JPH0347953Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of application of the invention] The present invention is used in a webbing retractor for restraining an occupant of a vehicle seat belt device, and is a retractor that engages with a ratchet wheel to prevent webbing from being pulled out in the event of a vehicle emergency. Regarding a lock bar for a device.

[Background technology]

Generally, a ratchet wheel is coaxially secured to the winding shaft, and a lock bar is provided to correspond to the ratchet wheel. When the webbing is attached or in a vehicle emergency, the lock mechanism is activated, the lock bar engages with the ratchet wheel, and rotation of the take-up shaft to pull out the webbing is prevented.

Therefore, in the event of a vehicle emergency, the webbing is prevented from being pulled out, and the occupant is restrained and protected by the webbing.

However, in order to reduce the weight of the winding device, it is necessary to reduce the thickness of the leg plates, etc.
When a sudden speed change occurs in the vehicle and a very large tensile force is applied to the webbing due to the inertia of the occupant, the lock bar engages each ratchet foil differently due to deformation of the parts, and stress concentrates on one engagement part. This may cause damage to parts.

[Purpose of invention]

In consideration of the above facts, the present invention aims to provide a lock bar for a winding device that has a simple structure and can ensure that the lock bar is engaged with each ratchet wheel even when a large webbing tensile force is applied in the event of a vehicle emergency. .

[Structure of the idea]

The present invention provides a lock bar for a take-up device that engages two ratchet wheels attached to a take-up shaft to prevent the take-up shaft from rotating to pull out the webbing. A tooth portion that can engage with each ratchet wheel is provided at a position that interferes with the ratchet wheel, and the tip of each tooth portion that is on the leg plate side with respect to the ratchet wheel is located on the side close to the winding shaft, and The tip of the ratchet foil that is on the webbing side is located on the side away from the take-up shaft, and the gap between the tip that is on the leg plate side and the tip that is on the webbing side is an inclined surface.

According to the above configuration, in the event of a vehicle emergency, the pair of teeth of the lock bar engages with each ratchet wheel, thereby preventing rotation of the winding shaft in the pull-out direction.

Here, if a relatively large tension is applied to the webbing and the leg plate etc. is slightly deformed, the state of engagement between the pair of teeth of the lock bar and each ratchet wheel will become symmetrical with respect to the axial middle part of the winding shaft. There is a risk that it will disappear. However, even in this case, according to the present invention, the tip of the leg plate side is located on the side closer to the take-up shaft with the ratchet foil of each tooth part as the center, and the webbing side is located with the ratchet foil of each tooth part as the center. The tip is located on the side away from the winding shaft, and there is an inclined surface between the tip on the leg plate side and the tip on the webbing side. The teeth of the locking bar move along said inclined surface relative to the ratchet wheel. This relative movement balances the engagement between the pair of teeth and avoids stress concentration on one of the engagement sections. Therefore, the engagement between the ratchet wheel and the lock bar is ensured.

Further, when a larger tension is applied to the webbing, the tip of the leg plate prevents the ratchet wheel from moving outward in the axial direction of the take-up shaft.
In other words, if the ratchet wheel attempts to move outward in the axial direction of the winding shaft by more than a predetermined amount (to the extent that it disengages from the teeth of the lock bar), the tip of this leg plate side prevents the ratchet wheel from moving. It functions as a stopper for For this reason,
Even when such a large tension is applied to the webbing, the engagement between the ratchet foil and the lock bar will not come off.

[Example of idea]

1 and 2 show a webbing retractor 10 to which a retractor lock bar according to the present invention is applied.

In this webbing retractor 10, a base 12 is fixed to a vehicle body 16 with bolts 14. A pair of leg plates 18 and 20 project from both ends of the base 12 in parallel with each other, and pivotally support the vicinity of both ends of the webbing take-up shaft 22.

One end of an occupant restraining webbing 24 is locked to the intermediate portion of the winding shaft 22. Further, the leg plate 20 is provided with a spring case 26, which houses a mainspring spring and biases and rotates the winding shaft 22 in the webbing winding direction.

Further, ratchet wheels 28 are fixed to the winding shaft 22 on both sides of the webbing 24 so as to rotate together with the winding shaft 22. Corresponding to this ratchet wheel 28 is a lock bar 30 which is pivotally supported on the leg plates 18, 20. Both ends of the lock bar 30 are housed in pivot holes 32 formed in the leg plates 18 and 20. As shown in FIG. 3, the lock bar 30 has projecting pieces 30A and 30B as teeth extending from the long side of the ratchet foil to the winding shaft 20.
They are arranged symmetrically with respect to the axially intermediate portion of the winding shaft 22, and when the tip thereof engages with the ratchet wheel 28, the rotation of the webbing pull-out of the winding shaft 22 is stopped.

