JPH11105671A - Seat belt retractor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a seat belt retractor that allows a larger number of turns of a turisted cut on its torsion bar despite of a limited size of its retractor base. SOLUTION: A seat belt retractor 100 comprises a torsion bar 2 coupled at its one end to a bobbin 3 by means of a retainer 40 against relative rotation and at the other to a locking base 5 against relative rotation, and an emergent lock means 300 for engaging the locking base 5 with a retractor base 1, at a vehicle emergency, to check the rotation of the torsion bar 2 or bobbin 3 in the webbing direction. The torsion bar 2 is coupled to the end of the bobbin 3 at its bobbin-connection part 2a, which is situated outside the side plate 1b of the retractor base 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a retractor (winding device) for a seat belt device, and more particularly to a seat belt retractor provided with an energy absorbing mechanism using a torsion bar.

[0002]

2. Description of the Related Art Conventionally, in a seat belt retractor for holding a vehicle occupant or the like safely in a seat, a retractor is physically locked by inertial sensing means that responds to sudden acceleration, collision or deceleration. Various emergency lock type retractors that include an emergency lock mechanism and effectively and safely restrain an occupant have been used.

[0003] Such an emergency lock type retractor is disclosed in, for example, Japanese Patent Application Laid-Open No. 50-79024 and Japanese Patent Publication No.
As in the seat belt retractor disclosed in Japanese Patent Publication No. 21624 and Japanese Utility Model Publication No. 2-45088, an engaging member disposed at one end of a winding shaft on which webbing is wound is provided with a retractor base in a vehicle emergency. There is a type provided with a lock means which can be engaged with the engaged portion to prevent the winding shaft from rotating in the webbing withdrawing direction.

On the other hand, in an emergency lock type retractor, when the emergency lock mechanism is actuated by collision to prevent the webbing from being pulled out, when the impact force due to the collision is extremely large, the retractor acts on the webbing as time elapses after the collision. As a result, the load applied to the occupant from the webbing becomes extremely large. Therefore, recently, when the tension acting on the webbing becomes equal to or more than a predetermined value set in advance, the webbing is extended by a predetermined amount to provide an energy absorbing mechanism that absorbs an impact generated on the occupant's body. There have been proposed various seatbelt retractors that provide more reliable protection.

[0005] As a seat belt retractor provided with the above energy absorbing mechanism, a substantially cylindrical take-up shaft on which webbing is wound, and one end of which is inserted through a center hole of the take-up shaft. A torsion bar coupled to the take-up shaft so as to be relatively non-rotatable and having the other end non-rotatably coupled to the locking base; and a torsion bar which engages the locking base with a retractor base in a vehicle emergency. Emergency lock means for preventing rotation of the winding shaft in the webbing withdrawal direction by preventing rotation of the winding shaft, when the tension applied to the webbing at the time of operation of the emergency lock means exceeds a predetermined value set in advance, Various arrangements have been proposed which absorb the collision energy by the torsional deformation of the torsion bar and control the tension acting on the webbing (Japanese Patent Laid-Open No. 6-15). Referring like 884 item and the 7-47923 JP).

[0006] As described above, the configuration in which the torsion deformation of the torsion rod inserted into the center hole of the winding shaft absorbs the collision energy is achieved by, for example, the plastic deformation of the winding shaft itself or the retractor base. Compared to the configuration that absorbs energy, the degree of freedom in designing the amount of energy absorption and the amount of webbing extended is high, and the structure is simple and suitable for reducing the size of the retractor.

[0007]

The number of rotations of the torsion bar in the conventional seat belt retractor decreases as the diameter of the torsion bar increases, and increases as the length of the torsion bar increases. Therefore, if the torsion bar is made thicker to obtain a high torsional torque, there arises a problem that the number of revolutions for threading becomes insufficient. When a long energy absorption length is required, the length of the torsion bar needs to be increased. However, the retractor for a seat belt attached to a vehicle body has dimensional restrictions, and the width of the retractor base is limited. However, there is a problem that it is not possible to simply increase the length of the torsion bar.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide a seat belt retractor capable of increasing the number of rotations of a torsion bar in a limited size of a retractor base. To provide.

