JP2014076786A - Occupant restraint system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an occupant restraint system in which a decrease in a total amount of kinetic energy to be absorbed through deformation is suppressed and furthermore a load which an occupant's body receives from a seat belt can be reduced.SOLUTION: In a seat belt device 10, when a motor 80 is actuated, a tension load corresponding to a stress with which a twisting deformation of a variable part 76 of a torsion bar 50 is changed from an elastic deformation to a plastic deformation is applied to a seat belt 26. In this state, when an occupant is inertially moved forward in a vehicle, the seat belt 26 is drawn out of a winding shaft 24, and the winding shaft 24 is rotated in the drawing direction. This causes the twisting deformation of the plastic deformation to occur in the variable part 76. Consequently, the stress in the variable part 76 is not increased any more and therefore, compared with a structure in which the twisting deformation of the variable part 76 begins with the elastic deformation, a total amount of kinetic energy to be absorbed can be increased. According to the increase, the stress, that is, a load which the occupant's body receives from the seat belt 26 can be set to be smaller.

Description

  The present invention relates to an occupant restraint device that restrains the body of an occupant seated on a vehicle seat by a seat belt.

  The retractor of the seatbelt apparatus which is one aspect | mode of the passenger | crew restraint apparatus currently disclosed by patent document 1 is provided with the brushless motor. The output shaft of this brushless motor is connected to one end of the torsion bar via a planetary gear train, and the winding shaft is the direction of rotation when the winding shaft winds up the seat belt with the forward driving force or the reverse driving force of the brushless motor. A rotational force in the drawing direction opposite to the take-up direction and the take-up direction can be applied to one end of the torsion bar. The other end of the torsion bar is connected to a take-up shaft, and the take-up shaft can be wound in the take-up direction by the forward rotation driving force of a brushless motor to wind up the seat belt.

  When the vehicle suddenly decelerates, the occupant's body tries to move inertially forward of the vehicle and pulls the seat belt to rotate the take-up shaft in the pull-out direction. In this state, when the rotation of one end of the torsion bar is regulated by the motor, the rotation of the torsion bar in the pulling direction, and consequently the rotation of the winding shaft in the pulling direction is restricted, and the winding shaft The withdrawal of the seat belt from the seat is regulated.

  On the other hand, the rotational force in the pull-out direction of the take-up shaft, that is, the tensile load applied to the seat belt from the occupant's body is input to the other end of the torsion bar via the take-up shaft. The torsion bar is twisted and deformed by this tensile load. Since the occupant's body pulls the seat belt and twists the torsion bar, the seat belt is pulled out from the take-up shaft by the torsional deformation of the torsion bar, and the occupant's body moves forward in the vehicle. To do. Further, kinetic energy having a magnitude corresponding to the product of the amount of movement of the occupant's body and the tensile load applied to the seat belt by the occupant's body is subjected to torsional deformation of the torsion bar and absorbed.

  Furthermore, in the configuration disclosed in Patent Document 1, when the torsional deformation such that the other end rotates with respect to one end of the torsion bar as described above, or when such a torsional deformation occurs, A forward drive force and a reverse drive force are output from the brushless motor. Thereby, the relative rotation of the other end with respect to one end of the torsion bar is adjusted, and the amount of energy to be absorbed is adjusted.

JP 2001-270423 A

  By the way, the energy absorbing member elastically deforms at the beginning of the deformation due to the energy absorbing member such as the torsion bar receiving a tensile load. For this reason, in this state, the kinetic energy having a magnitude proportional to the magnitude of the tensile load received by the energy absorbing member is absorbed by the deformation of the energy absorbing member. When the tensile load applied to the energy absorbing member increases and the value exceeds a predetermined size, the energy absorbing member is deformed plastically. After that, even if the tensile load increases, a certain amount It only absorbs kinetic energy corresponding to the magnitude of the tensile load.

  After the deformation of the energy absorbing member is switched from the elastic deformation to the plastic deformation, a load corresponding to the predetermined tensile load is applied from the seat belt to the occupant's body that moves inertially forward of the vehicle. . For this reason, if the load at the time of switching from elastic deformation to plastic deformation in the energy absorbing member is set low, the load applied from the seat belt to the occupant's body can be set small.

  On the other hand, the kinetic energy absorbed by the deformation of the torsion bar corresponds to the product of the amount of movement of the occupant's body and the tensile load applied to the seat belt by the occupant's body. For this reason, if the load at the time of switching from elastic deformation to plastic deformation in the energy absorbing member is set low, the total amount of kinetic energy absorbed by the deformation of the energy absorbing member is small if the movement amount of the occupant's body is the same. End up.

  An object of the present invention is to obtain an occupant restraint device that can reduce the load that the occupant's body receives from the seat belt while suppressing a decrease in the total amount of kinetic energy absorbed by deformation in consideration of the above facts.

  An occupant restraint device according to a first aspect of the present invention is provided to a seat belt that is pulled out of the belt storage portion and is attached to a body of an occupant seated on a vehicle seat, and is provided to the seat belt in an operable state. An energy absorbing member that allows the seat belt to be withdrawn from the belt storage portion while absorbing kinetic energy corresponding to the tensile load up to a predetermined upper limit by transmitting the tensile load. Tension applying means for pulling the seat belt and causing the tensile load to reach the upper limit value.

  In the occupant restraint device according to the first aspect, the seat belt is pulled when the tension applying means is actuated. As a result, the tensile load applied to the seat belt reaches a predetermined upper limit value. In this state, when the occupant's body, which intends to move inertially forward of the vehicle, pulls the seat belt with a pulling force equal to or greater than the upper limit, the energy absorbing member absorbs kinetic energy having a magnitude corresponding to the upper limit. Beginning, the energy absorbing member thus allows the seat belt to be withdrawn from the belt containment while absorbing kinetic energy (ie, allowing the occupant's body to move inertially forward of the vehicle). As a result, the load received from the seat belt by the occupant's body trying to move inertially forward of the vehicle has a magnitude obtained by subtracting the above upper limit value from the tensile load applied to the seat belt by the occupant, and the occupant's body receives from the seat belt. The load can be reduced.

