JPH09286302A - Seat belt retractor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To absorb collision energy which works upon an occupant's body at the time of vehicle collision effectively according to vehicle characteristics. SOLUTION: This seat belt retractor 100, which is fitted on a retractor base 1 so that it may rotate freely, is provided with a torsion bar 2 with a locking plate 5 provided at one end, an emergency locking means 300 which inhibits the locking plate 5 from rotating in the waving drawing-out direction at the time of vehicle emergency, a bobbin 3 around which waving is wound and is fitted at the other end of the torsion bar 2 so that it may rotate integrally, and a lock piece 15 which is disposed at a guide part 13 which is formed in a section facing the locking plate 5 and the bobbin 3. When the locking plate 5 and the bobbin 3 rotate relatively, the lock piece 15 conducts relative movement while deforming the narrow part of a guide groove 12 which constitutes the guide part 13.

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 having an energy absorbing mechanism.

[0002]

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

[0004] In the locking means, a locking mesh portion formed in a winding shaft through-hole of the retractor base through which the winding shaft passes, or an internal gear plate provided in parallel with the winding shaft through-hole. While the formed ratchet teeth are used as the engaged portion, a lock plate or a locking claw that rotates together with the winding shaft is used as the engaging member. Are engaged to prevent the take-up shaft from rotating in the webbing withdrawing direction.

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. As an example of a seat belt retractor having such a structure, an "energy absorbing device for a safety belt" described in Japanese Patent Application Laid-Open No. 46-7710 is known.

In the above-mentioned energy absorbing device, the energy absorbing device is provided with a winding member serving as a portion for transmitting a force, and a holder rotatable relative to the winding member. A torsion bar (energy absorbing mechanism) is arranged between the winding member and the winding member. Therefore, after the rotation of the take-up shaft is stopped in the event of a vehicle emergency, when a load is further applied to the locking means, the torsion bar is twisted around its own axis, so that the collision energy acting on the occupant's body is reduced. It is absorbed as deformation work of the torsion bar.

[0007]

However, the impact at the time of a collision differs depending on the vehicle structure, and in order to sufficiently protect the occupant's body, the load of the energy absorbing load (the load acting on the webbing) must be adjusted in accordance with the characteristics of the vehicle. It is necessary to obtain an arbitrary load characteristic by changing the curve. However, in the case of the energy absorbing mechanism using the torsion bar as described above, since the torsional deformation torque of the torsion bar is almost constant, the energy absorbing torque is almost constant over the entire operating range.

Therefore, an object of the present invention is to solve the above-mentioned problems, and to provide a good energy absorbing mechanism which can efficiently absorb the collision energy acting on the body of an occupant at the time of a vehicle collision in accordance with the vehicle characteristics. It is to provide a seat belt retractor.

[0009]

DISCLOSURE OF THE INVENTION The above object of the present invention is to provide a winding shaft rotatably mounted on a retractor base and having a locking plate at least at one end thereof, and a webbing withdrawing member for the winding shaft in case of a vehicle emergency. Emergency locking means for preventing rotation in the direction, a cylindrical bobbin around which the webbing is wound and which is rotatably supported by the winding shaft, and the locking plate and the bobbin, which are formed at opposing portions. A seatbelt retractor having a lock piece arranged in a guide portion, wherein when the locking plate and the bobbin rotate relative to each other, the lock piece relatively moves while deforming the guide portion. This is achieved by a seat belt retractor which is characterized by being possible.

In the present invention, the bobbin rotatably supported by the winding shaft is not permanently fixed to the winding shaft, but is always rotatable relative to the winding shaft. The bobbin that is axially supported and the take-up shaft rotate together with each other in a normal use state, but when a load larger than a predetermined amount is applied, the bobbin is axially supported so as to be relatively rotatable with respect to the take-up shaft. It includes a bobbin.

Therefore, preferably, the winding shaft is
The other end is attached so as to rotate integrally with the bobbin, and twists in response to a load greater than a predetermined value being applied to the locking means, thereby absorbing the collision energy acting on the body of the occupant as a deformation work. It is used as a torsion bar.
Also, preferably, the guide portion comprises a C-shaped guide groove formed on each of the facing surfaces of the locking plate and the bobbin, and at least one guide groove has a groove width larger than the width of the lock piece. A narrow deformation section is provided.

Further, preferably, the guide portion comprises a C-shaped guide groove formed in one of the facing surfaces of the locking plate and the bobbin, and is integrally formed on the other of the facing surface. The locked piece is projected. Further, preferably, the lock piece is pivotally supported by the winding shaft and is rotatably disposed in the guide portion.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a seat belt retractor according to the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a front vertical sectional view of a seat belt retractor 100 according to a first embodiment of the present invention.
FIG. 2 is a seat belt retractor 100 shown in FIG.
FIG. 4 is an exploded perspective view of a main part of FIG.

The seat belt retractor 100
Is a columnar torsion bar 2 which is a winding shaft rotatably attached to the retractor base 1 and has a disk-shaped locking plate 5 attached at least at one end, and a webbing withdrawal direction of the locking plate 5 in the event of a vehicle emergency. Emergency lock means 30 for preventing rotation of
0, a cylindrical bobbin 3 on which webbing is wound and which is attached to the other end of the torsion bar 2 so as to rotate integrally therewith; the locking plate 5 and the bobbin 3
And a lock piece 15 provided on a guide portion 13 formed at the opposite portion of the lock member.

