U.S. patent application number 12/036195 was filed with the patent office on 2008-08-28 for webbing retractor.
This patent application is currently assigned to KABUSHIKI KAISHA TOKAI-RIKA-DENKI-SEISAKUSHO. Invention is credited to Sayuri AOKI, Yoshiaki MAEKUBO, Tomonori NAGATA, Motoki SUGIYAMA.
Application Number | 20080203210 12/036195 |
Document ID | / |
Family ID | 39714773 |
Filed Date | 2008-08-28 |
United States Patent
Application |
20080203210 |
Kind Code |
A1 |
NAGATA; Tomonori ; et
al. |
August 28, 2008 |
WEBBING RETRACTOR
Abstract
To simplify the structure of a webbing retractor, at a second
locking mechanism 44 of the webbing retractor, when a gas generator
is not operated, a cam engages with an outer peripheral groove of a
lock ring, and a limit load by a torsion shaft is made to be a high
load. On the other hand, when the gas generator is operated, the
cam is moved apart from the outer peripheral groove of the lock
ring, and the limit load by the torsion shaft is made to be a low
load. Because only the cam is interposed between the lock ring and
a piston which is driven by the gas generator, the number of parts
of the second locking mechanism can be reduced, and the structure
of the second locking mechanism can be made simple.
Inventors: |
NAGATA; Tomonori;
(Aichi-ken, JP) ; SUGIYAMA; Motoki; (Aichi-ken,
JP) ; MAEKUBO; Yoshiaki; (Aichi-ken, JP) ;
AOKI; Sayuri; (Aichi-ken, JP) |
Correspondence
Address: |
ROBERTS MLOTKOWSKI SAFRAN & COLE, P.C.
P. O. BOX 10064
MCLEAN
VA
22102-8064
US
|
Assignee: |
KABUSHIKI KAISHA
TOKAI-RIKA-DENKI-SEISAKUSHO
Aichi-ken
JP
|
Family ID: |
39714773 |
Appl. No.: |
12/036195 |
Filed: |
February 22, 2008 |
Current U.S.
Class: |
242/396.1 ;
242/410 |
Current CPC
Class: |
B60R 2022/288 20130101;
B60R 2022/286 20130101; B60R 22/4676 20130101 |
Class at
Publication: |
242/396.1 ;
242/410 |
International
Class: |
B65H 23/08 20060101
B65H023/08; B65H 77/00 20060101 B65H077/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 28, 2007 |
JP |
2007-050144 |
Claims
1. A webbing retractor comprising: a winding shaft on which a
webbing, which can be applied to a vehicle occupant, is wound, the
webbing being pulled out by the winding shaft being rotated in a
pull-out direction; a force limiter mechanism which, at a time of
an emergency situation with respect to a vehicle, permits rotation
of the winding shaft in the pull-out direction and limits a load,
which is applied to the vehicle occupant from the webbing, to a
limit load; and a switching portion having a driving member which
is configured to be driven at a time of an emergency situation with
respect to the vehicle, an operating member directly operated by
driving of the driving member, and a moving member which is engaged
with the operating member and movement of which is permitted by
operation of the operating member, the switching portion switching
the limit load from a high load to a low load in response to the
movement of the moving member being permitted.
2. The webbing retractor of claim 1, wherein the winding shaft is
hollow along the central axis thereof, the force limiter mechanism
is accommodated within the winding shaft, and a first locking
portion and the switching portion, which serves as a second locking
portion, are coaxially connected at either end side of the winding
shaft.
3. The webbing retractor of claim 1, wherein the force limiter
mechanism, serving as a first energy absorbing member, includes a
first deforming portion which is connected between a portion which
is joined to the winding shaft and the first locking portion and a
second deforming portion which is connected between the portion
which is joined to the winding shaft and the second locking portion
(the switching portion), and is twistable by a rotational force in
the pull-out direction of the winding shaft.
4. The webbing retractor of claim 1, wherein a stopper
accommodating hole for accommodating a stopper wire serving as a
second energy absorbing member is formed in the winding shaft, one
end portion of the stopper wire is disposed within a wire guiding
portion which is formed at least either one of a first locking
portion side end portion of the winding shaft and a winding shaft
side end portion of the first locking portion, and the other end of
the stopper wire is disposed within an accommodating hole formed in
the second locking portion.
