Abstract:
An actuator is longitudinally aligned along a side of the vehicle body in the fore and aft direction of the vehicle, and a lower and upper links connected to the actuator is widely opened and lift the hood, thereby minimizing the occupancy of the actuator and linkage, and preventing interference with adjacent components without changing the structure of the vehicle body. Moreover, the hood is lifted high enough for pedestrian safety using a relatively short stroke of the actuator, contributing to a formation of a compact structure as a whole and a prevention of the weight increase of the vehicle.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is based on, and claims priority from, Korean Application Serial Number 10-2005-0106289, filed on Nov. 8, 2005, the disclosure of which is hereby incorporated by reference herein in its entirety. 
     FIELD OF THE INVENTION 
     The present invention relates to a vehicle hood and, more particularly, to a pedestrian protecting apparatus of the vehicle hood adapted to reduce the magnitude of injury to the pedestrian upon impact with the vehicle. 
     BACKGROUND OF THE INVENTION 
     The vehicle hood is generally a metal lid over the engine compartment and has its rear end connected to the vehicle body by hood hinges. 
     Nowadays, the regulation on pedestrian protection mandates that the vehicle hood be configured to attenuate injury to the pedestrian when the pedestrian is struck by the vehicle and fallen on the hood. 
     In order to satisfy the regulation, systems have been proposed for forcibly raising the hinged rear end of the hood in response to or immediately prior to the vehicle impacting the pedestrian, thus allowing the hood to deform downward and buffer collision impact of the pedestrian. 
     The hood lifting structure is typically performed with a hydraulic actuator or a pyrotechnic actuator using the explosion force for rapidly lifting the heavy hood. 
     However, for lifting the hood using the actuator, a mechanical structure is required to convert a linear motion of the actuator into an elevation force of the hood. This structure should be compact in configuration and facilitate the assembly and maintenance thereof. 
     SUMMARY OF THE INVENTION 
     Embodiments of the present invention form a compact structure as a whole, sufficiently and promptly raise the hood for pedestrian safety by using a short stroke of an actuator, and prevent the weight increase of the vehicle. 
     Furthermore, the actuator is facilitated in attachment, resulting in an improvement of the assembly and maintenance. 
     A pedestrian protecting apparatus of a vehicle hood comprises a controller that detects impact degree through a plurality of sensors of a bumper when a pedestrian impacts with the vehicle. An actuator is pivotally fixed at one end thereof via a support bracket to a vehicle body forming a side of an engine compartment and projects a cylinder rod by being actuated by the controller. A linkage is mounted between the vehicle body and hood and is widely opened for lifting the hood from the vehicle body while the cylinder rod of the actuator protrudes and applies a pressing force thereto. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a better understanding of the nature and objects of the present invention, reference should be made to the following detailed description with the accompanying drawings, in which: 
         FIG. 1(   a ) is a perspective view of a pedestrian protecting apparatus of a vehicle hood according to one embodiment of the present invention, and  FIG. 1(   b ) is a side elevation view of the apparatus; 
         FIG. 2(   a ) is a perspective view of a hood lifter according to one embodiment of the present invention, and  FIG. 2(   b ) is a partial side elevation view showing a portion of the hood lifter; 
         FIG. 3(   a ) is a side view and  FIG. 3(   b ) is a plan view of  FIG. 2 ; 
         FIGS. 4(   a )-( c ) illustrate deformations of a link latch while a hood lifter is ceased in operation according to one embodiment of the present invention; and 
         FIGS. 5(   a )-( c ) illustrate an operation of a pedestrian protecting apparatus of a vehicle hood according to one embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to  FIGS. 1 to 3 , one embodiment of the present invention includes a controller  2  that detects the impact degree through a plurality of sensors  1  of a bumper (B) when a pedestrian accidentally impacts with the vehicle. An actuator  4  is pivotally fixed at one end thereof via a support bracket (SB) to a vehicle body (C) forming a side of the engine compartment and projects a cylinder rod  4   c  by being actuated by controller  2 . A linkage is mounted between the vehicle body and hood (H) and is widely opened for lifting the hood (H) from the vehicle body while cylinder rod  4   c  of actuator  4  protrudes and applies a pressing force thereto. 
     Actuator  4  instantaneously and linearly projects cylinder rod  4   c ; and a pyrotechnic type actuator is preferably used in the present invention which protrudes out cylinder rod  4   c  by using the exploding force of the actuator. 
     While the hood (H) is in a closed state, actuator  4  is in parallel with the hood beneath the hood (H). When protruding out, cylinder rod  4   c  of actuator  4  faces the rear of the vehicle, and the support bracket (SB) supporting actuator  4  to the vehicle body (C) is fixed on the fender of the vehicle body (C). 
     Controller  2  is preferably an airbag control unit (ACU) that controls the airbag of the vehicle. 
     Under a slight impact detected via the sensors, the ACU generates an operation signal of the actuator so as to lift the hood and protect the pedestrian without inflating the airbag. 
     The linkage is pivotally connected to a vehicle body (C) via a vehicle body mounting bracket  7  and a vehicle body hinge pin (ch). Similarly, linkage is pivotally connected to the hood (H) via a hood mounting bracket  8  and a hood hinge pin (hh). 