[0009]

SUMMARY OF THE INVENTION The object of the present invention is to provide a winding shaft having a substantially cylindrical shape on which a webbing is wound, and one end of which is inserted through a center hole of the winding shaft and is relatively opposed to the winding shaft. A torsion bar that is non-rotatably coupled and the other end is non-rotatably coupled to the locking base, and that the locking base is engaged with a retractor base to prevent rotation of the torsion bar in a vehicle emergency. Emergency locking means for preventing the take-up shaft from rotating in the webbing withdrawing direction; if the tension acting on the webbing exceeds a predetermined value when the emergency locking means is actuated, the torsion of the torsion bar causes the occupant's body to twist. A retractor for a seat belt that absorbs an impact, wherein at least one of the torsion bars connected to the winding shaft and the locking base is connected to the retractor base. It is achieved by a seat belt retractor, characterized in that there is more side plate on the outside.

[0010] According to the above structure, the distance between the connecting portions provided at both ends of the torsion bar and connected to the winding shaft and the locking base is widened, so that the length of the torsion bar can be increased without increasing the total length. The substantial length of the torsional deformation portion formed between the coupling portions can be increased.

Preferably, a coupling portion of the torsion bar coupled to the winding shaft is inserted into an insertion hole of a retainer fitted in a fitting concave portion formed at one end of the winding shaft. Thus, the retainer is integrally rotatably coupled to the take-up shaft, the insertion hole of the retainer is a deep hole extending in the axial direction, and the coupling portion fitted into the insertion hole is located outside the side plate. It is configured as follows.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A seat belt retractor according to an embodiment of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a front longitudinal sectional view of a seat belt retractor 100 according to a first embodiment of the present invention, and FIG. 2 is an exploded perspective view of a main part of the seat belt retractor 100 shown in FIG.

The seat belt retractor 100 according to the first embodiment has a bobbin 3 as a substantially cylindrical take-up shaft on which webbing is wound, and the bobbin 3 is inserted through the bobbin 3 so as to be rotatable on the retractor base 1. And is integrally connected to the bobbin 3 at one end (right side in FIG. 1), and a disc-shaped locking base 5 at the other end (left side in FIG. 1).
A torsion rod 2 having a columnar shape integrally formed with the locking base 5 and an emergency locking means 300 for preventing the locking base 5 from rotating in the webbing withdrawing direction in a vehicle emergency.

The retractor base 1 is formed by press-forming a metal plate so that left and right side plates 1a and 1b rise from both sides of a back plate 1c fixed to a vehicle body and have a substantially U-shaped cross section. A torsion bar 2 combined with the bobbin 3 is rotatably bridged at a position facing the left and right side plates 1a and 1b. Side plate 1 of the retractor base 1
A known take-up spring device (not shown) for constantly urging the bobbin 3 in the webbing take-up direction via the torsion bar 2 is provided at one end of the torsion bar 2 through which the b is inserted.

At one end of the torsion bar 2, there is provided a bobbin connecting portion 2a for integrally rotating with the bobbin 3, and at the other end, a locking base connecting portion for integrally rotating with the locking base 5. 2b. Each of these connecting portions 2a and 2b has a cross-sectional shape formed into a hexagon. The bobbin coupling portion 2a has a hexagonal cross section, and is inserted into a hexagonal cross-section insertion hole 40a of a retainer 40 fitted into a hexagonal cross section fitting concave portion 3a formed at one end of the bobbin 3. Thus, it is integrally rotatably connected to one end of the bobbin 3.

Further, an insertion hole 40 of the retainer 40 rotatably supported on the side plate 1b via a bush 41.
a is a deep hole extending in the axial direction;
The bobbin connecting portion 2a inserted into the outer plate 0a is located outside the side plate 1b. The bobbin connecting portion 2a of the torsion bar 2 is rotatably connected to the bobbin 3 via the retainer 40 having sufficient strength. The bobbin connecting portion 2a is connected to one end of the bobbin 3 (see FIG. 1
Bobbin 3 in spite of being configured to be located outside the side plate 1b that is axially outward from the middle and right sides).
Is rotatably coupled to one end of the bobbin 3 with sufficient coupling strength without complicating the structure.

On the other hand, the locking base coupling portion 2b has a hexagonal cross section, and is inserted into a hexagonal cross section insertion hole 8a of a cylindrical boss portion 8 protruding from an end surface of the locking base 5 on the bobbin side. Thus, it is integrally rotatably coupled to the locking base 5. At the end of the bobbin 3 on the locking base side, a fitting recess 9 for receiving the boss 8 of the locking base 5 is recessed, and the bobbin 3 rotates relative to the torsion bar 2 via the fitting recess 9. It is supported as much as possible.