  By the way, the amount of change in kinetic energy absorbed by the energy absorbing member is represented by the product of the tensile load applied to the seat belt and the amount of movement (position change) of the occupant's body. The total kinetic energy absorbed by the energy absorbing member is the amount of change in kinetic energy from the start of applying the seat belt tensile load to the energy absorbing member until the energy absorbing member finishes absorbing kinetic energy. The sum of

  Here, if the tensile load applied to the seat belt is less than the upper limit value in a state where the energy absorbing member is operable, the magnitude of the tensile load less than the upper limit value until the tensile load reaches the upper limit value. It absorbs only the kinetic energy corresponding to the height. In contrast, in the occupant restraint device according to the present invention, the load applied to the seat belt is caused to reach the upper limit value in the energy absorbing member by operating the tension applying unit as described above. For this reason, after the tension applying means is activated, the energy absorbing member absorbs kinetic energy having a magnitude corresponding to the upper limit tensile load. As a result, if the movement amount when the body of the occupant is inertially moved forward while pulling the seat belt is the same, the kinetic energy absorbed by the energy absorbing member is increased in the occupant restraint device according to the present invention.

  Thus, if the sum of the kinetic energy in the energy absorbing member can be increased, if the sum of the kinetic energy absorbed by the energy absorbing member is made the same as before, the above-described upper limit value can be lowered. The load received from the seat belt by the occupant's body that moves inertially forward of the vehicle can be reduced.

  In the present invention described in claim 1, the operation start timing of the tension applying means is not particularly limited. That is, as will be described later, it is preferable that the tension applying means reaches the upper limit value of the tensile load applied to the seat belt at the start of energy absorption in the energy absorbing member. However, this does not exclude the configuration in which the tension applying means operates after the absorption of kinetic energy in the energy absorbing member is started. For example, even after the energy absorbing member has started to absorb kinetic energy, the tension applying means is activated and the tensile load applied to the seat belt is increased to the upper limit value, thereby increasing the total amount of absorbed kinetic energy. can do.

  An occupant restraint device according to a second aspect of the present invention is the occupant restraint device according to the first aspect of the present invention, wherein, in the first aspect of the present invention, the tension applying means sets the tensile load to the upper limit value until the energy absorbing member is in the operable state. The tension applying means is set so as to reach.

  According to the occupant restraint device of the second aspect, the tension applying means causes the tension load of the seat belt to reach the above-described upper limit value before the energy absorbing member becomes operable. For this reason, the energy absorbing member starts to absorb kinetic energy corresponding to the tensile load when the tensile load applied to the seat belt by the occupant's body exceeds the upper limit value.

  Thus, since the energy absorbing member absorbs the kinetic energy corresponding to the above-described upper limit tensile load from the start of the absorption of the kinetic energy, it is possible to effectively increase the sum of the kinetic energy absorbed by the energy absorbing member. it can. As a result, the above-described upper limit value can be effectively reduced, and the load received from the seat belt by the occupant's body that moves inertially forward of the vehicle can be reduced.

  The occupant restraint device according to a third aspect of the present invention is the occupant restraint device according to the first or second aspect of the present invention, wherein the energy absorbing member is deformed by the tensile load so that the movement corresponding to the tensile load is performed. While absorbing energy, the said tensile load when the deformation | transformation by the said tensile load switches from an elastic deformation to a plastic deformation is made into the said upper limit.

  According to the occupant restraint device of the third aspect, the energy absorbing member absorbs kinetic energy corresponding to the magnitude of the tensile load by being deformed by receiving the tensile load. Thus, since the energy absorbing member is configured to absorb kinetic energy by deformation, first, the energy absorbing member is elastically deformed until the tensile load reaches a certain magnitude, and the kinetic energy corresponding to the magnitude of the tensile load is obtained. Absorbs. When the tensile load exceeds a certain magnitude, the energy absorbing member starts plastic deformation. When the energy absorbing member starts plastic deformation, kinetic energy corresponding to the above-described integrated tensile load is absorbed thereafter.

  Here, in the occupant restraint device according to the present invention, the above-described upper limit value is set to the magnitude of the tensile load when the deformation of the energy absorbing member is switched from the elastic deformation to the plastic deformation. That is, in the occupant restraint device according to the present invention, when the tension applying means is operated, the tensile load applied to the seat belt becomes the magnitude of the tensile load when the deformation of the energy absorbing member is switched from the elastic deformation to the plastic deformation. When the occupant's body pulls the seat belt from this state to deform the energy absorbing member, the deformation of the energy absorbing member becomes plastic deformation, and after the start of deformation of the energy absorbing member, it corresponds to the magnitude of the upper limit tensile load. The kinetic energy to be absorbed is absorbed by the deformation of the energy absorbing member.

  The occupant restraint device according to a fourth aspect of the present invention is the portion of the present invention according to any one of the first to third aspects, wherein the seat belt is attached to a chest of the occupant's body. The belt is provided between a shoulder belt and the occupant's body, and applies a belt load applied to the occupant's body from the shoulder belt to at least one of a side in a longitudinal direction and a side in the width direction of the shoulder belt. Load dispersing means for dispersing is provided.

  According to the occupant restraint device of the fourth aspect, when the load applying means operates as described above and the tension of the seat belt increases, the belt load from the seat belt is applied to the chest of the occupant.

  Here, in a state in which the seat belt is attached to the occupant's body, a load distribution means is provided between the shoulder belt, which is a portion of the seat belt that is attached to the occupant's chest, and the occupant's chest. Thereby, the belt load based on the tension from the shoulder belt is distributed to at least one of the side in the longitudinal direction and the side in the width direction of the shoulder belt. Accordingly, the belt load does not concentrate at a position facing the shoulder belt in the occupant's body, and the belt load per unit area can be reduced.

  As described above, the occupant restraint device according to the present invention can reduce the force limiter load while suppressing a decrease in the total amount of kinetic energy to be absorbed.