5. The webbing retractor of claim 1, wherein only the operating
member is interposed between the moving member and the driving
member.
6. The webbing retractor of claim 1, wherein the operating member
is engaged with the moving member at one position.
7. The webbing retractor of claim 1, wherein a supporting position
of the operating member is disposed at a pull-out direction side of
the moving member, with respect to an engaging position of the
operating member with the moving member.
8. A webbing retractor comprising: a winding shaft on which a
webbing, which can be worn by a vehicle occupant, is wound, the
webbing being pulled out by the winding shaft being rotated in a
pull-out direction; a force limiter mechanism which, at a time of
an emergency situation with respect to a vehicle, permits rotation
of the winding shaft in the pull-out direction and limits a load,
which is applied to the vehicle occupant from the webbing, to a
limit load; and a switching portion having a driving member which
is configured to be driven at a time of an emergency situation with
respect to the vehicle, and a moving member which is engaged with
the driving member and movement of which is permitted by driving of
the driving member, the switching portion switching the limit load
from a high load to a low load in response to the movement of the
moving member being permitted.
9. The webbing retractor of claim 8, wherein the winding shaft is
hollow along the central axis thereof, the force limiter mechanism
is accommodated within the winding shaft, and a first locking
portion and the switching portion which serves as a second locking
portion are coaxially connected at either end side of the winding
shaft.
10. The webbing retractor of claim 8, wherein the force limiter
mechanism, serving as a first energy absorbing member, includes a
first deforming portion which is connected between a portion which
is joined to the winding shaft and the first locking portion and a
second deforming portion which is connected between the portion
which is joined to the winding shaft and the second locking portion
(the switching portion), and is twistable by a rotational force in
the pull-out direction of the winding shaft.
11. The webbing retractor of claim 8, wherein a stopper
accommodating hole for accommodating a stopper wire serving as a
second energy absorbing member is formed in the winding shaft, one
end portion of the stopper wire is disposed within a wire guiding
portion which is formed at least either one of a first locking
portion side end portion of the winding shaft and a winding shaft
side end portion of the first locking portion, and the other end of
the stopper wire is disposed within an accommodating hole formed in
the second locking portion.
12. The webbing retractor of claim 8, wherein nothing is interposed
between the driving member and the moving member.
13. The webbing retractor of claim 8, wherein the driving member is
engaged with the moving member at one position.
14. A webbing retractor comprising: a winding shaft on which a
webbing, which can be worn by a vehicle occupant, is wound, the
webbing being pulled out by the winding shaft being rotated in a
pull-out direction; a force limiter mechanism which, at a time of
an emergency situation with respect to a vehicle, permits rotation
of the winding shaft in the pull-out direction and limits a load,
which is applied to the vehicle occupant from the webbing, to a
limit load; and a switching portion having an operating member
which is configured to be operated at a time of an emergency
situation with respect to the vehicle, and a moving member which is
engaged with the operating member at one position with prevention
and permission of movement thereof being alternated between by
operation of the operating member, the switching portion switching
the limit load between a high load and a low load in response to
alternation between the operation and non-operation of the
operating member.
15. The webbing retractor of claim 14, wherein the winding shaft is
hollow along the central axis thereof, the force limiter mechanism
is accommodated within the winding shaft, and a first locking
portion and the switching portion which serves as a second locking
portion are coaxially connected at either end side of the winding
shaft.
16. The webbing retractor of claim 14, wherein the force limiter
mechanism, serving as a first energy absorbing member, includes a
first deforming portion which is connected between a portion which
is joined to the winding shaft and the first locking portion and a
second deforming portion which is connected between the portion
which is joined to the winding shaft and the second locking portion
(the switching portion), and is twistable by a rotational force in
the pull-out direction of the winding shaft.
17. The webbing retractor of claim 14, wherein a stopper
accommodating hole for accommodating a stopper wire serving as a
second energy absorbing member is formed in the winding shaft, one
end portion of the stopper wire is disposed within a wire guiding
portion which is formed at least either one of a first locking
portion side end portion of the winding shaft and a winding shaft
side end portion of the first locking portion, and the other end of
the stopper wire is disposed within an accommodating hole formed in
the second locking portion.
