JPH0320217Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a webbing retractor for retracting webbing for restraining an occupant, which is used in a seat belt device for protecting an occupant in an emergency for a vehicle.

A webbing take-up device used in a seat belt device uses a biasing force to wind up the end of the webbing for restraining an occupant, and in the event of a vehicle emergency, a lock device is used to instantly stop unwinding of the webbing.

This locking device has great strength because it is necessary to reliably support the inertia of the occupant who moves violently in the direction of collision in the event of a vehicle emergency.
For this reason, conventionally, a locking means has been widely used in which a ratchet wheel is fixed to the winding shaft, and a lock bar that is pivotally supported by a frame is engaged with the ratchet wheel.

However, although this meshing means consisting of a ratchet wheel fixed to the winding shaft and a lock bar can ensure the locking of the winding shaft, it has the disadvantage of increasing the outer diameter of the webbing winding device.

For this reason, a webbing take-up device has been proposed in which a lock plate is attached to a take-up shaft and this lock plate is engaged with an internal toothed ratchet in case of a vehicle emergency.

However, in this winding device, the internal ratchet is attached to a frame for supporting the winding shaft using rivets or the like, and the structure is complicated and assembly is complicated.

Japanese Patent Laid-Open No. 2003-193333 proposed a structure that attempted to solve this problem by carving internal teeth into one leg plate of the frame.
It is disclosed in Publication No. 52-111122.

However, in this structure, the center of engagement between the locking body and the internal teeth is offset from the center of the wall thickness of one of the leg plates, so that in the event of a vehicle emergency, the impact load applied to the locking body is reliably transmitted to the vehicle body via the leg plate. The problem arises that it is not possible to do so.

In consideration of the above facts, the present invention aims to provide a webbing retractor that has a simple structure, is easy to assemble, and is capable of reliably transmitting the impact load applied to the lock plate to the vehicle body in the event of a vehicle emergency. .

In order to achieve the above object, the present invention has a step portion formed near the outer periphery of the internal tooth ratchet of the leg plate on the side adjacent to the lock plate, so that the center of engagement between the internal tooth ratchet and the lock tooth is on the side adjacent to the lock plate. The thickness center of the leg plate near the side of the vehicle body is approximately aligned with the center of the thickness of the leg plate.

In addition, the internal tooth ratchet is characterized by being carved around a through hole formed in the leg plate, and a sheet is attached to the leg plate in which the through hole is formed to support the winding shaft. There is.

According to the above structure, since the internal tooth ratchet is carved directly into the leg plate, there is no need to manufacture a separate part with the internal tooth ratchet carved into it, and while positioning such a separate part, rivets etc. can be attached to the leg plate. There is no need to install it. Therefore, in the webbing retractor according to the present invention, which is provided with a leg plate in which internal ratchets are directly carved, the structure can be simplified, and the assembly work can be easily performed.

Furthermore, since the center of meshing between the internal ratchet and the lock teeth is approximately aligned with the center of wall thickness near the side of the adjacent leg plate on the vehicle body side,
This ensures reliable transmission of impact loads that occur during vehicle emergencies. Therefore, the occupants are reliably protected even in a vehicle emergency.

Next, the principle supporting the reliability of transmission of impact load in the event of a vehicle emergency according to the present invention will be explained using FIGS. 8A and 8B.

FIG. 8A shows a key feature of a structure in which, unlike the present invention, the center of meshing between the internal ratchet and the lock teeth is not approximately aligned with the center of wall thickness near the side of the adjacent leg plate on the vehicle body side. The section is shown enlarged. Further, in FIG. 8B, the stepped portion of the present invention is provided, and the center of engagement between the internal ratchet and the lock tooth is approximately aligned with the center of wall thickness near the side of the adjacent leg plate on the vehicle body side. The main parts of the structure are shown enlarged.

Here, in both the structures shown in FIGS. 8A and 8B, it is assumed that in the event of a vehicle emergency, the lock plate and the internal toothed ratchet engage, and at this time, the same impact load (rotational force) F is applied to the leg plate. . Also,
In this state, the moment applied to the leg plate
Length L′ of arm of M′ and length L of arm of moment M
is assumed to be the length from the center plane of the flesh pressure of the effective portion when the leg plate supports the load to the impact load F.

