JP2562640Y2 - Seat belt retractor - Google Patents

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 emergency lock mechanism.

[0002]

2. Description of the Related Art Conventionally, a seat belt for safely holding a vehicle occupant or the like in a seat is composed of a webbing, a buckle, a mounting device, and a retractor (winding device). The retractor is a device that automatically retracts the webbing when the seat belt is not used, and is a winding device that prevents damage to the webbing and that can freely change the length of the webbing when the seat belt is used.

[0003] Such retractors include automatic locking retractors and emergency locking retractors. However, in general, in order to solve the problem that the occupant is excessively restrained and the wearer feels oppression. In addition, an emergency lock mechanism that effectively and safely restrains an occupant and reduces the feeling of pressure due to webbing is provided with an emergency lock mechanism that physically locks the retractor by inertial sensing means that responds to sudden acceleration, collision or deceleration. Retractors are used.

Further, as an inertia sensing means used in such an emergency lock type retractor, there is a sensing means for sensing a webbing withdrawal speed. For example, when an inertia member causes a rotation delay with respect to a winding shaft, a lock member is detected. Connects the take-up shaft and the latch member, and the latch member rotates together with the take-up shaft in the webbing pull-out direction, so that the cam portion of the latch member acts on the driven portion of the claw member so that the claw member is In this configuration, the rotation of the winding shaft in the webbing pull-out direction is locked by engaging with an integral ratchet wheel.

As an emergency lock type retractor using such inertia sensing means, for example, Japanese Utility Model Laid-Open Publication No. 62-161.
No. 068 and Japanese Utility Model Unexamined Publication No. 2-127576 are emergency lock type retractors. These inertia sensing means include a claw wheel attached to an end of the winding shaft, an inertia member that rotates following the winding shaft, and a claw member that rotates together with the winding shaft in a webbing pull-out direction. A latch member that engages with the ratchet wheel to lock the rotation of the winding shaft in the webbing pull-out direction, and a latch member via the locking member when the inertia member has a rotation delay with respect to the winding shaft. Lock means connected to the winding shaft.

The inertia member follows the winding shaft via a friction spring that is frictionally engaged so as to be rotatable relative to the winding shaft, and when the rotational speed difference occurs between the inertia member and the winding shaft. Since the lock member attached to the take-up shaft is engaged with the latch member by the friction spring, the latch member is rotated together with the take-up shaft in the webbing pull-out direction. Then, the latch member rotated in the webbing pull-out direction,
The pawl member rotatably supported by the retractor base is engaged with the ratchet wheel to lock the winding shaft from rotating in the webbing pull-out direction.

[0007]

However, the friction spring used in the inertial sensing means disclosed in Japanese Utility Model Laid-Open No. 62-16068 and Japanese Utility Model Laid-Open No. 2-127576 is a linear spring steel formed in a substantially annular shape. The annular portion is slidably contacted with the mounting portion of the inertia member, and one end of the annular portion is engaged with the lock member, so that the inertia member is frictionally engaged with the winding shaft so as to be relatively rotatable. Therefore, there is a large difference in rotational slidability between the friction spring and the inertia member depending on the rotation direction of the winding shaft. That is,
Depending on the direction of the locking force acting on one end of the friction spring locked by the locking portion of the lock member, the friction spring receives a force in the direction of expanding or contracting in the radial direction. The frictional resistance with the inertia member increases or decreases.

For this reason, when the webbing is completely wound in accordance with the spring force of the winding spring from the webbing withdrawn state, the webbing is completely wound, the pretensioner is activated, or the webbing is rapidly locked in the webbing withdrawing direction. If the rotation direction of the shaft is suddenly changed, an excessive force acts between one end of the friction spring and the locking portion of the lock member to disengage, or the friction spring is disengaged from the mounting portion of the inertia member. There was a possibility of falling off.

Accordingly, an object of the present invention is to solve the above-mentioned problem, and even when a sudden change in the rotating direction of the winding shaft occurs, the friction spring of the emergency locking mechanism is moved from the locking portion of the locking member. An object of the present invention is to provide a seat belt retractor having a highly reliable emergency lock mechanism that is not likely to come off or fall off from a mounting portion of an inertia member.