The retractor base 1 has a substantially U-shaped cross section, and a torsion bar 2 combined with the bobbin 3 is rotatably bridged between the opposing side plates 1a and 1b. . The other end of the torsion bar 2, the webbing known winding spring device in the winding take the direction (direction of arrow X ₁₎ is normally urged to the torsion bar 2 (not shown) is disposed.

Outside the shaft through hole 20 provided in the side plate 1a, a substantially annular inner tooth ratchet 2 is provided.
1 are arranged side by side, and engagement inner teeth 25 are formed on the inner peripheral edge of the internal tooth ratchet 21. The internal tooth ratchet 21 is riveted by a rivet 26 that fits a hole 22 formed on the peripheral edge of the shaft through hole 20 and a hole 23 provided on the outer peripheral edge of the internal tooth ratchet 21. .

That is, the locking plate 5 is used in an emergency of the vehicle.
In order to prevent the webbing from rotating in the pulling-out direction, the engaged portion of the emergency locking means 300 to be engaged with an engagement member described later is constituted by the engagement inner teeth 25. The bobbin 3 constitutes an energy absorbing mechanism together with the torsion bar 2 and is formed into a substantially cylindrical shape in which aluminum alloy or steel and resin are combined, and the end portion of the webbing is attached to the body around which the webbing is wound. A slit opening 3a penetrating in the radial direction is provided so as to be inserted and held.

Square holes 3 are formed at both axial ends of the bobbin 3.
1 and a round hole 32 are respectively formed through. Further, a retainer 40 to be fitted into a shaft through hole of the side plate 1b is mounted on an end of the bobbin 3 on the side of the take-up spring device (not shown) in which the square hole 31 is formed. Further, the round hole 3
At the end of the bobbin 3 on the side of the emergency lock means 300 formed with 2, a guide groove 11 having a C-shaped bottomed groove is engraved along the outer peripheral edge thereof. Also, the guide groove 11
As shown in FIG. 3, a guide groove 12 which forms a guide portion 13 together with the guide groove 11 is formed on the inner surface of the locking plate 5 which faces the end of the bobbin 3 where the groove is formed. . The guide portion 13 has a curvature corresponding to the curvature of the guide grooves 11 and 12, and
An approximately cocoon-shaped lock piece 15 slidable along the inner wall surfaces of 1 and 12 is provided.

As shown in FIG. 4B, the guide groove 11 has an initial end portion 11A to a terminal end portion 11A of the guide groove 11.
B is set to be approximately three quarters of the outer peripheral distance of the bobbin 3, and the groove width is set to the lock piece 15 over the entire area.
Wider than the width. As shown in FIG. 4A, the guide groove 12 is set such that the distance from the initial end 12A to the end 12B of the guide groove 12 is substantially three-fourths of the outer circumference of the locking plate 5. And the initial end 12
On the A side, a wide portion 12a having a groove width larger than the width of the lock piece 15 is formed, and on the end portion 12B side, a narrow portion 12b which is a deformed portion having a groove width smaller than the width of the lock piece 15 is formed.

The set distance between the guide grooves 11 and 12 can be appropriately selected. Further, the ratio between the wide portion 12a and the narrow portion 12b is appropriately selected. Therefore, the lock piece 15 is relatively movable with respect to the bobbin 3 over the entire area of the guide groove 11, and is relatively movable with respect to the locking plate 5 at the wide portion 12 a of the guide groove 12.
On the other hand, in the narrow portion 12b of the guide groove 12, when a predetermined force or more is applied to the lock piece 15, the narrow portion 12b is pushed or expanded or cut to deform the narrow portion 12b. The lock piece 15 is movable relative to the locking plate 5.

On the outer surface of the locking plate 5, a pole 1 which is an engaging member engageable with the engaging internal teeth 25 is provided.
A support shaft 7 is provided so as to pivotally support 6 for swinging rotation, and a rotation support shaft 6 of the torsion bar 2 penetrating the locking plate 5 for supporting the bobbin 3 rotatably projects. . Here, the bobbin 3 or the locking plate 5 is formed as a through groove which penetrates the guide groove 11 or 12 in the thickness direction on a separately formed disk member, and these disk members are respectively formed on the bobbin 3 or the locking plate. It is good also as a structure which is integrated with 5 at the time of assembly. A configuration in which only one of the guide groove 11 and the guide groove 12 is formed is also suitable.

The locking plate 5 is a pole 16
Is pivoted in a direction in which it engages with the engagement internal teeth 25, the pole 16e (see FIG. 2) on the opposite side of the pivot side end of the pawl 16 is positioned and so,
When a large load is applied to the pole 16, the pole 16 has a pressure receiving surface 4 that receives the load. At both ends in the axial direction of the torsion bar 2, a prismatic portion 2 a sized so as to be press-fittable into the square hole 5 a of the locking plate 5, and press-fit into the square holes 31 and 40 a of the bobbin 3 and the retainer 40. A prismatic portion 2b set to a size that can be combined is formed.
Therefore, the rotation support shaft 6 of the torsion bar 2 and the prism-shaped portion 2
Each of the shafts b is rotatably supported by a shaft support portion 34b of a gear case 34 described later and a retainer 40 inserted into a shaft through hole of the side plate 1b. The retainer 40
Is rotatably supported via a ring-shaped bearing bush 41 fitted between the side plate 1b. In the present embodiment, the prisms 2a and 2b and the square holes 5a, 31 and 4 are used.
0a is a hexagonal shape, but is not limited to this.

