JP5464740B2 - Vehicle seat device - Google Patents

Description

  The present invention relates to a vehicle including a seat belt that restrains a seated person on a seat and a force limiter that operates to suppress an increase in tensile stress generated in the seat belt due to an external force from the seated person when the vehicle collides. The present invention relates to a sheet apparatus.

  Conventionally, there is a vehicle seat apparatus disclosed in Patent Document 1 below. According to this publication, a vehicle seat device includes a seat and a seat belt device that can restrain a seated person on the seat. The seat cushion frame of the seat includes a pair of left and right side frames that extend in the front-rear direction of the vehicle body, and a front and rear crossbars that extend in the width direction of the vehicle body and are installed at the front and rear of the left and right side frames. . On the other hand, the seat belt device is provided so as to cross the front surface of the seated person on the seat, and one end portion of the seat belt device is connected to the side frame side, and the other end portion side of the seat belt can be wound up. On the other hand, there is provided a retractor that can be locked when the seat belt is rewound by an external force applied to the seat belt by a seated person during a front collision.

  When the vehicle collides with a certain object ahead (front collision) during forward traveling of the vehicle, the seated person on the seat tries to move forward by the inertial force generated in the seated person. Here, if the forward movement of the seated person becomes excessive, the seated person may collide with the steering handle disposed in front of the seat, which may cause inconvenience. Is not preferable.

  Therefore, according to the above-described conventional technique, when the seated person moves greatly forward at the time of the front collision, the waist of the seated person collides with the front crossbar, and the front crossbar is plastically deformed. . According to this, further forward movement of the seat occupant is prevented, and when the forward movement is prevented, the burden on the seat occupant from the seat can be reduced.

  On the other hand, there is a conventional vehicle seat apparatus disclosed in Patent Document 2 below. According to this publication, in addition to the configuration of Patent Document 1, the seat belt device includes a pretensioner that causes the retractor to wind the seat belt by gas pressure at the time of a front collision, and a seat that is rewound from the retractor. A lock mechanism that locks the belt, and a force limiter that operates to suppress an increase in the tensile stress when the tensile stress generated in the seat belt by the external force reaches a predetermined value in a locked state of the seat belt by the lock mechanism; It has.

  At the time of the front collision, first, the other end side of the seat belt is wound around the retractor by the gas pressure generated by the gas generator of the pretensioner. As a result, the slack that is the play that has occurred in the seat belt is removed, and the seat belt is then ready for restraining the seated person.

  Next, when the seated person starts to move forward due to the inertial force, the other end side of the seat belt starts to be unwound from the retractor by the external force from the seated person. At this time, on the basis of a front collision detection signal from a sensor such as an acceleration sensor that has detected the front collision, the seat belt that starts to be unwound from the retractor is immediately locked by the lock mechanism, and this unwinding is prevented.

  When the seat occupant further moves forward from the locked state of the seat belt, a greater external force is applied from the seat occupant to the seat belt, and accordingly, the tensile stress generated in the seat belt tends to increase gradually. To do. However, when the tensile stress reaches a predetermined value, the force limiter operates and the increase of the tensile stress is suppressed. In other words, at the time of a front collision, the seat occupant moves forward and applies an external force to the seat belt, and is given a restraining force that is a reaction force from the seat belt, but the burden on the seat occupant due to this restraining force is the force limiter. Is alleviated by the operation of

JP 2006-193040 A JP 2005-349983 A

  By the way, when a seated person starts to move forward at the time of a front collision, usually, the seated person's waist tends to rotate upwardly. In this case, since the front surface of the chest of the seated person has a front-lowering shape, the portion of the seat belt that is in contact with the front surface of the chest moves so that the restraining performance of the seat belt is reduced. This is not preferable because it causes fear.

  In addition, when the seated person moves forward as described above, the tensile stress of the seat belt increases until the predetermined value is reached before the waist reaches the front crossbar, and the force limiter starts operating. Then, the above-described rotational movement of the seated person's lower back is promoted, which may further reduce the restraint performance of the seat belt.

  On the other hand, when the waist reaches the front crossbar due to the forward movement of the seated person and further forward movement is being suppressed, the tensile stress of the seat belt due to the external force from the seated person is still at the predetermined value. If the force limiter has not been reached, that is, if the force limiter is not activated, the seat belt is continuously unwound by the external force, and the chest of the seated person moves further forward. Therefore, in this case, since the restraint performance of the seat belt is insufficient, the upper body of the seated person becomes a front-end shape, which may cause an excessive burden on the seated person.

  The present invention has been made paying attention to the above-described circumstances, and an object of the present invention is to further improve the restraining performance of a seat belt that restrains a seated person on a seat.

