JP2010241250A - Seat belt device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a seat belt device capable of suitably restraining an occupant according to the status of a vehicle. <P>SOLUTION: The seat belt device for restraining the occupant of the vehicle includes a spool 30 for rolling-up the seat belt 10; a shaft 32 arranged at an inner side of the spool 30 relatively rotatably with the spool 30; a plurality of outer plates 36 integrally provided on an inner periphery of the spool 30; and a plurality of inner plates 38 integrally provided on an outer periphery of the shaft 32. The outer plate 36 and the inner plate 38 are alternately arranged in an axial X direction. An operation chamber C is formed between the inner periphery of the spool 30 and the outer periphery of the shaft 32, and a viscous fluid is filled in the operation chamber C. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a seat belt device that restrains a vehicle occupant.

  In general, a vehicle is provided with a seat belt device in order to protect an occupant from an impact at the time of a collision. The seat belt device includes a seat belt that restrains an occupant of the vehicle to the seat, a spool that winds up the seat belt, and a lock mechanism that operates under predetermined conditions to regulate the withdrawal of the seat belt.

  The lock mechanism operates when, for example, the acceleration at which the seat belt is pulled out is greater than or equal to a threshold, or when the vehicle deceleration is greater than or equal to the threshold. When activated, the lock mechanism regulates the rotation of the spool that winds up the seat belt in the pull-out direction, thereby regulating the pull-out of the seat belt.

  At the time of a frontal collision of the vehicle (that is, sudden deceleration), an inertial force that moves the occupant forward is generated, and the seat belt that restrains the occupant is pulled. Is regulated. Thereby, a passenger | crew can be restrained reliably at the time of the front collision of a vehicle (namely, at the time of sudden deceleration).

  Conventionally, in order to prevent an excessive load from being applied to the occupant's body during the operation of the lock mechanism, the seat belt can be pulled out when the load (tension) applied to the seat belt reaches the reference value in the operation state of the lock mechanism. A seat belt device provided with a force limiter mechanism is known (see, for example, Patent Document 1).

  The force limiter mechanism includes a torsion bar (shaft). The torsion bar is coaxially arranged inside the spool, and is integrally connected to the spool, for example, at one axial end portion of the spool. In this case, the above-described locking mechanism is provided on the other axial end side of the spool. When actuated, the lock mechanism restricts rotation of the other end portion in the axial direction of the torsion bar and restricts rotation of the spool coupled to the torsion bar in the pull-out direction.

  At the time of a frontal collision of the vehicle (that is, when suddenly decelerating), the occupant tries to move forward by the inertia force according to the collision speed of the vehicle (that is, the deceleration of the vehicle) and restrains the occupant Is pulled. The rotational force in the pull-out direction according to the pulling force is input to the connecting portion with the torsion bar, that is, the other axial end portion of the torsion bar via the spool. At this time, if the lock mechanism is activated to restrict the rotation of the one end portion in the axial direction of the torsion bar, the torsion bar does not basically rotate.

  However, when the pulling direction rotational force input to the other axial end portion of the torsion bar reaches a reference value, the axial direction other end portion of the torsion bar and the one axial end portion whose rotation is restricted by the lock mechanism Torsionally deform plastically. Due to this torsional deformation, the spool connected to the torsion bar rotates in the pulling direction, and the seat belt is allowed to be pulled out. Accordingly, it is possible to suppress the load (tension) applied to the seat belt from exceeding the reference value when the lock mechanism is operated, and it is possible to suppress an excessive load from being applied to the occupant's body.

JP 2008-238997 A

  However, in the above conventional seat belt device, the reference value of the load (tension) applied to the seat belt is determined by the mechanical strength of the torsion bar, and does not change according to the situation of the vehicle. Therefore, there may be a case where the occupant cannot be restrained appropriately according to the vehicle situation.

  The present invention has been made in view of the above, and an object of the present invention is to provide a seat belt device capable of appropriately restraining an occupant depending on the situation of the vehicle.

In order to achieve the above object, the present invention provides:
A seat belt to restrain the vehicle occupant;
A spool for winding the seat belt;
A shaft disposed inside the spool so as to be rotatable relative to the spool;
A plurality of outer plates integrally provided on the inner periphery of the spool;
A plurality of inner plates provided integrally with an outer periphery of the shaft, and arranged alternately with the plurality of outer plates;
A seat belt device in which a working chamber is formed between an inner periphery of the spool and an outer periphery of the shaft, and a viscous fluid is sealed in the working chamber.