On the outside of the locking plate 5, there is provided a ratchet wheel 18 as a lock actuating means for actuating the emergency locking means 300 in a vehicle emergency so as to be rotatable relative to the locking plate 5. An energy absorbing mechanism 200 mainly composed of the torsion bar 2 is formed between the bobbin 3 and the locking plate 5, and a predetermined amount or more of the locking plate 5 is provided on the locking plate 5 in a state where the webbing is prevented from being pulled out by the emergency locking means 300. When the load (the direction of rotating the bobbin 3) is applied, the torsion bar 2 can be twisted around its own axis to rotate the bobbin 3 under a predetermined torque, so that the emergency locking means 300 locks it. Although the plate 5 is prevented from rotating in the webbing pull-out direction, a predetermined amount of webbing can be pulled out under a predetermined webbing tension, and the kinetic energy of the occupant can be absorbed.

Further, when the bobbin 3 and the locking plate 5 rotate relative to each other by a predetermined angle or more and the torsion bar 2 is twisted, a force of a predetermined amount or more acts on the lock piece 15 reaching the narrow portion 12b of the guide groove 12. As a result, the lock piece 15 arranged in the guide portion 13 is
2b by expanding or shaving the narrow portion 12b
Are relatively moved with respect to the locking plate 5 while deforming. Therefore, the guide portion 13 and the lock piece 15
Accordingly, the collision energy acting on the occupant's body can be absorbed as deformation work.

As understood from FIG. 1, when the torsion bar 2, the locking plate 5, the bobbin 3, the lock piece 15 and the retainer 40 are assembled to the retractor base 1, both ends of the torsion bar 2 in the axial direction are assembled. The prismatic portion 2a and the prismatic portion 2b in the portion are square holes 31 and 4
0a and the square hole 5a are press-fitted respectively.
In a normal use state, the bobbin 3 rotates integrally with the locking plate 5.

Further, the gear case 34 arranged outside the inertia plate 30 has a shaft support portion 34b for rotatably supporting the rotation support shaft 6 of the torsion bar 2 at the center thereof.
Is provided, and the bottom surface of the shaft support portion 34b is a positioning surface of the torsion bar 2 in the axial direction. A box-shaped storage section 43 for storing vehicle acceleration detecting means (not shown) is provided below the gear case 34, and a sensor cover 35 is provided outside the side plate 1a that covers the gear case 34. .

Next, the seat belt retractor 1 described above.
The operation of 00 will be described. First, in a normal use state, the ratchet wheel 18 engaged with the locking plate 5 is rotatable integrally with the locking plate 5, and the emergency locking means 300 is in a non-operating state. Therefore, the retractor 100 is capable of winding the webbing by the urging force of a winding spring device (not shown) and pulling out the webbing against the spring force.

Next, when a certain amount of deceleration such as a sudden braking occurs in the vehicle, the occupant moves forward to pull out the webbing, and the torsion bar 2 and the locking plate 5 are moved through the bobbin 3 by a predetermined amount or more. When the impacting rotational force in the webbing pull-out direction (arrow X ₂ direction) is applied, the inertia plate 30 receives an inertial force and a rotation delay occurs with respect to the rotation of the locking plate 5 in the webbing pull-out direction. Then, the inertia plate 30 operates a lock arm (not shown) to lock the ratchet wheel 18 to the gear case 34.

As a result, the ratchet wheel 18 causes a rotation delay with respect to the locking plate 5 rotating in the webbing pull-out direction, and the pawl 16 is engaged with the engaging internal teeth 25 (direction Y _{1 in} FIG. 2). Since it is rocked and rotated to, the emergency locking means 300 operates. Also, the ratchet wheel 18, by the vehicle acceleration sensing means senses the acceleration of the vehicle (not shown), a rotation delay with respect to the locking plate 5 which rotates in the webbing pull-out direction (FIG. 2 in direction of arrow X ₂₎ As a result, the pawl 16 can be pivotally rotated in the direction of engagement with the engagement internal teeth 25.

Therefore, when the pawl 16 moves to a position where the pawl 16 is securely engaged with the engaging internal teeth 25, the rotation of the locking plate 5 pivotally supporting the pawl 16 in the direction of the arrow X ₂ is locked. At this time, the torsion bar 2 having one end connected to the locking plate 5 via the square hole 5a and the other end connected to the bobbin 3 via the square hole 31 does not receive a predetermined or more torsional force. The torsion bar 2 is not torsionally deformed.

Therefore, the rotation of the bobbin 3 in the direction of the arrow X ₂ is also locked, and the extension of the webbing is prevented. Then, in this state, when a large tension is further applied to the webbing, the bobbin 3 having one end of the webbing locked starts to rotate, and the torsion bar 2 having one end connected to the locking plate 5 whose rotation is locked. However, since it is twisted around its own axis, it functions as an energy absorbing mechanism.

That is, as shown in FIG. 4, the lock pieces 15 are located at the initial end portion 11A of the guide groove 11 and the initial end portion 12A of the guide groove 12 when the webbing begins to be loaded with a larger tension. ing. Then, the torsion bar 2 is torsionally deformed, and the length of the guide groove 11 (3 /
When the bobbin 3 is rotated with respect to the locking plate 5 in the direction of the arrow T in the figure and the lock piece 15 slides in the guide groove 11 and relatively moves in the direction of the arrow S at an angle corresponding to 4 rotations). As shown in FIG. 5, the lock piece 15 reaches the end portion 11B of the guide groove 11.

