JPH09164911A - Seat belt retractor - Google Patents

Abstract

(57) Abstract: A seat belt retractor having a good energy absorbing mechanism that can be easily combined with a pretensioner mechanism is provided. An emergency lock mechanism (2) for preventing the webbing (20) from being pulled out in an emergency occurs when a first gear (8) fixed to the other end of a winding shaft (4) and a rotational force of a predetermined amount or more act on the first gear (8). The torsion bar 21 that undergoes torsional deformation is attached to the clutch mechanism 10.
A second gear 9 that is attached via the second gear 9 that meshes with the first gear 8 and the clutch mechanism 1 in normal use.
0 in the disengaged state to disengage the second gear 9 from the torsion bar 21, and in the event of a vehicle emergency, the clutch mechanism 1
And a clutch control mechanism 12 that engages the second gear 9 with the torsion bar 21 with 0 being in the connected state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seat belt retractor (winding device), and more particularly to an improvement of a seat belt retractor having an energy absorbing mechanism.

[0002]

2. Description of the Related Art Conventionally, in a seat belt device for holding a vehicle occupant's body safely in a seat, in order to reduce the occupant's feeling of wearing the seat belt, the retractor has to reduce the force of winding the seat belt. Tend to. This increases the slack of the seatbelt worn on the occupant's body, increasing the amount of extension of the seatbelt when a large force is applied to the seatbelt in an emergency such as a vehicle collision, effectively restraining the occupant's body. Could not be done. In view of this, there is a seatbelt device provided with a pretensioner mechanism for removing slack of the webbing by retracting the webbing in the event of a vehicle emergency, thereby improving the performance of restraining an occupant in a seat at the beginning of a collision.

On the other hand, when the impact force due to the collision is extremely large, the webbing tension increases with the lapse of time after the collision, which causes a rapid deceleration of the occupant's body, resulting in an extremely large load on the occupant from the webbing. growing. Therefore, when the load acting on the webbing is equal to or greater than a predetermined value, the seat belt is extended by a predetermined amount to provide an energy absorbing mechanism for absorbing an impact generated on the occupant's body, thereby making the occupant's body more reliable. There have been proposed various types of seat belt devices for protecting the vehicle.

Therefore, a belt retractor having the above-mentioned pretensioner mechanism and energy absorbing mechanism is disclosed in, for example, Japanese Patent Laid-Open No. 6-156187. In the belt retractor, the driving force from the belt pretensioning device (pretensioner mechanism) is transmitted to the belt drum (winding shaft) via the gear transmission device, and rotates the belt drum in the belt winding direction at the time of a vehicle collision. The gear transmission device includes a first gear that is rotationally driven by a belt pretensioning device, and a second gear that is connected to the belt drum via a freewheel connecting device and meshes with the first gear. The first gear is connected to the first end of the torsion bar via another freewheel connecting device, and the second end of the torsion bar is supported so as not to rotate relative to the housing.

Therefore, when tension is applied to the belt web (webbing), the gear transmission connected to the torsion bar via the freewheel connecting device reduces the peak energy by torsionally deforming the torsion bar. .

[0006]

However, in order to attach the energy absorbing mechanism to the seat belt retractor having the pretensioner mechanism as described above, the pretensioner mechanism and the energy absorbing mechanism are combined to form an integral structure. Must. Therefore, there is a problem that the structure of the retractor is complicated and the manufacturing cost is likely to increase.

Further, in order to operate the energy absorbing mechanism in the belt retractor disclosed in Japanese Patent Laid-Open No. 6-156187, each freewheel connection provided between the belt pretensioning device and the belt drum. The device must remain positively engaged after the belt pretensioner has been activated. However, since these freewheel coupling devices lock the rotation by the inertia and frictional force of the roller element, there is a possibility that the positive meshing may not be performed after the belt pretensioning device is activated. Of course, if the belt pretensioning device does not operate, the energy absorbing mechanism also does not operate.