[0010]

SUMMARY OF THE INVENTION The object of the present invention is to provide a pawl attached to a winding shaft of a retractor on which a webbing is wound, an inertia member rotating following the winding shaft, and a winding shaft. A latch member for rotating the take-up shaft in the webbing pull-out direction by engaging the pawl member with the ratchet wheel by rotating in the webbing pull-out direction together with the take-up shaft; and a rotation delay of the inertia member with respect to the take-up shaft. In the seat belt retractor having an emergency lock mechanism including a locking means for connecting the latch member to the take-up shaft via the lock member when the friction occurs, an annular friction spring is rotated relative to the mounting portion of the inertia member. The two end portions of the locking member are frictionally engaged with each other at least while restricting deformation of the friction spring in the radial direction. It was engaged with an engaging portion provided achieved by a seat belt retractor according to claim.

[0011]

According to the above construction of the present invention, the friction spring whose both ends are locked by the lock member has its intermediate portion frictionally engaged with the mounting portion of the inertia member, so that it depends on the rotation direction of the winding shaft. The locking force between the locking portion of the lock member and the locking portion whose operating direction changes can be received by each of both end portions in each rotation direction. Therefore, the diameter of the annular friction spring does not expand or contract in the radial direction depending on the rotation direction of the winding shaft, so that the friction spring has the same frictional resistance with the inertial member for each rotation direction, Excessive sliding resistance does not occur with the inertial member.

[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. In the exploded perspective views of the seatbelt retractor shown in FIGS. 1 and 2, the base 1 has a substantially U-shaped cross section, and a through hole 1b is formed in the opposed side plate 1a in opposition. The through hole 1
A take-up shaft 4 on which a take-up reel 2 around which the webbing is wound is fixedly mounted on b through a left and right plastic bush 3 so as to be rotatable. At one end of the winding shaft 4,
A well-known take-up spring device 7 that constantly urges the take-up shaft 4 in a direction in which the webbing is taken up, and a pretensioner 8 that rotates the take-up shaft 4 in a direction in which the slack of the seat belt is removed at the time of a vehicle collision. Are arranged.

On the other hand, an emergency lock mechanism for preventing the webbing from being pulled out in an emergency is disposed at the other end of the winding shaft 4. The emergency lock mechanism has a latch plate 4a, which is a ratchet wheel, fixed to the other end of the winding shaft 4, and a part of the winding shaft 4 projects outside the latch plate 4a. 9 and a latch cup 13 which is a latch member having internal teeth 13d are loosely fitted. The spring hanger 1 formed on the latch cup 13
3b and the spring hanger 9a formed on the tension plate 9 is mounted a return spring 12, the latch cup 13 biasing force to rotate in the arrow direction X ₂ is operatively. The winding shaft 4 located outside the latch cup 13 is provided with a lock member 15 formed with a lock portion 15a engaging with the internal teeth 13d and a flange 14 which forms a lock means 31 together with the sensor spring 16. It is fixed. Further, a ratchet wheel 19 which is an inertia member loosely fitted to a tapping screw 20 screwed to the flange 14 via a plain washer 17 is provided outside the lock member 15,
On its outer peripheral surface, a plurality of teeth 19a oriented in a belt pull-out direction for engaging with a sensor arm 28 of a vehicle body acceleration sensing means 32 described later are formed. A friction spring 18 is slidably mounted on a mounting portion provided inside the ratchet wheel 19,
Since the friction spring 18 is engaged with the lock member 15, the ratchet wheel 19
, And can be displaced relative to the winding shaft 4.

The friction spring 18 is shown in FIG.
As shown in (1), a linear spring steel was formed in an annular shape, and both end portions were once bent inward in the radial direction, and then both ends were bent in the same axial direction to form the engaging portions 18a and 18b. It has a symmetrical shape. The engaging portions 18a and 18b are engaged with holes 15b and 15c, respectively, which are a pair of locking portions provided on the lock member 15, and the friction spring 18 is deformed in the radially increasing direction and the radially decreasing direction. Is regulated.

That is, the friction spring 18 mounted on the mounting portion of the ratchet wheel 19 has its middle portion frictionally engaged with the mounting portion, so that the operation direction depends on the rotation direction of the lock member 15 which rotates together with the winding shaft 4. The locking force between the holes 15b and 15c of the lock member, which changes, can be received by the respective engaging portions 18a and 18b in each rotation direction. Accordingly, the diameter of the friction spring 18 does not expand or contract in the radial direction depending on the rotation direction of the winding shaft 4, so that the friction spring 18 has equal frictional resistance with the ratchet wheel 19 in each rotation direction. Become ratchet wheel 1
Excessive sliding resistance does not occur between the first and second sliding members.