In the structure shown in FIG. 8A, the center of engagement with the internal teeth ratchet of the lock plate is shifted from the center plane of the wall thickness of the effective portion of the leg plate compared to the structure shown in FIG. 8B. , the arm length L' in the structure shown in FIG. 8A is longer than the arm length L in the structure shown in FIG. 8B. Therefore, the moment M'(=F×L') generated in the structure shown in FIG. 8A is greater than the moment M (=F×L) generated in the structure shown in FIG. 8B.
becomes larger than

As a result, in the structure shown in FIG. 8B, that is, in the present invention, the lock plate touches the tip of the tooth of the internal tooth ratchet at the moment the lock plate engages with the internal tooth ratchet, or conversely, the internal tooth ratchet touches the tooth of the lock plate. There is no possibility of misalignment caused by crushing the tip. Furthermore, if a large moment M' is repeatedly applied to the leg plate as in the structure shown in FIG. Nothing happens. Furthermore, if the leg plate is deformed, there is a risk that there will be a portion where the depth of engagement between the lock teeth of the lock plate and the internal tooth ratchet becomes shallow, but this does not occur with the present invention. From these points, according to the present invention, the impact load that occurs during a vehicle emergency can be reliably transmitted. Therefore, the occupants are reliably protected even in a vehicle emergency.

In the structure shown in FIG. 8A, in order to reliably support the impact load in the event of a vehicle emergency, it is necessary to take measures such as increasing the thickness of the leg plate, but according to the present invention, Even if relatively thin leg plates are used to reduce the weight of the vehicle, the impact load can be reliably supported.

Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIGS. 1 to 4, the webbing retractor 10 according to this embodiment has a frame 12 fixed to a vehicle body 16 by mounting bolts 14. As shown in FIGS.

A take-up shaft 22 is pivotally supported on leg plates 18 and 20 extending parallel to each other from both sides of the frame 12, and one end of an occupant restraint webbing 24 is layered in the center of the take-up shaft 22. It is wound up. Further, the inner end of a mainspring spring 26 is attached to the end of the winding shaft 22 that passes through the leg plate 20, and the outer end of this mainspring spring is connected to a spring case 28 fixed to the leg plate 20.
It is locked to. Therefore, the winding shaft 22 is biased in the winding direction of the webbing 24 (in the direction of arrow A in FIGS. 2 and 3).

One of the leg plates 18 has a deflection section 30 formed in the middle thereof via a stepped section. This deflection portion 30 is parallel to the leg plates 18 and 20, and the leg plate 2 of the leg plate 18 is parallel to the leg plates 18 and 20.
It stands out near 0. A circular hole 31 for supporting the winding shaft 22 is bored in the deflection portion 30 .

An internal ratchet 32 is cut into the stepped portion between the deflection portion 30 and the leg plate 18.

A second deflection section 64 is formed on the outer periphery of the internal ratchet 32 of the leg plate 18 so as to protrude from the leg plate 18 in a direction opposite to the deflection section 30 . Further, the center of engagement between the internal tooth ratchet 32 and the lock plates 34, 36 is arranged so that it coincides with the center of thickness of the portion of the leg plate 18 on the side separated from the lock plates 34, 36 with the second deflection portion 64 in between. Second deflection section 64
The protrusion length is set.

The internal toothed ratchet 32 is disposed coaxially with the circular hole 31 and the winding shaft 22, and corresponds to a pair of lock plates 34 and 36, which are also shown in FIGS.

These lock plates 34 and 36 have a rectangular protrusion 3 in the center that is a radial protrusion of the winding shaft 22.
A recess 40 is provided for receiving the lock plate 8, thereby giving the lock plates 34, 36 a generally C-shaped overall shape. Also, both ends of this C-shape,
That is, the lock plates 34, 3 which sandwich the winding shaft 22
The end face 42 of the winding shaft 22 is arranged on a straight line including the axis of the winding shaft 22, and serves as a contact surface with the other lock plate.

A lock pawl 44 is formed on a part of the outer periphery of the pair of lock plates 34, 36, and when the lock plates 34, 36 move in opposite directions, the lock plates 34, 36 engage with the internal toothed ratchet 32. The rotation of the winding shaft 36 around the winding shaft 22 is stopped (see FIG. 5). Furthermore, a pair of pins 46 protrudes from one side of each of the lock plates 34, 36 in parallel with the winding shaft 22.