Further, during the operation of the energy absorbing mechanism as described above, the belt web cannot be paid out from the retractor unless the belt drum lock mechanism (emergency lock mechanism) attached to the retractor is canceled. Therefore, a cancel mechanism for preventing the operation of the belt drum lock mechanism is required, and there is a problem that the structure is complicated.

Therefore, an object of the present invention is to solve the above problems and to provide a seat belt retractor having a good energy absorbing mechanism which can be easily combined with a pretensioner mechanism.

[0010]

SUMMARY OF THE INVENTION The above object of the present invention is capable of being deformed when a first gear attached to the winding shaft of a retractor for winding webbing and a predetermined or more rotational force is applied. A second gear that is attached to the energy absorbing member via a clutch mechanism and meshes with the first gear; and a second gear that holds the clutch mechanism in a disengaged state during normal use so that the second gear serves as the energy absorbing member. This is achieved by a seat belt retractor having a non-engaged state and an emergency lock mechanism including a clutch control mechanism that engages the second gear with the energy absorbing member by engaging the clutch mechanism in a vehicle emergency.

Further, the above object of the present invention is to provide a first gear rotatably supported by a winding shaft of a retractor for winding webbing and an energy which can be deformed when a rotational force of a predetermined amount or more acts. The first member is attached to the absorbing member and
Second gear that meshes with the above gear, a ratchet wheel attached to the winding shaft, and a claw member that is rotatably supported integrally with the first gear and is engageable with the ratchet wheel. And a retractor for a seat belt having an emergency lock mechanism that is configured to hold the pawl member in a non-engagement state with the pawl wheel during normal use and with a lock operating means that engages the pawl member with the pawl wheel during a vehicle emergency. Achieved by

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a front view of a seat belt retractor 1 with a pretensioner according to a first embodiment of the present invention, and FIG. 2 is a sectional view of a main part of the emergency locking mechanism shown in FIG.

Most of the retractor base 11 has a U-shaped cross section, and the winding shaft 4 having the winding reel 7 around which the webbing 20 is wound is fixedly mounted on the opposing side plates 11a and 11b. It is bridged freely. At one end of the take-up shaft 4, the take-up shaft 4 is wound in the direction in which the webbing 20 is taken up.
A well-known winding spring device 5 that constantly urges the pretensioner mechanism 3 that rotates the winding shaft 4 in a direction in which the slack of the seat belt is removed (winding direction) in the event of a vehicle collision.
Are arranged.

On the other hand, an emergency lock mechanism 2 for preventing the webbing 20 from being pulled out in an emergency is arranged at the other end of the winding shaft 4. As shown in FIG. 2, the emergency lock mechanism 2 includes a first gear 8 fixed to the other end of the winding shaft 4 and an energy absorbing member that is deformable when a rotational force of a predetermined amount or more acts. Clutch mechanism 1 on a torsion bar 21
0 and a second gear 9 that meshes with the first gear 8 and the clutch mechanism 10 in a non-connected state during normal use to keep the second gear 9 from the torsion bar 21. When the vehicle is in an emergency, the clutch mechanism 10 is engaged and the second gear 9 is engaged with the torsion bar 21.
And a clutch control mechanism 12 to be engaged with.

The second gear 9 having the outer teeth 9a meshing with the outer teeth 8a of the first gear 8 is relatively rotatable about the axis of the free end 21a of the torsion bar 21 penetrating the base side wall 11a. A plurality of cam surfaces 9b (see FIGS. 3 and 4) that are arranged and that form a wedge-shaped space between the outer peripheral surface of the free end portion 21a and the outer peripheral surface of the free end portion 21a are arranged in the circumferential direction. They are formed at equal intervals along the line. Then, in each wedge-shaped space, a cylindrical roller 22 which is a meshing element movable in the torsion bar engagement direction so as to enable torque transmission between the second gear 9 and the torsion bar 21, and A holder 23 which is a holding means for preventing the roller 22 from moving in the torsion bar engaging direction, and the roller 22 is attached to the second gear 9 through the holder 23 in a direction opposite to the torsion bar engaging direction. The elastic member 24 for urging the clutch mechanism 10 is provided.
Is composed.

