Abstract:
A passenger protection apparatus for a vehicle according to the invention has an excellent effect in that lower limbs of the vehicle occupant can be successfully held even during a frontal offset impact or an oblique impact. The passenger protection apparatus includes a pair of active knee bolsters provided in an instrument panel or at a vicinity thereof, each bolster being capable of restraining a corresponding lower limb of a passenger; a detector which, at a time of a collision, can detect a direction thereof; and a controller which, in accordance with the detection, can control the active knee bolsters independently from each other.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
         [0001]    This application claims priority under 35USC 119 from Japanese Patent Application No. 2002-333287, the disclosure of which is incorporated by reference herein.  
         BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The present invention relates to a passenger protection apparatus for a vehicle and, more particularly, to a passenger protection apparatus which is mounted in a motor vehicle or the like.  
           [0004]    2. Description of the Related Art  
           [0005]    A passenger protection apparatus, which is mounted in a vehicle such as, for example, an automobile or the like, and comprises a first protector (also called an active knee bolster) which is movably supported on the vehicle body side and a second protector (also called an active knee bolster), and first and second actuators for driving the first and second protectors, respectively, is known. During a collision, the first and second protectors are driven by the first and second actuators so as to restrain lower limbs of a passenger or occupant, who is seated on a passenger seat, from the vehicle front side. At the same time, a front side portion of a seat cushion separates from a rear side portion of the seat cushion and moves toward the vehicle front side. For example, refer to Japanese Patent Publication No. 2679405 (FIGS. 1 and 7).  
           [0006]    However, in the above-described prior art structure, the first and second protectors concurrently operate and restrain the (right and left) lower limbs of the passenger uniformly in a direction from front to rear of the vehicle. Accordingly, during a frontal offset impact, i.e., a frontal impact at a point, which is offset rightward or leftward with respect to a vehicle center line, of the vehicle front, or during an oblique impact, the passenger is likely to move diagonally forward or in an irregular direction. Therefore, with such first and second protectors, it is difficult to reliably restrain both of the lower limbs of the passenger.  
         SUMMARY OF THE INVENTION  
         [0007]    In light of the above-described circumstances, an object of the present invention is to provide a passenger protection apparatus for a vehicle, which apparatus enables reliable restraint of the lower limbs of a passenger during a collision even if it is a frontal offset collision or an oblique impact.  
           [0008]    In order to achieve at least the object described above, according to an aspect of the present invention, there is provided a passenger protection apparatus for a vehicle, said apparatus comprising: a pair of active knee bolsters provided in an instrument panel or at a vicinity thereof, each bolster being capable of restraining a corresponding lower limb of a passenger; a detector which, at a time of a collision, can detect a direction thereof; and a controller which, in accordance with the detection, can control the active knee bolsters independently from each other.  
           [0009]    According to another aspect of the present invention, there is provided a passenger protection apparatus for a vehicle, said apparatus comprising: a pair of active knee bolsters provided in an instrument panel or at a vicinity thereof, each bolster being capable of restraining a corresponding lower limb of a passenger; another active knee bolster provided in a vehicle front side door or at a vicinity thereof, said another bolster being capable of restraining one of the lower limbs; yet another active knee bolster provided in a center console or at a vicinity thereof, said yet another bolster being capable of restraining the other of the lower limbs; a detector which, at a time of a collision, can detect a direction thereof, and a controller which, in accordance with the detection, can control the active knee bolsters independently from one another.  
           [0010]    The foregoing and other objects, features and advantages of the present invention will become apparent to one skilled in the art from the following description of preferred embodiments of the invention, as illustrated in the accompanying drawings, and appended claims. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]    [0011]FIG. 1 is a side sectional view of a passenger protection apparatus for a vehicle according to a first embodiment of the present invention.  
         [0012]    [0012]FIG. 2 is a perspective view showing a main part of the passenger protection apparatus according to the first embodiment of the present invention, as seen obliquely from a vehicle front side.  