When the bobbin 3 is rotated in the direction of the arrow T in the drawing, the lock piece 15 pressed and urged by the terminal end portion 11B of the guide groove 11 moves the initial end portion 12A of the guide groove 12 of the locking plate 5. The sliding is started from, and along with that, the inside of the wide portion 12a of the guide groove 12 is moved to the position shown in FIG. 6A in the direction of the arrow T in the figure. During this time, the bobbin 3 is rotated about 405 degrees in the direction of the arrow T with respect to the locking plate 5 (for example, the extension amount of the webbing is 150 mm). Since only the sliding movement of the torsion bar 2 around the axis of the torsion bar 2 is absorbed, the collision energy acting on the occupant's body is merely absorbed as the work is slid only in the wide portion 12a of the guide groove 12 and the guide groove 12. That is, since the torsional deformation torque of the torsion bar 2 is substantially constant, the energy absorption torque is substantially constant over the entire operating range. Therefore, as shown in FIG. 8, the load curve of the energy absorption load (load acting on the webbing) with respect to the amount of extension of the webbing is in a proportional state with substantially the same slope.

When the bobbin 3 is further rotated in the direction of the arrow T in the figure and the torsion bar 2 is twisted, a predetermined force or more acts on the lock piece 15 reaching the narrow width portion 12b of the guide groove 12. Then, the lock piece 15 pushes or narrows the narrow portion 12b to remove the narrow portion 12b.
While deforming b, it moves in the narrow portion 12b of the guide groove 12 in the direction of arrow T in the figure to the end portion 12B shown in FIG.

That is, the bobbin 3 rotates about 405 degrees to about 540 degrees in the direction of arrow T with respect to the locking plate 5 (for example, the amount of extension of the webbing is 150 to 2).
(00 mm), the collision energy acting on the occupant's body can be absorbed as deformation work also by the deformation of the narrow portion 12b by the lock piece 15. Therefore, the load curve of the energy absorption load changes to a slope obtained by combining the torsion of the torsion bar 2 and the deformation (including the frictional force) of the narrow portion 12b as shown in FIG.

In this way, the lock piece 15 becomes the guide groove 1.
When the bobbin 3 reaches the second end portion 12B, relative rotation of the bobbin 3 with respect to the locking plate 5 is regulated by the lock piece 15, so that further twisting of the torsion bar 2 is prevented. As described above, in the seatbelt retractor 100 according to the first embodiment, the pole 16 engages with the engaging internal teeth 25 in the emergency of the vehicle, and the rotation of the locking plate 5 is temporarily blocked by the emergency locking means 300. After that, when a tension higher than a predetermined value is applied to the webbing, the torsion bar 2 is twisted corresponding to the rotation of the bobbin 3, and the webbing can be extended.
Operates as an energy absorption mechanism. Further, when the bobbin 3 and the locking plate 5 rotate relative to each other by a predetermined angle (about 405 degrees in the first embodiment), the lock piece 15 rotates the bobbin 3 while deforming the narrow portion 12b. The absorption load is a combined load of the twist of the torsion bar 2 and the deformation of the narrow portion 12b.

Therefore, the set distance of the guide grooves 11 and 12,
By appropriately selecting the ratio of the wide width portion 12a and the narrow width portion 12b, the groove width of the narrow width portion 12b, and the like, it is easy to change the load curve of the energy absorption load with respect to the webbing extension amount. Therefore, it is possible to configure an excellent energy absorption mechanism that can obtain an arbitrary load characteristic in accordance with the vehicle characteristic and can efficiently absorb the collision energy that acts on the body of the occupant during a vehicle collision.

The structure of the guide portion in the present invention is not limited to the structure of the guide groove 11 and the guide groove 12 in the first embodiment, and it goes without saying that various forms can be adopted. For example, a wide portion and a narrow portion may be provided in the guide groove 11, and the groove width of the guide groove 12 may be wider than the width of the lock piece 15 in the entire region. If the width of the guide groove is narrowed at the initial position, rattling of the lock piece can be prevented and rattling noise can be prevented. in this case,
If a taper portion is provided on the insertion side of the lock piece, the assembly will be easy.

Further, if the size and shape are such that the lock piece is press-fitted into the initial position of the guide groove, load correction can be performed so as to make the rise of the energy absorption load when the energy absorption mechanism operates. Therefore, the restraint performance of the seat belt device can be improved. 9 to 12
FIG. 8 is a cross-sectional view of a main part of a bobbin and a locking plate according to a second embodiment of the present invention.

In FIG. 9, the guide groove 61 of the bobbin 3 is shown.
Is the end portion 61B from the initial end portion 61A of the guide groove 61.
Is set to be approximately three-fourths of the outer peripheral distance of the bobbin 3, and the groove width is narrower than the width of the lock piece 15 in the entire region. However, only in the initial position, the groove width may be made wider than the width of the lock piece 15 in order to assemble the lock piece 15. On the other hand, since the guide groove of the locking plate 5 is the same as the guide groove 12 in the first embodiment, the same reference numerals are given to the other similar components and the description thereof will be omitted.