     The linkage includes a lower link  5  and an upper link  6 , wherein lower link  5  is coupled at one end thereof via an operation hinge pin (wh) to cylinder rod  4   c  of actuator  4 , while the other end of lower link  5  is coupled via the vehicle body hinge pin (ch) to vehicle body mounting bracket  7 . Upper link  6  is coupled at one end thereof via a transmission hinge pin (th) to lower link  5 , and the other end of upper link  6  is coupled via the hood hinge pin (hh) to hood mounting bracket  8 . 
     Lower link  5  includes a support body portion  5   a  coupled via the vehicle body hinge pin (ch) to vehicle body mounting bracket  7 . An extended connection portion  5   b  is extended out from support body portion  5   a  between the transmission hinge pin (th) (coupled with upper link  6 ) and the operation hinge pin (wh) (coupled with cylinder rod  4   c  of actuator  4 ). 
     A position restricting chin  5   c  protrudes downward from support body portion  5   a  for restraining the pivot of lower link  5 . While the hood (H) is closed, position restricting chin  5   c  is supported at the lower portion thereof by vehicle body mounting bracket  7 . 
     Hood mounting bracket  8  coupled with upper link  6  via a hinge is fixed at a hood reinforcing bracket (R) that reinforces the rigidity of the hood (H). 
     Vehicle body mounting bracket  7  and hood mounting bracket  8  are formed with a hood retreat preventing portion (Ka) for preventing a removal of the hood (H) toward the passenger compartment while the hood (H) is closed. 
     Hood retreat preventing portion (Ka) is composed of a lower hood receding lock chin  7   a  upwardly protruding at one side of vehicle body mounting bracket  7 , and an upper hood receding lock chin  8   a  bent to protrude out to the front of lower hood receding lock chin  7   a  at one side of hood mounting bracket  8 . 
     A link restrictor (Kb) restrains the pivot of upper link  6  while the hood is in a closed position. 
     The link restrictor (Kb) is constituted by a latch protrusion  13  protruding at one end of upper link  6 . A pivot latch  10  is coupled at one end thereof via a latch hinge pin (jh) to vehicle body mounting bracket  7  and is formed with a latch chin  10   a , which protrudes out for engaging with latch protrusion  13 . A spring  12  is interposed between an extended support end  11   a  (protruding from vehicle body mounting bracket  7 ) and an extended latch end  10   c  (one end of pivot latch  10 ) for retaining the engaged state of pivot latch  10  with latch protrusion  13  while the hood (H) is closed. 
     Pivot latch  10  is also formed with an extended hinge end  10   b  protrusively extended and fixed via the latch hinge pin Oh) to a hinge coupling end  11  projecting from vehicle body mounting bracket  7 . 
       FIG. 4  illustrates other embodiments of the link restrictor. 
     The link restrictor (Kb) of  FIG. 4(   a ) includes a latch protrusion  13  protruding from one end of upper link  6 . An extended pivot latch  14  extends from one end of lower link  5  toward latch protrusion  13  of upper link  6 . A latch chin  14   a  protrudes from one end of extended pivot latch  14  for engaging with latch protrusion  13  of upper link  6 . 
     The link restrictor (Kb) of  FIG. 4(   b ) includes a mount restraint end  18  formed at one end of upper link  6  in an arc sectional shape. A plate spring latch  15  is fixed at vehicle body mounting bracket  7  and generates a restricting force against upper link  6  through a stably mounting groove  15   a  that is dented for accommodating mount restraint end  18 . 
     The link restrictor (Kb) of  FIG. 4(   c ) includes a latch protrusion  13  that protrudes out from one end of upper link  6 . A pivot latch  16  is formed with an extended hinge end  16   b , which is fixed via a restricting hinge pin (sh) to hinge coupling end  11  protruding from vehicle body mounting bracket  7 , and a latch chin  16   a  protruding out for engaging with latch protrusion  13 . A torsion spring  17  is coupled to the restricting hinge pin (sh). One end of torsion spring  17  is fixed to pivot latch  16  while the other end is fixed to an extended support end  17   a  protruding from vehicle body mounting bracket  7 . 
     The operation of the present invention will now be described with reference to  FIG. 5 . 
     In a normal state, the front of the hood (H) is supported via a hood latch to the vehicle body, and the rear of the hood (H) is stably supported via the link restrictor (Kb) to the vehicle body (C). 
     If the user releases the hood latch for an inspection of the engine compartment or the like, the hood (H) pivots about the hood hinge pin (hh) as a pivot shaft and is opened upward. 
     The link restrictor permits the hood to stably be opened and closed about the hood hinge pin (hh) by restraining the end of upper link  6  from upwardly pivoting. 
     In case the pedestrian collides with the vehicle under a certain impact degree, the apparatus of the present invention lifts up the rear portion of the hood, thus preventing or attenuating the impact of the pedestrian. 
     When receiving the impact signal from sensors  1  corresponding to the collision of the pedestrian with vehicle, the ACU detects the intensity of impact and determines as to whether the operation of actuator  4  is required. 