It is a front view showing roughly the whole composition of the crew member restraint device concerning a 1st embodiment. It is a front view showing roughly the whole composition of the seatbelt retractor of the crew member restraint device concerning a 1st embodiment. It is a graph which shows the relationship between the distortion | strain and stress in an energy absorption member. FIG. 3 is an enlarged cross-sectional view taken along line 3-3 in FIG. 1 showing the structure of the load distribution means. In the passenger | crew restraint apparatus which concerns on 1st Embodiment, it is a graph which shows the relationship between the amount of movement of a passenger | crew's body at the time of vehicle rapid deceleration, and the stress which arises in an energy absorption member, (A) is stress F1 by a tension | tensile_strength provision means. It is a graph which shows the case of the structure to which the corresponding tensile load F1 is provided, (B) is a graph which shows the structure which does not have a tension | tensile_strength provision means, (C) is the kinetic energy absorbed by (A) and (B). It is a graph which shows the difference of the total amount of. In the passenger | crew restraint apparatus which concerns on 1st Embodiment, it is a graph which shows the relationship between the amount of movement of a passenger | crew's body at the time of vehicle rapid deceleration, and the stress which arises in an energy absorption member, (A) is stress F1 by a tension | tensile_strength provision means. (B) is a graph showing a configuration provided with a motor that applies only a load F2 smaller than the tensile load F1 to the seat belt even after the operation, in a graph showing a configuration in which the corresponding tensile load F1 is applied. (C) is a graph which shows the difference of the total amount of the kinetic energy absorbed by (A) and (B). It is a front view which shows roughly the whole structure of the seatbelt retractor of the passenger | crew restraint apparatus which concerns on 2nd Embodiment. In the passenger | crew restraint apparatus which concerns on 2nd Embodiment, it is a graph which shows the relationship between the amount of movement of a passenger | crew's body at the time of vehicle deceleration, and the stress which arises in an energy absorption member, (A) is stress F1 by a tension | tensile_strength provision means. It is a graph which shows the case of the structure to which the corresponding tensile load F1 is provided, (B) is a graph which shows the structure which does not have a tension | tensile_strength provision means, (C) is the kinetic energy absorbed by (A) and (B). It is a graph which shows the difference of the total amount of. In the passenger | crew restraint apparatus which concerns on 2nd Embodiment, it is a graph which shows the relationship between the amount of movement of a passenger | crew's body at the time of vehicle deceleration, and the stress which arises in an energy absorption member, (A) is stress F1 by a tension | tensile_strength provision means. FIG. 6B is a graph showing a configuration in which a corresponding tensile load F1 is applied, and FIG. 5B is a graph showing a configuration in which a pretensioner that applies only a load F2 smaller than the tensile load F1 to the seat belt is provided even after operation. (C) is a graph showing the difference in the total amount of kinetic energy absorbed between (A) and (B). It is a front view which shows roughly the whole structure of the passenger | crew restraint apparatus which concerns on 3rd Embodiment. It is a front view of the load distribution means of the passenger | crew restraint apparatus which concerns on 4th Embodiment. FIG. 12 is an enlarged cross-sectional view taken along line 12-12 in FIG.

  Next, each embodiment of the present invention will be described with reference to FIGS. In the following description of each embodiment, the same reference numerals are given to parts that are basically the same as those of the previous embodiment, and a detailed description thereof is given. Omitted.

<Configuration of First Embodiment>
FIG. 1 is a front view schematically showing an overall configuration of a seat belt device 10 as an occupant restraint device according to a first embodiment.

  As shown in this figure, the seat belt device 10 includes a seat belt retractor 14 as a seat belt storage portion. As shown in FIG. 2, the seat belt retractor 14 includes, for example, a frame 16 that is fixed to the vehicle body in the vicinity of the lower end portion of the center pillar of the vehicle. The frame 16 includes a pair of leg walls 20 and 22. For example, the leg walls 20 and 22 are formed in a plate shape whose thickness direction is along the front-rear direction of the vehicle, and are opposed to each other in the thickness direction.

  A winding shaft 24 is provided between the leg wall 20 and the leg wall 22. A longitudinal base end side of the seat belt 26 is locked to the winding shaft 24. When the take-up shaft 24 rotates in the take-up direction, which is one of the axes around the direction in which the opposing direction of the leg wall 20 and the leg wall 22 is the axial direction, the seat belt 26 is placed on the outer peripheral portion from the base end side in the longitudinal direction. Roll up and store in layers. When the seat belt 26 is pulled toward the leading end side, the seat belt 26 wound around the take-up shaft 24 is drawn out from the take-up shaft 24, and the take-up shaft 24 is pulled out opposite to the take-up direction. Rotate in the direction.

  The seat belt 26 is pulled out from the winding shaft 24 to the upper side of the vehicle. As shown in FIG. 1, the seat belt 26 pulled upward from the seat belt retractor 14 passes, for example, through a slit hole formed in a slip joint 28 provided in the center pillar of the vehicle, and is folded downward in the vehicle. The front end of the vehicle body or the seat belt device 10 is locked to the frame of the corresponding seat 32 or the like via the anchor member 30.

  A tongue 34 is provided between the slip joint 28 and the anchor member 30 in the seat belt 26 so as to be movable along the longitudinal direction of the seat belt 26. A buckle 36 is provided on the opposite side of the seat belt retractor 14 and the anchor member 30 via the seat 32 corresponding to the tongue 34. When the tongue 34 is attached to the buckle 36 while the seat belt 26 is hung around the body of the occupant 12, the seat belt 26 is attached to the body of the occupant 12.

  In this wearing state, a portion of the seat belt 26 between the slip joint 28 and the tongue 34 becomes a shoulder belt 38 and restrains the shoulder and chest on the slip joint 28 side of the body of the occupant 12. On the other hand, a portion of the seat belt 26 between the tongue 34 and the anchor member 30 serves as a lap belt 40 and restrains the waist of the occupant 12 body.

  On the other hand, as shown in FIG. 2, the take-up shaft 24 is formed with a torsion bar accommodating hole 42 along its central axis. Further, an adapter fitting insertion hole 44 is formed in the winding shaft 24. The adapter insertion hole 44 is a bottomed hole opened at the end of the winding shaft 24 on the leg wall 20 side, and the leg of the torsion bar accommodating hole 42 is formed at the bottom of the adapter insertion hole 44. The end on the wall 20 side is open. The inner peripheral shape of the adapter fitting hole 44 is a non-circular shape such as a spline shape or a polygon.