When a tension greater than a predetermined value is applied to the webbing in an emergency of the vehicle, the seat belt retractor according to the second embodiment, like the seat belt retractor 100 according to the first embodiment, is Bobbin 3
The torsion bar 2 is twisted corresponding to the rotation of
When the webbing is pulled out, the function as an energy absorbing mechanism acts.

That is, as shown in FIG. 9, the lock pieces 15 are located at the initial end portion 61A of the guide groove 61 and the initial end portion 12A of the guide groove 12 when the webbing starts to be loaded with a larger tension. ing. Then, when the bobbin 3 is rotated about the locking plate 5 in the direction of the arrow T in the figure by about 135 degrees (for example, the amount of extension of the webbing is 50 mm), the lock piece 15 also moves.
At the same time, it moves while sliding in the wide width portion 12a of the guide groove 12, and the lock piece 15 reaches the narrow width portion 12b of the guide groove 12 as shown in FIG.

During this time, the bobbin 3 rotates about 135 degrees in the direction of arrow T with respect to the locking plate 5, but the lock piece 15 simply slides in the wide portion 12a of the guide groove 12, so that the occupant's space is reduced. The collision energy acting on the body is only absorbed as deformation work by the torsion bar 2 twisting around its own axis. That is,
Since the torsional deformation torque of the torsion bar 2 is almost constant,
The energy absorption torque is almost constant over its operating range. Therefore, as shown in FIG. 13, the load curve of the energy absorption load (load acting on the webbing) with respect to the amount of extension of the webbing is in a proportional state with substantially the same slope.

When the bobbin 3 is further rotated in the direction of the arrow T in the figure, a force greater than a predetermined force acts on the lock piece 15 reaching the narrow width portion 12b of the guide groove 12, and the lock piece 15 is rotated. 11 expands the narrow portion 12b or scrapes the narrow portion 12b while deforming the narrow portion 12b.
It moves in the direction of arrow T in the figure up to the end portion 12B shown in (a). Thereafter, when the bobbin 3 is further rotated in the direction of the arrow T in the figure, the lock piece 15 relatively expands or scrapes the guide groove 61 to deform it, so that the lock piece 15 is relatively deformed as shown in FIG.
1 (b), the lock piece 15 moves toward the end portion 6 of the guide groove 61 as shown in FIG. 12 (b).
Reach 1B.

That is, the bobbin 3 rotates about 135 to about 540 degrees in the direction of arrow T with respect to the locking plate 5 (for example, the amount of extension of the webbing is 50 to 20).
(0 mm), the collision energy acting on the body of the occupant can be absorbed as a deformation work even by the deformation of the narrow portion 12b and the guide groove 61 by the lock piece 15. Therefore, as shown in FIG. 13, the load curve of the energy absorption load with respect to the amount of webbing extension is composed of the twisted portion of the torsion bar 2 and the deformed portion (including frictional force) of the narrow portion 12b and the guide groove 61. Turns into a slope.

In this way, the lock piece 15 is inserted into the guide groove 6
When the bobbin 3 reaches the end portion 61B of No. 1, relative rotation of the bobbin 3 with respect to the locking plate 5 is restricted by the lock piece 15, so that further twisting of the torsion bar 2 is prevented. In the above description of the second embodiment, the case where the lock piece 15 deforms the narrow portion 12b first and then the guide groove 61 is deformed has been described.
After the lock piece 15 deforms the guide groove 61 first,
The narrow portion 12b may be deformed.

FIG. 14 is a sectional view of the essential parts of a locking plate according to the third embodiment of the present invention. In FIG. 14, the guide groove 72 of the locking plate 5 is set such that the distance from the initial end portion 72A of the guide groove 72 to the terminal end portion 72B is approximately three quarters of the outer peripheral distance of the locking plate 5, On the side of the initial end portion 72A, the narrow width portion 72a is a deformed portion having a groove width narrower than the width of the lock piece 75.
In the middle portion, a wide width portion 72b having a groove width wider than that of the lock piece 75 is formed, and on the end portion 72B side, a narrow width portion 72c that is a deformed portion having a groove width smaller than the width of the lock piece 75 is formed again. ing. On the other hand, no guide groove is formed in the end portion of the bobbin 3, and only the lock piece 75 integrally formed on the end portion of the bobbin 3 is provided so as to project. Although different, the other components are the same.

When the webbing is applied with a predetermined tension or more in an emergency of the vehicle, the seatbelt retractor according to the third embodiment is similar to the seatbelt retractor in each of the above-described embodiments. The torsion bar 2 is twisted corresponding to the rotation of the, and the webbing is pulled out, so that the function as the energy absorbing mechanism acts.

That is, the torsion bar 2 is twisted and deformed,
When the bobbin 3 (not shown) is rotated with respect to the locking plate 5 in the direction of the arrow T in the figure, the lock piece 75 integrated with the bobbin 3 causes the narrow width portion 72 a and the wide width portion 7 of the guide groove 72.
2b, the end portion 7 of the guide groove 72 while sequentially moving in the narrow portion 72c and deforming the narrow portion 72a and the narrow portion 72c.
Reach 2B. When the lock piece 75 reaches the end portion 72B, the relative rotation of the bobbin 3 with respect to the locking plate 5 is restricted, and further twisting of the torsion bar 2 is prevented.

Therefore, the load curve of the energy absorption load (load acting on the webbing) during this period is as shown in FIG. 15 in which the twisted portion of the torsion bar 2 and the deformed portion (including frictional force) of the guide groove 72 are combined. It is possible to obtain various load characteristics. FIG. 16 is a sectional view of an essential part of a locking plate according to the fourth embodiment of the present invention.