         [0013]    [0013]FIG. 3 is a plan view showing an operation of the passenger protection apparatus according to the first embodiment of the present invention.  
         [0014]    [0014]FIG. 4 is a plan view showing another operation of the passenger protection apparatus according to the first embodiment of the present invention.  
         [0015]    [0015]FIG. 5 is a flowchart showing operation of the passenger protection apparatus according to the first embodiment of the present invention.  
         [0016]    [0016]FIG. 6 is a plan view showing a passenger protection apparatus according to a second embodiment of the present invention.  
         [0017]    [0017]FIG. 7 is a plan view showing the passenger protection apparatus according to the second embodiment of the present invention.  
         [0018]    [0018]FIG. 8 is a flowchart showing operation of the passenger protection apparatus according to the second embodiment of the present invention.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0019]    Referring now to FIGS.  1  to  5 , a first embodiment of a passenger protection apparatus according to the present invention will be described in detail below.  
         [0020]    In the figures, arrows “FR” indicate a vehicle forward direction, arrows “UP” indicate a vertical upwards direction, and arrows “IN” indicate a vehicle inward direction.  
         [0021]    As shown in FIG. 1, the passenger protection apparatus according to the present embodiment is provided with acceleration sensors  12 , which measure a deceleration of a vehicle to detect a vehicle collision and which, at a time of a collision, measure a direction thereof as collision direction measuring means. The acceleration sensors  12  are disposed at both sides of a front side member and are connected to a control circuit  14  serving as control means including a microcomputer. The control circuit  14  compares signals from both of the acceleration sensors  12 , and then, detects a vehicle collision and measures the direction of the collision.  
         [0022]    In an instrument panel  18  of a vehicle body  16 , active knee bolsters  24  and  25  are provided, which are positioned diagonally above the front of a seat cushion  22  of a front seat  20 . Each of the active knee bolsters  24  and  25  includes a body portion  30  to restrain a lower limb portion (especially, a knee portion), from diagonally above the front thereof, of a vehicle occupant  28  who is seated on the passenger seat  20 , and an actuator  32  to move the body portion  30  toward the lower limb portion of the vehicle occupant  28 .  
         [0023]    As shown in FIG. 2, the left side active knee bolster  24  can restrain a left lower limb portion  28 A of the vehicle occupant  28  and the right side active knee bolster  25  can restrain a right lower limb portion  28 B of the vehicle occupant  28 . The body portion  30  of each of the active knee bolsters  24  and  25  includes a base plate  30 A and an EA member  30 B, which is provided on a vehicle occupant side of the base plate  30 A and which is made of urethane material or the like.  
         [0024]    As shown in FIG. 1, a skin portion  30 C, which is made from resin material or the like, is provided on a vehicle occupant side of the EA member  30 B of each of the active knee bolster body portions  30 . Each of the skin portions  30 C constitutes part of a general surface  18 A of the instrument panel  18 .  
         [0025]    The actuator  32  of each of the active knee bolsters  24  and  25  comprises a cylinder that is operated by gas from an inflator, which inflator is operated by a squib that is connected to the control circuit  14 . A connecting shaft  34  is provided at a lower portion of the base plate  30 A along a vehicle widthwise direction, through which the body portion  30  is connected to the vehicle body  16 . When the actuator  32  operates, the body portion  30  is rotated around the connecting shaft  34  toward the lower limb portion  28 A/ 28 B of the vehicle occupant  28  (in an arrow A direction in FIG. 1), from a retracted position illustrated by full lines in FIG. 1 to a restrained position illustrated by double-dashed lines in FIG. 1.  