The torsion rod 2 is applied with a rotational torque of a predetermined value or more between the connecting portions 2a and 2b, and
This is an energy absorbing mechanism configured to absorb the impact energy acting on the occupant's body by causing the torsional deformation portion 2c formed between a and 2b to torsionally deform. That is, in the torsion bar 2 of the present embodiment, since the bobbin connecting portion 2a is located outside the side plate 1b, the interval between the connecting portions 2a and 2b is increased.
Without increasing the total length of the torsion bar 2, the substantial length of the torsionally deformable portion 2c formed between the coupling portions 2a and 2b can be increased.

In the present invention, various known structures can be employed as the specific structure of the emergency locking means 300 for restricting the rotation of the locking base 5 in the webbing withdrawing direction in the event of a vehicle emergency. For example, in the case of the first embodiment, as shown in FIG. 2, a pole 16 having a locking tooth 16a at the tip is rotatably supported on the support shaft 7 of the locking base 5. On the outside of the through hole 20 opened in the side plate 1a, an internal tooth ratchet 21 having an engagement internal tooth 25 on the inner periphery with which the locking tooth 16a can be engaged is provided.
Are juxtaposed.

The emergency locking means 300 provided in the sensor cover 35 is provided with the pole 1 in the event of a vehicle emergency.
The engagement teeth 16a of the sixth engagement teeth engage with the engagement internal teeth 25 of the internal ratchet 21, thereby preventing the locking base 5 from rotating in the webbing pull-out direction.

Next, the operation of the seat belt retractor 100 of the first embodiment will be described. When the emergency locking means 300 operates in the event of a vehicle emergency such as a collision, the locking base 5 connected to the other end of the torsion bar 2 is prevented from rotating in the webbing pull-out direction. Then, a rotation torque equal to or greater than a predetermined value is generated by the load acting on the
When it acts on one end side of the torsion bar 2 through the torsion bar, the torsion deformation of the torsion bar 2 starts and the impact energy is absorbed.

During the shock energy absorbing operation, the end of the bobbin 3 on the locking base side is connected to the torsion rod 2.
, The bobbin 3 having the fitting recess 9 rotatably supported by the boss 8 of the locking base 5 can slide smoothly. Therefore, the energy absorption load absorbed by the torsion bar 2 torsionally deforming stably changes according to the torsion angle.

The torsion bar 2 has a bobbin connection portion 2a located outside the side plate 1b, so that the bobbin connection portion 2a and the locking base connection portion 2b provided at both ends of the torsion bar 2 are formed. The distance between the connecting portions 2a, 2a is increased without increasing the total length of the torsion bar 2.
The substantial length of the torsionally deformed portion 2c formed between "b" and "b" is increased. Thus, the seat belt retractor 100 of the present embodiment can increase the number of threading rotations of the torsion bar 2 without increasing the axial width of the retractor base 1, and provides a stable margin of threading rotation. Number can be secured. Therefore, even if the torsion bar 2 is made thick to obtain a high torsional torque, or even if a long energy absorption length is required, it is possible to reliably avoid a situation in which the number of revolutions of the thread is insufficient.

FIG. 3 is a front vertical sectional view of a seat belt retractor 200 according to a second embodiment of the present invention.
The same components as those of the seat belt retractor 100 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. The seat belt retractor 200 of the second embodiment is rotatably supported by the retractor base 1 through the bobbin 3 and at one end (FIG. 3).
The middle and right sides) are integrally connected to the bobbin 3, and the other end side (the left side in FIG. 3) has a disc-shaped locking base 15.
A torsion rod 12 having a columnar shape and integrally connected to the main body, and an emergency locking means 300 for preventing the locking base 15 from rotating in the webbing withdrawing direction in a vehicle emergency.

At one end of the torsion bar 12, there is provided a bobbin connecting portion 12a which can rotate integrally with the bobbin 3.
On the other end side, there is a locking base connecting portion 12b that performs a rotatable connection with the locking base 15.
Each of these connecting portions 12a and 12b has a hexagonal cross section. The bobbin coupling portion 12a has a hexagonal cross section, and is inserted into a hexagonal cross-section insertion hole 42a of a retainer 42 fitted in a hexagonal cross section fitting concave portion 3a formed at one end of the bobbin 3. Thus, it is integrally rotatably connected to one end of the bobbin 3.