In FIG. 16, the guide groove 82 of the locking plate 5 is set such that the distance from the initial end portion 82A of the guide groove 82 to the terminal end portion 82B is approximately three quarters of the outer peripheral distance of the locking plate 5. At the initial end portion 82A side, a wide width portion 82a having a groove width wider than the width of the lock piece 75 is formed, and at an intermediate portion, a narrow width portion 82b which is a deformed portion having a groove width smaller than the width of the lock piece 75 is formed. On the side of the end portion 82B, a wide portion 82c having a groove width wider than the width of the lock piece 75 is formed again. The other components are the same as those in the third embodiment.

The load curve of the energy absorption load (load acting on the webbing) in case of an emergency of the vehicle is as shown in FIG. 17 in which the twist of the torsion bar 2 and the deformation of the guide groove 82 (including frictional force) are combined. It is possible to obtain various load characteristics. In the description of the above third and fourth embodiments, the case where the lock piece 75 is provided at the end of the bobbin 3 is described. However, the lock piece 75 is provided so as to project on the locking plate 5 and the guide groove 72 is provided. Alternatively, 82 may be engraved on the end of the bobbin 3.

FIG. 18 is a sectional view of the main part of a locking plate according to the fifth embodiment of the present invention, and FIG. 19 is FIG.
9 is a cross-sectional view taken along the line CC in FIG. In FIG. 18, the narrow portion 12 of the guide groove 12 in the locking plate 5
A lightening groove 91, which is a lightening portion, is provided inside the b in parallel with the narrow width portion 12b.

The lightening groove 91 has a lock piece 93.
The narrow portion 12 (which may be integral with the bobbin 3 or separate from the bobbin 3)
When passing through b, the inner side wall 92 of the narrow width portion 12b is thinned and easily deformed so that the narrow width portion 12b is easily expanded. When the narrow width portion 12b is easily deformed in this manner, the energy absorption load is easily adjusted. That is, the energy absorption load can be adjusted by the width E of the narrow portion 12b, the thickness F of the inner side wall 92, the depth G of the thinning groove 91, the side wall surface angle H, and the like, as shown in FIG. Since the amount of deformation of the inner side wall 92 can be increased as compared with the case where the lightening groove 91 is not provided, the load adjustment is easy and the narrow width portion 1 is provided.
The accuracy of the width E of 2b can be roughened.

The lightening portion in the fifth embodiment need not be a groove such as the lightening groove 91, and the narrow width portion 1
It suffices that the side wall of 2b is easily deformed. For example, the lightening portion may be formed by a substantially circular recess, or a lightening groove may be provided outside the narrow width portion 12. Further, the width E of the narrow portion 12b, the thickness F of the inner side wall 92, and the thinned groove 91.
The depth G, the side wall surface angle H, and the like can be changed according to the vehicle characteristics.

Further, the narrow width portion of each guide groove in each of the above embodiments has the groove width narrowed from both side wall sides of the narrow width portion, but the groove width is only from one side wall side of the inner side wall or the outer side wall. Of course, it is possible to narrow. 20A and 20B are a front view and a DD sectional view of the lock piece 95 according to the sixth embodiment of the present invention.

The lock piece 95 has a recess 9 at the center.
5a is provided to facilitate compression and deformation in the width direction.
Therefore, when the lock piece 95 passes through the narrow width portion 12b, the lock piece 95 itself is also compressed and deformed while expanding the narrow width portion 12b. Therefore, the energy absorption load is stabilized, the set value is easily adjusted, and the dimensional accuracy of the lock piece 95 and the narrow portion 12b can be roughened.

FIG. 21 is a sectional view of the main parts of a locking plate according to the seventh embodiment of the present invention. 21, in the guide groove 102 of the locking plate 105, the distance from the initial end portion 102A of the guide groove 102 to the terminal end portion 102B is approximately 4 times the outer peripheral distance of the locking plate 105.
The initial end portion 102A is set to 3/3.
On the side, a wide portion 102a having a groove width wider than the width of the lock piece (not shown) is formed, and on the end portion 102B side, the interval between the projection tips of the serrated projections 103, 103 protruding on both side walls is the width of the lock piece. Narrower portion 102b slightly narrower than
It has been.

The groove width of the narrow portion 102b (distance between the projection tips of the projections 103, 103 protruding on both side walls), the size, pitch, apex angle and number of the projections 103 are It can be changed appropriately according to the characteristics. That is,
When the lock piece passes through the narrow portion 102b, the lock piece advances while squeezing the protrusions 103, 103, so that the precision of the narrow portion 102b and the lock piece can be roughened, and even if the fitting is tight, it is stuck on the way. The movement stroke is secured without any movement. Further, by making the shape of each protrusion 103 asymmetrical as shown in FIG. 21, it is possible to prevent the lock piece from returning backward.

Further, the protrusion 103 as described above is provided in the narrow portion 1
It may be provided only on one side wall of 02b. or,
The guide groove 102 having the narrow width portion 102b including the protrusion 103 can be provided on at least one of the opposing surfaces of the bobbin and the locking plate. 22 is a sectional view of a main part of a seat belt retractor 110 according to the eighth embodiment of the present invention, and FIGS. 23 and 24 are partial perspective views of the bobbin 113 and the lock piece 115 shown in FIG. It is the whole perspective view. The same members as those of the seat belt retractor 100 according to the first embodiment are designated by the same reference numerals and detailed description thereof will be omitted.