The invention of claim 1 includes a seat cushion frame 18 of a seat 12 having a pair of left and right side frames 23, 24, front and rear crossbars 25, 26 before and after the left and right side frames 23, 24. The seat belt 51 is provided so as to cross the front surface of the seated person 4 on the seat 12, and one end portion thereof is connected to the side frames 23 and 24, and the other end portion of the seat belt 51 can be wound up. On the other hand, a retractor 57 that allows the seat belt 51 to be rewound by an external force applied to the seat belt 51 from the seated person 4 at the time of a front collision, and a lock mechanism that locks the seat belt 51 rewound from the retractor 57. 65, and the seat belt 51 is locked by the lock mechanism 65. When the tensile stress reaches a predetermined value that, in the seat apparatus for a vehicle with a force limiter 66 which operates to suppress an increase in the tensile stress,
Before the front crossbar 25 is arranged away from the front and back, the seat member 4 includes rear members 35 and 36, and the rear member 36 is lower in position and lower in rigidity than the front member 35, and moves forward at the time of a front collision. When the lower part of the waist collides with the rear member 36, the rear member 36 suppresses the rotational movement A in the upward direction of the waist part, and when the waist part further moves forward and collides with the front member 35, The front member 35 suppresses further forward movement of the waist, and the force limiter 66 starts to operate simultaneously with or before the waist starts to collide with the front member 35. This is a vehicle seat device.

  The invention of claim 2 extends in the width direction of the vehicle body 2, one end portion in the longitudinal direction thereof is fixed to the front portion of one of the left and right side frames 23 and 24, and the other end portion is A torsion bar 39 that is a free end, a link bar 40 that is disposed in front of and above the torsion bar 39, extends along the torsion bar 39, and is fixed to the other end side of the torsion bar 39; A net sheet 20 stretched between the cross bar 26 and the link bar 40, and at least one of the torsion bar 39 and the link bar 40 being the front member 35. The vehicle seat device according to claim 1, wherein the seat device is a vehicle seat device.

  According to a third aspect of the present invention, one end portion of the seat belt 51 is fixed to the rear portions of the left and right side frames 23, 24, and the upper portions of the front portions of the side frames 23, 24 support the end portions of the rear member 36. The vehicle seat device according to claim 1 or 2, wherein a fragile portion (32) is formed between an upper portion and a lower portion of a front portion of the side frames (23, 24).

  In addition, in this section, the reference numerals and drawing numbers appended to the above terms are not intended to limit the technical scope of the present invention to the “Example” section and the contents of the drawings described later.

  The effects of the present invention are as follows.

The invention of claim 1 crosses the seat cushion frame of a seat having a pair of left and right side frames, the front cross section of the left and right side frames, the rear crossbar, and the front of the seated person on the seat. A seat belt whose one end side is connected to the side frame side, and the other end side of the seat belt can be wound, while an external force applied to the seat belt from a seated person at the time of a front collision A retractor that enables the seat belt to be rewound, a lock mechanism that locks the seat belt that is rewound from the retractor, and a tensile stress generated in the seat belt by the external force when the seat belt is locked by the lock mechanism. A force limiter that operates to suppress this increase in tensile stress when the value is reached. In both of the seat device,
Before the front crossbar is arranged at the front and rear, the rear member is provided with a rear member, the rear member is at a lower position and lower rigidity than the front member, and the waist of the seated person who moves forward at the time of the front collision is the rear member When a collision occurs, the member subsequently restrains the rotational movement of the waist from rising forward. Further, when the waist moves forward and collides with the front member, the front member moves further forward of the waist. The force limiter starts to operate at the same time as or before the waist starts to collide with the front member.

  For this reason, when the seat occupant moves forward with the inertial force and the waist collides with the rear member at the time of the frontal collision of the vehicle, the rear member suppresses the forward movement of the seat occupant's waist. As described above, since the rear member is set at a lower position than the front member, the lower part of the waist when colliding with the rear member collides with the rear member. Therefore, the rotational movement of the seat occupant's lower back is more reliably suppressed.

  In addition, as described above, the rear member has a lower rigidity than the front member. Therefore, when the seat member's waist collides with the rear member, the rear member of the rear member tends to bend easily in the longitudinal direction downward. And Since the rear member is bent downward, the reaction force from the rear member to the lower back is applied to a lower part of the lower back. Therefore, the forward movement of the lower back is more reliably suppressed. The

  And, as described above, the forward movement of the waist of the seated person who moves forward at the time of a frontal collision is more reliably suppressed, so that the front surface of the chest of the seated person is more reliably lowered forward. In particular, the restraint performance of the seat belt against the chest is improved. Moreover, due to the bending of the rear member, the impact force at the time of the collision of the waist to the rear member is effectively relieved.