         [0026]    The control circuit  14  receives input signals from the acceleration sensors  12  and compares the input signals to determine whether a collision has occurred. If a frontal impact or collision to the vehicle  16  without offset (i.e., a frontal non-offset impact to the vehicle) has occurred, the actuators  32  of the active knee bolsters  24  and  25  are operated so that the left and right lower limb portions  28 A and  28 B of the vehicle occupant  28  are restrained by the body portions  30  of the active knee bolsters  24  and  25 , as shown in FIG. 2.  
         [0027]    If a frontal (offset) impact to a vehicle front left portion, as indicated by arrow L in FIG. 3, has occurred, only the actuator  32  of the active knee bolster  24  is operated such that only the left lower limb portion  28 A of the vehicle occupant  28  is restrained by the body portion  30  of the active knee bolster  24 , as shown by double-dashed lines in FIG. 3.  
         [0028]    If a frontal (offset) impact to a vehicle front right portion, as indicated by arrow R in FIG. 4, has occurred, only the actuator  32  of the active knee bolster  25  is operated such that only the right lower limb portion  28 B of the vehicle occupant  28  is restrained by the body portion  30  of the active knee bolster  25 , as shown by double-dashed lines in FIG. 4.  
         [0029]    As shown in FIG. 1, in the present embodiment, an air bag for a passenger seat is mounted at a top portion  18 B within the instrument panel  18 , and an air bag  52  for a driver seat is mounted in a steering wheel  50  (only the air bag  52  for a driver seat is shown in FIG. 1). Inflators, which operate these air bags  52 , are each connected to the control circuit  14 .  
         [0030]    Reference numeral  56  in FIG. 1 denotes a seat belt.  
         [0031]    Operation of the first embodiment of the invention will now be described with reference to a flowchart shown in FIG. 5.  
         [0032]    In the present embodiment, at a time of a vehicle collision, by comparing input signals from the acceleration sensors  12 , the control circuit  14  determines whether a frontal non-offset impact to the vehicle  16  has occurred, at step S  100 .  
         [0033]    If the determination at step S  100  is affirmative (i.e., that a frontal non-offset impact to the vehicle has occurred), the process proceeds to step S  102 . At step S  102 , the control circuit  14  causes the actuators  32  of the active knee bolsters  24  and  25  to operate such that the lower limb portions  28 A and  28 B of the vehicle occupant  28  are held or restrained by the body portions  30  of the active knee bolsters  24  and  25 , as shown in FIG. 2.  
         [0034]    If the determination at step S  100  is negative (i.e., that a frontal non-offset impact to the vehicle has not occurred or that a collision is not a frontal non-offset impact to the vehicle), the process proceeds to step S  104 .  
         [0035]    At step S  104 , it is determined whether a frontal (offset) impact to the vehicle front left portion has occurred. If the determination at step S  104  is affirmative (i.e., that a frontal (offset) impact to the vehicle front left portion has occurred), the process proceeds to step S  106 . At step S  106 , only the actuator  32  of the left side active knee bolster  24  is operated such that only the left lower limb portion  28 A of the vehicle occupant  28  is held or restrained by the body portion  30  of the left side active knee bolster  24 , as shown by double-dashed lines in FIG. 3.  
         [0036]    If the determination at step S  104  is negative (i.e., that a frontal (offset) impact to the vehicle front left portion has not occurred or that a collision is not a frontal (offset) impact to the vehicle front left portion), the process proceed to step S  108 .  
         [0037]    At step S  108 , it is determined whether a frontal (offset) impact to the vehicle front right portion has occurred. If the determination at step S  108  is affirmative (i.e., that a frontal (offset) impact to the vehicle front right portion has occurred), the process proceeds to step S  110 . At step S  110 , only the actuator  32  of the right side active knee bolster  25  is operated such that only the right lower limb portion  28 B of the vehicle occupant  28  is held or restrained by the body portion  30  of the right side active knee bolster  25 , as shown by double-dashed lines in FIG. 4.  
