Patent Publication Number: US-2007102910-A1

Title: Air belt apparatus

Description:
BACKGROUND  
      The present invention relates to an air belt apparatus for use in a motor vehicle, provided with a chest expanding portion in a chest-restraint webbing.  
      An air belt apparatus, in which tensile force generated in a shoulder belt (chest-restraint webbing) when expanded is also transmitted to a lap belt (lumbar-restraint webbing), is disclosed in Unexamined Japanese Patent Application Publication No. 2000-255358 and Unexamined Japanese Patent Application Publication No. 2001-294111.  
     SUMMARY OF THE INVENTION  
      According to one embodiment of the invention, an air belt apparatus for use in a motor vehicle includes a chest-restraint webbing having a chest expanding portion corresponding to a chest portion of an occupant at expansion, lumbar-restraint webbing to be pulled out from a retractor and corresponding to a lumbar portion of the occupant, a pretensioner for raising restraining force for the occupant at a motor vehicle collision by raising the tensile force of the lumbar-restraint webbing by gas pressure and a single gas-supplying source for supplying gas at the time of a motor vehicle collision to the chest expanding portion and the pretensioner.  
      According to another embodiment of the invention, an ignition electric current is transmitted to a gas supplying source when a motor vehicle collision is detected by a sensor, the gas supplying source is activated, and gas is instantaneously blown out from the gas-supplying source. The gas is promptly supplied to the chest expanding portion and the pretensioner, and the chest expanding portion is expanded by means of gas pressure corresponding to the chest portion of the occupant. Further, the pretensioner is operated to raise tensile force of the lumbar restraint webbing, and thus restraining force for the lumbar portion is raised. By expanding the chest expanding portion corresponding to the chest portion of the occupant, inertia force of the chest portion of the occupant at a front collision can be absorbed.  
      According to yet another embodiment of the invention, since the gas-supplying source for supplying the gas to the chest expanding portion and the pretensioner at the motor vehicle collision is unified and commoditized, the gas-supplying source can be mounted on a limited mounting space in a motor vehicle seat. According to still another embodiment of the invention, the pretensioner is disposed in the retractor.  
      According to another embodiment of the invention, since the pretensioner is disposed in the retractor, more mounting space is saved than when the pretensioner is provided separately from the retractor, and the tensile force of the lumbar-restraint webbing is increased at a predetermined time, upon reducing a driving loss when operating the pretensioner.  
      According to yet another embodiment of the invention, a gas-supplying pathway is provided for connecting the chest expanding portion and the pretensioner to the single gas-supplying source.  
      According to still another embodiment of the invention, since the chest expanding portion, the pretensioner and the single gas-supplying source are connected by means of the gas-supplying pathway, the gas-supplying source can be disposed at a position distant from the chest expanding portion and the pretensioner, namely at a position other than, for example, the position by the side of the seat with little mounting space. That is, since there is no need to dispose the gas-supplying source in the vicinity of the gas inlet of the chest expanding portion or in the pretensioner, the gas inlet of the chest expanding portion or the pretensioner can have a small size.  
      According to another embodiment of the invention, a single wire harness is connected to the single gas-supplying source, and the gas supplying source is activated through the wire harness.  
      According to still another embodiment of the invention, a single wire harness is connected to the single gas-supplying source, and if a collision sensor provided in the motor vehicle detects a collision, an ignition electric current is transmitted to the gas-supplying source through the wire harness. By using the single gas-supplying source and the single wire harness, parts costs and assembly costs can be reduced and the mounting space required can also be reduced.  
      According to another embodiment of the invention, the single gas-supplying source is disposed at a lower part of a seat cushion of a motor vehicle seat. According to yet another embodiment of the invention, since the single gas-supplying source is disposed at the lower part of the seat cushion having sufficient mounting space, in the motor vehicle seat, there is no possibility that a design of the motor vehicle seat or that of a console or the like in a circumference of the motor vehicle seat is limited by the mounting of the gas-supplying source. Accordingly, the air belt apparatus, allows for flexibility in the design of the motor vehicle seat, the console, or the like. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is an elevation view showing an air belt apparatus for use in a motor vehicle.  
       FIG. 2  is an elevation view showing a condition in the air belt apparatus for use in a motor vehicle, in which a cheat portion expanding portion is expanded and tensile force of lumbar-restraint webbing is raised.  
       FIG. 3  is a perspective view showing chest-restraint webbing, and a retractor therefor, lumbar-restraint webbing and a retractor therefor, a tongue plate in which the chest-restraint webbing and the lumbar-restraint webbing are respectively connected, and a buckle device.  