  In addition, as described above, the force limiter starts to operate at the same time as or before the waist starts to collide with the front member. Thus, after the collision with the rear member, the operation of the force limiter with respect to the seat belt prevents the chest from receiving a reaction force from the seat belt, thereby preventing the upper body of the seated person from turning forward. . Accordingly, the burden on the seated person due to the upper body being turned forward after the collision with the rear member is prevented, and the restraint performance of the seat belt is more reliably improved.

  The invention according to claim 2 extends in the width direction of the vehicle body, one end portion in the longitudinal direction thereof is fixed to the front portion of one of the left and right side frames, and the other end portion is a free end. A torsion bar, a link bar that is disposed at the front upper side of the torsion bar, extends along the torsion bar, and is fixed to the other end side of the torsion bar; and the rear cross bar and the link bar are stretched. A net sheet is provided, and at least one of the torsion bar and the link bar is used as the front member.

  For this reason, as described above, in the seat in which the net seat is stretched by the link bar elastically biased by the torsion bar, the waist of the seated person who moves forward at the time of the front collision collides with the net seat. Since the torsion bar and the link bar are used as the front member that suppresses the forward movement of the vehicle, the above-described improvement in the restraining performance of the seat belt can be achieved with a simple configuration.

  Here, when a torsion bar is used as the front member, this torsion bar has a large rigidity in terms of its function. Therefore, when the waist of a seated occupant moving forward collides with the torsion bar, By the torsion bar, further forward movement of the waist of the seated person is more reliably prevented. On the other hand, when a link bar is used as the front member, since the link bar is positioned above the torsion bar, the waist of the seated occupant who moves forward collides more reliably with the link bar. . Therefore, also in this respect, further forward movement of the seated person's waist is more reliably prevented.

  According to a third aspect of the present invention, one end of the seat belt is fixed to the rear part of the left and right side frames, the upper part of the front part of the side frame supports the end part of the rear member, and the front part of the side frame A fragile part is formed between the upper and lower parts.

  For this reason, as described above, when the lumbar part of the seated person who moved forward at the time of the front collision collided with the rear member, the external force from the lumbar part is supported by the side frames supporting the rear member via the rear member. Given in the front upper part. Then, stress concentration occurs in each fragile portion, and the front upper portion of each side frame supporting each end portion of the rear member is easily tilted inward toward the inner side in the width direction of the seat. Each fragile part is bent.

  Therefore, the front upper part of each side frame easily falls inward, and the downward bending of the rear member supported by the front upper part is promoted. Since the rear member is bent downward, the reaction force from the rear member to the lower back is applied to a lower part of the lower back. Therefore, the forward movement of the lower back is more reliably suppressed. And the impact force at the time of the collision of the waist | lumbar part with a rear member is relieve | moderated effectively.

  As described above, since the forward movement of the waist of the seated person who moves forward at the time of the front collision is more reliably suppressed, the chest of the seated person is prevented from being lowered downward. In particular, the improvement of the restraining performance of the seat belt with respect to the chest is achieved more reliably.

  Also, as described above, when the lumbar part of the seated person who moves forward collides with the rear member, the weak part of each side frame is bent so that the front upper part thereof falls inward. It is possible to prevent the entire side frames from being deformed by an external force from the waist.

  Therefore, first, the overall deformation of each side frame prevents the rear member from bending excessively downward, and the waist of the seated person who moves forward during a front collision sinks excessively. It is prevented. Secondly, in each side frame, the seat belt whose one end is connected to the rear part thereof has an effect on the inward deformation of the front upper part of each side frame based on the external force of the seated person at the time of the front collision. Therefore, also in this respect, the restraint performance of the seat belt is improved.

It is a side view. It is a perspective view. FIG. 3 is a partial cross-sectional view taken along line III-III in FIG. 1. FIG. 4 is an enlarged cross-sectional view of a part IV in FIG. 3. FIG. 5 is a cross-sectional view taken along line VV in FIG. 1. FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 1. FIG. 7 is a sectional view taken along line VII-VII in FIG. 1. It is the figure which showed the tensile stress of the seatbelt, and the reaction force from a sheet | seat over time. It is the figure which showed the vehicle diagrammatically.

  In order to realize the object of further improving the restraint performance of a seat belt that restrains a seated person on a seat, the form for carrying out the present invention relates to the vehicle seat device of the present invention. That's right.

  That is, a vehicle seat device includes a seat and a seat belt device that can restrain a seated person on the seat.