  ADVANTAGE OF THE INVENTION According to this invention, the seatbelt apparatus which can restrain a passenger | crew appropriately according to the condition of a vehicle is obtained.

1 is a partial cross-sectional view illustrating a configuration of a seat belt device according to a first embodiment of the present invention. It is sectional drawing along the AA line of FIG. It is a figure which shows an example of the relationship between the pull-out amount of a seatbelt at the time of front collision of a vehicle, and tension | tensile_strength. It is a partial cross section figure which shows the structure of the seatbelt apparatus which concerns on 2nd Embodiment of this invention. It is a figure for demonstrating the structure and operation | movement of the pretensioner mechanism 50, Comprising: It is a figure which shows the state before the action | operation of the pretensioner mechanism 50. FIG. It is a figure for demonstrating the structure and operation | movement of the pretensioner mechanism 50, Comprising: It is a figure which shows the state in operation | movement of the pretensioner mechanism 50. FIG. It is a figure for demonstrating the structure and operation | movement of the pretensioner mechanism 50, Comprising: It is a figure which shows the state after the action | operation of the pretensioner mechanism 50. FIG. It is a figure which shows another example of the relationship between the pull-out amount of the seatbelt at the time of front collision of a vehicle, and tension | tensile_strength. It is a principal part figure which shows the structure of the seatbelt apparatus which concerns on 3rd Embodiment of this invention. It is a figure which shows another example of the relationship between the pull-out amount of the seatbelt at the time of front collision of a vehicle, and tension | tensile_strength.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. In the present embodiment, a seat belt device that restrains an occupant (driver) seated in a driver's seat will be described, but the present invention may be applied to a seat belt device that restrains an occupant seated in any seat. .

  FIG. 1 is a cross-sectional view showing a configuration of a seat belt device according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line AA in FIG. The seat belt device includes a seat belt 10 that restrains an occupant to a seat of a vehicle. The seat belt 10 is made of resin and is formed in a long band shape. The seat belt 10 is hung around the occupant's body, and a tongue plate (not shown) provided on the seat belt 10 is detachably fitted to a buckle (not shown) provided on the seat. Restrain an occupant to a vehicle seat.

  As shown in FIG. 1, the seat belt device includes a frame 20, a spool 30, and a shaft 32. The frame 20, the spool 30, and the shaft 32 are manufactured by machining a metal material such as chromium molybdenum steel or steel.

  The frame 20 is a member connected to the vehicle body by bolts or the like. The frame 20 is integrally formed with a pair of leg plates 22a and 22b facing each other. A spool 30 is disposed between the pair of leg plates 22a and 22b.

  The spool 30 is arranged so that its axial direction is parallel to the direction connecting the pair of leg plates 22a, 22b, and is rotatable about its own axis with respect to the frame 20. The spool 30 is biased in one rotational direction R1 (hereinafter referred to as “winding direction R1”) by a spiral spring (not shown).

  As shown in FIG. 2, the longitudinal base end portion of the seat belt 10 is locked to the outer periphery of the spool 30. When the spool 30 rotates in the winding direction R1, the seat belt 10 is wound around the outer periphery of the spool 30. On the other hand, when the spool 30 rotates in the direction R2 opposite to the winding direction R1 (hereinafter referred to as “drawing direction R2”), the seat belt 10 is pulled out from the spool 30. The seat belt 10 is drawn around the occupant's body while being pulled out of the spool 30.

  The shaft 32 is coaxially arranged inside the spool 30 so as to be rotatable. The shaft 32 is inserted into insertion holes 24a and 24b provided in the leg plates 22a and 22b. Both ends of the shaft 32 in the direction of the axis X are rotatably supported by the inner peripheral surfaces of the pair of insertion holes 24a and 24b. In this way, the shaft 32 is rotatable about its own axis with respect to the frame 20.

  Annular covers 34 are integrally fixed to both end surfaces of the spool 30 in the axial direction. Each cover 34 is formed by punching a metal plate with a press or the like. Each cover 34 is arranged coaxially with the spool 30. The outer diameter of each cover 34 is set larger than the outer diameter of the spool 30. Each cover 34 guides the movement of the seat belt 10 as the spool 30 rotates. The inner diameter of each cover 34 is set slightly larger than the outer diameter of the shaft 32. The inner peripheral surface of each cover 34 is slidably in contact with the outer peripheral surface of the shaft 32.