The other end of the torsion bar 21 is fixed to the base side wall 11b on which the winding spring device 5 and the pretensioner mechanism 3 are arranged, and the free end 2
It is an energy absorbing member that is torsionally deformed when a rotational force of a predetermined amount or more acts on 1a. The holder 23 is preferably made of resin, and has an annular base plate portion 23a having a circular hole through which the free end portion 21a of the torsion bar 21 is inserted, and four pairs of roller holders suspended from the base plate portion 23a. Piece 23
b, 23b. Then, the tip ends of the roller holding pieces 23b, 23b are inserted into the wedge-shaped spaces of the second gears 9 provided adjacent to each other, and the rollers 22 are not engaged with the outer peripheral surface of the free end 21a. Holds in a state.

Further, the inner diameter of the second gear 9 is larger than the outer diameter of the free end portion 21a of the torsion bar 21, and the roller 22 clamped by the roller holding pieces 23b, 23b of the holder 23 is The rod 21 has a clearance with respect to the outer peripheral surface of the free end portion 21a. That is, the roller 22 is securely held by the holder 23 in a state in which torque cannot be transmitted.

Further, the holder 23 rotates relative to the second gear 9 in the torsion bar engaging direction against the urging force of the elastic member 24, and the roller 22 is rotated by the cam surface 9b to rotate the torsion bar central axis. When biased in the direction, the roller holding pieces 23b, 23b can be easily deformed so as not to hinder the movement of the roller 22 in the biting direction. That is, when the holder 23 is rotated relative to the second gear 9 in the torsion bar engaging direction (the arrow Y ₁ direction in FIG. 3) by the clutch control mechanism 12 described later, the roller 22 moves to By biting between the cam surface 9b and the outer peripheral surface of the free end portion 21a, the second gear 9 and the torsion bar 21 are connected, and the rotational torque of the second gear 9 is transmitted to the torsion bar 21. It has become so.

The clutch control mechanism 12 includes a latch cup 13 which is a latch member loosely fitted to a part of the winding shaft 4 protruding outward of the first gear 8 and the outside of the latch cup 13. Lock portion 15a fixed to the take-up shaft 4 located at the position and engaged with the inner teeth 13b of the latch cup 13.
The lock member 15 and the sensor spring 1 having the
6 together with the flange 14 which constitutes the locking means 17, and the ratchet wheel 1 which is an inertia member loosely fitted to the tapping screw 25 screwed to the end of the winding shaft 4.
9

On the outer peripheral surface of the ratchet wheel 19, teeth 19a for engaging with a sensor arm of a vehicle body acceleration sensing means (not shown) are formed. A friction spring 18 having a substantially annular shape is frictionally engaged with a mounting portion provided inside the ratchet wheel 19, and both bent end portions of the friction spring 18 are engaged with the lock member 15. Therefore, the ratchet wheel 19 rotates integrally with the winding shaft 4 and can be displaced relative to the winding shaft 4. The outer peripheral surface 13a of the latch cup 13 is engaged with the outer peripheral portion of the base plate portion 23a of the holder 23, and the latch cup 13 loosely fitted to the winding shaft 4 is rotated as the holder 23 rotates. To be At this time, the outer diameter of the base plate portion 23a is larger than the outer diameter of the second gear 9 and the outer diameter of the latch cup 13 is smaller than the outer diameter of the first gear 8. The rotation is increased in the same direction as the take-up shaft 4.

A sensor cover 26 is provided outside the side plate 11a that covers the emergency lock mechanism 2. The pretensioner mechanism 3 is a well-known one that has been conventionally used, and although not described in detail, a drive that rotates the winding shaft 4 in the webbing winding direction by the gas pressure generated by the gas generator 29. Means 6 and a control device (not shown) for operating the gas generator 29 in the event of a vehicle collision are provided.

Next, the operation of the seat belt retractor 1 with the pretensioner will be described. First,
In the normal use state, the lock portion 15a of the lock member 15 is urged by the urging force of the sensor spring 16 to a position that does not mesh with the inner teeth 13b of the latch cup 13, and the latch cup 13 is rotatable. .