Sides 30C at the tips of the protrusions 30A and 30B are inclined in opposite directions with respect to the axial direction of the winding shaft 22, and when the protrusions 30A and 30B engage with the latchet wheel 28, the force that the protrusions 30A and 30B receive from the latchet wheel is greater than the winding force. It has a component force in the axial direction of the shaft 22. The direction of this component force is on the longitudinal end side of the lock bar 30 (arrow X direction, Y direction), and the projections 30A and 30B
It is in the opposite direction. In addition, protrusions 30A and 30
The magnitude of the component force for B is usually the same.

Further, a winding diameter sensing arm 34 is fixed to the middle portion of the lock bar 30, and the curved tip of the winding diameter sensing arm 34 is in contact with the outer surface of the webbing on the winding shaft 22. This winding diameter sensing arm 34 detects that when the webbing 24 exceeds a predetermined amount, the mainspring spring winding device 26
When the webbing 24 is wound around the take-up shaft 22, the outer diameter of the webbing 24 increases to maintain the lock bar 30 in a position where it is not engaged with the ratchet wheel 28. However, when the occupant pulls out and attaches the webbing 24, the outer diameter of the webbing 24 becomes smaller, allowing the lock bar 30 to engage with the ratchet wheel 28.

End portion 22A of the winding shaft 22 protruding from the leg plate 18
As shown in FIG. 2, a spring member 36 is fitted therein. This spring member 36 has a forked shape and includes two legs 38 and 40, the tips of which are curved outward from each other and pressed against the end 22A of the winding shaft 22. The tip of the spring member 36, that is, both legs 3
The connecting portions 8 and 40 can come into contact with the lock bar 30.

Since the spring member 36 has a spring property in the direction in which the legs 38 and 40 approach each other, when the winding shaft 22 rotates, the spring member 36 rotates following the rotation of the winding shaft 22 due to frictional force. However, spring member 3
Since the pins 42 and 44 are arranged on both sides of the winding shaft 6, the rotation of the spring member 36 is restricted between the two pins 42 and 44, and when the winding shaft 22 further rotates, the spring member 36 rotates relative to the winding shaft 22. It's starting to slip. Therefore, the two pins 42 and 44 constitute a turning angle regulating means for the spring member 36.

On the other hand, since a tension coil spring 48 is connected to the lock bar 30 as shown in FIG. ing. This figure shows a state in which the webbing is slightly pulled out from a fully wound state, and the lock bar 30 is prevented from rotating by the winding diameter sensing arm 34.

The spring member 36 rotates until it comes into contact with the pin 42 when the take-up shaft 22 rotates in the webbing pulling direction. In this state, the lock bar 30 is spaced apart from the ratchet wheel 28. When the spring member 36 rotates in the winding direction from this state, it comes into contact with the pin 44 and the lock bar 30 is able to lock the ratchet wheel 28.

The webbing retractor 10 of this embodiment configured as described above performs an automatic locking operation in the following order.

In order to attach the webbing 24, the occupant can attach the intermediate portion of the webbing 24 by pulling out an end (not shown) of the webbing 24 and engaging the tongue plate attached to this end with the buckle.

When the webbing 24 is fully wound, the lock bar 30 is pressed down by the winding diameter sensing arm 34, and the lock bar 30 is disengaged. However, as the webbing 24 is slightly pulled out, the spring member 36 rotates until it comes into contact with the pin 42, and the tip of the spring member 36 prevents the lock bar 30 from pivoting. Therefore, even if the occupant pulls out the webbing 24 and the outer diameter of the webbing on the take-up shaft 22 is reduced, the lock bar 30 remains out of engagement with the ratchet wheel 28.

Next, when the occupant puts on the webbing 24, the occupant's posture changes and abdominal changes such as breathing occur before or immediately after assuming the driving position, so the webbing 24 is wound around the winding shaft 22 by a small amount. It will be done. As a result, the spring member 36 also turns in the winding direction (counterclockwise direction in FIG. 2), and the spring member 36
The rotation prevention effect of the lock bar 30 is released. Therefore, the lock bar 30 engages with the ratchet wheel 28 by the biasing force of the tension coil spring 48, and rotation of the take-up shaft 22 in the webbing unwinding direction is prevented.

Note that since the ratchet wheel 28 has a sawtooth shape, it is possible to wind the webbing 24 around the winding shaft 22. Therefore, when the webbing 24 is attached to a passenger or luggage, a reliable restraining force can be obtained by the automatic locking action.

To cancel the webbing unwinding stop of the winding device, it is sufficient to remove the tongue plate from the buckle and wind up a predetermined amount or more of the webbing 24 onto the winding shaft 22 using the mainspring spring built into the spring case 26. As the winding diameter of the webbing on the winding shaft 22 increases, the winding diameter sensing arm 34 pivots clockwise in FIG. 2, and the lock bar 30 also separates from the ratchet wheel 28 and returns to its initial state.

Next, in a vehicle emergency, a very large webbing tensile force acts due to the inertia of the occupant, and the leg plate 18,
The effect when 20 etc. is deformed will be explained.