  In this way, the spool 30 and the shaft 32 are configured to be relatively rotatable about the axis X direction via the pair of covers 34. A working chamber C is formed in an annular space surrounded by the spool 30, the shaft 32, and the pair of covers 34. In the working chamber C, silicon oil L as a viscous fluid is sealed. A seal member such as an O-ring may be interposed between the inner peripheral surface of each cover 34 and the outer peripheral surface of the shaft 32.

  As shown in FIG. 1, a plurality of outer plates 36 and a plurality of inner plates 38 are arranged in the working chamber C. Each outer plate 36 and each inner plate 38 are made by punching a metal thin plate with a press or the like.

  Each outer plate 36 is formed in an annular shape and is integrally provided on the inner periphery of the spool 30. The outer periphery of each outer plate 36 is spline fitted to the inner periphery of the spool 30. A plurality of slits (not shown) are formed at predetermined intervals in the circumferential direction on the inner circumference of each outer plate 36. The inner diameter of each outer plate 36 is set larger than the outer diameter of the shaft 32.

  Each inner plate 38 is formed in an annular shape and is integrally provided on the outer periphery of the shaft 32. The inner periphery of each inner plate 38 is splined to the outer periphery of the shaft 32. A plurality of slits (not shown) are formed at predetermined intervals in the circumferential direction on the outer periphery of each inner plate 38. The outer diameter of each inner plate 38 is set smaller than the inner diameter of the spool 30.

  The outer plate 36 and the inner plate 38 are alternately arranged in the axis X direction. Spacer rings (not shown) are arranged on the outer peripheral side of the inner plate 38 between the adjacent outer plates 36. The inner diameter of each spacer ring is set larger than the outer diameter of the inner plate 38. By this spray saling, the interval between the adjacent outer plates 36 in the axis X direction is maintained at a predetermined value.

  As shown in FIG. 1, the seat belt device includes a lock mechanism 40. The lock mechanism 40 operates under a predetermined condition and regulates the rotation of the shaft 32 in the pull-out direction R2. The lock mechanism 40 operates, for example, when the acceleration at which the seat belt 10 is pulled out is greater than or equal to a reference value, or when the vehicle deceleration is greater than or equal to a reference value.

  The lock mechanism 40 is disposed outside the one leg plate 22a, that is, on the opposite side of the other leg plate 22b with respect to the one leg plate 22a. The lock mechanism 40 has a ratchet wheel 42 that is integrally connected to the shaft 32. The ratchet wheel 42 is formed in a disc shape and is provided coaxially with the shaft 32. When the lock mechanism 40 is operated, the rotation of the ratchet wheel 42 in the pull-out direction R2 is restricted, thereby restricting the rotation of the shaft 32 connected to the ratchet wheel 42 in the pull-out direction R2. The configuration and operation of the lock mechanism 40 are well known, and detailed description thereof is omitted.

  Next, the operation of the seat belt device having the above-described configuration will be described. First, the case where the seat belt 10 is wound will be described, and then the case where the seat belt 10 is pulled out will be described.

  When the seat belt 10 is wound, the spool 30 rotates in the winding direction R1. When there is a rotational speed difference between the spool 30 and the shaft 32, a rotational speed difference is generated between each outer plate 36 integrated with the spool 30 and each inner plate 38 integrated with the shaft 32. A shearing stress is generated in the silicon oil L in accordance with this rotational speed difference, the rotational torque of the spool 30 is transmitted to the shaft 32, and the shaft 32 rotates in the winding direction R1. As a result, when there is no difference in rotational speed between the spool 30 and the shaft 32, the torque of the spool 30 is not transmitted to the shaft 32.

  When the seat belt 10 is pulled out, the spool 30 rotates in the pulling direction R2. When there is a rotational speed difference ΔV between the spool 30 and the shaft 32, a shear stress F is generated in the silicon oil L according to the rotational speed difference ΔV.

  As shown in the following Equation 1, the shear stress F includes a rotation speed difference ΔV between the spool 30 and the shaft 32, a gap ΔX (see FIG. 1) between the outer plate 36 and the inner plate 38, an outer plate, It is determined by the area S (see FIG. 1) that overlaps in the direction of the axis X between the inner plate 38 and the inner plate 38 and the viscosity μ of the silicon oil L. The parameters ΔX, S, and μ other than the rotational speed difference ΔV are optimized in advance according to the vehicle type and the like.