  The adapter 46 is inserted into the adapter insertion hole 44 from the opening end on the leg wall 20 side. The outer peripheral shape of the portion of the adapter 46 that is inserted into the adapter insertion hole 44 is the same as the inner peripheral shape of the adapter insertion hole 44 (strictly, a similar shape slightly smaller than the inner peripheral shape of the adapter insertion hole 44). The adapter 46 is inserted into the adapter insertion hole 44 so that relative rotation in the winding direction and the drawing direction with respect to the winding shaft 24 is restricted.

  A first connecting portion insertion hole 48 is formed in the adapter 46. The first connecting portion insertion hole 48 is a bottomed hole that opens toward the center in the central axis direction of the winding shaft 24 in a state where the adapter 46 is inserted into the adapter insertion hole 44. The first connection portion 52 of the torsion bar 50 as an energy absorbing member is inserted into the first connection portion insertion hole 48.

  The inner peripheral shape of the first connecting portion fitting insertion hole 48 is a non-circular shape such as a spline shape or a polygon, and the outer peripheral shape of the first connecting portion 52 of the torsion bar 50 is the inside of the first connecting portion fitting insertion hole 48. It is the same as the peripheral shape (strictly, a similar shape slightly smaller than the inner peripheral shape of the first connecting portion fitting insertion hole 48). Therefore, the first connection portion 52 of the torsion bar 50 is inserted into the first connection portion insertion hole 48 of the adapter 46 so that the relative rotation in the winding direction and the pulling direction with respect to the adapter 46 and eventually the winding shaft 24 is achieved. Is regulated.

  On the other hand, a lock rotor insertion hole 54 is formed in the winding shaft 24. The lock rotor insertion hole 54 is a circular hole coaxial with the central axis of the take-up shaft 24, and opens at the end surface of the take-up shaft 24 on the leg wall 22 side. A bottom portion is formed on the center side in the central axis direction of the winding shaft 24 in the lock rotator insertion hole 54, and the end of the torsion bar housing hole 42 on the leg wall 22 side is the bottom of the lock rotator insertion hole 54. Open at.

  The lock rotating body fitting insertion hole 54 is fitted with a fitting insertion portion 60 of a lock rotating body 58 constituting a lock device 56 as a winding shaft rotation restricting means. The insertion portion 60 has a circular shape whose outer periphery is the same as the inner periphery of the lock rotator insertion hole 54 (strictly, a similar shape slightly smaller than the inner periphery of the lock rotator insertion hole 54). Yes. For this reason, the lock rotator 58 is basically rotatable relative to the take-up shaft 24 in the take-up direction and the pull-out direction.

  The lock rotator 58 includes a lock member accommodating portion 62. The lock member accommodating portion 62 is located on the side of the end portion of the winding shaft 24 on the leg wall 22 side in a state where the fitting insertion portion 60 is fitted into the lock rotating body fitting insertion hole 54, and is formed on the leg wall 22. It faces the ratchet hole 64 of the internal tooth in the rotational radius direction of the winding shaft 24. A lock member accommodation hole 66 is formed in the lock member accommodation portion 62. The lock member accommodation hole 66 opens at the outer peripheral surface of the lock member accommodation portion 62, and the lock member 68 protrudes from the opening at the outer peripheral surface of the lock member accommodation portion 62 in the lock member accommodation hole 66 (hereinafter referred to as “the lock member accommodation hole 66”). This direction is referred to as the “lock actuation direction” for convenience) and in the opposite direction.

  The lock member 68 is formed with ratchet teeth. When the lock member 68 moves in the lock operation direction and the lock member 68 protrudes from the opening on the outer peripheral surface of the lock member accommodating portion 62 in the lock member accommodating hole 66, The ratchet teeth of the lock member 68 mesh with the ratchet teeth formed on the inner peripheral portion of the ratchet hole 64. Thus, when the ratchet teeth of the lock member 68 mesh with the ratchet teeth of the ratchet hole 64, the rotation of the lock rotating body 58 in the pull-out direction is restricted.

  A case 70 is fixed to the frame 16 on the outer side of the leg wall 22 (on the side opposite to the leg wall 20 of the leg wall 22). Inside the case 70, various components constituting a VSIR mechanism that operates based on acceleration during sudden deceleration of the vehicle and moves the lock member 68 in the lock operation direction, and rotational acceleration in the pull-out direction of the lock member housing portion 62. Various components constituting the WSIR mechanism that moves when the lock member 68 is moved in the lock operation direction by operating when is greater than or equal to a predetermined size are accommodated.

  On the other hand, the lock rotating body 58 is formed with a second connecting portion fitting insertion hole 72. The second connecting portion insertion hole 72 is a bottomed opening that opens toward the center in the central axis direction of the winding shaft 24 in a state where the insertion portion 60 of the lock rotator 58 is inserted into the lock rotator insertion hole 54. It is a hole. The second connection portion 74 of the torsion bar 50 is inserted into the second connection portion insertion hole 72. The inner peripheral shape of the second connecting part fitting insertion hole 72 is a non-circular shape such as a spline shape or a polygon, and the outer peripheral shape of the second connecting part 74 of the torsion bar 50 is the inner part of the second connecting part fitting insertion hole 72. It is the same as the circumferential shape (strictly, a similar shape slightly smaller than the inner circumferential shape of the second connecting portion fitting insertion hole 72).

  A variable portion 76 is provided between the first connecting portion 52 and the second connecting portion 74 of the torsion bar 50. The variable portion 76 is formed in a rod shape whose axial direction is along the central axis direction of the winding shaft 24, and the first connecting portion 52 and the second connecting portion 74 are connected by the variable portion 76. The variable portion 76 is relative to the second connecting portion 74 by rotating relative to the second connecting portion 74 around the axis in which the first connecting portion 52 has the same direction as the central axis of the winding shaft 24. The first connecting portion 52 side is deformed so as to be twisted.

  Further, as shown in FIG. 3, when the first connecting portion 52 side of the variable portion 76 is twisted with respect to the second connecting portion 74 side, the variable portion 76 is first twisted to the second connecting portion 74 side. As the strain ε on the first connecting portion 52 side increases, the stress σ due to the application of torsional load increases. In this way, the variable portion 76 is elastically deformed while the stress σ increases with the increase of the strain ε. Further, when the strain ε becomes a constant magnitude ε1 and the stress σ reaches F1 (that is, the torsional load is F1), the subsequent torsional deformation in the variable portion 76 becomes plastic deformation and the strain ε increases. However, the stress σ does not increase.