         [0038]    As seen from the foregoing, in the above-described first embodiment, during a vehicle collision, e.g., a frontal offset impact, the vehicle occupant or passenger  28  is likely to move in an obliquely forward direction. Then, one of the active knee bolsters  24  or  25 , which is positioned at the frontal offset impact side, is selectively or independently operated so as to reliably restrain the corresponding one of the lower limbs  28 A or  28 B, which is positioned at the same side, of the vehicle occupant  28  seated on the passenger seat  20 .  
         [0039]    Next, a second embodiment of the present invention will be described in detail with reference to FIGS. 6 and 7.  
         [0040]    Note that portions or parts that are substantially the same as in the first embodiment are given the same reference numerals, and descriptions thereof are appropriately omitted.  
         [0041]    In the second embodiment, as shown in FIG. 6, another active knee bolster  62  is provided at a front portion within a front side door  60  (in this illustrated embodiment, a front left side door), which active knee bolster extends diagonally inward from front to rear. The active knee bolster  62  includes a body portion  30  to restrain a left lower limb portion  28 A, from a diagonally outward and frontward side thereof, of the vehicle occupant  28  who is seated on the passenger seat  20 , and an actuator  32  to move the body portion  30  toward the left lower limb portion  28 A of the vehicle occupant  28 .  
         [0042]    Yet another active knee bolster  66  is provided at a front side portion, in the vicinity of the instrument panel  18 , within a center console  64 , which active knee bolster extends in a vehicle widthwise direction approximately toward the passenger seat. The active knee bolster  66  includes a body portion to restrain a right lower limb portion  28 B of the vehicle occupant  28  from an inner side in the vehicle widthwise direction, and an actuator  32  to move the body portion  30  toward the right lower limb portion  28 B of the vehicle occupant  28 .  
         [0043]    The actuators  32  of the active knee bolsters  62  and  66  are each connected to the control circuit  14 , in a manner similar to those of the first embodiment.  
         [0044]    The control circuit  14  receives input signals from the acceleration sensors  12  and compares the input signals to determine whether a collision has occurred. If a frontal impact or collision to the vehicle  16  without offset has occurred, the actuators  32  of the active knee bolsters  24  and  25  are operated such that the left and right limb portions  28 A and  28 B of the vehicle occupant  28  are restrained by the body portions  30  of the active knee bolsters  24  and  25 , similarly to the first embodiment.  
         [0045]    If a frontal (offset) impact to the vehicle front left portion has occurred, the actuators  32  of the active knee bolsters  24  and  25  are operated. At the same time, the actuator  32  of the active knee bolster  62  in the front side door  60  is operated such that the left lower limb portion  28 A of the vehicle occupant  28  is restrained by the body portion  30  of the active knee bolster  62  (together with the body portion  30  of the left side active knee bolster  24 ), as shown by double-dashed lines in FIG. 6.  
         [0046]    If a frontal (offset) impact to the vehicle front right portion has occurred, the actuators  32  of the active knee bolsters  24  and  25  are operated. At the same time, the actuator  32  of the active knee bolster  66  in the center console  64  is operated such that the right lower limb portion  28 B of the vehicle occupant  28  is restrained by the body portion  30  of the active knee bolster  66  (together with the body portion  30  of the right side active knee bolster  25 ), as shown by double-dashed lines in FIG. 7.  
         [0047]    Operation of the second embodiment of the invention will now be described with reference to a flowchart shown in FIG. 8.  
         [0048]    In the present embodiment, at a time of a vehicle collision, by comparing input signals from the acceleration sensors  12 , the control circuit  14  determines whether a frontal non-offset impact to the vehicle  16  has occurred, at step S 200 .  
         [0049]    If the determination at step S 200  is affirmative (i.e., that a frontal non-offset impact to the vehicle has occurred), the process proceeds to step S 202 . At step S 202 , the control circuit  14  causes the actuators  32  of the active knee bolsters  24  and  25  to operate such that the lower limb portions  28 A and  28 B of the vehicle occupant  28  are held or restrained by the body portions  30  of the active knee bolsters  24  and  25 , similarly to the first embodiment.  