ロック機構４０の非作動時に、シリコンオイルＬに剪断応力Ｆが発生すると、スプール３０の回転トルクがシャフト３２に伝達され、シャフト３２が引き出し方向Ｒ２に回転する。その結果、スプール３０とシャフト３２との間の回転速度差ΔＶがなくなると、スプール３０のトルクがシャフト３２に伝達されなくなる。

When shearing stress F is generated in the silicon oil L when the lock mechanism 40 is not operated, the rotational torque of the spool 30 is transmitted to the shaft 32, and the shaft 32 rotates in the pulling direction R2. As a result, when the rotational speed difference ΔV between the spool 30 and the shaft 32 disappears, the torque of the spool 30 is not transmitted to the shaft 32.

  On the other hand, when shearing stress F is generated in the silicon oil L during the operation of the lock mechanism 40, the rotation of the shaft 32 in the pulling direction R2 is restricted, so that instead of the shaft 32 rotating in the pulling direction R2, the spool 30 Tries to rotate in the winding direction R1. Thereby, the tension | tensile_strength T generate | occur | produces in the seatbelt 10 and it can suppress a passenger | crew's movement to the vehicle front.

  FIG. 3 is a diagram illustrating an example of the relationship between the pull-out amount of the seat belt and the tension at the time of a frontal collision of the vehicle. Here, a dummy doll was used as an occupant. In FIG. 3, the relationship when the vehicle collision speed is high is indicated by a solid line, and the relationship when the vehicle collision speed is low is indicated by a two-dot chain line. In FIG. 3, the pull-out amount of the seat belt 10 is the pull-out amount from the start of operation of the lock mechanism 40.

  At the time of a frontal collision of the vehicle (that is, when the vehicle is suddenly decelerated), the occupant tries to move forward by the inertial force according to the collision speed of the vehicle (that is, the deceleration of the vehicle) and restrains the occupant. The seat belt 10 is pulled. When the seat belt 10 is pulled out by this pulling force, the spool 30 rotates in the pull-out direction R2 at a rotation speed corresponding to the pull-out speed of the seat belt 10.

  At this time, if the rotation of the shaft 32 in the pull-out direction R2 is restricted by the lock mechanism 40, a rotational speed difference ΔV corresponding to the pull-out speed of the seat belt 10 is generated between the shaft 32 and the spool 30. In accordance with this rotational speed difference ΔV, a shear stress F is generated in the silicon oil L, and a tension T is generated in the seat belt 10. Therefore, the tension T of the seat belt 10 increases as the pull-out speed of the seat belt 10 increases. As a result, the occupant can be restrained more strongly as the collision speed at the time of frontal collision of the vehicle (that is, the deceleration of the vehicle) increases. Therefore, the occupant can be restrained appropriately according to the situation of the vehicle.

  Further, when the tension T is applied to the seat belt 10, the movement of the occupant to the front of the vehicle is suppressed, so the pulling speed of the seat belt 10 is reduced. Then, the rotation of the spool 30 in the pulling direction R2 is decelerated, and the rotational speed difference ΔV between the spool 30 and the shaft 32 becomes small. As a result, the shear stress F of the silicon oil L decreases, and the tension T applied to the seat belt 10 decreases as shown in FIG. Therefore, it is possible to suppress an excessive tension T from being applied to the seat belt 10 during the operation of the lock mechanism 40, and it is possible to suppress an excessive load from being applied to the occupant's body.

  If the spool 30 and the shaft 32 are connected as in the conventional example and the shaft 32 is plastically deformed when the lock mechanism 40 is operated, it is necessary to replace the seat belt device including the shaft 32 after use.

  On the other hand, in the present embodiment, the spool 30 and the shaft 32 are relatively rotatable, and the shaft 32 is not plastically deformed when the lock mechanism 40 is operated. Therefore, it is not necessary to replace the shaft 32 after use. .

  As described above, according to the present embodiment, the tension T of the seat belt 10 increases as the pull-out speed of the seat belt 10 increases. Therefore, the collision speed at the time of frontal collision of the vehicle (that is, deceleration of the vehicle). The larger the is, the stronger the occupant can be restrained. Therefore, the occupant can be restrained appropriately according to the situation of the vehicle.

  In the present embodiment, the shaft 32 is rotatable about its own axis with respect to the frame 20, and the lock mechanism 40 operates under a predetermined condition to move in a predetermined direction of the shaft 32 (drawing direction R2). However, the present invention is not limited to this.