The seat belt retractor 110
Is rotatably attached to the retractor base 1 and has a disk-shaped locking plate 10 at least at one end.
5 is a columnar torsion bar 112 which is a take-up shaft, and the torsion bar 11 in case of a vehicle emergency.
The emergency locking means 300 for preventing the rotation of the webbing 2 in the pulling-out direction, the cylindrical bobbin 113 around which the webbing is wound and which is rotatably supported by the torsion bar 112, the locking plate 105, and the bobbin. The lock piece 115 is provided in the guide portion 120 formed in the facing portion 113.

Emergency lock means 3 having a round hole 114
At the end of the bobbin 113 on the 00 side, a substantially circular recess 1
18 is recessed. Further, as shown in FIG. 25, on the inner surface of the locking plate 105 facing the end of the bobbin 113 in which the recess 118 is provided, as shown in FIG.
A guide groove 119 that forms a guide portion 120 together with 18 is engraved. The guide portion 120 has a round hole 117 that is rotatably supported by the torsion bar 112.
A lock piece 115 is disposed so as to be slidable along the bottom wall surface of the recess 118.

The lock piece 115 has a ring-shaped portion 1.
It has an engaging portion 121 that projects outward in the radial direction from the outer peripheral edge of 15a in a substantially trapezoidal shape. The engaging portion 121 has a thickness almost double that of the ring-shaped portion 115a. As shown in FIG. 23, the recess 118 has a locking portion 116 in which a part of the inner peripheral wall projects inward in the radial direction in a trapezoidal shape. As shown in FIG. 25 (a), a part (end region) of the inner peripheral wall of the concave portion 118 adjacent to the locking portion 116 is biased inward in the radial direction, and the outer end portion of the engaging portion 121 is A small-diameter portion 118a that is in pressure contact is formed. On the other hand, the inner peripheral wall other than the small diameter portion 118a has a sufficient diameter with respect to the outer end portion of the engaging portion 121.

In the guide groove 119, as shown in FIG. 25B, the distance from the initial end portion 119A of the guide groove 119 to the end portion 119B is approximately three quarters of the outer peripheral distance of the locking plate 105. Are set as follows, and the engaging portion 12 of the lock piece 115 is provided on the initial end portion 119A side.
The groove width is more than 1 width. On the other hand, the terminal part 1
On the side of 19B, a part of the inner wall of the guide groove 119 is biased outward in the radial direction to form a large-diameter portion 119a that is in pressure contact with the inner end of the engaging portion 121.

That is, as shown in FIG. 25, when the emergency locking means 300 (not shown) is actuated and the webbing begins to be loaded with a larger tension, the lock piece 11 is released.
The engaging portion 121 of No. 5 is located in the initial region of the recess 118 and the initial end portion 119A of the guide groove 119. Then, when the bobbin 113 is rotated with respect to the locking plate 105 in the direction of the arrow T in the drawing at an angle corresponding to the length (3/4 rotation) of the guide groove 119, the lock piece 115 is placed on the bottom wall surface of the recess 118. And relatively rotates in the direction of arrow S, and the engaging portion 121 also slides in the guide groove 119 and relatively moves in the direction of arrow S, as shown in FIG.
The engaging portion 121 reaches the end region of the recess 118. At this time, the engagement portion 121 is compressed inward in the radial direction by the small diameter portion 118a, and the small diameter portion 118a is compressed by the engagement portion 121a.
With this, the energy absorption load can be increased by being pushed outward in the radial direction.

When the bobbin 113 is further rotated in the direction of the arrow T in the figure, the engaging portion 121 of the lock piece 115, which is biased by the engaging portion 116 of the bobbin 113, is engaged with the guide groove of the locking plate 105. Initial end 1 of 119
Sliding is started from 19A, and along with that, the inside of the guide groove 12 is moved to the position shown in FIG. 27 in the direction of arrow T in the figure.

Further, the bobbin 113 is indicated by an arrow T in the figure.
When rotated in the direction, the large diameter portion 11 of the guide groove 119 is rotated.
The engaging portion 121 of the lock piece 115 that has reached 9a is extended outward in the radial direction by the large diameter portion 119a, and the large diameter portion 119a is compressed inward by the engaging portion 121 inwardly of the guide groove 119. It can generate frictional force with the wall and increase the energy absorption load.

Lock piece 11 in the eighth embodiment
5 is rotatably supported by the torsion bar 112. Therefore, when the energy is absorbed only by the torsion of the torsion bar 112, the lock piece 115 can rotate smoothly without coming into contact with the inner peripheral wall of the recess 118 and both side walls of the guide groove 119. Therefore, the surface accuracy of the inner peripheral wall of the recess 118, both side walls of the guide groove 119 and the outer peripheral wall of the lock piece 115 can be reduced, and the groove width of the guide groove 119 can be made sufficiently wider than the width of the engaging portion 121 to achieve dimensional accuracy. Since it can be roughened, the manufacturing cost can be kept low.

In the eighth embodiment, the guide groove 119 is provided with the large diameter portion 119a as a deformed portion, but a narrow groove may be provided as the deformed portion. The seatbelt retractor of the present invention does not necessarily have to be combined with the torsion bar as in the seatbelt retractor of each of the above-described embodiments, and the energy absorbing load can be handled only by the guide portion. In this case, a pair of engaging members are arranged at both ends of a bobbin which is rotatable relative to the winding shaft, and a seat belt retractor having non-engaging portions formed on both side plates of the retractor base is also used. Can be applied.