  The seat cushion frame of the seat includes a pair of left and right side frames that extend in the front-rear direction of the vehicle body, and a front and rear crossbars that extend in the width direction of the vehicle body and are installed at the front and rear of the left and right side frames. . On the other hand, the seat belt device is provided so as to cross the front surface of the seated person on the seat, and one end portion of the seat belt device is connected to the side frame side, and the other end portion side of the seat belt can be wound up. On the other hand, a retractor that enables the seat belt to be rewound by an external force applied from the seated person to the seat belt at the time of a front collision, a lock mechanism that locks the seat belt that is rewound from the retractor, and the lock mechanism A force limiter that operates to suppress an increase in the tensile stress when the tensile stress generated in the seat belt by the external force reaches a predetermined value in the locked state of the seat belt is provided.

  The front crossbar includes a rear member before and after being disposed apart from each other in the front-rear direction. The rear member is lower in position and lower in rigidity than the front member. When a lumbar part of a seated person who moves forward at the time of a front collision collides with the rear member, the rear member restrains the rotational movement of the lumbar part from rising forward, and the lumbar part moves forward to the front member. When there is a collision, the front member suppresses further forward movement of the waist. Also, the force limiter starts to operate simultaneously with or before the waist starts to collide with the front member.

  In order to explain the present invention in more detail, an embodiment thereof will be described with reference to the accompanying drawings.

  1-7, the code | symbol 1 is a vehicle illustrated by the motor vehicle, The arrow Fr has shown the front of the advancing direction of this vehicle 1. FIG. The left and right described below refer to the width direction of the vehicle body 2 of the vehicle 1 toward the front of the vehicle 1.

  The interior of the vehicle body 2 is a casing 3. In the vehicle compartment 3, a seat device 5 on which a seated person 4 can sit toward the front of the vehicle body 2, a steering handle 6 disposed in front of the seat device 5, and an airbag device attached to the handle 6. 7 is provided. The seat device 5 includes a seat 12 installed via a seat rail 11 on a floor panel 10 that forms the lower surface of the passenger compartment 3, and a three-point seat belt device that can restrain a seated person 4 on the seat 12. 13.

  The seat 12 includes a seat cushion 16 that is supported on the floor panel 10 via a seat rail 11, and a seat back 17 that protrudes upward from a rear end portion of the seat cushion 16. The seat cushion 16 constitutes a skeleton member, and the seat cushion frame 18 supported on the floor panel 10 via the seat rail 11, and the seat cushion frame 18 covering the seat cushion frame 18 from above the seat cushion frame 18. A cushion member 19 to be attached is provided, and the cushion member 19 is specifically a net sheet 20.

  The seat cushion frame 18 is disposed apart in the width direction of the vehicle body 2 and extends in the front-rear direction of the vehicle body 2 respectively, and the left and right side frames 23 and 24 extending in the width direction of the vehicle body 2. The front crossbars 25 and 26 are provided before the front and rear portions.

  Each of the side frames 23 and 24 is made of sheet metal, and includes inner and outer panels 28 and 29 that face each other in the width direction of the vehicle body 2. The side frames 23 and 24 are coupled to each other by spot welding and have a closed cross-sectional structure having a large rigidity as a whole.

  In the upper portions of the front portions of the side frames 23 and 24, the inner and outer panels 28 and 29 are overlapped with each other to form an overlapping portion 30 having high strength and rigidity. In addition, a plurality of front and rear (two) beads 31 extending in the vertical direction are formed on the inner and outer panels 28 and 29 at the lower portions of the front portions of the side frames 23 and 24, respectively. Each bead 31 is formed by bulging each part of the inner and outer panels 28 and 29 toward the inner side of the side frames 23 and 24, respectively. The outer surfaces of the beads 31 are brought into contact with each other and are coupled to each other by a plurality of (three) upper and lower spot welds S. And by these each bead 31, the front lower part of each said side frames 23 and 24 is firmly reinforced.

  The lower end edge of the overlapping portion 30 is linearly inclined in a front-down manner. On the other hand, the upper end portion of each bead 31 is linearly arranged in a forwardly descending manner along the lower end edge in the vicinity of the lower end edge portion of the overlapping portion 30. As a result, a fragile portion 32 where stress concentration is likely to occur due to an external force is formed between the upper and lower portions of the front portions of the side frames 23 and 24, and the fragile portion 32 is formed on the side frames 23 and 24. It extends linearly from the upper edge to the front edge.

  The front crossbar 25 is provided with rear members 35 and 36 before being disposed apart from each other in the front-rear direction. Among these, the front member 35 includes a torsion bar 39 having a circular cross section extending in the width direction of the vehicle body 2. One end portion (right end portion) of the torsion bar 39 is fixed to the front end portion of the overlapping portion 30 of the right side frame 24 among the left and right side frames 23, 24, and the other end portion (left end portion) is a free end. The left side frame 23 is supported at the front end portion of the overlapping portion 30 so as to be rotatable about its axis.