  For example, the shaft 32 may be constantly fixed with respect to the frame 20. Also in this case, since a rotational speed difference ΔV corresponding to the pulling speed of the seat belt 10 is generated between the shaft 32 and the spool 30, the tension T of the seat belt 10 increases as the pulling speed of the seat belt 10 increases. In this case, the lock mechanism 40 becomes unnecessary.

  On the other hand, in the present embodiment, the lock mechanism 40 operates under a predetermined condition to restrict the rotation of the shaft 32 in the pull-out direction R2, so that the seat belt 10 can be easily pulled out when the lock mechanism 40 is not operated. be able to. Therefore, it can suppress giving a passenger a complicated feeling.

  FIG. 4 is a partial cross-sectional view showing the configuration of the seat belt device according to the second embodiment of the present invention. FIG. 4 is a partial cross-sectional view showing a state when the pretensioner mechanism 50 is in operation. The seat belt device shown in FIG. 4 further includes a pretensioner mechanism 50. Other configurations are the same as the configuration of the seat belt device shown in FIG.

  The pretensioner mechanism 50 is a mechanism that winds up the seat belt 10 in an emergency of the vehicle. The pretensioner mechanism 50 is disposed on the opposite side of the lock mechanism 40 with respect to the spool 30. For example, the pretensioner mechanism 50 is disposed on the outer side of the other leg plate 22b, that is, on the side opposite to the one leg plate 22a with respect to the other leg plate 22b.

  The pretensioner mechanism 50 includes first and second pinions 52 and 54, a rack 56, and an inflator 58.

  The first pinion 52 is connected to the spool 30 via the cover 34, and a plurality of first external teeth 52a are formed on the outer periphery at predetermined intervals in the circumferential direction. The first pinion 52 is disposed coaxially with the spool 30.

  The second pinion 54 is integrally connected to the shaft 32, and a plurality of second external teeth 54a are formed on the outer periphery at predetermined intervals in the circumferential direction. The second pinion 54 is disposed coaxially with the shaft 32.

  In this way, the first and second pinions 52 and 54 are arranged coaxially and are relatively rotatable. In the present embodiment, the outer diameters of the first and second pinions 52 and 54 are set to be substantially the same. Further, the interval between the adjacent first external teeth 52a and the interval between the adjacent second external teeth 54a are set to be substantially the same.

  The rack 56 has a plurality of internal teeth 56a that can mesh with the plurality of first and second external teeth 52a, 54a. The plurality of internal teeth 56 a are formed at the tip of the rack 56. A base end portion of the rack 56 is slidably inserted into the cylinder 60. A gas chamber 62 is formed in a space surrounded by the base end surface of the rack 56 and the inner wall surface of the cylinder 60.

  The inflator 58 has an ignition device and a gas generating agent. The inflator 58 is connected to an electronic control unit (not shown) via an in-vehicle network. The electronic control unit transmits an ignition signal to the inflator 58 in an emergency of the vehicle (for example, when a time integral value of acceleration applied to the vehicle exceeds a threshold value). When the inflator 58 receives the ignition signal from the electronic control unit, the inflator 58 generates gas by burning the gas generating agent by the ignition device. The generated gas is supplied to the gas chamber 62.

  Next, the operation of the pretensioner mechanism 50 will be described with reference to FIGS. 5-7, (A) is a figure which shows the relationship between the rack 56 and the 1st pinion 52, (B) is a figure which shows the relationship between the rack 56 and the 2nd pinion 54. In FIG.

  As shown in FIG. 5, before the operation of the pretensioner mechanism 50, the rack 56 is not engaged with the first and second pinions 52 and 54, and the first and second pinions 52 and 54 are rotated. The spool 30 and the shaft 32 are in a rotatable state.

  As shown in FIG. 6, when the pretensioner mechanism 50 is operated, the inflator 58 supplies gas to the gas chamber 62, the internal pressure of the gas chamber 62 increases, and the rack 56 moves in a direction protruding from the cylinder 60.

  In conjunction with the movement of the rack 56, the rack 56 and the first and second pinions 52, 54 mesh with each other, and the first and second pinions 52, 54 are at substantially the same rotational speed in the winding direction R1. Rotate. As a result, the spool 30 and the shaft 32 rotate at the same rotational speed in the winding direction R1 and the seat belt 10 is wound, so that looseness of the seat belt 10 can be removed in the event of a vehicle emergency.