A support shaft 48 is disposed coaxially with the rectangular protrusion 38 of the winding shaft 22 and rotates in pairs with the winding shaft 22 . A lock ring 50 is supported on this support shaft 48 so as to be rotatable relative to the support shaft 48, and as shown in FIG. 6, four elongated holes 52 are formed in the lock plate side surface of this lock ring 50. has been done. Pins 46 protruding from the lock plates 34 and 36 are accommodated in these long holes 52, respectively, so that the pair of lock plates 34 and 36 can move in opposite directions by the stroke of the long holes 52.

A torsion coil spring 54 is interposed between the lock ring 50 and the support shaft 48, and the lock ring 50 is urged clockwise (webbing pulling direction) with respect to the winding shaft 22 in FIG. 3. Therefore, the lock ring 50
When the take-up shaft 22 is pulled out in the webbing pull-out direction at a predetermined acceleration or less, it receives a spring biasing force, follows the take-up shaft 22, and rotates integrally with the take-up shaft 22. However, when the webbing pull-out acceleration of the take-up shaft exceeds a predetermined value, the torsion coil spring 54 is deflected to cause a rotation delay. When this rotational delay occurs, the winding shaft 22 moves the lock plates 34, 36 in opposite directions as shown in FIG.
moves within the elongated hole 52.

A pin 55 protrudes from the surface of the lock ring 50 facing the lock plates 34, 36 in parallel with the axis of the winding shaft, and together with the rectangular projection 38 of the winding shaft 22 constitutes positioning means. This pin 55 abuts against the rectangular protrusion 38 to position the lock ring 50, as shown in FIG. 3, in a normal state in which the take-up shaft is not rapidly rotating to draw out the webbing. As a result, the relative rotation between the locking wheel 50 and the winding shaft 22 is maintained accurately.

The lock ring 50 has ratchet teeth 56 on its outer periphery.
is engraved and corresponds to the pawl 58 pivotally supported on the leg plate 18. This pole 58 is the leg plate 18
It is pushed up by an inertia ball 62 housed in a case 60 of the casing 60 so as to mesh with the ratchet teeth 56. This inertial ball 62 separates the pawl 58 from the ratchet teeth 56 when the vehicle is normally running, but when the vehicle acceleration reaches a predetermined value, it moves and meshes the pawl 58 with the ratchet teeth 56.
The rotation of the lock ring 50 in the webbing pull-out direction is stopped to create a rotation delay between the lock ring 50 and the take-up shaft 22.

Winding device 10 of the present embodiment configured as described above
In this case, since the internal tooth ratchet 32 is carved directly into the leg plate 18, there is no need to manufacture a separate part on which the internal tooth ratchet is carved, and while positioning such a separate part, it is possible to rivet the leg plate 18 etc. No need to install.

To explain the operation of this embodiment, the occupant unwinds the webbing 24 from the take-up shaft 22 and puts it on. The drawer in the normal use state of this webbing 24,
During the winding operation, a large rotational acceleration is not generated on the winding shaft 22, so the locking wheel 50 rotates following the winding shaft 22, and the rotation of the winding shaft 22 to be pulled out is not locked.

When the vehicle is in an emergency situation such as a collision, the occupant wearing the webbing 24 moves violently in the direction of the collision, so the webbing 24 is suddenly unwound from the take-up shaft 22, and a large unwinding acceleration is generated on the take-up shaft 22. do.

As a result, the lock wheel 50 lags in rotation with respect to the winding shaft 22, and the rectangular protrusion 38 drives the lock plates 34, 36 in opposite directions through the recess 40, causing the lock wheels 50 to rotate in opposite directions as shown in FIG. It meshes with the tooth ratchet 32. Therefore, the rotation of the webbing pull-out of the take-up shaft 22 is stopped instantaneously, and the occupant can unload the webbing 2.
Safety can be ensured through the secure restraint state described in step 4.

In addition, since the vehicle acceleration that occurs in a vehicle emergency moves the inertia pole 62, the pawl 58 meshes with the ratchet teeth 56 and the rotation of the webbing pull-out of the lock wheel 50 is stopped. A relative rotation occurs between the webbing 24 and the webbing 24, so that the occupant can be reliably restrained by the webbing 24.

When the emergency state of the vehicle ends, the lock play 34, 3 is released by slightly winding up the webbing 24.
6 is again separated from the internal tooth ratchet 32 to the state shown in FIGS. 1 and 3, and can be used as a normal winding device.