    
    
     DETAILED DESCRIPTION  
      Embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the following description is intended to describe exemplary embodiments of the invention, and not to limit the invention.  
      The present invention will be explained below on the basis of the drawings. In  FIG. 1 , an air belt apparatus  10  for use in a motor vehicle, according to one embodiment of the invention, is a kind of seat belt for restraining an occupant  14  seated in a motor vehicle seat  12 . The air belt apparatus  10  for use in a motor vehicle includes chest-restraint webbing  16 , lumbar-restraint webbing  18 , a pretensioner  20 , a gas-supplying source  22 , and a gas-supplying pathway  24 .  
      The motor vehicle seat  12  is provided with a seat cushion  25  in which a seat frame  32  is provided and the occupant  14  is seated, a seat back  26  for supporting a back of the occupant  14 , and a headrest  28  provided above the seat back  26 . The motor vehicle seat  12  is attached on a seat rail  33  provided on a floor panel  30  in a manner so as to be able to slide in a front-and-back direction of the motor vehicle. A retractor  34  is mounted on the seat frame  32  inside the vehicle interior on a side of the seat frame  32  adjacent to the outside of the vehicle so as to be able to swing in the front-and-back direction of the motor vehicle, and in the same manner as that of the retractor  34 , a buckle apparatus  36  is mounted on the seat frame  32 , inside the vehicle interior on a side of the seat frame  32  opposite to the outside of the vehicle.  
      According to one embodiment of the invention, the chest-restraint webbing  16  is a belt-shaped member that corresponds to a chest portion  14 B of the occupant  14 , and is connected to a retractor  42  disposed in a center pillar  38  via a shoulder anchor  40  provided, for example, at an upper part of the center pillar  38 . The chest-restraint webbing  16  is constantly receiving tensile force applied by the retractor  42 , mainly in a retracing direction for retracting the webbing  16 . The chest-restraint webbing  16  can be pulled out from the retractor  42  in accordance with a body type of the occupant  14 , when the air belt apparatus  10  for use in a motor vehicle is worn. A tongue plate  44  capable of being fitted with a buckle device  36  is provided at a tip end of the chest-restraint webbing  16 . Further, a chest expanding portion  46  is provided in the chest-restraint webbing  16 . Incidentally, the shoulder anchor  40  is not limited to that provided at a position in the center pillar  38  at a certain height, and the same may be constructed so as for the height of the portion to be adjustable.  
      According to one embodiment of the invention, the chest expanding portion  46  is an air belt that corresponds to the chest portion  14 B of the occupant  14  when expanded. During normal operation, the chest expanding portion  46  is folded back in a manner so as to have an equivalent width as that of, for example, the chest-restraint webbing  16 . In addition, a folded-back condition of the chest expanding portion  46  is retained by using a control stitching, in which a seam is ruptured in a case that internal pressure at a certain degree or more is applied thereto. In other words, the folded-back condition is retained by stitching the chest expanding portion  46  using a so-called tear seam (not shown). Thus, the chest expanding portion  46  is configured such that the tear seam is ruptured if a motor vehicle encounters a collision, and gas is k supplied into the chest expanding portion  46  from a gas-supplying source in the buckle device  36  via a portion in the vicinity of the tongue plate  44 . Further, the chest expanding portion  46  is configured to be expanded to a bag-shaped condition from the folded-back condition.  
      According to one embodiment of the invention, the chest expanding portion  46  may overlap the chest-restraint webbing  16  that extends from the retractor  42  to the tongue plate  44 . Further, the chest expanding portion  46  may be connected to an end portion of the chest-restraint webbing  16 . Namely, in the chest-restraint webbing  16 , a portion corresponding to the chest portion  14 B of the occupant  14  may be replaced by the chest expanding portion  46 . An attaching position of the retractor  42  is not limited to the center pillar  38 , and the same may be set to, for example, a back face of the seat back  26  or a vehicle body portion (not shown) at a rear side of the motor vehicle seat  12 .  
      According to one embodiment of the invention, the lumbar-restraint webbing  18  is a so-called lap belt capable of being pulled out from the retractor  34  mounted on the seat frame  32  inside the vehicle interior on a side of the seat frame  32  adjacent to the outside of the vehicle, and corresponds to a lumbar portion  14 W of the occupant  14 . The lumbar-restraint webbing  18  constantly receives tensile force applied by, for example, the retractor  34  mainly in a retracting direction for retracting the lumbar-restraint webbing  18 , and an end portion thereof is connected to the tongue plate  44 . The lumbar-restraint webbing  18  is not provided with an expanding portion, being different from the chest-restraint webbing  16 .  