  Further, the front member 35 includes a link bar 40 that is a circular pipe in cross section that is disposed on the front upper side of the torsion bar 39 and extends along the torsion bar 39. Arms 41 are provided so as to project from one end (right end) and the other end (left end) of the link bar 40, respectively. The arm 41 at the other end of the link bar 40 is fixed to the other end of the torsion bar 39, and the arm 41 at one end of the link bar 40 rotates around the axis of the one end of the torsion bar 39. It is supported so that it can move.

  The rear member 36 is a pipe having a circular cross section, and each end thereof is fixed to the rear end of the overlapping portion 30 of each of the side frames 23 and 24. Further, the rear member 36 has a lower position and lower rigidity than the cushion member 49 and the link bar 40 of the front member 35. Specifically, the rear member 36 has a smaller section modulus such as a smaller outer diameter or a thinner wall.

  The rear cross bar 26 has the same configuration as the front member 35 of the front cross bar 25 described above, and includes a torsion bar 43, a link bar 44, and an arm 45. In this case, the link bar 44 is disposed on the rear upper side of the torsion bar 43.

  The net sheet 20 is installed on the link bar 40 of the front member 35 of the front cross bar 25 and the link bar 44 of the rear cross bar 26. In the free state of the net sheet 20, the link bars 40, 44 are elastically urged so as to be separated from each other in the front-rear direction by the initial return of the torsion bars 39, 43. Thereby, a tensile force is always applied to the net sheet 20.

  The seat back 17 constitutes the skeleton member, and is attached to the seat back frame 48 so as to cover the seat back frame 48 from the front thereof and to be supported by the rear end portion of the seat cushion frame 18. The cushion member 49 is provided.

  The seat belt device 13 includes a seat belt 51 provided so as to cross the front surface of the seated person 4 on the seat 12. The end on the one end side of the seat belt 51 is connected to the rear portion of the left side frame 23 of the left and right side frames 23 and 24 by an anchor 52, but may be connected to the floor panel 10. Further, a buckle 53 is connected to the rear portion of the right side frame 24, and a tongue plate 54 engaged with a midway portion in the longitudinal direction on one end side of the seat belt 51 is detachably locked to the buckle 53, Thereby, the midway part of the one end part side of the seat belt 51 is connected to the rear part of the right side frame 24.

  A belt engagement body 56 for attaching a midway portion in the longitudinal direction of the seat belt 51 is attached to the upper left end portion of the seat back frame 48 of the seat back 17. A retractor 57 that is attached to the seat back frame 48 below the belt engaging body 56 and that can wind up the other end side of the seat belt 51 after being inserted through the belt engaging body 56 is provided. . The retractor 57 includes a housing 58 fixed to the seat back frame 48, a winding shaft 59 supported by the housing 58 and capable of winding the other end of the seat belt 51, and the seat belt 51. And a spring 60 that elastically urges the take-up shaft 59 to take up.

  The waist portion of the seated person 4 on the seat 12 is restrained from the front by the midway portion of the seat belt 51 from the anchor 52 to the tongue plate 54 locked to the buckle 53. Further, the chest part of the seated person 4 on the seat 12 is restrained from the front by the other middle part of the seat belt 51 from the tongue plate 54 to the belt engaging body 56.

  When the seat occupant 4 moves forward due to an inertial force generated in the seat occupant 4 at the time of a frontal collision of the vehicle 1, the seat belt 51 is moved by the external force applied to the seat belt 51 from the seat occupant 4. The retractor 57 can be rewound while opposing the urging force of 60. This unwinding is also possible when the seated person 4 pulls the seat belt 51.

  An acceleration sensor 62 is provided that detects a change in acceleration at the time of a frontal collision of the vehicle 1 and outputs a detection signal indicating that the vehicle is a frontal collision. In addition, a gas generator 63 that instantaneously generates gas based on a detection signal from the acceleration sensor 62 at the time of a front collision is provided. A known pretensioner 64 is provided for winding the other end of the seat belt 51 around the take-up shaft 59 of the retractor 57 by the gas pressure generated by the gas generator 63. The gas generator 63 instantly generates combustion gas by igniting and burning explosives. Further, the retracting operation of the retractor 57 by the gas pressure is temporarily performed.

  A known lock mechanism 65 that locks the seat belt 51 rewound from the retractor 57 based on the detection signal of the acceleration sensor 62 is provided. The locking mechanism 65 allows the seat belt 51 to be retracted by the spring 60 and the pretensioner 64 of the retractor 57, while immediately locking only the seat belt 51 to be rewound as described above.