Then, when the second gear 9 rotates, the roller holding piece 2 is inserted into each wedge-shaped space of the second gear 9.
The holder 23 pressed by the elastic member 24 against the wall 9c by inserting the tip portions of 3b and 23b is also rotated integrally. The latch cup 13 engaged with the holder 23 is rotatable as described above. At this time, since the roller 22 is biased by the biasing force of the elastic member 24 in the direction opposite to the torsion bar engaging direction with respect to the second gear 9, the free end portion 21 a of the torsion bar 21.
The outer peripheral surface of is in a non-engaged state.

Therefore, when the clutch mechanism 10 is disengaged and the first gear 8 rotates integrally with the winding shaft 4, the second gear having the outer teeth 9a meshing with the outer teeth 8a of the first gear 8. The gear 9 of the retractor 1 is also rotated and the retractor 1 is rotated.
The webbing 20 can be wound by the urging force of the winding spring device 5, and the webbing 20 can be pulled out against the spring force.

On the other hand, the pretensioner mechanism 3 is also in a non-engaged state with the winding shaft 4 by a clutch mechanism (not shown) in a normal use state, and comes into contact with the winding shaft 4 from the retractor. It does not affect the pull-up winding of the webbing 20 and the operation of the emergency locking mechanism 2. Next, when a certain amount of deceleration such as sudden braking occurs in the vehicle, the occupant moves forward and the webbing 2
When a tension is applied to 0 and a rotational force in the webbing withdrawing direction (arrow X ₁ direction) which is more than a predetermined impact is applied to the winding shaft 4, the ratchet wheel 19 receives an inertial force and the winding shaft 4 moves. A rotation delay occurs with respect to the rotation in the webbing pull-out direction. When the force by which the friction spring 18 mounted on the mounting portion of the ratchet wheel 19 pushes the lock portion 15a of the lock member 15 with the inner teeth 13b is stronger than the biasing force of the sensor spring 16, the lock is generated. The member 15 is moved in the direction in which the lock portion 15a meshes with the inner teeth 13b.

Further, when the take-up shaft 4 rotates in the webbing pull-out direction, the lock portion 15a of the lock member 15 and the inner teeth 13b of the latch cup 13 mesh with each other as shown in FIG. For this reason, the latch cup 13 cannot rotate at an increased speed with respect to the winding shaft 4. Therefore, the brake is applied to the rotation of the holder 23 in the Y ₂ direction. Then, the latch cup 13
The holder 23, which is engaged with, causes a rotation delay with respect to the rotation of the second gear 9 against the biasing force of the elastic member 24, and the holder 23 engages with the second gear 9 in the torsion bar engagement direction (see FIG. 4 in the direction of arrow Y ₁ ).

When the holder 23 is rotated relative to the second gear 9 in the direction of the arrow Y ₁ , the roller 22 is urged by the cam surface 9b toward the center of the torsion bar. At this time,
In the roller holding pieces 23b and 23b, the roller 22 has the outer peripheral surface of the free end 21a of the torsion bar 21 and the second gear 9a.
It is possible to move the torsion bar in the direction of the center of the torsion bar by elastic deformation of the holding piece until it bites into the cam surface 9b.

Then, when the roller 22 moves to a position where it is surely bitten between the outer peripheral surface of the free end portion 21a and the cam surface 9b, the rotation of the second gear 9 is transmitted to the torsion bar 21. The other end of the torsion bar 21 is fixed to the base side wall 11b and opposes the rotation of the second gear 9. At this time, the free end portion 21a is not subjected to a rotational force greater than a predetermined value, and the torsion bar 21 is not twisted and deformed.

Therefore, the rotation of the first gear 8 meshing with the second gear 9 in the webbing pull-out direction (arrow X ₁ direction) is locked. This allows the webbing 2
Although the extension of 0 is prevented, the control device (not shown) does not operate the gas generator 29, so the take-up shaft 4
Is not driven by the drive means 6 in the webbing winding direction.