18. A webbing retractor comprising: a winding shaft on which a
webbing, which can be worn by a vehicle occupant, is wound, the
webbing being pulled out by the winding shaft being rotated in a
pull-out direction; a force limiter mechanism which, at a time of
an emergency situation with respect to a vehicle, permits rotation
of the winding shaft in the pull-out direction and limits a load,
which is applied to the vehicle occupant from the webbing, to a
limit load; and a switching portion having an operating member
which is configured to be operated at a time of an emergency
situation with respect to the vehicle, and a moving member which is
engaged with the operating member with prevention and permission of
movement thereof being alternated between by operation of the
operating member, a supporting position of the operating member
being disposed at a moving direction side with respect to an
engaging position of the operating member, and the switching
portion switching the limit load between a high load and a low load
in response to alternation between the operation and non-operation
of the operating member.
19. The webbing retractor of claim 18, wherein the winding shaft is
hollow along the central axis thereof, the force limiter mechanism
is accommodated within the winding shaft, and a first locking
portion and the switching portion which serves as a second locking
portion are coaxially connected at either end side of the winding
shaft.
20. The webbing retractor of claim 18, wherein the force limiter
mechanism, serving as a first energy absorbing member, includes a
first deforming portion which is connected between a portion which
is joined to the winding shaft and the first locking portion and a
second deforming portion which is connected between the portion
which is joined to the winding shaft and the second locking portion
(the switching portion), and is twistable by a rotational force in
the pull-out direction of the winding shaft.
21. The webbing retractor of claim 18, wherein a stopper
accommodating hole for accommodating a stopper wire serving as a
second energy absorbing member is formed in the winding shaft, one
end portion of the stopper wire is disposed within a wire guiding
portion which is formed at least either one of a first locking
portion side end portion of the winding shaft and a winding shaft
side end portion of the first locking portion, and the other end of
the stopper wire is disposed within an accommodating hole formed in
the second locking portion.
22. The webbing retractor of claim 18, wherein the operating member
is engaged with the moving member at one position.
23. A webbing retractor comprising: a winding shaft on which a
webbing, which can be worn by a vehicle occupant, is wound, the
webbing being pulled out by the winding shaft being rotated in a
pull-out direction; a force limiter mechanism which, at a time of
an emergency situation with respect to a vehicle, permits rotation
of the winding shaft in the pull-out direction and limits a load,
which is applied to the vehicle occupant from the webbing, to a
limit load; and a switching portion having an operating member
which is configured to be operated via pressure of a fluid at a
time of an emergency situation with respect to the vehicle and with
an operated state thereof being maintained via the pressure of the
fluid, and a moving member, prevention and permission of movement
thereof being alternated between by operation of the operating
member, the switching portion switching the limit load between a
high load and a low load in response to alternation between the
operation and non-operation of the operating member.
24. The webbing retractor of claim 23, wherein the winding shaft is
hollow along the central axis thereof, the force limiter mechanism
is accommodated within the winding shaft, and a first locking
portion and the switching portion which serves as a second locking
portion are coaxially connected at either end side of the winding
shaft.
25. The webbing retractor of claim 23, wherein the force limiter
mechanism, serving as a first energy absorbing member, includes a
first deforming portion which is connected between a portion which
is joined to the winding shaft and the first locking portion and a
second deforming portion which is connected between the portion
which is joined to the winding shaft and the second locking portion
(the switching portion), and is twistable by a rotational force in
the pull-out direction of the winding shaft.
26. The webbing retractor of claim 23, wherein a stopper
accommodating hole for accommodating a stopper wire serving as a
second energy absorbing member is formed in the winding shaft, one
end portion of the stopper wire is disposed within a wire guiding
portion which is formed at least either one of a first locking
portion side end portion of the winding shaft and a winding shaft
side end portion of the first locking portion, and the other end of
the stopper wire is disposed within an accommodating hole formed in
the second locking portion.
27. The webbing retractor of claim 23, wherein the operating member
is engaged with the moving member at one position.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority under 35 USC 119 from
Japanese Patent Application No. 2007-050144, the disclosure of
which is incorporated by reference herein.
BACKGROUND
[0002] 1. Technical Field
[0003] The present invention relates to a webbing retractor in
which a force limiter mechanism limits, to a limit load, the load
which is applied from a webbing to a vehicle occupant at the time
of an emergency situation with respect to the vehicle.