Further, the pole 11 is a claw member to prevent the rotation of the webbing pull-out direction of the latch plate 4a by engaging the latch plate 4a (direction of arrow X ₁₎ is, latch plate 4a via the pawl pin 10
From the side plate 1a so as to be disengageable. One end of the pole pin 10 is inserted into a through hole 33 formed in the side plate 1a, and the other end is inserted into a through hole 9b of the tension plate 9, so that the engagement load between the pole 11 and the latch plate 4a is increased. Is prevented from falling down. Therefore, the pole 11 can swing and rotate about the through hole 33. The pole 11 is provided with a pole guide protrusion 11b, and the pole guide protrusion 11b is inserted into a pole guide hole 13c formed on the outer periphery of the latch cup 13.

Further, a sensor case 27 constituting a vehicle body acceleration sensing means 32 is fixed below the side plate 1a, and a ball weight 2 serving as a sensor is provided in the hollow portion.
9 is mounted, and a sensor arm 28 having a projection 28a is swingably attached. A sensor cover 21 is provided outside the side plate 1a that covers these emergency lock mechanisms.

Next, the operation of the seat belt retractor will be described. First, in the normal use state, as shown in FIG. 4, the latch cup 13 is moved in the webbing winding direction (arrow X ₂₎ by the urging force of the return spring 12 mounted on the spring hanger 13 b and the spring hanger 9 a of the tension plate 9. is biased in a direction), the pole 11 of the pole guide protrusion 11b to the pole guide hole 13c is engaged is biased latch plate 4a and a disengaged arrow Z ₂ direction and the locking of the locking member 15 Since the portion 15a is urged by the urging force of the sensor spring 16 to a position that does not engage with the internal teeth 13d of the latch cup 13, the webbing can be freely pulled out.

[0019] Thus, when the tension in the webbing (not shown) in an emergency such as a collision takes, rotational force of the winding to the shaft 4 over a predetermined stunning webbing pullout direction (the direction of arrow X ₁₎ is acted, the ratchet The wheel 19 receives an inertial force and a rotation delay occurs with respect to the rotation of the winding shaft 4 in the webbing withdrawing direction. Then, the ratchet wheel 19 is more pressed than the urging force of the sensor spring 16.
When the force of the engaging portion 18a of the friction spring 18 mounted on the mounting portion of the lock member 15 pushing the inner surface of the hole 15b of the lock member 15 in the direction in which the lock portion 15a meshes with the internal teeth 13d wins, the lock member 15 locks. The part 15a is moved in a direction in which the part 15a meshes with the internal teeth 13d. At this time, the intermediate portion of the friction spring 18 is frictionally engaged with the inner peripheral wall 19b of the mounting portion of the ratchet wheel 19 with an appropriate frictional force.
There is no possibility that an excessive force acts between the a and the hole 15b of the lock member 15 to cause disengagement or the friction spring 18 to fall off from the mounting portion of the ratchet wheel 19.

Further, when the take-up shaft 4 rotates in the webbing pull-out direction, the lock portion 15a of the lock member 15 meshes with the internal teeth 13d of the latch cup 13, as shown in FIG. 13 is transmitted to and rotates integrally with the winding shaft 4 in the arrow X ₁ direction against the biasing force of the return spring 12 to the latch cup 13. Then, as shown in FIG. 6, the pole guide hole 13c is engaged portion 11a on the latch plate 4a by rotating the pawl 11 in the arrow Z ₁ direction via the pawl guide projection 11b which engages with the pawl guide projection 11b Is engaged. As a result, pawl 11 is locked suppresses rotation in the direction of arrow X ₁ of the latch plate 4a, i.e. the withdrawal of the webbing.

When the speed of the vehicle changes more than a predetermined value in an emergency, the ball weight 29 rolls and swings the sensor arm 28 so that its tip 28a meshes with the teeth 19a of the ratchet wheel 19. The rotation of the ratchet wheel 19 in the belt withdrawing direction is prevented. When the webbing is further pulled out in a state where the rotation of the ratchet wheel 19 is prevented, the rotation of the ratchet wheel 19 is delayed with respect to the rotation of the winding shaft 4 in the webbing pulling-out direction. The webbing drawer is locked as described above.