Further, when the vehicle undergoes a speed change more than a predetermined speed in an emergency, the sensor arm of the vehicle body acceleration sensing means (not shown) engages with the teeth 19a of the ratchet wheel 19 to rotate the ratchet wheel 19 in the belt withdrawing direction. Block. Therefore, if the webbing is further pulled out while the ratchet wheel 19 is prevented from rotating, the ratchet wheel 19 is delayed in rotation with respect to the rotation of the winding shaft 4 in the webbing pull-out direction. As described above, the extension of the webbing 20 is locked.

On the other hand, when a very large predetermined deceleration occurs at the time of a vehicle collision or the like, a control device (not shown) detects this deceleration and ignites the gas generator 29. When the ignited gas generator 29 ejects the drive gas, the drive means 6 rotates the winding shaft 4 in the direction for winding the webbing 20, so that the webbing 20 is tightened and the play of the seat belt is removed.

When the driving of the driving means 6 due to the expansion pressure of the driving gas is stopped, a large tension is generated in the webbing 20, and the winding shaft 4 has a shocking webbing pulling-out direction (direction of arrow X ₁ ) above the predetermined level. Since the turning force is applied, the emergency lock mechanism 2 described above operates. At this time, when a torque larger than a predetermined value is applied to the free end portion 21a of the torsion bar 21, the torsion bar 21 that locks the extension of the webbing 20 is twisted and deformed. Therefore, in the emergency lock mechanism 2, the torsion bar 21 is twisted and deformed, so that the kinetic energy of the occupant is effectively consumed, and the webbing 20 can be extended from the retractor while maintaining a constant pulling force. . Therefore, the emergency lock mechanism 2 including the energy absorbing mechanism as described above
Can effectively reduce the impact on the occupant. The twist bar 21 is regulated by a stopper means (not shown) so as not to be twisted and deformed beyond a predetermined twist angle.

That is, in the seat belt retractor 1 with a pretensioner, the energy absorption mechanism is incorporated in the emergency lock mechanism 2 and is completely independent of the pretensioner mechanism 3. It is not necessary to configure the pretensioner mechanism and the energy absorbing mechanism as in the conventional case, and the combination with any pretensioner mechanism is easy. Further, since the energy absorbing mechanism can feed the webbing 20 out of the retractor while the emergency lock mechanism 2 is in the operating state, it is necessary to prevent the operation of the emergency lock mechanism 2 during the operation of the energy absorbing mechanism as in the conventional case. No cancellation mechanism is required.

Therefore, the retractor 1 for a seat belt with a pretensioner has a simpler retractor structure, and the manufacturing cost is lower than that of a conventional retractor for a seat belt with a pretensioner. The reliability of the emergency lock mechanism in the tractor can be significantly improved. Of course, the emergency lock mechanism 2 having the energy absorbing mechanism as described above can also be used in a retractor having no pretensioner mechanism.

FIG. 5 is a sectional view of an essential part of a seat belt retractor 50 with a pretensioner according to a second embodiment of the present invention, and FIGS. 6 and 7 are front views of the essential part of the emergency locking mechanism shown in FIG. It is a figure. The same components as those of the seatbelt retractor 1 with a pretensioner of the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

The seatbelt retractor 50 with a pretensioner is similar to the retractor 1 for a seatbelt with a pretensioner of the first embodiment, and has a winding shaft having a pretensioner mechanism (not shown) at one end thereof. At the other end of 54, an emergency lock mechanism 51 for preventing the webbing 20 from being pulled out in an emergency of the vehicle is arranged.