  Further, when the seat belt 51 is locked by the lock mechanism 65, when a tensile stress generated in the seat belt 51 by an external force from the seated person 4 reaches a predetermined value, a known force limiter that suppresses an increase in the tensile stress. 66 is provided. The force limiter 66 locks only one end portion of the take-up shaft 59 to the housing 58 side of the retractor 57 by the lock mechanism 65, and causes the take-up shaft 59 to function as a torsion bar. That is, the seat belt 51 to be rewound by an external force from the seated person 4 elastically returns and deforms the take-up shaft 59, whereby the tensile stress generated in the seat belt 51 is maintained at a substantially constant value. The

  While the vehicle 1 is traveling forward, the waist of the seated person 4 seated on the net seat 20 of the seat 12 pushes down the net seat 20 against the return elastic force of the torsion bars 39 and 43. (A solid line in FIG. 1).

  At the time of a frontal collision of the vehicle 1 in the above state, the seated person 4 tries to further push down the net seat 20 by the inertia force (the chain line in FIG. 1). Then, due to the tensile stress generated in the net sheet 20, the link bars 40, 44 of the front and rear cross bars 25, 26 are attracted to each other in the front-rear direction and rotate upward about the torsion bars 39, 43. (Dash-dot line in FIG. 1). In conjunction with these rotations, the return elastic force of each of the torsion bars 39, 43 increases, and the reaction force applied from the net seat 20 to the seated person 4 increases. For this reason, it is possible to effectively prevent the waist portion of the seated person 4 from rotating upward A by the upward rotation of the link bars 40 and 44 and the increase in the reaction force of the net seat 20. The

  Further, when the seat occupant 4 moves forward with its inertia force and the waist collides with the rear member 36 at the time of the frontal collision of the vehicle 1 (indicated by the one-dot chain line in FIG. 1), the rear member 36 causes the waist of the seated person 4 to move. Rotating operation A in the upward direction is suppressed. In this case, since the rear member 36 is set at a lower position than the front member 35 as described above, a lower part of the waist when colliding with the rear member 36 collides with the rear member 35. Therefore, the forward movement-like rotational motion A of the waist of the seated person 4 is more reliably suppressed.

  In addition, as described above, the rear member 36 has a lower rigidity than the front member 35. Therefore, when the waist of the seated person 4 collides with the rear member 36, the rear half of the rear member 36 is directed downward. Try to bend easily. At this time, an external force from the waist is applied to the front upper portions of the side frames 23 and 24 supporting the rear member 36 via the rear member 36. Then, stress concentration occurs in each of the fragile portions 32, and the front upper portions of the side frames 23 and 24 that support the end portions of the rear member 36 easily move toward the inner side in the width direction of the seat 12. The fragile portions 32 are bent so as to fall inward.

  Therefore, the front upper portions of the side frames 23 and 24 are easily tilted inward, thereby facilitating the downward bending of the rear member 36 supported by the front upper portions (one point in FIGS. 3 and 4). Chain line). Since the rear member 36 is bent downward, a reaction force from the rear member 36 to the waist is applied to a lower part of the waist. In addition, the impact force at the time of the collision of the waist to the rear member 36 is effectively relieved.

  Further, as described above, the rotational movement A in the front-up state of the waist of the seated person 4 that moves forward at the time of the front collision is more reliably suppressed, so that the chest of the seated person 4 is more surely lowered in the front-down direction. In particular, the restraint performance of the seat belt 51 with respect to the chest is improved more reliably.

  Further, as described above, when the waist part of the seated person 4 moving forward collides with the rear member 36, the fragile part 32 of each side frame 23, 24 is bent, and the front upper part thereof is tilted inward. It is possible to prevent the entire side frames 23 and 24 from being deformed by an external force from the waist of the seated person 4 at the time of the front collision.

  Therefore, first, the overall deformation of each of the side frames 23 and 24 prevents the rear member 36 from being excessively bent downward, and the waist portion of the seated person 4 that moves forward during a front collision. Is prevented from sinking excessively. Secondly, in each of the side frames 23 and 24, the seat belt 51 having one end connected to the rear portion having high rigidity is connected to the side frames 23 and 24 based on the external force of the seated person 4 at the time of the front collision. Since this is not affected by the inwardly deforming deformation of the front upper portion 24, the improvement of the restraining performance of the seat belt 51 is also achieved in this respect.

  Further, when the forward movement of the seated person 4 proceeds, the waist of the seated person 4 collides with at least one of the torsion bar 39 and the link bar 40 of the front member 35 of the front cross bar 25. Thus, further forward movement is suppressed (the two-dot chain line in FIG. 1). Therefore, the occurrence of inconvenience such as the seated person 4 moving excessively forward and colliding with the handle 6 disposed in front of the seat 12 is prevented.