Here, in this embodiment, by providing the second deflection section 64, the internal tooth ratchet 32 and the lock plates 34, 36 are engaged with each other, and the second deflection section 64 is interposed between the meshing center and the lock plates 34, 36. Since the thickness centers of the leg plates 18 on the side separated from each other are set to coincide with each other, it is possible to reliably transmit the impact load applied to the lock plates 34 and 36 to the vehicle body 16 via the leg plates 18 in the event of a vehicle emergency. can. Therefore, it is possible to improve the restraint of the occupant during a vehicle emergency. Note that the principle supporting the reliability of transmission of the impact load in the event of a vehicle emergency in this embodiment is the same as the principle explained using FIGS. 8A and 8B, so its explanation will be omitted.

In addition, in the present invention, by appropriately adjusting the protruding length of the second deflection portion 64, the lock plate 3
No matter what the wall thickness dimensions of 4 and 36 are,
There is an advantage that the center of engagement and the center of wall thickness can be adjusted to match.

Next, FIG. 7 shows a second embodiment of the present invention. In this embodiment, a through hole is formed in the leg plate 18, and an internal tooth ratchet 32 is carved around the through hole. Further, a plurality of small holes 66 parallel to the winding shaft 22 are bored at appropriate positions in the leg plate 18, so that a sheet 68 which is brought into contact with the inside of the leg plate 18 can be attached. That is, sheet 6
A plurality of bullet holes 70 protrude from 8 in correspondence with the small holes 66, and if the tips 70A of the bullet holes 70 are expanded after passing through the small holes 66, the seat 68 will be locked to the leg plate 18. It's getting old.

This seat 68 is adapted to abut against the lock plates 34 and 36, and is adapted to pivotally support the winding shaft 22 through a circular hole 72 formed in its shaft center.

In this third embodiment, the internal ratchets can be carved at the same time as the through holes are drilled in the leg plate 18, so that manufacturing is easier than in the first embodiment.

In the above embodiment, a structure using a pair of lock plates has been described, but the present invention can be applied to any structure in which the lock plate attached to the winding shaft meshes with the internal tooth ratchet in case of a vehicle emergency.

As explained above, the webbing retractor according to the present invention has a simple structure, is easy to assemble, and has the excellent effect of being able to reliably transmit the impact load applied to the lock plate to the vehicle body in the event of a vehicle emergency. .

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing a first embodiment of the webbing retractor according to the present invention, Fig. 2 is a left side view of Fig. 1, Fig. 3 is a sectional view taken along the line of Fig. 1, and Fig. 4 is a frame. and an exploded perspective view showing related parts; FIG. 5 is an operating diagram showing the locking state of the locking mechanism; FIG. 6 is a side view of the lock ring as seen in the line direction of FIG. 1;
FIG. 7 is a sectional view corresponding to FIG. 1 showing a second embodiment of the present invention, and FIGS. 8A and 8B are operation diagrams for explaining the difference in the way the impact load is transmitted in the event of a vehicle emergency. It is a principle diagram. 10... Winding device, 12... Frame, 18,
20... Leg plate, 22... Winding shaft, 24... Webbing, 30... Deviation part, 32... Internal tooth ratchet, 34, 36... Lock plate, 68... Sheet.

Claims (1)

[Claims for Utility Model Registration] (1) A winding shaft for winding occupant restraint webbing in layers, and a pair of leg plates that are partially attached to the vehicle body and are substantially parallel to each other, and the winding shaft has a a frame whose axially opposite ends are pivotally supported by the pair of leg plates; and a frame which is held near one end of the winding shaft and is movable substantially in the radial direction of the winding shaft, at least on the moving direction side. a pair of lock plates having teeth formed at the ends thereof, and a recess for accommodating the pair of lock plates in a leg plate on a side adjacent to the lock plates, and facing the teeth of the recess. an internal toothed ratchet carved on a side surface, the webbing take-up device comprising: an internal toothed ratchet carved on a side surface, wherein a stepped portion is formed near the outer periphery of the internal toothed ratchet on the adjacent leg plate; A webbing retractor characterized in that the center of engagement with the lock teeth substantially coincides with the center of wall thickness near the end of the adjacent leg plate on the vehicle body side. (2) The internal ratchet is carved around a through hole formed in the leg plate, and a sheet is attached to the leg plate in which the through hole is formed to support the winding shaft. A webbing take-up device according to claim (1) of the utility model registration.