As shown in FIG. 5, the emergency lock mechanism 51 is deformed when a first gear 56 rotatably supported on the other end of the winding shaft 54 and a rotational force of a predetermined amount or more act thereon. A second gear 57 that is attached to a torsion rod 58 that is a possible energy absorbing member and that meshes with the first gear 56; a latch plate 55 that is a ratchet wheel attached to the winding shaft 54; A pole 61 which is supported by a support plate 60 that rotates integrally with the first gear 56 and is engageable with the latch plate 55.
In normal use, the pole 61 is connected to the latch plate 5
5, the lock operating means 5 for keeping the pole 61 from engaging with the latch plate 55 in the event of a vehicle emergency.
3

The first gear 56 is rotatably supported by the winding shaft 54 between the latch plate 55 and the base side wall 11a. Second gear 5 having outer teeth 57a that mesh with outer teeth 56a of the first gear 56
7 is attached to the free end portion of the torsion bar 58 that penetrates the base side wall 11a so as not to rotate relative to each other. The other end of the torsion bar 58 is fixed to the other base side wall 11b (not shown) similarly to the torsion bar 21 of the first embodiment, and the free end of the torsion bar 58 has a rotational force of a predetermined value or more. When it acts, it is twisted and deformed.

As shown in FIG. 6, the support plate 60 is attached to the outer surface of the first gear 56 so as not to rotate relative to it, and a pole 61 is attached to a support shaft 60a extending from the extending portion thereof. Is rotatably supported. The pawl 61 can swing and rotate about a support shaft 60a, and an engaging portion 61a formed on the swing end side thereof can be engaged with and disengaged from an engaging tooth 55a of the latch plate 55. The pole 61 is constantly urged by a torsion coil spring 68, the other end of which is hooked to the edge of the support plate 60, in a direction not engaged with the engaging tooth 55a.

Further, a pole guide projection 61b is provided on the pole 61 so as to project into a pole guide hole 59a formed on an outer peripheral portion of a latch cup 59 of a lock operating means 53, which will be described later. It is inserted (see FIG. 7). That is, when the pawl 61 is engaged with the latch plate 55 by the lock operating means 53 described later, the latch plate 55 and the support plate 60 are
And the rotational torque of the latch plate 55 is transmitted to the first gear 56 via the support plate 60.

The lock operating means 53 is located on the outside of the latch cup 59, which is a latch member that is loosely fitted to a part of the take-up shaft 54 that projects outward from the latch plate 55. A lock portion 65 fixed to the winding shaft 4 and engaged with the inner teeth 59b of the latch cup 59.
a flange 64 that constitutes a locking means 67 together with the locking member 65 having the a formed therein and the sensor spring 16;
The ratchet wheel 19 is an inertia member that is loosely fitted to a tapping screw 25 screwed to the end of the winding shaft 54.

The pole guide hole 5 of the latch cup 59
A pole guide protrusion 61b is inserted in 9a,
The latch cup 59 loosely fitted to the take-up shaft 54 is rotated by the rotation of the pole 61 pivotally supported by the support shaft 60a of the support plate 60. Next, the operation of the seat belt retractor 50 with the pretensioner will be described.

First, in a normal use state, the lock portion 65a of the lock member 65 is urged to a position that does not mesh with the inner teeth 59b of the latch cup 59, and the pole 61
Is urged by the urging force of the torsion coil spring 68 in a direction not engaging with the engaging teeth 55a of the latch plate 55, so that the webbing 20 can be pulled out freely.

Next, when a certain amount of deceleration such as sudden braking occurs in the vehicle, the ratchet wheel 19 receives inertial force to rotate the winding shaft 54 in the webbing pull-out direction, as in the first embodiment. However, a rotation delay occurs. The friction spring 18 mounted on the mounting portion of the ratchet wheel 19 is stronger than the biasing force of the sensor spring 16 by the lock portion 6 of the lock member 65.
When the force pushing the 5a in the direction of engaging the inner teeth 59b is superior,
The lock operating means 53 operates to move the lock member 65 in a direction in which the lock portion 65a meshes with the inner teeth 59b.

Further, when the winding shaft 54 rotates in the webbing pull-out direction, the lock portion 65a of the lock member 65 and the inner teeth 59b of the latch cup 59 mesh with each other as shown in FIG. 59, and the latch cup 59 is rotated integrally with the winding shaft 54 in the arrow X ₁ direction against the biasing force of the torsion coil spring 68. Then, the pole guide hole 59a that engages with the pole guide protrusion 61b swings and rotates the pole 61 in the arrow Z ₁ direction through the pole guide protrusion 61b, and the engagement portion 61a is attached to the engagement tooth 55a of the latch plate 55. Engage.

