JP4597755B2 - Seat belt device - Google Patents

Description

  The present invention relates to a seat belt device that restrains an occupant seated on a vehicle seat by webbing, and more particularly, to a seat belt device that pulls in a webbing by the power of a motor when the vehicle collides.

In a seat belt device mounted on a vehicle, an occupant-restraining webbing is wound around a reel in a retractor and is pulled out from the retractor at the time of mounting. In recent years, a sensor for detecting a collision of a vehicle (in this specification, “a collision” includes an impact input other than an objective collision such as a vehicle overturning) is provided, and when the sensor detects a collision, A seat belt device in which webbing is retracted by a motor has been developed (see Patent Documents 1 and 2).
JP 2004-224263 A JP-A-9-132113

  However, in this conventional seat belt device, since the webbing is started to be retracted after the sensor detects the collision, it takes time until the webbing is loosened and the restraining force (tension) actually starts to act on the occupant. It may take. In addition, it is also considered to detect the unstable behavior of the vehicle that shows a sign of collision with a sensor and control the pull-in of the webbing at that stage. This is likely to occur, and there is a concern that this shift may give the passenger an uncomfortable feeling.

  Therefore, the present invention is intended to provide a seat belt device that can quickly apply a restraining force to an occupant in accordance with a change in the occupant's posture without causing the occupant to feel uncomfortable.

As a means for solving the above-described problems, the present invention winds a webbing (for example, a webbing 5 in an embodiment described later) that restrains an occupant seated on a seat (for example, a seat 2 in an embodiment described later). In a seat belt apparatus provided with a reel (for example, a reel 12 in an embodiment described later) and a motor (for example, a motor 10 in an embodiment described later) that drives the reel to rotate and pulls in webbing, the motor and the reel A speed reduction mechanism (for example, a speed reduction mechanism 13 in an embodiment described later) interposed therebetween, and a clutch (for example, an embodiment described later) interposed between the motor and the reel to connect / disconnect a power transmission system therebetween. Clutch 20) and vehicle behavior determining means for determining the unstable behavior of the vehicle (for example, vehicle behavior in the embodiments described later) Disconnecting means 38) and seat belt control means (for example, a seat belt control means 40 in an embodiment described later) for controlling the motor and the clutch based on the determination result of the vehicle behavior determining means. When the determination means determines the unstable behavior, the seat belt control means makes the clutch engaged and does not wind the webbing by the motor, and the motor side power transmission system ( For example, the rotational resistance of the motor side power transmission system 22) in the embodiment described later is applied to the reel as a load.
In the case of the present invention, when the behavior of the vehicle becomes unstable, the vehicle behavior determination means determines the unstable behavior of the vehicle, and the seat belt control means puts the clutch in a connected state. As a result, the rotational resistance of the motor-side power transmission system acts on the reel via the speed reduction mechanism with the motor stopped, and a load corresponding to the movement of the occupant acts as tension on the webbing. As a result, when the vehicle shifts to a collision as it is, the webbing is drawn from a state where the webbing is not slack.

According to the present invention, when the unstable behavior of the vehicle is determined, the clutch is engaged, and the motor is stopped while the webbing is not taken up. Because tension can be applied to the webbing, occupant movement caused by sudden changes in the attitude of the vehicle is regulated by the pulling drag of the webbing that accompanies it, so that the restraining force can be ensured without giving the passenger a sense of incongruity Can be granted.
In particular, in the present invention, since the static torque due to the rotational resistance of the motor-side power transmission system can be amplified by the speed reduction mechanism when the clutch is connected, a large tension according to the movement of the occupant is reliably applied to the webbing, The amount of movement of the webbing can be suppressed, and the slack of the webbing caused thereby can be reduced.
In addition, when the webbing is continuously shifted in the event of a collision or the like, the time until the slack is eliminated can be shortened, and the restraint force can be applied to the occupant more quickly.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows an overall schematic configuration of a seat belt device 1 according to the present invention. In FIG. 1, reference numeral 2 denotes a seat on which an occupant 3 is seated. The seat belt device 1 of this embodiment is a so-called three-point seat belt device, and a webbing 5 is drawn upward from a retractor 4 attached to a center pillar (not shown), and the webbing 5 is supported on the upper side of the center pillar. The tip of the webbing 5 is fixed to the vehicle body floor via an outer anchor 7 near the outside of the passenger compartment of the seat 2. A tongue plate 8 is inserted between the through anchor 6 and the outer anchor 7 of the webbing 5, and the tongue plate 8 can be attached to and detached from the buckle 9 fixed to the vehicle body floor of the seat 2 on the inner side of the vehicle body. It has become.
The webbing 5 is wound around the retractor 4 in the initial state, and the occupant 3 pulls it out by hand to fix the tongue plate 8 to the buckle 9, thereby restraining the chest and abdomen mainly of the occupant 3 with respect to the seat 2. To do. In the case of this seat belt device 1, the webbing 5 is retracted by an electric motor 10 at the time of a collision.