On the other hand, the locking base connecting portion 12b
Has a hexagonal cross section, and is inserted into a hexagonal cross-section insertion hole 18a of a cylindrical boss portion 18 protruding from the bobbin-side end surface of the locking base 15 so that the locking base 15
And are integrally rotatable. The insertion hole 18a is
The locking base coupling portion 12b inserted into the insertion hole 18a is a deep hole extending in the axial direction.
It is configured to be located outside of a. At the end of the bobbin 3 on the locking base side, a fitting recess 9 for receiving the boss portion 18 of the locking base 15 is provided, and the bobbin 3 is rotated relative to the torsion bar 12 through the fitting recess 9. It is supported as much as possible.

The torsion bar 12 is connected to the connecting portions 12a, 1
A rotation torque equal to or more than a predetermined value acts between the joints 2b and the torsional deformation portion 12c formed between the coupling portions 12a and 12b causes torsional deformation, thereby absorbing impact energy acting on the occupant's body. It is a configured energy absorption mechanism. That is, the torsion bar 1 in the present embodiment
2, since the locking base 12b is located outside the side plate 1b, the distance between the connecting portions 12a, 12b is widened, so that the connecting portions 12a, 12b can be increased without increasing the total length of the torsion bar 2. The substantial length of the torsional deformation portion 12c formed therebetween can be increased.

Accordingly, similarly to the seat belt retractor 100 of the first embodiment, the seat belt retractor 200 of the second embodiment can be provided with a torsion bar without increasing the axial width of the retractor base 1. The twelve screw rotation speeds can be increased, and a stable margin of screw rotation speed can be secured. Therefore, even if the torsion bar 12 is made thicker to obtain a high torsion torque, or even if a long energy absorption length is required, it is possible to reliably avoid a situation where the number of revolutions of the thread is insufficient.

In each of the above embodiments, one of the connecting portions of the winding shaft and the torsion bar connected to the locking base is located outside the side plate of the retractor base. The connecting portion of the torsion bar connected to the locking base may be located outside the side plate of the retractor base. In the emergency locking means in the above embodiment, the pawl rotatably supported by the locking base is locked to the engaged portion of the retractor to prevent the locking base from rotating in the webbing pull-out direction. However, the present invention is not limited to this, and the locking means may be configured by providing latch teeth on the locking base and pivotally supporting the pole on the retractor.

Further, the seat belt retractor of the present invention is not limited to the configuration of the winding shaft, the torsion bar, and the like in the above-described embodiment, but may take various forms. For example, the configuration of the winding shaft is not limited to the one integrally formed by die cast molding of a lightweight alloy like the bobbin 3 in the above embodiment,
A structure in which a winding shaft made of a steel material is fitted into a bobbin made of a lightweight material such as a resin may be used. Further, the seatbelt retractor of the present invention may include a pretensioner mechanism for removing slack of the webbing by retracting the webbing in a vehicle emergency.

[0031]

As described above, according to the present invention, the distance between the connecting portions provided at both ends of the torsion bar and connected to the winding shaft and the locking base is widened, so that the total length of the torsion bar is reduced. Without increasing the length, the substantial length of the torsionally deformed portion formed between these coupling portions can be increased.

Therefore, the seatbelt retractor of the present invention can increase the number of rotations of the torsion bar without increasing the axial width of the retractor base, and provides a stable margin of rotation. Can be secured. Therefore, even if the torsion rod is made thick to obtain a high torsional torque, or even if a long energy absorption length is required, it is possible to reliably avoid a situation where the number of revolutions of the thread is insufficient.

[Brief description of the drawings]

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

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

FIG. 3 is a front vertical sectional view of a seat belt retractor according to a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Retractor base 1a Side plate 1b Side plate 2 Torsion rod 2a Bobbin connection part 2b Locking base connection part 2c Torsion deformation part 3 Bobbin 5 Locking base 40 Retainer 100 Seat belt retractor 300 Emergency locking means

Claims (1)

[Claims] 1. A substantially cylindrical take-up shaft on which a webbing is wound, one end of which is inserted through a center hole of the take-up shaft so as to be relatively non-rotatable and the other end is locked. A torsion bar coupled to the base so that it cannot rotate relative to the base, and in a vehicle emergency, the locking base is engaged with a retractor base to prevent the torsion bar from rotating, thereby preventing the winding shaft from rotating in the webbing withdrawing direction. An emergency lock means for preventing the seat belt, wherein when the tension applied to the webbing at the time of activation of the emergency lock means exceeds a predetermined value, the retractor for the seat belt absorbs an impact generated on the occupant's body by the torsional deformation of the torsion bar. And a connecting portion of at least one of the torsion bar connected to the winding shaft and the locking base is located outside a side plate of the retractor base. Retractor for a seat belt.