[0004] 2. Related Art
[0005] Among webbing retractors, there are those in which a torsion
shaft limits, to a limit load, the load which is applied to a
vehicle occupant from a webbing belt, and the limit load by the
torsion shaft is alternated between a high load and a low load due
to switching between a state in which a lock pawl meshes with a
ratchet wheel and a state in which the lock pawl does not mesh with
the ratchet wheel (see, for example, Japanese Patent Application
Laid-Open (JP-A) No. 2005-1648).
[0006] However, in this webbing retractor, the meshing state and
the non-meshing state of the lock pawl with the ratchet wheel is
alternated between by the lock pawl being rotated due to a piston
being driven and a cam plate being rotated. This is therefore a
structure in which the cam plate and the lock pawl are interposed
between the piston and the ratchet wheel, and there is a large
number of parts and a complex structure.
[0007] Further, plural ratchet teeth are formed at the lock pawl,
and the lock pawl meshes with the ratchet wheel at plural places.
Therefore, there is the possibility that the aligning of the lock
pawl with respect to the ratchet wheel will become complicated.
[0008] Moreover, as compared with the position where the lock pawl
meshes with the ratchet wheel, the supporting position of the lock
pawl (the position of a guide pin) is disposed at the side opposite
to the direction of rotation in the pull-out direction of the
ratchet wheel. Therefore, in order for the lock pawl to mesh with
the ratchet wheel and prevent rotation of the ratchet wheel in the
pull-out direction, the ratchet teeth of the lock pawl must be
formed in shapes which are inclined toward the side opposite to the
direction of rotation in the pull-out direction of the ratchet
wheel. Due thereto, there is the possibility that the shape of the
ratchet tooth portion of the lock pawl will become complex.
[0009] In addition, at the time when the piston is driven and the
meshing of the lock pawl with the ratchet wheel is released, it is
preferable to be able to suppress the meshing of the lock pawl with
the ratchet wheel.
SUMMARY
[0010] In view of the aforementioned, the present invention
provides a webbing retractor whose structure can be simplified, a
webbing retractor in which the alignment of an operating member
with respect to a moving member can be made to be simple, a webbing
retractor in which the shape of the operating member can be made to
be simple, and a webbing retractor in which it is possible to
suppress the operating member being set in a non-operating state at
the time when the operating member is operated.
[0011] A webbing retractor of a first aspect has: a winding shaft
on which a webbing, which can be applied to a vehicle occupant, is
wound, the webbing being pulled out by the winding shaft being
rotated in a pull-out direction; a force limiter mechanism which,
at a time of an emergency situation with respect to a vehicle,
permits rotation of the winding shaft in the pull-out direction and
limits a load, which is applied to the vehicle occupant from the
webbing, to a limit load; and a switching portion having a driving
member which is configured to be driven at a time of an emergency
situation with respect to the vehicle, an operating member directly
operated by driving of the driving member, and a moving member
which is engaged with the operating member and movement of which is
permitted by operation of the operating member, the switching
portion switching the limit load from a high load to a low load in
response to the movement of the moving member being permitted.
[0012] A webbing retractor of a second aspect has: a winding shaft
on which a webbing, which can be worn by a vehicle occupant, is
wound, the webbing being pulled out by the winding shaft being
rotated in a pull-out direction; a force limiter mechanism which,
at a time of an emergency situation with respect to a vehicle,
permits rotation of the winding shaft in the pull-out direction and
limits a load, which is applied to the vehicle occupant from the
webbing, to a limit load; and a switching portion having a driving
member which is configured to be driven at a time of an emergency
situation with respect to the vehicle, and a moving member which is
engaged with the driving member and movement of which is permitted
by driving of the driving member, the switching portion switching
the limit load from a high load to a low load in response to the
movement of the moving member being permitted.
[0013] A webbing retractor of a third aspect has: a winding shaft
on which a webbing, which can be worn by a vehicle occupant, is
wound, the webbing being pulled out by the winding shaft being
rotated in a pull-out direction; a force limiter mechanism which,
at a time of an emergency situation with respect to a vehicle,
permits rotation of the winding shaft in the pull-out direction and
limits a load, which is applied to the vehicle occupant from the
webbing, to a limit load; and a switching portion having an
operating member which is configured to be operated at a time of an
emergency situation with respect to the vehicle, and a moving
member which is engaged with the operating member at one position
with prevention and permission of movement thereof being alternated
between by operation of the operating member, the switching portion
switching the limit load between a high load and a low load in
response to alternation between the operation and non-operation of
the operating member.