  In the present embodiment, the pretensioner mechanism 50 has the first and second pinions 52 and 54, but the present invention is not limited to this. The pretensioner mechanism 50 may have only one of the first and second pinions 52 and 54.

  For example, as a first modification, when the pretensioner mechanism 50 has only the second pinion 54, the rack 56 and the second pinion 54 mesh with the movement of the rack 56, and the second pinion 54 Rotates in the winding direction R1. As a result, a rotational speed difference ΔV is generated between the spool 30 and the shaft 32, a shear stress F is generated in the silicon oil L in accordance with the rotational speed difference ΔV, and the rotational torque of the shaft 32 is transmitted to the spool 30. The spool 30 rotates in the winding direction R1. Therefore, since the seat belt 10 is wound up, it is possible to remove the looseness of the seat belt 10 in an emergency of the vehicle. However, if a transmission loss occurs when the rotational torque of the shaft 32 is transmitted to the spool 30, the spool 30 is insufficiently rotated. Therefore, there is a possibility that the looseness of the seat belt 10 cannot be sufficiently removed.

  As a second modification, when the pretensioner mechanism 50 has only the first pinion 52, the rack 56 and the first pinion 52 mesh with each other in conjunction with the movement of the rack 56, and the first pinion 52 Rotates in the winding direction R1. As a result, the spool 30 connected to the first pinion 52 rotates in the winding direction R1 and the seat belt 10 is wound, so that looseness of the seat belt 10 can be removed in the event of a vehicle emergency.

  As shown in FIG. 7, after the pretensioner mechanism 50 is actuated, the rack 56 is stopped and fixed to the cylinder 60 at the stop position. In this state, the engagement between the rack 56 and the first pinion 52 is released, the first pinion 52 becomes rotatable, and the spool 30 becomes rotatable. In this state, the engagement between the rack 56 and the second pinion 54 is maintained, the second pinion 54 becomes non-rotatable, and the shaft 32 becomes non-rotatable.

  Thus, in a state after the pretensioner mechanism 50 is actuated, the spool 30 is rotatable and the shaft 32 is not rotatable. Then, in the state after the operation of the pretensioner mechanism 50, as in the operation of the lock mechanism 40, the rotation of the shaft 32 in the pull-out direction R2 is restricted, so that the seat 32 is interposed between the shaft 32 and the spool 30. A rotational speed difference ΔV corresponding to the pulling speed of the belt 10 is generated.

  In accordance with this rotational speed difference ΔV, a shear stress F is generated in the silicon oil L, and a tension T is generated in the seat belt 10. Therefore, the tension T of the seat belt 10 increases as the pull-out speed of the seat belt 10 increases. As a result, the occupant can be restrained more strongly as the collision speed at the time of frontal collision of the vehicle (that is, the deceleration of the vehicle) increases. Therefore, the occupant can be restrained appropriately according to the situation of the vehicle.

  When the tension T is applied to the seat belt 10, movement of the occupant to the front of the vehicle is suppressed, so that the pull-out speed of the seat belt 10 is reduced. Then, the rotation of the spool 30 in the pulling direction R2 is decelerated, and the rotational speed difference ΔV between the spool 30 and the shaft 32 becomes small. As a result, the shear stress F of the silicon oil L decreases, and the tension T applied to the seat belt 10 decreases. Therefore, after the pretensioner mechanism 50 is actuated, it is possible to suppress an excessive tension T from being applied to the seat belt 10, and it is possible to suppress an excessive load from being applied to the occupant's body.

  FIG. 8 is a diagram illustrating another example of the relationship between the pull-out amount of the seat belt and the tension at the time of a frontal collision of the vehicle. Here, a dummy doll was used as an occupant. In FIG. 8, the relationship in 2nd Embodiment is shown as a continuous line, the relationship in the 1st modification of 2nd Embodiment is shown with a dashed-two dotted line, and the relationship in 1st Embodiment is shown with a dotted line. In FIG. 8, the pull-out amount of the seat belt 10 is the pull-out amount from the start of the operation of the lock mechanism 40.

  In the first embodiment, since the pretensioner mechanism 50 is not provided and the slack of the seat belt 10 is not removed in advance when the operation of the lock mechanism 40 is started, as shown by the dotted line, the seat belt 10 is retracted with respect to the pulling amount. The tension T of the belt 10 increases relatively slowly.

  On the other hand, in the second embodiment, the slack of the seat belt 10 is removed in advance after the pretensioner mechanism 50 is actuated and when the lock mechanism 40 is actuated. The tension T of the seat belt 10 increases relatively rapidly with respect to the amount. Thereby, a passenger | crew can be restrained rapidly at the time of emergency of a vehicle.