  Note that the relationship between the strain ε and the stress σ of the variable portion 76 in FIG. 3 is merely an example, and the relationship between the strain ε and the stress σ in the variable portion 76 is not a linear relationship as shown in FIG. It may be.

  On the other hand, the opposite side of the second connecting portion 74 from the variable portion 76 is a shaft portion 78. The shaft portion 78 is formed coaxially with the take-up shaft 24 and enters the case 70, and is supported by the case 70 so as to be directly or indirectly rotatable.

  On the other hand, the seat belt retractor 14 of the seat belt apparatus 10 is provided with a motor 80 as tension applying means. The motor 80 is held between the leg wall 20 and the leg wall 22 by being connected to the frame 16 via a bracket or the like (not shown). A gear box 82 is attached to the frame 16 outside the leg wall 20 (on the opposite side of the leg wall 20 from the leg wall 22). On the inner side of the gear box 82, a speed reduction means constituted by a gear, a clutch or the like is provided.

  The output shaft of the motor 80 passes through the leg wall 20, enters the inside of the gear box 82, and is connected to the speed reducing means in the gear box 82. The speed reducing means in the gear box 82 is connected to the shaft portion of the adapter 46 that passes through the gear box 82. When the forward rotation driving force is output from the motor 80, the clutch in the gear box 82 is coupled, and the forward rotation driving force is decelerated from the motor 80 by the reduction means and transmitted to the shaft portion of the adapter 46. As a result, the winding shaft 24 is rotated in the winding direction.

  The motor 80 is electrically connected to a front monitoring device that detects the distance to an obstacle ahead of the vehicle via a control unit such as an ECU, and when the distance to the obstacle ahead of the vehicle becomes less than a certain value. The motor 80 is actuated to rotate the winding shaft 24 in the winding direction. As a result, the slack of the seat belt 26 hung around the body of the occupant 12 is eliminated, and the take-up shaft 24 is rotated in the take-up direction to cause the seat belt 26 to have a tensile load of size F1 (hereinafter referred to as this size). A tensile load of F1 is referred to as “tensile load F1”). The magnitude of the tensile load F1 corresponds to the magnitude of the stress F1 when the torsional deformation of the variable portion 76 described above is switched from elastic deformation to plastic deformation.

  A spring case 88 is provided on the opposite side of the gear box 82 from the leg wall 20. A shaft portion that is coaxially formed with respect to the take-up shaft 24 from the adapter 46 enters the inside of the spring case 88, and this shaft portion is supported directly or indirectly by the spring case 88 so as to be rotatable. ing.

  Further, for example, a mainspring spring is accommodated inside the spring case 88. The mainspring spring has an outer end in the spiral direction locked directly or indirectly to the spring case 88. On the other hand, the spiral direction inner end of the mainspring spring is directly or indirectly locked to the shaft portion that is formed to protrude from the adapter 46.

  The mainspring spring biases the adapter 46 in the winding direction, and tightens when the adapter 46 rotates in the pulling direction, and the biasing force that biases the adapter 46 in the winding direction increases.

  On the other hand, as shown in FIG. 1, the seat belt device 10 includes a load distribution plate 92 as load distribution means. The load distribution plate 92 includes a flat plate main body 94.

  The plate body 94 is provided between the shoulder belt 38 of the seat belt 26 and the body of the occupant 12 with the occupant 12 wearing the seat belt 26. The area of the plate body 94 facing the body of the occupant 12 is sufficiently larger than the area of the shoulder belt 38 of the seat belt 26 facing the body of the occupant 12, and as shown in FIG. With the seat belt 26 attached to the body, the plate body 94 faces the body of the occupant 12 at the upper end side between the vicinity of the right shoulder of the occupant 12 and the vicinity of the left shoulder, and the occupant at the lower end side between the right side of the abdomen and the left side of the abdomen. Opposite 12 bodies.

  As shown in FIG. 4, which is a cross-sectional view taken along line 4-4 in FIG. 1, the plate main body 94 includes a plate portion 96. The plate portion 96 is entirely formed in a flat plate shape or a sheet shape from a relatively hard synthetic resin material or metal. A pad portion 98 is integrated with the plate portion 96 on one side in the thickness direction of the plate portion 96, that is, on the body side of the occupant 12 in the plate portion 96 when the seat belt 26 is attached to the occupant 12 body. Is formed. The plate portion 96 is formed in a flat plate shape or a sheet shape as a whole. The plate portion 96 is made of a material having lower rigidity than the plate portion 96, such as foamed polystyrene, rubber material, or a relatively soft synthetic resin material.

  On the other hand, a locking band 100 is formed on the opposite side of the plate body 94 from the plate portion 96. The locking band 100 is formed in a flexible band shape, and an intermediate portion in the longitudinal direction thereof is integrally fixed to the plate body 94 (particularly, the plate portion 96) by fastening means such as a rivet.

  Connecting means such as hook-and-loop fasteners and hooks are attached to both ends of the locking band 100 in the longitudinal direction, and the locking band 100 is locked on the opposite side of the plate body 94 via a fixing portion with the plate body 94. The locking band 100 can be formed into an annular shape by connecting one end side and the other end side in the longitudinal direction of the band 100. The locking band 100 is connected at one end side and the other end side in the longitudinal direction so that the shoulder belt 38 (seat belt 26) passes through the inside thereof, whereby the locking band 100, and hence the load distribution plate 92, is connected to the shoulder belt. 38 (seat belt 26) is detachably attached.

<Operation and Effect of First Embodiment>
Next, the operation and effect of the present embodiment will be described.