[0014] A webbing retractor of a fourth aspect has: a winding shaft
on which a webbing, which can be worn by a vehicle occupant, is
wound, the webbing being pulled out by the winding shaft being
rotated in a pull-out direction; a force limiter mechanism which,
at a time of an emergency situation with respect to a vehicle,
permits rotation of the winding shaft in the pull-out direction and
limits a load, which is applied to the vehicle occupant from the
webbing, to a limit load; and a switching portion having an
operating member which is configured to be operated at a time of an
emergency situation with respect to the vehicle, and a moving
member which is engaged with the operating member with prevention
and permission of movement thereof being alternated between by
operation of the operating member, a supporting position of the
operating member being disposed at a moving direction side with
respect to an engaging position of the operating member, and the
switching portion switching the limit load between a high load and
a low load in response to alternation between the operation and
non-operation of the operating member.
[0015] A webbing retractor of a fifth aspect has: a winding shaft
on which a webbing, which can be worn by a vehicle occupant, is
wound, the webbing being pulled out by the winding shaft being
rotated in a pull-out direction; a force limiter mechanism which,
at a time of an emergency situation with respect to a vehicle,
permits rotation of the winding shaft in the pull-out direction and
limits a load, which is applied to the vehicle occupant from the
webbing, to a limit load; and a switching portion having an
operating member which is configured to be operated via pressure of
a fluid at a time of an emergency situation with respect to the
vehicle and with an operated state thereof being maintained via the
pressure of the fluid, and a moving member, prevention and
permission of movement thereof being alternated between by
operation of the operating member, the switching portion switching
the limit load between a high load and a low load in response to
alternation between the operation and non-operation of the
operating member.
[0016] A webbing retractor of a sixth aspect is characterized that,
in any one of the webbing retractors of the first to the fifth
aspects, the winding shaft is hollow along the central axis
thereof, the force limiter mechanism is accommodated within the
winding shaft, and a first locking portion and the switching
portion, which serves as a second locking portion, are coaxially
connected at either end side of the winding shaft.
[0017] A webbing retractor of a seventh aspect is characterized
that, in any one of the webbing retractors of the first to the
fifth aspects, the force limiter mechanism, serving as a first
energy absorbing member, includes a first deforming portion which
is connected between a portion which is joined to the winding shaft
and the first locking portion and a second deforming portion which
is connected between the portion which is joined to the winding
shaft and the second locking portion (the switching portion), and
is twistable by a rotational force in the pull-out direction of the
winding shaft.
[0018] A webbing retractor of a eighth aspect is characterized
that, in any one of the webbing retractors of the first to the
fifth aspects, a stopper accommodating hole for accommodating a
stopper wire serving as a second energy absorbing member is formed
in the winding shaft, one end portion of the stopper wire is
disposed within a wire guiding portion which is formed at least
either one of a first locking portion side end portion of the
winding shaft and a winding shaft side end portion of the first
locking portion, and the other end of the stopper wire is disposed
within an accommodating hole formed in the second locking
portion.
[0019] In the webbing retractor of the first aspect, the webbing,
which can be applied to a vehicle occupant, is wound on the winding
shaft. The webbing is pulled-out due to the winding shaft being
rotated in the pull-out direction.
[0020] At a time of an emergency situation with respect to the
vehicle, the force limiter mechanism permits rotation of the
winding shaft in the pull-out direction such that the load, which
is applied to the vehicle occupant from the webbing, is limited to
the limit load.
[0021] At the switching portion, the driving member can be driven
at a time of an emergency situation with respect to the vehicle.
Due to the driving of the driving member, the operating member is
operated, and movement of the moving member is permitted. The limit
load by the force limiter mechanism is thereby alternated from high
load to low load. Here, the operating member is directly operated
by the driving of the driving member, and the operating member is
engaged with the moving member. Therefore, because there is a
structure in which only the operating member is interposed between
the driving member and the moving member, the number of parts can
be reduced, and the structure can be made to be simple.
[0022] In the webbing retractor of the second aspect, the webbing,
which can be applied to a vehicle occupant, is wound on the winding
shaft. The webbing is pulled-out due to the winding shaft being
rotated in the pull-out direction.
[0023] At a time of an emergency situation with respect to the
vehicle, the force limiter mechanism permits rotation of the
winding shaft in the pull-out direction such that the load, which
is applied to the vehicle occupant from the webbing, is limited to
the limit load.