      According to one embodiment of the invention, as shown in  FIG. 3 , a gas inlet  48  of the chest expanding portion  46  is provided in the tongue plate  44 . Further, an insertion portion  50 , into which the gas inlet  48  is fitted when the tongue plate  44  is fitted into the buckle device  36 , is provided in the buckle device  36 . A gas-supplying pathway  24  is connected to the insertion portion  50 , so that the gas is supplied into the chest expanding portion  46  from the insertion portion  50  via the gas inlet  48 , in a condition in which the tongue plate  44  is fitted into the buckle device  36 .  
      According to an embodiment of the invention, as shown in  FIG. 1 , the pretensioner  20  is a device that raises restraining force for the lumbar portion  14 W of the occupant  14  by raising tensile force of the lumbar-restraint webbing  18  by means of gas pressure, at the time of a motor vehicle collision. The pretensioner  20  is disposed in the retractor  34 , and the gas is configured to be supplied into the pretensioner  20  from the gas-supplying source  22  via the gas supplying pathway  24 .  
      According to one embodiment of the invention, the gas-supplying source  22  is a device, namely, for example, an inflator for supplying gas into the chest expanding portion  46  and the pretensioner  20 . According to one embodiment of the invention, one gas-supplying source  22  is provided at a lower portion of the seat cushion  25  of the motor vehicle seat  12 , namely, for example, in a case  56  installed on the seat frame  32 . A gas-blowing outlet  22 A of the gas-supplying source  22  is positioned in the case  56 . The gas-supplying pathway  24  is connected to the case  56 , and a portion other than the gas-supplying pathway  24  is sealed so that the gas is not leaked out.  
      According to one embodiment of the invention, a single wire harness  52  is connected to a single gas-supplying source  22  via a connector  54 . When the gas is blown out from the gas-blowing outlet  22 A by activating the gas-supplying source  22 , the gas-supplying source  22  is configured to be activated by an ECU (not shown) through the wire harness  52 .  
      The gas-supplying pathway  24  is a gas supplying pipe that connects the chest expanding portion  46  and the pretensioner  20 , and the single gas-supplying source  22 , and is connected to the case  56 . According to one embodiment of the invention, the gas-supplying pathway  24  branches into two directions in a lateral direction with respect to the motor vehicle at a branching point  24 A, and one branch of the gas-supplying pathway  24  is connected to the pretensioner  20 , and the other branch of the gas-supplying pathway  24  is connected to the insertion portion  50  provided together in the buckle device  36 , respectively.  
      The position of the branching point  24 A is determined in consideration of operation timing for the pretensioner  20  and an expanding timing for the chest expanding portion  46 . According to one embodiment of the invention, in a case that the gas is simultaneously supplied to the pretensioner  20  and the chest expanding portion  46 , the position of the branching point  24 A is preferably in the vicinity of a middle portion between the pretensioner  20  and the gas inlet  48 . According to another embodiment of the invention, if the operation timing for the pretensioner  20  or for the chest expanding portion  46  is delayed in relation to the other, it is possible to adopt a means to form a length of the gas supplying pipe to be an uneven length or the like, by causing the position of the branching point  24 A to approach a side of the pretensioner  20  or a side of a buckle device  35 , or by partially folding back each of the gas-supplying pathways  24  led from the branching point  24 A to the pretensioner  20  and the chest expanding portion  46 , and so forth.  
      As shown in  FIG. 2 , in the air belt apparatus  10  for use in a motor vehicle, when a motor vehicle collision is detected by means of a sensor (not shown), an ignition electric current is transmitted from the ECU to the gas-supplying source  22 , and the gas-supplying source  22  is thereby activated. Then, the gas is instantaneously blown out from the gas-blowing outlet  22 A of the gas-supplying source  22  into the case  56 . The gas is promptly supplied to the chest expanding portion  46  and the pretensioner  20  from the case  56  through the gas-supplying pathway  24 . The chest expanding portion  46  is expanded corresponding to the chest portion  14 B of the occupant  14  and the pretensioner  20  is operated by means of the gas pressure. As a result, the tensile force of the lumbar-restraint webbing  18  is increased and the restraining force for the lumbar portion  14 W is thereby increased. By expanding of the chest expanding portion  46  corresponding to the chest portion  14 B of the occupant  14 , inertial force of the chest portion  14 B of the occupant  14  generated at a front collision can be absorbed.  
