Vehicle hood deployment device for pedestrian protection

[0002] The present invention relates generally to a vehicle hood that is deployable upwardly in response to the vehicle impacting a pedestrian to provide additional crush space between the hood and underhood components.

[0003] In modern automotive design it is desirable for visibility, aerodynamic and styling reasons that the hood line be kept as low as possible. As a result, there is generally very little clearance between the hood and the engine bay contents of the automotive vehicle. As a result, the hood is unable to yield enough to provide significant cushioning when a pedestrian strikes the hood during an accident. Pedestrian safety performance can be improved by increasing the clearance between the hood and the vehicle components beneath the hood.

[0004] One way to achieve a greater clearance while maintaining a low hood line during normal vehicle operations is to provide a device to raise the hood in response to or immediately prior to the vehicle impacting a pedestrian.

[0005] Systems have been proposed for raising a vehicle hood using an actuating cylinder/piston with its line of action oriented vertically and acting on the hood to urge it upward when activated. Examples of such systems are disclosed in U.S. Pat. Nos. 6,217,108 and 6,182,782.

[0006] The present invention provides a pedestrian safety device for an automotive vehicle having a body structure with an upper surface and a hood with a trailing edge and a leading edge. The safety device comprises a hinge arm having a pivot end rotatably connected to the hood adjacent the trailing edge and a sliding end restrained for movement along a path generally parallel with the upper surface of the body structure. The hinge arm is movable between a normal operating position wherein the slide end is adjacent the forward end of the path and the pivot end is relatively close to the upper surface of the vehicle body structure, and a raised position wherein the slide end is adjacent the rear end of the path and the pivot end is raised with respect to the normal position, movement of the hinge arm from the normal position to the raised position causing the trailing edge of the hood to move upwardly. An actuator is disposed on the body structure and engages the hinge arm, acting along a line of action generally parallel with the path. The actuator has a retracted condition wherein the hinge arm is in the normal operating position and is movable to an extended condition to urge the hinge arm to the raised position. Movement of the hinge arm to the raised position results in the trailing edge of the hood being lifted upward, thus creating a greater amount of crush space between the hood and underhood components so that the hood may absorb more kinetic energy when struck by a pedestrian. The alignment of the actuator and path generally parallel with the upper surface of the vehicle structure permits the actuator to be mounted on or near the top of the body structure immediately beneath the hood, thus reducing the cost and complexity of installation and repair of the actuator.

[0007] According to another feature of the invention, the pedestrian safety device further comprises a pivot structure connecting the body structure with the hood adjacent the leading edge and providing a lateral axis about which the hood rotates relative to the body structure when the hinge arm moves to the raised position. The pivot structure preferably is part of a latch mechanism used to alternatively secure the hood closed and permit the hood to be opened during normal operation. The pivot structure also preferably enables the hood leading edge to translate rearward when the trailing edge of the hood moves upwardly. This rearward translation ensures that the hood leading edge does not impinge on other portions of the vehicle structure during deployment, such as the headlamp or grille.

[0008] According to another feature of the invention, the pivot end of the hinge arm is connected to the hood by a pivot mechanism about which the hood rotates for normal opening and closing of the hood when the hinge arm is in the normal operating position. The pivot end of the hinge arm is engaged by a retaining member disposed on the vehicle structure when in the normal operating position and is retained in a proper location for opening and closing of the hood. The retaining member preferably comprises a slot that has an open end facing upward to direct the pivot end to move upward when moving to the raised position and to prevent the hood trailing edge from being raised when the actuator is in the retracted condition. The invention device thus provides a simple, compact hinge mechanism that allows the hood to function normally prior to deployment of the hood.

[0009] According to another feature of the invention, the actuator pivotingly is connected to the body structure so that it may rotate as necessary to maintain an optimum alignment with the hinge arm during upward deployment of the hood.

[0010] Other features and advantages of the present invention will be readily appreciated and better understood after reading the subsequent description when considered in connection with the accompanying drawings.

[0011] FIG. 1 is a side view of an embodiment of a hood deployment device according to the present invention in a normal operating condition.

[0012] FIG. 2 is a side view of the hood deployment device of FIG. 1 in a raised or deployed condition.