[0024] At the switching portion, at a time of an emergency
situation with respect to the vehicle, the driving member can be
driven. Due to the driving of the driving member, movement of the
moving member is permitted. The limit load by the force limiter
mechanism is thereby switched from high load to low load.
[0025] Here, the driving member is engaged with the moving member.
Therefore, because there is a structure in which nothing is
interposed between the driving member and the moving member, the
number of parts can be reduced, and the structure can be made to be
simple.
[0026] In the webbing retractor of the third aspect, the webbing,
which can be applied to a vehicle occupant, is wound on the winding
shaft. The webbing is pulled-out due to the winding shaft being
rotated in the pull-out direction.
[0027] At a time of an emergency situation with respect to the
vehicle, the force limiter mechanism permits rotation of the
winding shaft in the pull-out direction such that the load, which
is applied to the vehicle occupant from the webbing, is limited to
the limit load.
[0028] At the switching portion, the operating member can be
operated at a time of an emergency situation with respect to the
vehicle. Due to the operation of the operating member, prevention
and permission of movement of the moving member are alternated. The
limit load by the force limiter mechanism is thereby alternated
between high load and low load.
[0029] Here, the operating member can engage with the moving member
at one position. Therefore, aligning of the operating member with
respect to the moving member can be made to be easy.
[0030] In the webbing retractor of the fourth aspect, the webbing,
which can be applied to a vehicle occupant, is wound on the winding
shaft. The webbing is pulled-out due to the winding shaft being
rotated in the pull-out direction.
[0031] At a time of an emergency situation with respect to the
vehicle, the force limiter mechanism permits rotation of the
winding shaft in the pull-out direction such that the load, which
is applied to the vehicle occupant from the webbing, is limited to
the limit load.
[0032] At the switching portion, the operating member can be
operated at a time of an emergency situation with respect to the
vehicle. Due to the operation of the operating member, prevention
and permission of movement of the moving member are alternated. The
limit load by the force limiter mechanism is thereby alternated
between high load and low load.
[0033] Here, the operating member can engage with the moving
member. The position at which the operating member is supported is
disposed at the moving member moving direction side with respect to
the engaging position of the operating member with the moving
member. Therefore, in order for the operating member to engage with
the moving member and prevent movement of the moving member, there
is no need to make the engaging portion of the operating member
with the moving member be a shape which is inclined toward the side
opposite to the moving direction of the moving member. The shape of
the engaging portion of the operating member with the moving member
can be made to be simple.
[0034] In the webbing retractor of the fifth aspect, the webbing,
which can be applied to a vehicle occupant, is wound on the winding
shaft. The webbing is pulled-out due to the winding shaft being
rotated in the pull-out direction.
[0035] At a time of an emergency situation with respect to the
vehicle, the force limiter mechanism permits rotation of the
winding shaft in the pull-out direction such that the load, which
is applied to the vehicle occupant from the webbing, is limited to
the limit load.
[0036] At the switching portion, the operating member can be
operated at a time of an emergency situation with respect to the
vehicle. Due to the operation of the operating member, prevention
and permission of movement of the moving member are alternated. The
limit load by the force limiter mechanism is thereby alternated
between high load and low load.