  In the seat belt device 10, the motor 80 is activated when the distance to the obstacle ahead of the vehicle becomes less than a certain value in a state where the seat belt 26 is attached to the body of the occupant 12. When the motor 80 is operated, the driving force of the motor 80 is transmitted to the adapter 46 via the reduction gear train in the gear box 82, and the adapter 46 is rotated in the winding direction. When the adapter 46 is inserted into the adapter insertion hole 44 of the seat belt 26, relative rotation with respect to the winding shaft 24 is restricted. For this reason, when the adapter 46 rotates in the winding direction, the winding shaft 24 is rotated in the winding direction, and the seat belt 26 is wound around the winding shaft 24. As the seat belt 26 is wound on the take-up shaft 24 in this way, the tension of the take-up shaft 24 is increased, and a tensile load F1 is applied to the take-up shaft 24.

  On the other hand, when the vehicle suddenly decelerates, the lock device 56 operates. When the locking device 56 is operated, the ratchet teeth of the lock member 68 are engaged with the ratchet teeth of the ratchet hole 64 formed in the leg wall 22, and the rotation of the lock rotating body 58 in the pull-out direction is restricted. The relative rotation of the second connecting portion 74 with respect to the lock rotating body 58 is restricted by inserting the second connecting portion 74 of the torsion bar 50 into the second connecting portion insertion hole 72 formed in the lock rotating body 58. . For this reason, as described above, the rotation of the lock rotator 58 in the pull-out direction is restricted, whereby the second connecting portion 74 of the torsion bar 50 is restricted from rotating in the pull-out direction.

  The first connection portion 52 of the torsion bar 50 is inserted into the first connection portion insertion hole 48 of the adapter 46 to restrict relative rotation with respect to the adapter 46, and the adapter 46 is inserted into the adapter of the take-up shaft 24. The relative rotation with respect to the winding shaft 24 is restricted by being inserted into the hole 44. Therefore, the rotation of the lock rotating body 58 in the pull-out direction is restricted as described above, whereby the rotation of the take-up shaft 24 in the pull-out direction is indirectly restricted, and the seat belt 26 is pulled out from the take-up shaft 24. It is suppressed.

  In this state, when the body of the occupant 12 moves inertially toward the front side of the vehicle, the seat belt 26 is pulled by the body of the occupant 12, whereby the seat belt 26 is pulled out from the winding shaft 24. When the seat belt 26 is withdrawn from the take-up shaft 24, the take-up shaft 24 rotates in the pull-out direction by the length of the withdrawn seat belt 26. In this state, the rotation of the lock rotator 58 in the pull-out direction is restricted as described above, whereby the second connecting portion 74 of the torsion bar 50 is restricted from rotating in the pull-out direction. For this reason, when the seat belt 26 is pulled out and the take-up shaft 24 rotates in the pull-out direction, in the variable portion 76 of the torsion bar 50, the first connecting portion 52 side rotates in the pull-out direction with respect to the second connecting portion 74 side. The torsional deformation occurs in the variable portion 76.

  By the way, as described above, the tensile load F1 is applied to the seat belt 26 when the body of the occupant 12 starts inertial movement (the movement distance S of the body of the occupant 12 in FIG. 5 is S0). As the body of the occupant 12 moves inertially from this state, a tensile load larger than the load F1 is applied to the seat belt 26.

  Here, the tensile load F1 already applied to the seat belt 26 at the start of inertial movement of the body of the occupant 12 is the magnitude of the stress F1 when the torsional deformation of the variable portion 76 switches from elastic deformation to plastic deformation. It corresponds. For this reason, as shown in FIG. 5A, when the inertial movement of the body of the occupant 12 toward the front of the vehicle is started in the variable portion 76, the variable portion 76 of the torsion bar 50 starts plastic deformation. For this reason, even if the body of the occupant 12 pulls the seat belt 26 and twists and deforms the variable portion 76, the stress F of the variable portion 76 does not increase.

  As shown in FIG. 5B, the variable portion 76 of the torsion bar 50 is elastically deformed until the movement distance S of the occupant 12 reaches the distance S1 after the body of the occupant 12 starts inertial movement. In the configuration, the stress F of the variable portion 76 increases in proportion to the movement distance S until the movement distance S of the occupant 12 reaches the distance S1. Here, the body of the occupant 12 absorbed by the torsional deformation generated in the variable section 76 from when the body of the occupant 12 starts inertial movement until the movement distance S reaches the distance S2 is absorbed. The total amount of kinetic energy is equal to the area L11 in FIG. 5A and equal to the area M11 in FIG.

  As described above, in this embodiment, since the tensile load F1 is already applied to the seat belt 26 at the start of inertial movement of the occupant 12, the area L11 in FIG. Comparing the area of the area M11 in (B), the total amount of kinetic energy absorbed by the area of the area N11 in (C) of FIG. 5 can be increased.

  Here, if the total amount of kinetic energy to be absorbed by the torsional deformation of the variable portion 76 is the same as the area of the area M11 in FIG. 5B, it can be changed by the area of the area N11 in FIG. The stress F1 at which the torsional deformation of the portion 76 switches from elastic deformation to plastic deformation, that is, the tensile load F1 applied to the seat belt 26 can be set small. Since the load received by the occupant 12 from the seat belt 26 while the body of the occupant 12 is inertial is the tensile load F1, the load received by the occupant 12 from the seat belt 26 can be reduced by reducing the tensile load F1. Can be small.

  In addition, if a motor is provided that has a smaller output than the motor 80 of the present embodiment and can apply only a tensile load F2 that can be applied to the seat belt 26 by operating, the tensile load F2 is smaller than the tensile load F1. As shown in FIG. 6B, the stress F generated in the variable portion 76 at the start of inertial movement of the occupant 12 is smaller than the stress F1 at which the torsional deformation of the variable portion 76 switches from elastic deformation to plastic deformation. F2.

  For this reason, the torsional deformation of the variable portion 76 becomes an elastic deformation until the stress F generated in the variable portion 76 by inertial movement to the distance S3 of the occupant 12 reaches the stress F1, and the stress F in the variable portion 76 is the stress F1. Gradually increases until For this reason, the total amount of kinetic energy of the body of the occupant 12 absorbed by the torsional deformation generated in the variable section 76 until the body of the occupant 12 reaches the distance S2 in such a configuration is shown in FIG. This corresponds to the area of the area M12 in (B).