  As shown in FIGS. 2 to 5, the retractor 4 has a webbing 5 wound around a reel 12 rotatably supported by a casing 11, and a planetary gear on a shaft 12 a of the reel 12 protruding to one end side of the casing 11. A reduction mechanism 13 of the type is engaged, and the reduction mechanism 13 is linked to the rotating shaft 10a of the motor 10 through a motor side power transmission system 22 composed of a plurality of gear groups. The speed reduction mechanism 13 decelerates the rotation of the motor 10 and transmits it to the reel 12. However, the rotation of the reel 12 is transmitted to the motor side in an accelerated manner.

  In the speed reduction mechanism 13, the sun gear 14 is integrally coupled to the drive input external teeth 15, and the carrier 17 that supports the plurality of planetary gears 16 is coupled to the shaft 12 a of the reel 12. A plurality of ratchet teeth 19 are formed on the outer peripheral side of the ring gear 18 meshed with the planetary gear 16, and the ratchet teeth 19 constitute a part of a clutch 20 described later. The clutch 20 appropriately connects and disconnects the power transmission system between the motor 10 and the reel 12 under the control of the controller 21.

  The motor-side power transmission system 22 has a small-diameter first connect gear 23 that is always meshed with an external tooth 15 that is integral with the sun gear 14, and a large-diameter that is provided coaxially with the first connect gear 23 and can rotate integrally. Second connect gear 24, and first and second idler gears 26, 27 that are between the second connect gear 24 and the motor gear 25 (integrated with the rotating shaft 10a of the motor 10) and are always meshed so that power can be transmitted. ing. The driving force in the forward direction of the motor 10 is transmitted to the first and second connect gears 23 and 24 through the gears 25, 27 and 26 as indicated by solid arrows in FIG. 14 is transmitted to the reel 12 via the planetary gear 16 and the carrier 17. The driving force in the forward direction of the motor 10 rotates the reel 12 in the direction in which the webbing 5 is pulled. However, the driving force transmitted from the sun gear 14 to the planetary gear 16 is all transmitted to the carrier 17 side as described above when the ring gear 18 is fixed. However, when the ring gear 14 is free to rotate, the planetary gear is transmitted. The ring gear 18 is idled by 16 rotations. A clutch 20, which will be described later, turns on / off the transmission of motor driving force to the reel 12 (carrier 17) by controlling the locking and unlocking of the rotation of the ring gear 14.

Here, the clutch 20 will be described.
The clutch 20 is rotatably supported by a casing (not shown), and can be engaged with a pawl 29 having a locking claw 28 at the tip, a clutch spring 30 for operating the pawl 29, and a locking claw 28 of the pawl 29. And the ratchet teeth 19 of the ring gear 18 , and when the pawl 29 is operated in the direction of the ratchet teeth 19, the locking claw 28 abuts against a surface substantially orthogonal to the inclined surface of the ratchet teeth 19, It is designed to lock the rotation in one direction.

  In addition, the clutch spring 30 is bent in a circular arc shape at the base portion side, and the bent portion 31 is locked in a state of being wound around the outer periphery of the shaft portion of the first connect gear 23. The tip of the clutch spring 30 extends in the direction of the pawl 29 and engages with the operation window 32 of the pawl 29. The curved portion 31 of the clutch spring 30 is engaged with the shaft portion of the first connect gear 23 by friction, and when a torque greater than a set value acts between the first connect gear 23 and the first connect gear 23, Slips between the two.

Therefore, in the clutch 20, when the motor 10 rotates in the forward rotation direction (see the solid line arrow in FIG. 3), the clutch spring 30 changes from the posture shown by the solid line in FIG. 4 to the posture shown by the chain line. As shown in FIG. 3, the pawls 29 of the pawl 29 mesh with the ratchet teeth 19 to lock the rotation of the ring gear 18. At this time, since the ratchet teeth 19 are inclined in one rotation direction, the rotation of the ring gear 18 in one direction can be reliably locked, but when the ring gear 18 tries to rotate in the reverse direction, In order for the ratchet teeth 19 to push up the locking claws 28, a certain level of force is required. For this reason, the clutch spring 30 imparts a certain level of resistance to the reverse rotation of the ring gear 18.
When the rotation of the ring gear 18 is thus locked, all the rotational force transmitted to the sun gear 14 as described above is transmitted to the reel 12 as the rotation of the carrier 17 (clutch-on state).