[0037] Here, the operating member can be operated via pressure of a
fluid. When the operating member is operated, the operating state
thereof is maintained via the pressure of the fluid. Therefore, the
operating member entering into a non-operating state can be
suppressed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0038] Exemplary embodiments of the present invention will be
described in detail based on the following figures, wherein:
[0039] FIG. 1 is an exploded perspective view showing the structure
of a second locking mechanism of a webbing retractor relating to a
first exemplary embodiment of the present invention;
[0040] FIG. 2 is a front view showing a summary of the structure of
the second locking mechanism in the webbing retractor relating to
the first exemplary embodiment of the present invention;
[0041] FIG. 3 is a front view corresponding to FIG. 2 and showing
an operating state of the second locking mechanism in the webbing
retractor relating to the first exemplary embodiment of the present
invention;
[0042] FIG. 4 is a front view corresponding to FIG. 2 and showing
an unlocked state of a lock ring of the second locking mechanism in
the webbing retractor relating to the first exemplary embodiment of
the present invention;
[0043] FIG. 5 is a front sectional view showing a summary of the
structure of the webbing retractor relating to the first exemplary
embodiment of the present invention;
[0044] FIG. 6 is an exploded perspective view showing the structure
of the second locking mechanism of the webbing retractor relating
to the first exemplary embodiment of the present invention;
[0045] FIG. 7A is a front view showing the positional relationship
between a spool and a stopper wire in the webbing retractor
relating to the first exemplary embodiment of the present
invention, and showing a state before the stopper wire moves;
[0046] FIG. 7B is a front view showing the positional relationship
between the spool and the stopper wire in the webbing retractor
relating to the first exemplary embodiment of the present
invention, and showing a state in which the stopper wire has
moved;
[0047] FIG. 8 is a front view of a first lock base in the webbing
retractor relating to the first exemplary embodiment of the present
invention;
[0048] FIG. 9 is an exploded perspective view showing the structure
of a second locking mechanism of a webbing retractor relating to a
second exemplary embodiment of the present invention;
[0049] FIG. 10 is a front view showing a summary of the structure
of the second locking mechanism in the webbing retractor relating
to the second exemplary embodiment of the present invention;
[0050] FIG. 11 is a front view corresponding to FIG. 10 and showing
an operating state of the second locking mechanism in the webbing
retractor relating to the second exemplary embodiment of the
present invention;
[0051] FIG. 12 is a front view corresponding to FIG. 10 and showing
an unlocked state of a lock ring of the second locking mechanism in
the webbing retractor relating to the second exemplary embodiment
of the present invention;
[0052] FIG. 13 is an exploded perspective view showing the
structure of a second locking mechanism of a webbing retractor
relating to a third exemplary embodiment of the present
invention;
[0053] FIG. 14 is a front view showing a summary of the structure
of the second locking mechanism in the webbing retractor relating
to the third exemplary embodiment of the present invention;
[0054] FIG. 15 is a front view corresponding to FIG. 14 and showing
an operating state of the second locking mechanism in the webbing
retractor relating to the third exemplary embodiment of the present
invention;
[0055] FIG. 16 is a front view corresponding to FIG. 14 and showing
an unlocked state of a lock ring of the second locking mechanism in
the webbing retractor relating to the third exemplary embodiment of
the present invention;
[0056] FIG. 17 is an exploded perspective view showing the
structure of a second locking mechanism of a webbing retractor
relating to a fourth exemplary embodiment of the present
invention;
[0057] FIG. 18 is a front view showing a summary of the structure
of the second locking mechanism in the webbing retractor relating
to the fourth exemplary embodiment of the present invention;
[0058] FIG. 19 is a front view corresponding to FIG. 18 and showing
an operating state of the second locking mechanism in the webbing
retractor relating to the fourth exemplary embodiment of the
present invention;
[0059] FIG. 20 is a front view corresponding to FIG. 18 and showing
an unlocked state of a lock ring of the second locking mechanism in
the webbing retractor relating to the fourth exemplary embodiment
of the present invention;
[0060] FIG. 21 is an exploded perspective view showing the
structure of a second locking mechanism of a webbing retractor
relating to a fifth exemplary embodiment of the present
invention;
[0061] FIG. 22 is a front view showing a summary of the structure
of the second locking mechanism in the webbing retractor relating
to the fifth exemplary embodiment of the present invention;
[0062] FIG. 23 is a front view corresponding to FIG. 22 and showing
an operating state of the second locking mechanism in the webbing
retractor relating to the fifth exemplary embodiment of the present
invention;
[0063] FIG. 24 is a front view corresponding to FIG. 22 and showing
an unlocked state of a lock ring of the second locking mechanism in
the webbing retractor relating to the fifth exemplary embodiment of
the present invention;
[0064] FIG. 25 is an exploded perspective view showing the
structure of a second locking mechanism of a webbing retractor
relating to a sixth exemplary embodiment of the present
invention;
[0065] FIG. 26 is a front view showing a summary of the structure
of the second locking mechanism in the webbing retractor relating
to the sixth exemplary embodiment of the present invention;
[0066] FIG. 27 is a front view corresponding to FIG. 26 and showing
an operating state of the second locking mechanism in the webbing
retractor relating to the sixth exemplary embodiment of the present
invention; and
[0067] FIG. 28 is a front view corresponding to FIG. 26 and showing
an unlocked state of a lock ring of the second locking mechanism in
the webbing retractor relating to the sixth exemplary embodiment of
the present invention.
