 9 according to the invention. In these figures, the striker wire 9 is inserted into the first 10 and second 15 elongated openings respectively made in the first blank 7 and in the second blank 8. In these figures, the striker wire 9 is in its original position before the pedestrian impact, inserted on the side of the elongated openings 10 and 15 which are furthest from the fixing base 22 of the keeper 6 on the cover 1. The first and second elongated openings, 10 and 15, have variable widths L as a function of the distance from the fixing base 22. The first elongated opening 10 comprises a first portion 11, and the second elongated opening 15 comprises a second portion 16. The two portions 11 and 16 are located at the end of their respective elongated openings, on the side of the openings which is furthest from the fixing base 22 and the cover 1. In its original position, the wire keeper 9 is inserted and positioned by interlocking in the first and second portions, 11 and 16, of elongated openings. To allow this interlocking, the first and second portions 11 and 16 of the elongated openings have shapes complementary to the sections of the striker wire 9 respectively inserted in the elongated openings.

The first portion 11 of the first elongated opening 10 leads to a third portion 12 of the first elongated opening 10 located on the side of the first elongated opening 10 which is closest to the fixing base 22 of the keeper 6. The second portion 12 of the second elongated opening 15 opens onto a fourth portion 17 of the second elongated opening 15 situated on the side of the second elongated opening 15 which is closest to the fixing base 22 of the keeper 6.

The third and fourth portions 12 and 17 of the elongated openings 10 and 15 have widths L less than the width of the sections of the striker wire 9 inserted in the elongated openings. In this way, the strike wire 9 cannot slide freely along the elongated openings in the second direction 14 and remains in the original position fitted into the first and second portions of the elongated openings. In this embodiment, the elongated openings of the two blanks 7 and 8 of the keeper 6 are geometrically similar to each other. The first and second portions 11 and 16 of the elongated openings are in the form of arcs of circles whose diameter is substantially equal to the diameter of the keeper wire 9, this wire having a cylindrical section.

The third and fourth portions 12 and 17 of the elongated openings have a width less than the diameter of the striker wire 9 and are in the form of grooves whose sides are substantially parallel to each other.

FIG. 4 represents a keeper according to the invention with its keeper wire 9 in the extreme position. In its extreme position, the striker wire 9 is translated into the elongated openings and positioned in the third and fourth portions of the elongated openings, at the end of the elongated openings which is close to the fixing base 22 and the cover 1. Under the influence of pedestrian impact, the hood tends to sink in the first direction 5. The strike wire 9 abuts against the second part 3 of the lock which is integral with the bodywork element 4. A resistant force oriented in the second direction 14 is correspondingly applied to the striker wire 9 in abutment at the bottom of the striker wire passage opening 23. The striker wire 9 then slides along the first and second openings 10 and 15 of the blanks 7 and 8 of the keeper 6 and is positioned in portions of these elongated openings 10 and 15 whose width is less than the diameter of the keeper wire 9.

The passage from the original position to the extreme position of the striker wire 9 is made by displacement of the wire in the elongated openings 10 and 15 and by mechanical deformation of the striker wire 9 and / or on the sides of the elongated openings 10 and 15 The assembly constituted by the strike wire 9 and the elongated openings is dimensioned to accept the normal operating forces of the lock such as the closing and opening of the cover, but also to absorb a part of the mechanical energy of a pedestrian impact, by passing the striker from its original configuration to its extreme configuration.

The mechanical deformation of the striker wire and / or the sides of the elongated openings 10 and 15 allows the absorption of part of the amount of mechanical energy produced by the pedestrian impact. This quantity varies according to the nature of the materials constituting the striker wire, the blanks, and also according to their geometric dimensions. For this, the striker wire 9 is generally constructed of a material whose hardness is greater than that of the blanks 7 and 8 so that only the sides of the elongated openings 10 and 15 undergo mechanical deformation by symmetrical rolling. The thicknesses of the blanks 7 and 8 are chosen in order to control the minimum mechanical stress necessary to carry out the rolling of the sides of the elongated openings, and correlatively to control the evolution of the force resisting the advance of the striker wire 9 between its original position and its extreme position.

Initially, after the pedestrian impact, the striker wire 9 moves until it disengages from its respective sockets in the elongated openings 10, 15 and leaves its original position. Preferably, the resistive force evolves in this first time in proportion to the advance of the striker wire 9.