         [0050]    If the determination at step S 200  is negative (i.e., a frontal non-offset impact to the vehicle has not occurred or that a collision is not a frontal non-offset impact to the vehicle), the process proceeds to step S 204 .  
         [0051]    At step S 204 , it is determined whether a frontal (offset) impact to the vehicle front left portion has occurred. If the determination at step S 204  is affirmative (i.e., that a frontal (offset) impact to the vehicle front left portion has occurred), the process proceeds to step S 206 . At step S 206 , the active knee bolster  62  in the front side door  60  as well as the active knee bolsters  24  and  25  are activated such that the left and right limb portions  28 A and  28 B of the vehicle occupant  28  are restrained by the body portions  30  of the active knee bolsters  24 ,  25  and  62 , as shown by double-dashed lines in FIG. 6.  
         [0052]    If the determination at step S 204  is negative (i.e., that a frontal (offset) impact to the vehicle front left portion has not occurred or that a collision is not a frontal non-offset impact to the vehicle), the process proceed to step S 208 .  
         [0053]    At step S 208 , it is determined whether a frontal (offset) impact to the vehicle front right portion has occurred. If the determination at step S 208  is affirmative (i.e., that a frontal (offset) impact to the vehicle front right portion has occurred), the process proceeds to step S 210 . At step S 210 , the active knee bolster  66  in the center console  64  as well as the active knee bolsters  24  and  25  are activated such that the left and right limb portions  28 A and  28 B of the vehicle occupant  28  are restrained by the body portions  30  of the active knee bolsters  24 ,  25  and  66 , as shown by double-dashed lines in FIG. 7.  
         [0054]    As seen from the foregoing, in the above-described second embodiment, during a vehicle collision, e.g., a frontal offset impact, the vehicle occupant or passenger  28  is likely to move in an obliquely forward direction. Then, one of the active knee bolsters  62  or  66 , which is positioned at the frontal offset impact side, is selectively or independently operated so as to reliably restrain the corresponding one of the lower limbs  28 A or  28 B, which is positioned at the same side, of the vehicle occupant  28  seated on the passenger seat  20 .  
         [0055]    Further, in the present embodiment, as shown by double-dashed lines in FIG. 6, the active knee bolster  62  disposed in the front side door  60  can effectively restrain solely or in combination with the active knee bolster  24 , the left side lower limb  28 A of the passenger  28 , and the active knee bolster  66  disposed in the center console  64  can effectively restrain solely or in combination with the active knee bolster  25 , the right side lower limb  28 B of the passenger  28 .  
         [0056]    It is to be understood that the present invention is by no means limited to the specific embodiments as illustrated and described herein, and that various modifications thereof may be made which fall within the scope of the present invention as defined in the appended claims. A structure in which, during an oblique impact or a side impact collision, the active knee bolsters are selectively operated can be adopted.  
         [0057]    Further, in the second embodiment described above, at step S 206 , only one active knee bolster, e.g., the active knee bolster  62  may be operated and, at step S 210 , only one active knee bolster, e.g., the active knee bolster  66  may be operated.  
         [0058]    Still further, the present invention is not limited to the above embodiments with respect to the number of active knee bolsters to be provided, the arrangement thereof, or the number of active knee bolsters to be operated in accordance with traits of a vehicle collision.  
         [0059]    Furthermore, in the respective embodiments, the acceleration sensors  12  serve both as collision detecting means and collision direction detecting means. However, the invention is not limited to such a configuration. A structure is possible in which acceleration sensors are provided and used as collision detecting means and a camera or the like is provided and used as collision direction detecting means.  
         [0060]    As described above, according to the present invention, lower limbs of the vehicle occupant can be successfully restrained even during a frontal offset impact or an oblique impact.