Further, the emergency lock means is not limited to the configuration in the above-described embodiment, but various modifications can be made. For example, the inertial sensing means which operates in an emergency of the vehicle includes the vehicle body acceleration sensing means and the webbing. The configuration may be such that only one of the acceleration sensing means is provided. Further, the configuration of the guide portion formed in the facing portion of the locking plate and the bobbin is not limited to the configuration of each of the above embodiments, for example, by appropriately combining the configuration of each guide groove in each of the embodiments, It is possible to obtain an energy absorption mechanism having various energy absorption load characteristics.

[0071]

As described above, in the seat belt retractor of the present invention, the energy absorption load characteristics can be adjusted according to the vehicle characteristics simply by changing the shape of the guide portion formed at the opposing portion of the locking plate and the bobbin. Can be changed arbitrarily. Therefore, it is possible to provide a seat belt retractor equipped with a good energy absorbing mechanism that can efficiently absorb the collision energy that acts on the body of an occupant in the event of a vehicle collision, in accordance with the vehicle characteristics.

[Brief description of drawings]

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

FIG. 2 is an exploded perspective view of essential parts of the seat belt retractor shown in FIG.

FIG. 3 is a perspective view of a main part of the locking plate shown in FIG. 1;

FIG. 4 is an explanatory diagram for explaining the operation of the energy absorbing mechanism of the seat belt retractor shown in FIG. 1,
(a) is an AA sectional view in FIG. 1, and (b) is a BB sectional view in FIG. 1.

FIG. 5 is an explanatory diagram for explaining an operation of an energy absorbing mechanism of the seat belt retractor shown in FIG. 1;

FIG. 6 is an explanatory diagram for explaining an operation of the energy absorbing mechanism of the seat belt retractor shown in FIG. 1;

7 is an explanatory diagram for explaining the operation of the energy absorbing mechanism of the seat belt retractor shown in FIG.

FIG. 8 is a graph showing a relationship between a webbing extension amount and an energy absorption load in the first embodiment.

FIG. 9 is an explanatory view for explaining the operation of the energy absorbing mechanism of the bobbin and the locking plate according to the second embodiment of the present invention, (a) is a sectional view of the locking plate,
(b) is a cross-sectional view of the bobbin.

10 is an explanatory diagram for explaining the operation of the energy absorbing mechanism of the bobbin and the locking plate shown in FIG.

FIG. 11 is an explanatory diagram for explaining the operation of the energy absorbing mechanism of the bobbin and the locking plate shown in FIG. 9.

12 is an explanatory diagram for explaining an operation of the energy absorbing mechanism of the bobbin and the locking plate shown in FIG.

FIG. 13 is a graph showing a relationship between a webbing extension amount and an energy absorption load in the second embodiment.

FIG. 14 is a sectional view of an essential part of a locking plate according to a third embodiment of the present invention.

FIG. 15 is a graph showing a relationship between a webbing extension amount and an energy absorption load in the third embodiment.

FIG. 16 is a cross-sectional view of essential parts of a locking plate according to a fourth embodiment of the present invention.

FIG. 17 is a graph showing the relationship between the amount of webbing extension and the energy absorption load in the fourth embodiment.

FIG. 18 is a sectional view of an essential part of a locking plate according to a fifth embodiment of the present invention.

19 is a cross-sectional view taken along the line CC of FIG.

FIG. 20 is a front view of a lock piece according to a sixth embodiment of the present invention and a DD sectional view thereof.

FIG. 21 is a sectional view of essential parts of a locking plate according to a seventh embodiment of the present invention.

FIG. 22 is a cross-sectional view of essential parts of a seat belt retractor based on an eighth embodiment of the present invention.

23 is a partial perspective view of the bobbin shown in FIG. 22. FIG.

24 is an overall perspective view of the lock piece shown in FIG.

FIG. 25 is an explanatory view for explaining the operation of the energy absorbing mechanism of the seat belt retractor shown in FIG. 22, (a) is a sectional view taken along the line JJ in FIG. 22, and (b) is a view. 22 is a sectional view taken along line KK in FIG.

26 is a sectional view of the bobbin for explaining the operation of the energy absorbing mechanism of the seat belt retractor shown in FIG. 22.

FIG. 27 is a sectional view of a locking plate for explaining the operation of the energy absorbing mechanism of the seat belt retractor shown in FIG. 22.

[Explanation of symbols]

 1 Retractor base 2 Torsion bar 3 Bobbin 5 Locking plate 11 Guide groove 12 Guide groove 13 Guide part 16 Pole 100 Seat belt retractor 200 Energy absorption mechanism 300 Emergency locking means

Claims (1)

[Claims] 1. A take-up shaft rotatably attached to a retractor base and having a locking plate at least at one end, and an emergency locking means for preventing the take-up shaft from rotating in a webbing pull-out direction in case of a vehicle emergency. A cylindrical bobbin on which the webbing is wound and which is rotatably supported by the winding shaft relative to the winding shaft, and a lock piece disposed on a guide portion formed on the locking plate and the facing portion of the bobbin. A seatbelt retractor provided, characterized in that, when the locking plate and the bobbin rotate relative to each other, the lock piece is relatively movable while deforming the guide portion. Retractor.