[0013] FIG. 3 is an enlarged view from the opposite side of the hood deployment device of FIG. 1.

[0014] FIG. 4 is a side view of a second embodiment of a hood deployment device according to the present invention in a normal operating condition.

[0015] FIG. 5 is a side view of the hood deployment device of FIG. 4 in raised or deployed position.

[0016] Referring to FIGS. 1-3, an embodiment of a hood deployment device according to the present invention is shown in combination with a vehicle body structure, generally indicated at 12, and a hood 14. While the following description is directed to a vehicle having a hood that is hinged at a trailing edge, the invention may also be applied to a hood hinged at its leading edge. All references to directions herein are relative to the vehicle as a whole and use the convention shown by the coordinate axes indicated in FIG. 1, wherein the X-axis is the longitudinal axis of the vehicle, the Y-axis is the lateral axis, and the Z-axis is the vertical axis.

[0017] A vehicle will preferably have two substantially identical hood deployment devices, one adjacent each lateral edge of the hood. The following description applies to each of the devices.

[0018] A hinge assembly 16 is secured to the vehicle structure 12 adjacent its upper surface in the area of the vehicle body commonly known as the shotgun. Hinge assembly 16 includes a retaining member 18 disposed approximately below the trailing edge of hood 14 and having an upward-facing retaining slot 20. Hinge assembly 16 further includes a guide member 22 extending forward from the retaining member 18 along the X-axis of the vehicle and having a track 24 formed therein. Track 24 defines a path oriented generally parallel with the upper surface of the vehicle structure 12. The upper surface of vehicle structure 12 is depicted in FIGS. 1 and 2 as being generally horizontal, but may be inclined from horizontal and/or may be curved depending on the design of the particular vehicle.

[0019] A hinge arm 26 has a slide end 26aengaging the track 24 for sliding movement therealong. A pivot end 26bof hinge arm 26 rotatably engages a hood hinge 28 secured to hood 14 adjacent the trailing edge thereof. During normal vehicle operating conditions, as shown in FIG. 1, the slide end 26aof hinge arm 26 is disposed adjacent the forward end of the track 24 and the pivot end 26bis relatively close to the vehicle structure 12 and seated in retaining slot 20. In this normal condition, hood 14 and hood hinge 28 are free to rotate about hinge arm pivot end 26bin order to open and close the hood in a conventional fashion.

[0020] A lock pin 30 passes through hinge assembly 16 immediately above hinge arm 26 and contacts or is closely adjacent the upper of the hinge arm 26. Lock pin 30 blocks rotation of hinge arm 26 about its slide end 26aas long as the slide end remains adjacent the forward end of track 24. Accordingly, lock pin 30 prevents the trailing edge of hood 14 from being lifted upward so as to thwart attempts to steal, vandalize, or otherwise tamper with components in the engine compartment beneath the hood. Even in the absence of lock pin 30, engagement of hinge arm 26 with slot 20 prevents the trailing edge of the hood from being lifted by blocking the rotation of hinge arm 26 about its slide end 26aas long as the slide end remains adjacent the forward end of track 24.

[0021] A latch 32 is attached to vehicle structure 12 below the leading edge of hood 14, and a striker 34 is attached to the underside of hood 14 in a position to engage the latch 32 to secure the hood 14 in a closed position. Latch 32 may be manually and/or remote mechanically actuated to release striker 34 in order to permit the hood to be opened, as is well known in the art.

[0022] An actuator 36 is secured to vehicle structure 12 immediately forward of hinge assembly 16 and comprises a linearly movable piston 38, the distal end of which engages hinge arm 26. Actuator 36 is mounted to vehicle structure 12 so that the line of action of piston 38 is parallel with track 24. During normal vehicle operating conditions piston 38 is in a retracted condition (shown in FIG. 1).

[0023] Actuator 36 is preferably powered by a pyrotechnic charge, but any appropriate means (mechanical, electrical, hydraulic, magnetic, pneumatic, etc.) of driving a piston or other movable member may be used.