      In the air belt apparatus  10  for use in a motor vehicle, since the gas-supplying source  22  for supplying the gas to the chest expanding portion  46  and the pretensioner  20  at a motor vehicle collision is a single gas-supplying source and is commoditized, the gas-supplying source  22  can be mounted without taking up a large amount of mounting space in the motor vehicle seat  12 .  
      Further, since the pretensioner  20  is disposed in the retractor  34 , the pretensioner  20  requires less mounting space as compared with providing the pretensioner  20  separately from the retractor  34 . In addition, a driving loss occurring when operating the pretensioner  20  is reduced, and the tensile force of the lumbar-restraint webbing  18  can be increased at a predetermined timing.  
      According to one embodiment of the invention, since the chest expanding portion  46 , the pretensioner  20 , and the single gas-supplying source  22  are connected by means of the gas-supplying pathway  24 , the gas-supplying source  22  can be disposed at a position distant from the chest expanding portion  46  and the pretensioner  20 , namely a position other than, for example, the position by the side of the seat having a small amount of mounting space. That is, since there is no need to dispose the gas-supplying source  22  in the vicinity of the gas inlet  48  of the chest expanding portion  46 , or in the pretensioner  20 , the gas inlet  48  of the chest expanding portion  46  or the pretensioner  20  can have a small size.  
      Since the single gas-supplying source  22  and the single wire harness  52  are used, the number of parts can be decreased as compared to if a gas-supplying source  22  is respectively provided in the retractor  34  and the buckle device  36 . As a result, the parts costs and assembly costs can be reduced and mounting space is saved.  
      Moreover, since the single gas-supplying source  22  is disposed at a lower part of the seat cushion  25  having sufficient mounting space, in the motor vehicle seat  12 , there is no possibility that a design of the motor vehicle seat  12  or that of a console or the like (not shown) in a circumference of the motor vehicle seat  12  is limited by mounting of the gas-supplying source  22 . Accordingly, in a case that the air belt apparatus  10  for use in a motor vehicle is mounted on a motor vehicle, flexibility of the design of the motor vehicle seat  12 , the console, or the like, can be maintained.  
      Incidentally, in the aforementioned embodiment, although the mounting position of the single gas-supplying source  22  is set to the lower part of the seat cushion  25 , the single gas-supplying source  22  may be provided at a portion having sufficient mounting space, other than the above-described, without being limited to a lower part of the seat cushion in the air belt apparatus for use in a motor vehicle.  
      In addition to the aforementioned hitherto known example, it is possible to provide a pretensioner for raising the tensile force of the lumbar-restraint webbing at a collision. However, when a gas-supplying source for the pretensioner and that for a chest expanding portion are separately mounted on a motor vehicle seat in a case that the pretensioner is operated by means of gas pressure from a gas-supplying source, much mounting space for mounting the gas-supplying sources is required. In particular, when the gas-supplying sources are mounted by the side of a seat, there is a possibility that sufficient mounting space cannot be secured.  
      The above described air belt apparatus has several advantages. For example, by mounting the pretensioner with the retractor a significant amount of mounting space is saved in comparison with mounting the pretensioner separately from the retractor. In addition, the tensile force of the lumbar-restraint webbing can be raised at a predetermined time.  
      Further, since the gas-supplying source can be disposed at a position distant from the chest expanding portion and the pretensioner, namely at a position other than, for example, the position by the side of the seat having little mounting space, and since there is no need to dispose the gas-supplying source in the vicinity of the gas inlet of the chest expanding portion, or in the pretensioner, the gas inlet of the chest expanding portion or the pretensioner can be small. In addition parts costs and assembly costs is reduced, and the required mounting space is also reduced.  
      In addition, another advantage is that the design of the motor vehicle seat, the console or the like in a circumference of the motor vehicle seat is not limited by the mounting of the gas-supplying source. Therefore, the flexibility of the design of the motor vehicle seat, the console, or the like can be maintained. Accordingly, an object of the present invention is to enable the gas-supplying source for operating the chest expanding portion and the pretensioner, to be mounted on a limited mounting space in the motor vehicle seat by commoditizing the gas-supplying source.  
      Japan Priority Application 2005-326391, filed Nov. 10, 2005 including the specification, drawings, claims and abstract, is incorporated herein by reference in its entirety.  
      The foregoing description of a preferred embodiment of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and modifications and variations are possible in light of the above teaching or may be acquired from practice of the invention. The embodiment was chosen and described in order to explain the principles of the invention and as a practical application to enable one skilled in the art to utilize the invention in various embodiments and with various modification are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto and their equivalents.