  Further, as described above, in the seat 12 in which the net seat 20 is stretched by the link bars 40 and 44 elastically biased by the torsion bars 39 and 43, the seated person 4 moves forward at the time of the front collision. Since the torsion bar 39 and the link bar 40 are used as the front member 35 that suppresses further forward movement due to the collision of the lower back portion, the use of the torsion bar 39 and the link bar 40 improves the restraining performance of the seat belt 51. This is achieved with a simple configuration.

  Here, the torsion bar 39 has high rigidity in function. For this reason, when the waist part of the seated person 4 moving forward collides with the torsion bar 39 as the front member 35, the torsion bar 39 prevents the seat part 4 from moving further forward. Is done. On the other hand, the link bar 40 is located above the torsion bar 39. For this reason, the waist part of the seated person 4 moving forward collides with the link bar 40 as the front member 35 more reliably. Therefore, also in this respect, further forward movement of the waist of the seated person 4 is more reliably prevented.

  The upper part of FIG. 8 shows the state of increase in the reaction force from the seat 12 to the seated person 4 with the forward movement of the seated person 4 at the time of the front collision.

That is, before abutting the first, the waist of the seated person 4 moving forward by the front crash is the time to reach the member 36 after the front cross bar 25 is t _a, the waist of the seated person 4 members 36 thereafter , The reaction force of the rear member 36 against the seated person 4 increases. Furthermore, as the seated person 4 moves forward, the time from the beginning of the front collision until the waist of the seated person 4 moving forward as described above collides with the front member 35 of the front crossbar 25 is t _b , When the waist of the seated person 4 collides with the member 35, the reaction force of the front member 35 on the seated person 4 further increases.

  On the other hand, at the time of a front collision, first, the other end portion side of the seat belt 51 is wound around the retractor 57 by the gas pressure generated by the gas generator 63 of the pretensioner 64. As a result, the slack that is the play that has occurred in the seat belt 51 is removed, and the seat belt 51 makes preparations for restraining the seated person 4 thereafter.

  Next, when the seated person 4 starts to move forward due to its inertial force, the other end side of the seat belt 51 starts to be unwound from the retractor 57 by the external force from the seated person 4. At this time, the seat belt 51 that starts to be unwound from the retractor 57 is immediately locked by the lock mechanism 65 based on a front collision detection signal from a sensor such as the acceleration sensor 62 that has detected the front collision, and this unwinding is prevented. Is done.

  When the seat occupant 4 further moves forward from the locked state of the seat belt 51, a greater external force is applied from the seat occupant 4 to the seat belt 51. Accordingly, the tensile force generated on the seat belt 51 is applied. The stress tends to increase gradually. However, when the tensile stress reaches a predetermined value, the force limiter 66 operates to suppress an increase in the tensile stress, and the tensile stress is kept almost constant. That is, at the time of a frontal collision, the seated person 4 moves forward to apply an external force to the seat belt 51, while a restraining force that is a reaction force from the seat belt 51 is given. This is alleviated by the operation of the force limiter 66.

  The lower diagram of FIG. 8 shows the increase in reaction force from the seat belt 51 to the seated person 4 over time as the seated person 4 moves forward in the frontal collision.

That is, before the abutting first time until after the pretensioner 64 is activated to rewind the seat belt 51 is locked by the locking mechanism 65 is in t _1, from this point until the force limiter 66 is activated time is _{t 2.}

In the upper and lower diagrams of FIG. 8, the force limiter 66 starts to operate simultaneously with or before the waist starts to collide with the front member 35 as described above. That is, t _b ≧ t ₁ + t ₂ .

Here, from the hip point 70 of the seated person 4 when the seated person 4 is seated on the seat 12 in a normal state, the front crossbar can be obtained so that t _b ≧ t ₁ + t ₂ is obtained. A distance L in the front-rear direction of the vehicle body 2 up to 25 front members 35 is calculated. This distance L corresponds to the amount of forward movement of the lumbar part until the lumbar part of the seated person 4 moves forward at the time of a front collision until the lumbar part collides with the front member 35.

  FIG. 9 schematically shows the vehicle 1, the seated person 4, and the seat belt 51 for the above calculation. Hereinafter, a description will be given with reference to FIG.

  m: An equivalent mass of the seated person 4 is assumed to be 45 to 80 kg.

ｙ：前突時の着座者４の変位量で、

ｘ_０，ｙ_０：初期変位であって、０とする。 k: spring function of the seat belt 51 x: displacement of the vehicle body 2 at the time of the front collision,

y: The displacement of the seated person 4 at the time of the front collision,

x ₀ , y ₀ : Initial displacement, which is 0.