When the webbing is rapidly wound up from the webbing pulled-out state according to the spring force of the wind-up spring device, the intermediate portion of the friction spring 18 is connected to the inner peripheral wall 19b of the mounting portion of the ratchet wheel 19, as shown in FIG. since the frictional engagement with a suitable friction between the ratchet wheel 19 without completely follow the rotation of the winding shaft 4, the friction spring 18 and the sliding relatively in the direction of arrow X ₁ Rotate dynamically. At this time, the engaging portion 18 of the friction spring 18
b locks the inner surface of the hole 15 c of the lock member 15
a remains pressed in the direction away from the internal teeth 13d,
The lock member 15 is not engaged with the latch cup 13 and the diameter of the friction spring 18 does not expand in the radial direction, so that excessive sliding resistance with the ratchet wheel 19 does not occur. Furthermore, when the webbing is fully wound, although slide and rotate the ratchet wheel 19 at the impact and friction spring 18 to relatively direction of arrow X _2, the friction spring 18 frictional resistance at both the rotation of the ratchet wheel 19 Since excessive sliding resistance does not occur in the same direction, an excessive force acts between the engaging portions 18a, 18b and the holes 15b, 15c to disengage, or the friction spring 18 is disengaged from the ratchet wheel. There is no possibility of dropping out of the 19 mounting portions. The same applies to the case where the webbing is suddenly wound by actuation of the pretensioner 8 that rotates the winding shaft 4 in a direction in which the seat belt is slackened during a vehicle collision.

Therefore, the reliability of the emergency lock mechanism in the seat belt retractor, particularly in the retractor with a pretensioner, can be remarkably improved. In the above embodiment, the engaging portion of the lock member for locking both end portions of the friction spring has a pair of holes 15b, 1b.
5c, the present invention is not limited to this. For example, the engaging portion may be formed by one long hole.

Further, it goes without saying that each member such as the friction spring in the present invention can be replaced by another member having the same function.

[0025]

In other words, according to the present invention, the diameter of the annular friction spring does not expand or shrink in the radial direction depending on the rotation direction of the winding shaft. The frictional resistance with the inertia member becomes equal, and no excessive sliding resistance occurs with the inertia member.

Therefore, even when a sudden change in the rotating direction of the winding shaft occurs, there is a possibility that the friction spring of the emergency lock mechanism may come off the locking portion of the lock member or fall off from the mounting portion of the inertia member. It is possible to provide a seat belt retractor provided with a reliable emergency lock mechanism.

[Brief description of the drawings]

FIG. 1 is a partial exploded perspective view of a seat belt retractor according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view of a remaining portion of the seat belt retractor shown in FIG.

FIG. 3 is an overall perspective view of the friction spring shown in FIG. 2;

FIG. 4 is a cutaway side view of a main part for explaining a webbing drawer locking operation of the seat belt retractor shown in FIGS. 1 and 2;

FIG. 5 is an enlarged view of a main part for explaining a pull-out locking operation of the webbing of the seat belt retractor shown in FIGS. 1 and 2.

FIG. 6 is an enlarged view of a main part for explaining a locking operation of pulling out a webbing of the seat belt retractor shown in FIGS. 1 and 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Retractor 1a Side plate 1b Through-hole 2 Take-up reel 3 Plastic bush 4 Take-up shaft 4a Latch plate 7 Take-up spring device 8 Pretensioner 9 Tension plate 10 Pole pin 11 Pole 11a Engagement part 11b Pole guide protrusion 12 Return spring 13 Latch Cup 13b Spring hanger 13c Pole guide hole 13d Internal teeth 14 Flange 15 Lock member 15a Engagement part 15b Hole 15c hole 16 Sensor spring 17 Plain washer 18 Friction spring 18a Engagement part 18b Engagement part 19 Ratchet wheel 19a Tooth 19b Inner peripheral wall Reference Signs List 20 tapping screw 21 sensor cover 22 return spring 27 sensor case 28 sensor arm 29 ball weight 31 Click means 32 vehicle acceleration sensing means 33 through hole

Claims (1)

(57) [Scope of request for utility model registration] 1. A claw wheel attached to a winding shaft of a retractor on which a webbing is wound, an inertia member rotating following the winding shaft, and rotating together with the winding shaft in a webbing pull-out direction. A latch member for engaging a pawl member with the ratchet wheel to lock the rotation of the take-up shaft in the webbing pull-out direction; and a latch member via the lock member when the inertial member has a rotational delay with respect to the take-up shaft A seat belt retractor having an emergency lock mechanism including a lock means for connecting a member to a take-up shaft, wherein an annular friction spring is frictionally engaged with a mounting portion of the inertia member so as to be relatively rotatable, and at least the friction is increased. Both ends of the spring are locked to locking portions provided on the lock member so as to restrict deformation of the spring in the radial direction. And seat belt retractor.