[0024] Actuator 36 is activated by a control system 40 indicated schematically at in FIG. 1. The control system 40 comprises a pedestrian impact sensor 42, which may detect physical impacts with the vehicle or may be a pre-impact detector utilizing, for example, radar, laser, sonar, optical, or any other appropriate remote detection means. A control module 44 receives signals from sensor 42, evaluates the signals, and activates actuator 36 when the signals indicate that the vehicle has struck or is about to strike a pedestrian.

[0025] When control system 40 detects an actual or impending impact with a pedestrian (not shown), actuator 36 is activated to move piston 38 from the retracted condition to the extended condition shown in FIG. 2, driving hinge arm 26 to the rear. The engagement between latch 32 and striker 34 restrains hood against rearward movement so that hinge arm 26 rotates about slide end 26aand pivot end 26blifts upward, thereby moving hood 14 to the raised position.

[0026] As hinge arm 26 begins to move away from the normal operating position, the pivot end 26bis constrained by retaining slot 20 and so moves purely along the axis of the slot. Retaining slot 20 thus directs the initial movement of hood 14 upward, preventing rearward movement until the hood trailing edge has lifted upward a sufficient amount to avoid interference with other body panels to the rear of the hood.

[0027] In the raised position, hood 14 is spaced from vehicle components (not shown) in the engine compartment to provide space for the hood to deflect downward when struck by the pedestrian and so absorb kinetic energy of the impact. Additional cushioning may be provided by actuator 36, which may be designed to provide an energy-absorbing damper effect when in the deployed condition.

[0028] In the preferred embodiment shown, movement of hood 14 to the raised position results in a pivoting motion about a lateral axis adjacent the leading edge of the hood 14. The lateral pivot axis is provided by the interaction between latch 32 and striker 34, which together comprise a latch structure. Latch 32 and striker 34 are designed to permit a small amount of rearward movement of hood 14 during deployment after the pivot end 26bof hinge arm 26 has cleared retaining slot 20. As seen in FIG. 2, striker 34 is able to move rearward relative to latch 32 by an amount sufficient to allow the leading edge of the hood to move downward during deployment without interference with front end components such as grille, headlamps, front fascia, etc.

[0029] Referring now to FIGS. 3 and 4, a second embodiment of the invention is shown to comprise a track 52 disposed on the upper surface of vehicle structure 12 and a hinge arm 54 having a slide end 54aengaged with the track 52 and an opposite pivot end 54bengaged with a hood hinge 56 secured to hood 14. As in the first embodiment, hinge arm 54 is movable between a normal operating position wherein the end 54ais adjacent the forward end of track 52 and the pivot end 54bis relatively close to the vehicle structure 12, and a raised position wherein the slide end 54ais adjacent the rear end of track 52 and the pivot end 54bis raised with respect to the normal position to lift the trailing edge of the hood 14 upwardly.

[0030] In the second embodiment, a forward end of actuator 58 is attached to vehicle structure 12 at a pivot point 60 and piston 62 engages a stub 64 extending downward from hinge arm 54. As seen in FIG. 4, in the normal operating condition actuator 58 is in a generally horizontal orientation so that the line of action of piston 62 is parallel to but offset from track 52. Actuator 58 is preferably attached to the inboard side of the shotgun, thus freeing more package space between hood 14 and the upper surface of vehicle structure 12.

[0031] When actuator 58 is activated by a control system, as described in relation to the first embodiment, piston 62 moves to an extended condition and urges hinge arm 54 to the raised position as shown in FIG. 5. As hinge arm 54 moves to the raised position, it rotates upwardly about its slide end 54aand the offset distance between track 52 and the line of action of piston 62 changes. This results in actuator 58 rotating about pivot point 60 as necessary.

[0032] In both disclosed embodiments of the invention, the actuator is mounted adjacent the upper surface of the vehicle structure in the vicinity of the shotgun and with the line of action of the piston generally parallel with the upper surface of the vehicle structure. This mounting improves the underhood packaging of the actuator and allows the actuator to be more easily installed and serviced than if installed in a vertical or upright position. In particular, hinge assembly 16 can be installed in the vehicle before the vehicle is painted and the actuator can be easily installed after the vehicle is painted so that actuator is not damaged by the painting process.

[0033] While the best modes for carrying out the invention have been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention as defined by the appended claims.