     If the ACU determines to operate actuator  4 , cylinder rod  4   c  rapidly protrudes out from actuator  4 , as illustrated in  FIG. 5 , and the linkage raises the rear portion of the hood (H). Cylinder rod  4   c  of actuator  4  slightly pivots upward, accordingly. 
     That is, if lower link  5  of the linkage receives a force from cylinder rod  4   c , extended connection portion  5   b  of lower link  5  pivots upward about the vehicle body hinge pin (ch) of vehicle body mounting bracket  7 . 
     Next, upper link  6  connected via the transmission hinge pin (th) to lower link  5  moves upward via the rotational force of lower link  5 . Thus, the hood (H) is raised at the rear portion thereof about the hood latch as a pivot point. This separates the hood (H) from an engine cover (E) and forms a gap therebetween for absorbing or lessening impact of the pedestrian fallen on the hood (H). 
     When the hood (H) is lifted, the link restrictor (Kb) releases the restraint of upper link  6 . 
     That is, when upper link  6  is raised by lower link  5  and latch protrusion  13  pushes latch chin  10   a  of pivot latch  10 , pivot latch  10  slightly pivots about the latching hinge pin (jh) and latch protrusion  13  of upper link  6  escapes from latch chin  10   a  of pivot latch  10 . 
     Spring  12  supporting pivot latch  10  is compressed in response to the pivot degree of pivot latch  10 . 
     Identical operation is accomplished in the other embodiments of the link restrictor (Kb). 
     In case of  FIG. 4(   c ), under a normal state, latch chin  16   a  of pivot latch  16  restricts latch protrusion  13  of upper link  6 , and thus, the rear portion of the hood (H) is stably supported by the vehicle body (C); however, once actuator  4  operates, latch protrusion  13  of upper link  6  moves upward and pushes latch chin  16   a  of pivot latch  16 . The pivot of pivot latch  16  deforms torsion spring  17  and allows an upward motion of upper link  6 . 
     If extended pivot latch  14  is integrally formed at a distal end of lower link  5  (see  FIG. 4(   a )), as actuator  4  operates, extended pivot latch  14  pivots with lower link  5  according to the pivot of lower link  5  and withdraws from latch protrusion  13  of upper link  6 , thus allowing the release of upper link  6 . 
     If mount restraint end  18  of upper link  6  is restrained by plate spring latch  15  (see  FIG. 4(   b )), as actuator  4  operates, mount restraint end  18  elastically deforms plate spring latch  15  corresponding to the pivot of upper link  6  and escapes from stably mounting groove  15   a.    
     Since upper hood receding lock chin  8   a  of hood mounting bracket  8  (fixed to the hood (H)) and lower hood receding lock chin  7   a  of vehicle body mounting bracket  7  (fixed to the vehicle body (C)) are distantly installed in a fore/aft direction of the vehicle (see  FIG. 3 ), the hood retreat preventing portion (Ka) gives no effect to each other while the hood (H) ascends. 
     Provided that the hood (H) is raised, lower link  5  and upper link  6  are widely opened, as shown in  FIG. 5(   c ), by cylinder rod  4   c . This state is maintained with the gas pressure maintained in actuator  4 . In case the pedestrian is fallen on the hood (H) of the vehicle and applies impact thereon, actuator  4 , lower link  5 , and upper link  6  attenuate the impact. 
     If the impact from the pedestrian on the hood (H) is transmitted to upper link  6 , upper link  6  pivots downward and presses lower link  5 . As lower link  5  moves down, actuator  4  connected to lower link  5  is shortened in length and descends the hood (H) for absorbing impact transmitted to the pedestrian. 
     When lower link  5  inserts cylinder rod  4   c  into actuator  4 , cylinder rod  4   c  exhausts the gas of actuator  4  and smoothly buffers the impact applied to the pedestrian. 
     The gas exhaust from actuator  4  is a typical structure of the pyrotechnic type actuator, wherein when cylinder rod  4   c  forcibly presses the gas in actuator  4 , the gas is discharged by a piston formed with a vent hole, or the like. 
     The gas discharging speed of actuator  4  should appropriately be set through experiments and calculations for optimally buffering the impact of the pedestrian. 
     As apparent from the foregoing, there is an advantage in that the apparatus of the present invention is configured to allow a linkage, connected to each other via hinges, to be widely opened and lift the hood (H) according to the linear motion of an actuator longitudinally aligned along a side of the vehicle body in the fore/aft direction of the vehicle, thereby minimizing the occupancy of the actuator and linkage, and obviating interference with adjacent components without changing the structure of the vehicle body. 
     Furthermore, the actuator of the present invention is aligned lengthwise along the side of the vehicle body and fixed at both ends thereof via hinge pins so that only the linkage is installed in the vehicle during the print coating process and the actuator may be attached after the completion of the coating process. 
     Still further, the cylinder rod of the actuator is designed to pressurize the center portion of the hinged linkage for opening the linkage, thereby enabling to lift the hood high enough according to the length adjustment of the linkage and form a compact structure by using the actuator having a relatively short stroke.