In a second step, once the striker wire 9 is completely disengaged from its housings in the elongated openings and completely engaged in the portions 12, 17 of the elongated openings, the striker wire is subjected to a force resistant to advancement which is relatively constant until it reaches its extreme position.

The lock produced according to the invention allows precise control of the intensity of the damping forces applied to the striker wire 9 throughout its movement relative to the elongated openings 10 and 15.

By way of example, when the strike wire 9 is in an extreme position offset by about 20 mm from its original position, this wire should preferably undergo a force resistant to its advance of about 1000 N. This indicative value may be adapted according to the specific needs of each vehicle.

Preferably, the force resisting the advance of the striker wire 9 beyond its original position up to its maximum extreme position must be increasing up to a maximum safety threshold. Thus, to a certain extent, the impact force of the cover 22 on the pedestrian victim of an impact can be limited in intensity. The curve of the resisting force as a function of the amplitude of movement of the striker wire 9 is generally linearly increasing up to the maximum safety threshold, then remains relatively constant until the maximum amplitude of movement of the striker wire by compared to the waste. As a preferred example, the safety threshold not to be exceeded corresponds to a damping force of the striker wire 9 of approximately 1000 N.

The keeper of the new shock absorption lock can be adapted on many vehicles without causing significant modifications to the bodywork, while adapting to the types of locks generally used in the automotive industry.

Claims

1. Lock for a hood (1) of a motor vehicle, comprising first (2) and second parts (3), one of which is integral with the hood (1) and the other of which is integral with a body element (4 ) on which the cover (1) is selectively applied by a movement of mutual approximation of the two lock parts in a first direction (5), the first part mainly comprising a keeper (6), and the keeper (6) comprising at least a first blank (7) and a strike wire (9), said lock being characterized in that the strike (6) selectively adopts an original configuration and an extreme configuration and passes from its original configuration to its extreme configuration by movement of the cover (1) in the first direction (5) beyond a relative position for closing the two parts of the lock ensuring closure of the cover, in that a first elongated opening (10) according to the first direction (5) is practiced in the first blank (7) of the keeper (6), in that the keeper wire (9) is inserted into the first elongated opening, perpendicular to this opening and to said blank, and in that the keeper wire (9) passes through the first opening from an original position to an extreme position by pressing on the second part (3) of the lock, and with absorption of mechanical energy, when the keeper (6) changes from its original configuration to its extreme configuration.

2. Lock according to the preceding claim, characterized in that a safety hook (13) is secured to the cover (1), in that a safety stop (25) is secured to the bodywork element (4) , and in that in an opening configuration of the lock, obtained by moving the first part (2) away from the second part (3) in a second direction (14) opposite to the first direction (5), the safety hook

(13) abuts against the safety stop (25), thus limiting the amplitude of movement of the first part (2) relative to the second part (3) in the second direction

(14).

3. Lock according to claim 2, characterized in that the safety hook (13) is movably mounted on the keeper (6).

4. Lock according to any one of the preceding claims, characterized in that it comprises a second blank (8) substantially parallel to the first blank (7), in that a second elongated opening (15) similar to the first opening elongated (10) is formed in the second blank (8), said second opening being elongated in the first direction (5), in that the striker wire (9) is also inserted in the second elongated opening (15), perpendicular to this second opening (15) and to said second blank (8), and in that the striker wire (9) passes from an original position in the second elongated opening (15) to an extreme position in the second elongated opening (15), by pressing on the second part (3 ) of the lock and with absorption of mechanical energy, when the keeper changes from its original configuration to its extreme configuration.

5. Lock according to any one of the preceding claims, characterized in that at least a portion (12) of the first elongated opening (10) located between the original position and the extreme position of the striker wire (9) in the first opening (10) has a minimum width less than the diameter of the striker wire (9).

6. Lock according to any one of claims 4 or 5 characterized in that at least a portion (17) of the second elongated opening (15) located between the original position of the striker wire (9) in the second opening (15) and the extreme position of the strike wire in the second opening (15) has a minimum width less than the diameter of the strike wire (9).

7. Lock according to any one of the preceding claims, characterized in that the absorption of mechanical energy is produced by a resistant force opposed to the passage of the striker wire (9) from its original position to its extreme position , said resistant force being increasing throughout the movement of the striker wire (9) beyond its original position in the first direction (14) and in that said force is limited to a maximum safety threshold.

8. Lock according to the preceding claim, characterized in that the maximum security threshold is limited to approximately 1000 N.