On the other hand, when the motor 10 rotates in the reverse direction from this clutch-on state, the first connect gear 23 rotates as indicated by the dotted line arrow in FIG. 3 and rotates the clutch spring 30 as indicated by the solid line in FIG. As a result, the pawls 28 of the pawl 29 are pulled away from the ratchet teeth 19 and the lock of the ring gear 17 is released as shown in FIG.
When the lock of the ring gear 18 is released in this way, the rotational force transmitted to the sun gear 14 rotates the planetary gear 16 as described above. At this time, the ring gear 18 is idled and power is supplied to the carrier 17 (reel 12) side. Prevent transmission (clutch off state).

  In addition, as shown in FIG. 2, when the webbing 5 is pulled out at a speed higher than a set speed, or when a deceleration higher than a set value acts on the other end of the casing 11 of the retractor 4. A known emergency lock mechanism 33 for mechanically locking the drawer of the webbing 5 and a winding spring for winding the webbing 5 are provided.

  By the way, as shown in FIG. 1, the vehicle detects a radar 35 that detects a stationary object, a traveling vehicle, and the like, an acceleration sensor 36 that detects the deceleration of the vehicle, and an angular velocity in the rotation direction of the vehicle. An angular velocity sensor 37 such as a gyro is provided, and these are connected to the controller 21. The controller 21 includes vehicle behavior determining means 38 for determining unstable behavior of the vehicle based on detection signals of the acceleration sensor 36 and the angular velocity sensor 37, and a vehicle collision (vehicle vehicle) based on the detection signal of the acceleration sensor 36. Based on the determination results of the collision determination means 39, the vehicle behavior determination means 38, and the collision determination means 39 that determine the presence or absence of a fall, etc., and determine the magnitude of the collision possibility based on the detection signal of the radar 35. Seat belt control means 40 for controlling the motor 10 and the clutch 20. However, in this embodiment, the operation of the clutch 20 can be simultaneously controlled only by the control of the motor 10 in combination with the configuration of the clutch 20 described above.

That is, since the clutch 20 is provided with a clutch spring 30 that frictionally engages the shaft of the first connect gear 23, when the forward rotation of the motor 10 is started, the pawl 29 of the clutch 20 is moved by the clutch spring 30 to the ring gear. When the motor 10 is driven in the reverse direction, the ring gear 18 is unlocked (clutch off) by the clutch spring 30. When the motor 10 is driven in the forward direction instantaneously (set short time) by the seat belt control means 40, only the clutch 20 is turned on (the ring gear 18 is locked) after transmission of the driving force of the motor 10 is stopped. Is done.

  When the motor 10 is stopped with the clutch 20 turned off, the reel 12 and the motor-side power transmission system 22 are disconnected by the clutch 20, and in this state, the webbing 5 is freely pulled out. And winding of the webbing 5 by a winding spring is permitted.

  The vehicle is equipped with a by-wire brake device (not shown), and when the vehicle behavior determination means 38 determines the unstable behavior of the vehicle, the controller 21 responds to the brake device according to the vehicle state. Braking control is performed.

Hereinafter, the control by the controller 21 will be described with reference to the flowchart of FIG.
First, in S101, the collision determination means 39 receives the detection signal from the acceleration sensor 36 to determine whether or not there is a collision. If it is determined that there is no collision, the process proceeds to S102. If it is determined that there is a collision, the process proceeds to S103. The motor 10 is continuously operated in the forward rotation direction. At this time, when the motor 10 is driven to rotate in the forward direction, the clutch 20 is turned on, the ring gear 18 is locked, and the driving force is transmitted to the reel 12 as shown by the solid line arrow in FIG. Is pulled in and the occupant is firmly restrained to the seat 2.

  When it is determined that there is no collision in S101 and the process proceeds to S102, the vehicle behavior determining means 38 receives the detection signals of the acceleration sensor 36 and the angular acceleration sensor 37 to determine the behavior of the vehicle, and the vehicle is unstable here. When it is determined that there is no behavior, the process exits (RETURN), and when it is determined that there is an unstable behavior, the process proceeds to S104. When the routine proceeds to S104, the motor 10 is operated in the instantaneous forward rotation direction to turn on the clutch 20.

  When the clutch 20 is thus turned on, the motor-side power transmission system 22 is connected to the reel 12 via the speed reduction mechanism 13 while the motor 10 is stopped. The rotational resistance of the transmission system 22 acts as a load that prevents the webbing 5 from being pulled out. Therefore, when the behavior of the vehicle becomes unstable at the time of predicting a collision, a large drag force corresponding to the movement of the occupant acts on the webbing 5.