As a result, the rotating torque of the latch plate 55 in the arrow X ₁ direction is transmitted to the pole 61,
Rotational torque in the direction of arrow X ₁ is also transmitted to the support plate 60 that supports the pole 61. Then, the rotation torque of the winding shaft 54 is transmitted to the second gear 57 and the torsion rod 58 via the first gear 56 that rotates integrally with the support plate 60. The other end of the torsion bar 58 is fixed to the base side wall 11b and opposes the rotational torque acting on the second gear 57 in the arrow Y ₃ direction. At this time, the second
The rotating force of a predetermined amount or more does not act on the gear 57, and the torsion bar 58 is not twisted and deformed.

Therefore, the webbing pull-out direction of the first gear 56 meshing with the second gear 57 (arrow X ₁
The rotation of the webbing 20 is locked by the emergency locking mechanism 51. Of course, the pretensioner mechanism (not shown) does not operate to drive the winding shaft 54 in the webbing winding direction. Further, the lock actuating means 53 is actuated by engaging the sensor arm (not shown) of the vehicle body acceleration sensing means with the teeth 19a of the ratchet wheel 19 to prevent the ratchet wheel 19 from rotating in the belt withdrawing direction. Thus, the extension of the webbing 20 is locked.

On the other hand, when an extremely large predetermined deceleration occurs at the time of a vehicle collision or the like, a pretensioner mechanism (not shown) is actuated similarly to the seatbelt retractor 1 with a pretensioner of the first embodiment, Since the winding shaft 54 is rotated in the winding direction of the webbing 20, the webbing 20 is tightened and the play of the seat belt is removed.

When the driving of the driving means in the pretensioner mechanism is stopped, a large tension is generated in the webbing 20, and the winding shaft 54 is rotated in the webbing pull-out direction (the arrow X ₁ direction) which is more than a predetermined impact. Since the power is applied, the above-mentioned lock actuating means 53 is actuated. At this time, the second gear 5 attached to the torsion bar 58
When a rotational force in the direction of the arrow Y ₃ above a predetermined value is applied to 7, the torsion bar 5 that locks the extension of the webbing 20
8 is torsionally deformed. Therefore, the emergency lock mechanism 51
When the torsion bar 58 is twisted and deformed, the kinetic energy of the occupant is effectively consumed, and the webbing 20 can be extended from the retractor while maintaining a constant pulling force. Therefore, the emergency lock mechanism 51 having the energy absorbing mechanism as described above can effectively reduce the impact applied to the occupant.

Further, when the torsion bar 58 is torsionally deformed, the second rod rotating in the direction of the arrow Y ₃
The gear 57 has an engaging projection 57b formed on the outer peripheral portion thereof.
Comes into contact with the locking portion 62 provided on the base side wall 11a,
Further rotation is prevented. Therefore, when the second gear 57 rotates more than a predetermined rotation, the engaging protrusion 57b
Further, the stopper means composed of the locking portion 62 prevents the webbing 20 from extending from the retractor, and the operation of the energy absorbing mechanism is stopped. Therefore, the webbing 20 does not extend out of the retractor more than necessary and does not hinder the restraint of the occupant.

That is, also in the seat belt retractor 50 with the pretensioner, the energy absorbing mechanism is incorporated in the emergency locking mechanism 51,
Since it is completely independent of a pretensioner mechanism (not shown), it is more manufactured than the conventional seatbelt retractor with a pretensioner, like the retractor 1 for a seatbelt with a pretensioner of the first embodiment. The cost is reduced, and the reliability of the emergency locking mechanism can be remarkably improved particularly in the retractor with a pretensioner.