Due to this deformation, the state of engagement with the ratchet wheel 28 differs between the protrusions 30A and 30B.
However, along with this, protrusions 30A and 30B
Since the magnitude of the component force in the axial direction of the winding shaft 22 received from the ratchet wheel 28 also changes, the lock bar 30 moves in its longitudinal direction. The direction of this movement is such that the engaged states of the protrusions 30A and 30B are the same due to the movement. For example, the first
In the figure, the engagement of the protrusion 30A is stronger than the engagement of the protrusion 30B, and the value of the component force in the direction of arrow
When the force becomes larger than the value of the component force in the direction, the lock bar 30 moves in the direction of the arrow X. As a result, the engaged states of the protrusions 30A and 30B are approximately the same,
The magnitude of each component force is also approximately the same. Furthermore, the component forces in the protruding direction of the protrusions 30A, 30B that the protrusions 30A, 30B receive from the ratchet foil 28 are also approximately the same. In addition, the leg plates 18, 20 and the lock bar 3
0 is also approximately the same on the protrusion 30A side and the protrusion 30B side.

In this way, the force applied to each part of the winding device is
The left side and the right side in FIG. 1 are approximately the same, making it possible to avoid concentration of stress. Therefore, the structure of the winding device 10 as a whole becomes strong.

Further, the tips of the protrusions 30A and 30B on the side of the leg plates 18 and 20 are located on the side close to the winding shaft 22,
Since the tips of the protrusions 30A and 30B on the webbing 24 side are located on the side away from the take-up shaft 22, a large tension is applied to the webbing 24 in the event of a vehicle emergency, causing the ratchet wheel 28 to move out of the axial direction of the take-up shaft 22. Even when the latch wheel 28 attempts to move in the opposite direction, the tips on the side of the leg plates 18, 20 prevent the latch wheel 28 from moving, so the latch wheel 28 and the protrusions 30A, 30B of the lock bar 30 do not come out of engagement.

Next, FIG. 4 shows a lock bar 50 according to a second embodiment of the present invention.

This lock bar 50 is provided with a protrusion 50A having a shape in which the protrusions 30A and 30B in FIG. 3 are connected. Also, the side 5 at the tip of the protrusion 50A
0C is curved.

Note that the tips of the protrusions 30A and 30B that engage with each of the ratchet wheels 28 are located on the side closer to the take-up shaft 22 on the side of the leg plates 18 and 20, and the tips on the webbing 24 side are located closer to the take-up shaft 22. It is sufficient that they are located on the side that separates from each other, and that there is an inclined surface between the tips of the two, and the angle of inclination of this inclined surface is equal to the angle of inclination of the winding shaft 22.
It does not necessarily have to be symmetrical about the axially intermediate portion of.

Further, the tooth tip surface of the ratchet foil may be inclined in accordance with this inclination.

The locking mechanism is not limited to automatic locking type.
It may be a mechanism that locks only in case of vehicle emergency.

[Effect of idea]

In the lock bar for a take-up device according to the present invention, the tip of each tooth of the lock bar that engages with each ratchet wheel is located on the side close to the take-up shaft, and the tip that is on the webbing side is located on the side that is close to the take-up shaft. It is located on the side away from the axis, and there is an inclined surface between the two tips, so even if the leg plate etc. deforms when a relatively large tension is applied to the webbing,
It is possible to reliably maintain the engagement state between each tooth of the lock bar and each ratchet foil, and even when a large tension is applied to the webbing, the tip of the tooth on the leg plate side is outside the axial direction of the winding shaft of the ratchet foil. This has an excellent effect in that the engaged state can be reliably maintained since movement in the opposite direction is prevented.

[Brief explanation of the drawing]

FIG. 1 is a partially sectional front view showing a first embodiment of the winding device lock bar according to the present invention, FIG. 2 is a left side view with the leg plate 18 of FIG. 1 removed, and FIG. 1 is a partial perspective view of FIG. 1, and FIG. 4 is a perspective view of a lock bar showing a second embodiment of the present invention. 10...Webbing take-up device, 28...Ratchet foil, 30, 50...Lock bar, 30
A, 30B, 50A... protrusion, 30C, 50C...
...side.

Claims (1)

[Scope of utility model registration request] In a take-up device lock bar that engages with two ratchet wheels attached to a take-up shaft to prevent the take-up shaft from rotating to pull out the webbing, the take-up device lock bar has a position that interferes with the rotation locus of each ratchet wheel. are each provided with a tooth portion that can engage with each ratchet wheel, and the end of each tooth portion that is on the leg plate side is located on the side closer to the winding shaft with the ratchet foil of each tooth portion as the center. A lock bar for a take-up device, characterized in that a tip end facing the webbing side is located on a side away from the take-up shaft, and an inclined surface is formed between the front end facing the leg plate side and the front end facing the webbing side. .