  After this, when the unstable behavior of the vehicle is resolved, when the process reaches S102, the process is terminated without proceeding to S104, the clutch 20 is turned off, and the initial state is restored. Further, if the unstable behavior of the vehicle is not eliminated and a vehicle collision is determined in S101, the webbing 5 is immediately pulled by the power of the motor 10 from a state in which there is no slack. Therefore, in this seat belt device, the start of occupant restraint by pulling in the webbing 5 can be accelerated.

  FIG. 7 is a characteristic diagram showing the webbing tension and the occupant movement amount at the time of a vehicle collision when the seat belt device 1 is adopted, and FIG. It is the same characteristic view when a seat belt device is adopted. As is clear from the comparison of these two characteristic diagrams, when the seat belt device 1 according to the present invention is adopted, since a large tension of the webbing 5 acts from the initial stage of the collision, it is compared with the conventional one. Thus, the actual movement amount of the occupant can be reliably reduced.

  FIG. 9 is a characteristic diagram showing the webbing tension and the occupant movement amount when the seat belt device 1 is employed and the vehicle behavior once becomes unstable and then returns to a stable state without reaching a collision. . As is clear from this figure, even when the collision does not occur, in the case of this seat belt device 1, the webbing tension immediately rises when the unstable behavior of the vehicle is detected and the clutch 20 is turned on. As a result, the amount of occupant movement is kept small.

  In the case of the seat belt device 1, since the inertial mass of the motor side power transmission system 22 is added to the reel 12 when the unstable behavior is detected, the tension acting on the webbing 5 at this time This corresponds to the force to be moved, and there is no deviation between the actual occupant movement and the generated tension. Therefore, the trouble which gives discomfort to the passenger does not occur.

  In the case of the seat belt device 1 of this embodiment, since the speed reduction mechanism 13 for reducing the rotation on the motor 10 side and transmitting it to the reel 12 is interposed between the motor 10 and the reel 12, there is no vehicle failure. The static torque due to the rotational resistance of the motor-side power transmission system 22 when the stable behavior is detected and the clutch 20 is turned on can be amplified by the speed reduction mechanism 13. Therefore, a large tension according to the movement of the occupant can be reliably applied to the webbing 5 before the vehicle collides.

  In addition, this invention is not limited to said embodiment, A various design change is possible in the range which does not deviate from the summary. For example, in the above embodiment, the clutch 20 is operated by the operation of the motor 10, but the clutch 20 can be controlled independently of the motor 10 by an electromagnetic valve or the like.

1 is an overall schematic configuration diagram illustrating a seat belt device according to an embodiment of the present invention. The schematic sectional drawing of the seatbelt apparatus which shows the embodiment. The schematic block diagram of the power transmission system of the seatbelt apparatus which shows the same embodiment. The elements on larger scale of FIG. 3 which show the same embodiment. The schematic block diagram of the power transmission system of the seatbelt apparatus which shows the same embodiment. The flowchart which shows the flow of control of the seatbelt apparatus of the embodiment. The characteristic view which shows the webbing tension | tensile_strength at the time of a collision and the passenger | crew movement amount when the seatbelt apparatus of the embodiment is employ | adopted. The characteristic view which shows the webbing tension | tensile_strength at the time of a collision and the passenger | crew movement amount when the conventional seatbelt apparatus is employ | adopted. The characteristic view which shows the webbing tension | tensile_strength and passenger | crew movement amount at the time of returning to the stable state, without reaching a collision after becoming unstable once employ | adopting 1st Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Seat belt apparatus 2 ... Seat 5 ... Webbing 10 ... Motor 12 ... Reel 13 ... Deceleration mechanism 20 ... Clutch 22 ... Motor side power transmission system 38 ... Vehicle behavior judgment means 40 ... Seat belt control means

Claims (1)

In a seat belt apparatus including a reel on which a webbing that restrains an occupant seated on a seat is wound, and a motor that rotationally drives the reel to retract the webbing,
A speed reduction mechanism interposed between the motor and the reel;
A clutch interposed between the motor and the reel to connect and disconnect the power transmission system between the two;
Vehicle behavior judging means for judging the unstable behavior of the vehicle;
Seat belt control means for controlling the motor and clutch based on the determination result of the vehicle behavior determination means;
With
When the vehicle behavior judging means judges the unstable behavior, the seat belt control means puts the clutch in a connected state and does not take up the webbing by the motor, and the motor side power A seat belt device characterized in that a rotational resistance of a transmission system acts on the reel as a load.

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