  On the other hand, in the first modified example of the second embodiment, the looseness of the seat belt 10 is not sufficiently removed by the pretensioner mechanism 50 as compared with the second embodiment. The tension T of the seat belt 10 increases relatively gradually with respect to the amount of withdrawal of the seat belt 10.

  As described above, according to the seat belt device of the present embodiment, the slack of the seat belt 10 can be removed by the pretensioner mechanism 50 in the event of an emergency of the vehicle.

  In the present embodiment, the lock mechanism 40 is activated after the pretensioner mechanism 50 is activated, but the present invention is not limited to this. After the pretensioner mechanism 50 is operated, the spool 30 is in a rotatable state and the shaft 32 is in a non-rotatable state. Therefore, even when the lock mechanism 40 is not operated, the same effect as when the lock mechanism 40 is operated is obtained. can get.

  FIG. 9 is a main part diagram showing the configuration of the seat belt device according to the third embodiment of the present invention. Hereinafter, the configuration of the seat belt apparatus shown in FIG. 9 will be described. The same components as those of the seat belt apparatus shown in FIG.

  The seat belt device shown in FIG. 9 includes a seat belt 10, a spool 30, a lock mechanism 40, a torsion bar 70, and an inertia weight 80. The torsion bar 70 and the inertia weight 80 are manufactured by machining a metal material such as chromium molybdenum steel or steel.

  First, the configuration of the torsion bar 70 will be described.

  Similar to the shaft 32 shown in FIGS. 1 and 2, the torsion bar 70 is coaxially disposed inside the spool 30, and is integrally connected to the spool 30, for example, at one axial end portion of the spool 30. . In this case, the above-described lock mechanism 40 is provided on the other axial end side of the spool 30. When actuated, the lock mechanism 40 restricts rotation of the other axial end portion of the torsion bar 70 and restricts rotation of the spool 30 in the pull-out direction R2.

  Next, the operation of the torsion bar 70 will be described.

  At the time of a frontal collision of the vehicle (that is, when the vehicle is suddenly decelerated), the occupant tries to move forward by the inertial force according to the collision speed of the vehicle (that is, the deceleration of the vehicle) and restrains the occupant. The seat belt 10 is pulled. The rotational force in the pulling direction R2 according to the pulling force is input to the connecting portion with the torsion bar 70 via the spool 30, that is, one axial end portion of the torsion bar 70. At this time, if the lock mechanism 40 is actuated to restrict the rotation of the other axial end portion of the torsion bar 70, the torsion bar 70 basically does not rotate.

  However, when the rotational force in the pulling direction R2 input to one axial end portion of the torsion bar 70 reaches a reference value, the axial one end portion of the torsion bar 70 and the other axial end portion whose rotation is restricted by the lock mechanism 40. And torsionally deform plastically. Due to this torsional deformation, the spool 30 connected to the torsion bar 70 rotates in the pull-out direction R2, and the seat belt 10 is allowed to be pulled out. Therefore, it is possible to suppress an excessive tension T from being applied to the seat belt 10, and it is possible to suppress an excessive load from being applied to the occupant's body.

  Next, the configuration of the inertia weight 80 will be described.

  The inertia weight 80 is disposed coaxially with the spool 30. The inertia weight 80 is formed in a disk shape, for example, and is disposed on one axial end side of the spool 30. A one-way clutch mechanism (not shown) is interposed between the spool 30 and the inertia weight 80.

  The one-way clutch mechanism is a mechanism that allows the inertia weight 80 to rotate in the pull-out direction R2 and restricts the rotation of the inertia weight 80 in the winding direction R1. The one-way clutch mechanism may have a well-known configuration, and includes, for example, a ratchet tooth or ratchet pawl formed on the inertia weight 80 side and a ratchet pawl or ratchet tooth formed on the spool 30 side.

  Next, the operation of the inertia weight 80 will be described.

  At the time of a frontal collision of the vehicle (that is, when the vehicle suddenly decelerates), the occupant tries to move forward by the inertial force according to the collision speed of the vehicle (that is, the deceleration of the vehicle) and restrains the occupant. The seat belt 10 is pulled. The rotational force in the pulling direction R2 corresponding to the pulling force is input to the inertia weight 80 via the spool 30 and the one-way clutch mechanism. Accordingly, the inertia weight 80 starts to passively rotate in the pulling direction R2.