である。 v ₀ : Initial speed at the time of the frontal collision of the vehicle 1,

It is.

  Then, the distance L is determined so that y (t) derived from the equation of motion satisfies the following function. The distance L sets the position of the front member 35 in the longitudinal direction of the vehicle body 2.

According to the above configuration, since t _b ≧ t ₁ + t ₂ , the force limiter for the seat belt 51 after the seated person 4 moves forward and the waist collides with the rear member 36 as described above at the time of the front collision. When the operation of 66 is started, the chest is given a reaction force from the seat belt 51 and a reaction force is also given from the inflated airbag device 7 to prevent the upper body of the seated person 4 from turning forward. Is done. Therefore, the occurrence of a burden on the seated person 4 due to the upper body turning forward after the collision with the rear member 36 is prevented, and the restraint performance of the seat belt 51 is more reliably improved.

  In addition, although the above is based on the example of illustration, among the side frames 23 and 24, the outer panels 28 and 29 may be provided with only one of the panels. Further, the front member 35 of the front cross bar 25 may be composed of only one of the torsion bar 39 and the link bar 40. Further, as a drive source for the pulling-up operation of the link bars 40 and 44 of the front and rear crossbars 25 and 26 at the time of a front collision, a configuration like the gas generator 63 of the pretensioner 64 may be used.

  In addition, the front and rear crossbars 25 and 26 may be formed of a single pipe, and the end portions thereof may be fixed to the side frames 23 and 24. In this case, the cushion member 19 may be a cushion pad instead of the net sheet 20. Further, the fragile portion 32 may be formed by thinning a part of the side frames 23 and 24 or arranging through holes.

  Further, instead of the belt engaging body 56, the belt engaging body 56 may be a retractor 57. Further, the belt engaging body 56 and the retractor 57 may be supported on the side wall of the vehicle body 2 on the side of the seat 12, and the retractor 57 may be supported on the floor panel 10. Further, the lock mechanism 65 may mechanically lock the seat belt 51.

DESCRIPTION OF SYMBOLS 1 Vehicle 2 Car body 4 Seated person 5 Seat apparatus 12 Seat 13 Seat belt apparatus 16 Seat cushion 17 Seat back 18 Seat cushion frame 20 Net seat 23 Side frame 24 Side frame 25 Cross bar 26 Cross bar 32 Fragile part 35 Member 36 Member 39 Torsion Bar 40 link bar 51 seat belt 52 anchor 53 buckle 54 tongue plate 57 retractor 58 housing 59 take-up shaft 60 spring 62 acceleration sensor 63 gas generator 64 pretensioner 65 lock mechanism 66 force limiter 70 hip point A rotational operation L distance S spot welding

Claims (3)

A seat cushion frame of a seat having a pair of left and right side frames, a front crossbar disposed before and after the left and right side frames, a rear crossbar, and one end portion of the seat cushion frame provided across the front of the seated person on the seat The seat belt whose side is connected to the side frame side and the other end side of the seat belt can be wound up, and the seat belt is rewound by an external force applied to the seat belt by a seated person at the time of a front collision. A retractor that can be enabled, a lock mechanism that locks the seat belt unwound from the retractor, and when the tensile stress generated in the seat belt by the external force reaches a predetermined value in a locked state of the seat belt by the lock mechanism, A vehicle seat device including a force limiter that operates to suppress an increase in tensile stress. Stomach,
Before the front crossbar is arranged at the front and rear, the rear member is provided with a rear member, the rear member is at a lower position and lower rigidity than the front member, and the waist of the seated person who moves forward at the time of the front collision is the rear member When a collision occurs, the member subsequently restrains the rotational movement of the waist from rising forward. Further, when the waist moves forward and collides with the front member, the front member moves further forward of the waist. A vehicle seat device characterized in that the force limiter starts to operate simultaneously with or before the waist starts to collide with the front member.   A torsion bar extending in the width direction of the vehicle body, one end in the longitudinal direction thereof being fixed to the front part of one of the left and right side frames, and the other end being a free end, and the torsion bar A link bar that is disposed on the front upper side and extends along the torsion bar, and is fixed to the other end of the torsion bar; and a net sheet that is stretched between the rear crossbar and the link bar. The vehicle seat device according to claim 1, wherein at least one of the torsion bar and the link bar is used as the front member.   One end of the seat belt is fixed to the rear part of the left and right side frames, the upper part of the front part of the side frame supports the end part of the rear member, and the upper part of the front part of the side frame is weak between the upper part and the lower part. The vehicle seat device according to claim 1, wherein a portion is formed.

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