The clutch mechanism, the clutch control mechanism, the lock actuating means, the energy absorbing member, and the like in the emergency lock mechanism of the present invention are not limited to the configurations of the above-described embodiments, but may take various forms. Needless to say. For example, as the clutch mechanism in the present invention,
Not limited to the structure of the clutch mechanism 10 in the first embodiment, a known clutch mechanism based on the gist of the present invention can be used. Therefore, in the present embodiment, the cylindrical roller is used as the meshing element, but a meshing element such as a ball or sprag may be used. Also, the configuration of the pretensioner mechanism can be changed as appropriate.

[0053]

According to the seat belt retractor of the present invention, the energy absorbing mechanism is incorporated in the emergency locking mechanism, and it can be constructed completely independently when combined with the pretensioner mechanism. . Therefore,
It is not necessary to combine the pretensioner mechanism and the energy absorbing mechanism as in the conventional case, and the combination with any pretensioner mechanism is easy. or,
Since the energy absorption mechanism can feed the webbing from the retractor while the emergency lock mechanism is in the operating state, there is no need for a cancel mechanism for preventing the operation of the emergency lock mechanism during the operation of the energy absorption mechanism as in the conventional case. .

Therefore, the retractor for a seat belt according to the present invention has a simple structure even when combined with a pretensioner mechanism, has a lower manufacturing cost than a conventional retractor with a pretensioner, and has a reliable emergency locking mechanism. It is possible to remarkably improve the sex. Also, since a common emergency lock mechanism can be used regardless of the presence or absence of a pretensioner mechanism, parts can be shared,
Manufacturing costs can be reduced.

Therefore, it is possible to provide a seat belt retractor having a good energy absorbing mechanism which can be easily combined with a pretensioner mechanism.

[Brief description of the drawings]

FIG. 1 is a front view of a seat belt retractor with a pretensioner according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of essential parts of the emergency lock mechanism shown in FIG.

3 is a cross-sectional view of essential parts of the clutch control mechanism and the clutch mechanism shown in FIG.

FIG. 4 is a sectional view of relevant parts for explaining an operating state of the clutch mechanism shown in FIG.

FIG. 5 is a sectional view of an essential part of an emergency lock mechanism in a seat belt retractor with a pretensioner according to a second embodiment of the present invention.

6 is an enlarged cross-sectional view of a main part of the emergency lock mechanism shown in FIG.

FIG. 7 is a cross-sectional view of main parts for explaining the operating state of the lock operating means shown in FIG.

[Explanation of symbols]

1 Seatbelt retractor with pretensioner 2 Emergency locking mechanism 3 Pretensioner mechanism 4 Winding shaft 5 Winding spring device 6 Driving means 7 Winding reel 8 First gear 9 Second gear 10 Clutch mechanism 11 Retractor base 12 Clutch Control Mechanism 13 Latch Cup 14 Flange 15 Locking Member 17 Locking Means 19 Ratchet Wheel 20 Webbing 21 Torsion Rod 22 Roller 23 Holder

Claims (2)

[Claims] 1. A first gear attached to a take-up shaft of a retractor for winding webbing, and an energy absorbing member that is deformable when a rotational force of a predetermined amount or more is applied, via a clutch mechanism. Along with the second gear, which meshes with the first gear, the clutch mechanism is held in a disengaged state during normal use to disengage the second gear from the energy absorbing member, and the clutch mechanism is engaged in a vehicle emergency. A seat belt retractor having an emergency lock mechanism including a clutch control mechanism that engages the second gear with the energy absorbing member in a connected state. 2. A first gear, which is rotatably supported by a winding shaft of a retractor for winding webbing, and an energy absorbing member which is deformable when a rotational force of a predetermined amount or more acts, and A second gear meshing with the first gear; a ratchet wheel attached to the winding shaft;
Claw member that is rotatably supported integrally with the gear of (1) and is engageable with the ratchet wheel, and holds the claw member in a disengaged state with the ratchet wheel during normal use, and in the vehicle emergency, the claw member A retractor for a seat belt having an emergency lock mechanism including a lock actuating means for engaging the wheel with the ratchet wheel.