  Thereafter, when the tension T of the seat belt 10 decreases and the pulling speed of the seat belt 10 decreases, the rotational speed of the spool 30 in the pulling direction R2 becomes slower than the rotating speed of the inertia weight 80 in the pulling direction R2. Then, the engagement state between the spool 30 and the inertia weight 80 by the one-way clutch mechanism is released, so that the tension T of the seat belt 10 is not input to the inertia weight 80.

  FIG. 10 is a diagram illustrating another example of the relationship between the pull-out amount of the seat belt and the tension at the time of a frontal collision of the vehicle. Here, a dummy doll was used as an occupant. In FIG. 10, the relationship in the third embodiment when the vehicle collision speed is high is indicated by a solid line, the relationship in the third embodiment when the vehicle collision speed is low is indicated by a two-dot chain line, and the inertia weight 80 and the one-way clutch The relationship in the conventional example without a mechanism is shown by a dotted line. In FIG. 10, the pull-out amount of the seat belt 10 is the pull-out amount from the start of the operation of the lock mechanism 40.

  In the conventional example, the torsion bar 70 is plastically deformed when the tension T of the seat belt 10 reaches the reference value T0 regardless of the collision speed of the vehicle (that is, the deceleration of the vehicle). In addition, the tension T of the seat belt 10 does not exceed the reference value T0. Therefore, it can suppress that an excessive load is added to a passenger | crew's body.

  On the other hand, in the third embodiment, since the tension T of the seat belt 10 is input to the inertia weight 80 in addition to the torsion bar 70, even if the tension T of the seat belt 10 reaches the reference value T0, Does not plastically deform. Therefore, as shown by the solid line and the alternate long and short dash line in FIG. 10, the tension T of the seat belt 10 increases beyond T0 until the torsion bar 70 is plastically deformed. For this reason, the amount of plastic deformation of the torsion bar 70 is relatively small with respect to the amount by which the seat belt 10 is pulled out, and a torsional dimension of the torsion bar 70 can be provided.

  In general, the rotational torque input to the inertia weight 80 increases in proportion to the angular acceleration of the inertia weight 80. When the vehicle collision speed (that is, the vehicle deceleration) is large, the pull-out acceleration of the seat belt 10 is large as compared with the case where the vehicle collision speed is small. Therefore, the angular acceleration in the pull-out direction R2 of the inertia weight 80 is large. Therefore, when the vehicle collision speed (that is, the vehicle deceleration) is large, a large rotational torque is applied to the inertia weight 80 as compared with the case where the vehicle collision speed is small, so that the solid line and the alternate long and short dash line in FIG. The tension T of the seat belt 10 is increased.

  In this manner, the tension T of the seat belt 10 increases as the pull-out acceleration of the seat belt 10 increases, so that the occupant can be strongly restrained as the collision speed (ie, vehicle deceleration) at the time of a frontal collision of the vehicle increases. it can. Therefore, the occupant can be restrained appropriately according to the situation of the vehicle.

  Thereafter, when the tension T of the seat belt 10 decreases and the pulling speed of the seat belt 10 decreases, the rotational speed of the spool 30 in the pulling direction R2 becomes slower than the rotating speed of the inertia weight 80 in the pulling direction R2. Then, the engagement state between the spool 30 and the inertia weight 80 by the one-way clutch mechanism is released, so that the tension T of the seat belt 10 is not input to the inertia weight 80. At this time, the tension T of the seat belt 10 becomes the reference value T0 as shown by the solid line and the alternate long and short dash line in FIG.

  Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications and substitutions are made to the above-described embodiments without departing from the scope of the present invention. be able to.

10 Seat belt 30 Spool 32 Shaft 36 Outer plate 38 Inner plate 40 Lock mechanism

Claims (2)

A seat belt to restrain the vehicle occupant;
A spool for winding the seat belt;
A shaft disposed inside the spool so as to be rotatable relative to the spool;
A plurality of outer plates integrally provided on the inner periphery of the spool;
A plurality of inner plates provided integrally with an outer periphery of the shaft, and arranged alternately with the plurality of outer plates;
A seat belt device in which a working chamber is formed between an inner periphery of the spool and an outer periphery of the shaft, and a viscous fluid is sealed in the working chamber.   The seat belt device according to claim 1, further comprising a lock mechanism that operates under a predetermined condition to restrict rotation of the shaft in a predetermined direction.

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