  Comparing the area of the area M12 and the area of the area L11 described above, the present embodiment that can apply the tensile load F1 to the seat belt 26 by the driving force of the motor 80 is the area of the area N12 in FIG. The total amount of kinetic energy absorbed can be increased. As a result, the stress F1 at which the torsional deformation of the variable portion 76 is switched from the elastic deformation to the plastic deformation, that is, applied to the seat belt 26, compared to the case where a motor whose output is smaller than the motor 80 in the present embodiment is provided. The pulling load F1 to be performed can be set small, and the load that the body of the occupant 12 receives from the seat belt 26 can be reduced.

  In the present embodiment, the plate body 94 of the load distribution plate 92 is interposed between the shoulder belt 38 and the body of the occupant 12. As described above, the upper end side of the plate body 94 faces the occupant 12 body between the vicinity of the right shoulder of the occupant 12 and the vicinity of the left shoulder, and the lower end side faces the occupant 12 body between the right side of the abdomen and the left side of the abdomen. doing. For this reason, the tensile load F <b> 1 that the body of the occupant 12 receives from the shoulder belt 38 of the seat belt 26 is distributed in a range facing the plate body 94 in the body of the occupant 12. Thereby, the load per unit area given to the passenger | crew's 12 body can be made small.

  Further, since the load distribution plate 92 is detachable from the shoulder belt 38 of the seat belt 26, the load distribution plate 92 is removed from the shoulder belt 38 when unnecessary (for example, when the occupant 12 gets off). Thus, the seat belt 26 can be easily retracted by the take-up shaft 24 and retracted.

<Configuration of Second Embodiment>
Next, a second embodiment will be described.

  As shown in FIG. 7, the seat belt retractor 114 of the seat belt device 110 according to the present embodiment includes a pretensioner 120 as a tension applying unit instead of the pretensioner 120. The pretensioner 120 includes, for example, a cylinder that accommodates a piston. When a micro gas generator mounted on the cylinder is operated and the internal pressure of the cylinder rises, the piston slides inside the cylinder. Yes. For example, a rack bar is formed on the piston. When the piston slides as described above, the rack bar rotates the pinion gear provided on the adapter 46 in the winding direction. The rotation of the pinion gear in the winding direction is transmitted to the adapter 46 through the clutch to rotate the adapter 46 in the winding direction, and consequently the winding shaft 24 is rotated in the winding direction.

  Here, in the present embodiment, when the pretensioner 120 operates in a state where the seat belt 26 is mounted on the occupant 12, the tension load F1 described in the first embodiment is applied to the seat belt 26. The output of the micro gas generator is set as follows.

<Operation and Effect of Second Embodiment>
As described above, in the pretensioner 120 according to the present embodiment, when the micro gas generator mounted on the cylinder is operated and the internal pressure of the cylinder rises, the piston slides inside the cylinder, and the rack bar formed on the piston. Rotates the pinion gear provided on the adapter 46 in the winding direction. Accordingly, when the adapter 46 rotates in the winding direction, the winding shaft 24 rotates in the winding direction, the seat belt 26 is wound around the winding shaft 24, and a tensile load F1 is applied to the seat belt 26.

  For this reason, if the operation start timing of the pretensioner 120 is earlier than the operation start timing of the lock device 56, the occupant 12 inertially moves forward of the vehicle, thereby causing torsional deformation generated in the variable portion 76 of the torsion bar 50. Is plastically deformed as in the first embodiment. For this reason, in this case, the present embodiment basically has the same effect as the first embodiment, and can obtain the same effect as the first embodiment.

  On the other hand, when the operation start timing of the pretensioner 120 is later than the operation start timing of the locking device 56, as shown in FIG. 8A, the body of the occupant 12 until the pretensioner 120 is operated. Moves to the distance S4. For this reason, the stress F generated in the variable portion 76 of the torsion bar 50 increases in proportion to the moving distance S until the distance 12 is reached after the body of the occupant 12 starts the inertial movement.

  Next, when the pretensioner 120 is activated, the seat belt 26 is wound around the take-up shaft 24 as described above, and the tension of the seat belt 26 is increased. A tensile load F1 is applied. For this reason, when the body of the occupant 12 further inertially moves from this state, the torsional deformation of the variable portion 76 of the torsion bar 50 becomes plastic deformation, and thereafter, the stress F generated in the variable portion 76 does not increase.

  As shown in FIG. 8B, the variable portion 76 of the torsion bar 50 is elastically deformed until the movement distance S of the occupant 12 reaches the distance S1 after the body of the occupant 12 starts inertial movement. In the configuration, the stress F of the variable portion 76 increases in proportion to the movement distance S until the movement distance S of the occupant 12 reaches the distance S1. Here, the body of the occupant 12 absorbed by the torsional deformation generated in the variable section 76 from when the body of the occupant 12 starts inertial movement until the movement distance S reaches the distance S2 is absorbed. The total amount of kinetic energy is equal to the area L21 in FIG. 8A and equal to the area M21 in FIG. 8B.

  As described above, in the present embodiment, after the pretensioner 120 is actuated, the tensile load F1 is applied to the seat belt 26. Therefore, the area L21 in FIG. ), The total amount of kinetic energy absorbed by the area of the area N21 in (C) of FIG. 8 can be increased.

  That is, even if the operation start timing of the pretensioner 120 is later than the operation start timing of the lock device 56, the tension load F1 is applied to the seat belt 26 by the operation of the pretensioner 120. The same effect as in the first embodiment can be obtained, and the same effect as in the first embodiment can be obtained.

  Further, if a pretensioner is provided that has a smaller output than the pretensioner 120 of the present embodiment and can apply only a tensile load F2 that can be applied to the seatbelt 26 when activated, the tensile load F2 is smaller than the tensile load F1. As shown in FIG. 9B, the stress F generated in the variable portion 76 even after the pretensioner is operated is greater than the stress F1 at which the torsional deformation of the variable portion 76 switches from elastic deformation to plastic deformation. Small stress F2.

  For this reason, even after the pretensioner operation ends, the torsional deformation of the variable portion 76 becomes an elastic deformation until the stress F generated in the variable portion 76 by inertial movement to the distance S5 of the occupant 12 reaches the stress F1, The stress F in the variable portion 76 gradually increases until the stress F1 is reached. For this reason, the total amount of kinetic energy of the body of the occupant 12 absorbed by the torsional deformation generated in the variable section 76 until the body of the occupant 12 reaches the distance S2 in such a configuration is shown in FIG. This corresponds to the area of the area M22 in (B).

  When the area of the area M22 is compared with the area of the area L21 described above, the present embodiment in which the tension load F1 can be applied to the seat belt 26 by the driving force of the pretensioner 120 is the same as that of the area N22 in FIG. The total amount of kinetic energy absorbed by the area can be increased. Thereby, even when compared with the case where a pretensioner having an output smaller than that of the pretensioner 120 in the present embodiment is provided, the stress F1 at which the torsional deformation of the variable portion 76 switches from elastic deformation to plastic deformation, that is, The tensile load F <b> 1 applied to the seat belt 26 can be set small, and the load that the occupant 12 receives from the seat belt 26 can be reduced.

  In the first embodiment, the motor 80 is a tension applying unit, and in the present embodiment, the pretensioner 120 is a tension applying unit. However, the tension applying means is not limited to the motor 80 or the pretensioner 120, and any structure may be used as long as it can apply the tensile load F1 to the seat belt 26 by operating.

  Further, for example, the motor 80 and the pretensioner 120 may be used in combination, and the tension load F1 may be applied to the seat belt 26 by operating the pretensioner 120 in a state where the motor 80 has finished operating. Thus, by dividing the function as the tension applying means to both the motor 80 and the pretensioner 120, the output of each of the motor 80 and the pretensioner 120 can be reduced. Thus, you may comprise a tension | tensile_strength provision means combining two or more structures.

<Third Embodiment>
Next, a third embodiment will be described.

  FIG. 10 shows a seat belt device 130 as an occupant restraint device according to the third embodiment in a front view corresponding to FIG. 1 explaining the first embodiment.

  As shown in this figure, the seat belt device 130 includes a load distribution plate 132 as a load distribution means instead of the load distribution plate 92. The load distribution plate 132 includes a plate body 134. The structure of the plate main body 134 is basically the same as that of the plate main body 94 of the load distribution plate 92 in the first embodiment, and although it is not shown in the drawing, the plate main body 134 includes a plate portion 96 and a pad portion 98.

  However, the plate body 134 is different from the plate body 94 in a state where the load distribution plate 132 is attached to the shoulder belt 38 of the seat belt 26 and the lower end side of the plate body 134 is the waist of the occupant 12 and the lap belt 40 of the seat belt 26. Intervene between. For this reason, in the present embodiment, not only the belt load F applied from the shoulder belt 38 of the seat belt 26 to the body of the occupant 12 but also the belt load applied from the lap belt 40 of the seat belt 26 to the body of the occupant 12. Can also be dispersed.

<Fourth embodiment>
Next, a fourth embodiment will be described.

  FIG. 11 shows a front view of a load distribution plate 142 as load distribution means of a seat belt device 140 as an occupant restraint device according to the fourth embodiment. As shown in this figure, the load distribution plate 142 includes a plurality (two in the present embodiment) of plate bodies 144 and 146. The structure of the plate bodies 144 and 146 is basically the same as that of the plate body 94 of the load distribution plate 92 in the first embodiment, and is shown in FIG. 12 which is an enlarged sectional view taken along line 12-12 in FIG. As shown, the plate main body 144 and the 146 plate portion 96 and the pad portion 98 are configured.

  As shown in FIG. 12, the plate main body 144 and the plate main body 146 are lined up and down with the load distribution plate 142 attached to the seat belt 26. Further, the load distribution plate 142 includes a pair of left and right hinges 148. One hinge 148 connects the lower end side of the plate main body 144 and the upper end side of the plate main body 146 on the right side with the load distribution plate 142 attached to the seat belt 26, and the other hinge 148 connects the load distribution plate 142 to the upper end side. The lower end side of the plate main body 144 and the upper end side of the plate main body 146 are connected to each other on the left side in the state attached to the seat belt 26.

  The plate main body 144 and the plate main body 146 connected by the hinge 148 can rotate one of the plate main body 144 and the plate main body 146 with respect to the other about the connecting shaft 150 of the hinge 148 shown in FIG. Therefore, one of the plate main body 144 and the plate main body 146 can be rotated and folded with respect to the other with the load distribution plate 142 removed from the seat belt 26.

  In the present embodiment, the load distribution plate 142 includes the two plate main bodies 144 and the plate main body 146. However, when the load distribution plate 142 includes a plurality of plate main bodies, the number of plate main bodies is the same. May be three or more.

DESCRIPTION OF SYMBOLS 10 Seat belt apparatus 12 Crew 26 Seat belt 32 Seat 50 Torsion bar (energy absorption member)
80 motor (tensioning means)
92 Load distribution plate (Load distribution means)
110 seat belt device 120 pretensioner (tensioning means)
130 seat belt device 132 load distribution plate (load distribution means)
140 Seat belt device 142 Load distribution plate (load distribution means)

Claims (4)

A seat belt that is pulled out of the belt storage and is attached to the body of an occupant seated on a vehicle seat;
When the tension load applied to the seat belt is transmitted in an operable state, the seat belt is pulled out from the belt storage portion while absorbing kinetic energy corresponding to the tension load up to a predetermined upper limit value. An energy absorbing member that allows
Tension applying means for operating and pulling the seat belt to reach the upper limit of the tensile load;
An occupant restraint device.   The occupant restraint device according to claim 1, wherein the tension applying means is set so that the tension applying means reaches the upper limit value until the energy absorbing member is in the operable state.   The energy absorbing member is deformed by the tensile load to absorb the kinetic energy corresponding to the tensile load, and the tensile load when the deformation due to the tensile load is switched from elastic deformation to plastic deformation is set to the upper limit value. The occupant restraint device according to claim 1 or 2.   The seat belt is provided so as to be interposed between a shoulder belt, which is a portion to be mounted on the chest of the occupant's body, and the occupant's body, and a belt load applied from the shoulder belt to the occupant's body. The occupant restraint device according to any one of claims 1 to 3, further comprising a load distribution unit that distributes the shoulder belt to at least one of a lateral side and a lateral side of the shoulder belt.

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