DETAILED DESCRIPTION
First Exemplary Embodiment
[0068] A first exemplary embodiment of the present invention will
be described next by using FIG. 1 through FIG. 8.
[0069] A summary of the structure of a webbing retractor 10
relating to the first exemplary embodiment of the present invention
is shown in a cross-sectional view in FIG. 5.
[0070] As shown in FIG. 5, the webbing retractor 10 has a frame 12.
The frame 12 has a plate-shaped rear plate 14 which is fixed to a
vehicle body. A leg plate 16 extends, substantially orthogonally to
the rear plate 14, from one transverse direction end portion of the
rear plate 14. In contrast, a leg plate 18 extends, in the same
direction as the direction in which the leg plate 16 extends, from
the other transverse direction end portion of the rear plate 14.
The frame 12 has a substantially convex shape as seen in plan
view.
[0071] A spool 20 serving as a winding shaft is provided between
the leg plate 16 and the leg plate 18. The axial direction of the
spool 20 runs along the direction in which the leg plate 16 and the
leg plate 18 oppose one another. The base end portion of a webbing
belt 22 (seat belt), which is shaped as an elongated strip and
serves as a webbing, is anchored to the axial direction
intermediate portion of the spool 20. Due to the spool 20 rotating
in a winding direction (the direction of arrow A in FIG. 2) which
is one direction around the axis thereof, the spool 20 winds the
webbing belt 22 from the base end side thereof and accommodates the
webbing belt 22. The webbing belt 22 is pulled-out due to the spool
20 being rotated in a pull-out direction (the direction of arrow B
in FIG. 2) which is the other direction around the axis
thereof.
[0072] On the other hand, the spool 20 is hollow along its central
axis. A torsion shaft 24, which serves as a force limiter mechanism
and a first energy absorbing member, is accommodated within the
spool 20. The torsion shaft 24 has a portion 26 which is joined to
the spool. The portion 26 which is joined to the spool is
positioned between the axial direction both ends of the spool 20.
The torsion shaft 24 is integrally connected to the spool 20 at
this portion 26 which is joined to the spool.
[0073] A rod-shaped first deforming portion 28 is formed
continuously from the leg plate 16 side end surface of the portion
26 which is joined to the spool. A first joining portion 30 is
formed at the leading end side of the first deforming portion 28,
so as to be coaxial and integral with the first deforming portion
28. The first joining portion 30 is coaxially and integrally
connected to a first lock base 34 which serves as a rotating body
which structures a first locking mechanism 32 serving as a first
locking portion.
[0074] The first lock base 34 is fit-together by insertion from the
leg plate 16 side end portion of the spool 20, so as to be coaxial
with the spool 20 and able to rotate relative to the spool 20.
However, due to the first joining portion 30 being connected
integrally to the first lock base 34 as described above, the first
lock base 34 is basically connected coaxially and integrally with
the spool 20.
[0075] A first lock pawl 36 is provided at the radial direction
outer side of the first lock base 34. The first lock pawl 36 is
pivotally-supported so as to rotate freely at the leg plate 16.
When the first lock pawl 36 rotates in a predetermined one
direction, ratchet teeth formed at the first lock pawl 36 approach
the outer peripheral portion of the first lock base 34, and can
mesh-together with the ratchet teeth which are formed at the outer
peripheral portion of the first lock base 34.
[0076] On the other hand, at the side of the first lock base 34
opposite to the side where the spool 20 is disposed, a rotating
member 38 is provided so as to be coaxial with the first lock base
34 and able to rotate relative to the first lock base 34. The
rotating member 38 is structured so as to rotate following the
first lock base 34, due to the biasing force of an unillustrated
biasing portion such as a compression coil spring, a torsion coil
spring, or the like.
[0077] Further, although details thereof are not illustrated, the
first locking mechanism 32 has one or plural restricting portions
which restrict rotation of the rotating member 38. When a large
inertia arises at the vehicle at the time of a rapid deceleration
of the vehicle (at the time of an emergency), or when the first
lock base 34 rotates rapidly in the pull-out direction, the
restricting portion operates, and rotation of the rotating member
38 is restricted. The first lock pawl 36 moves so as to approach
the outer peripheral portion of the first lock base 34,
interlockingly with the relative rotation between the first lock
base 34 and the rotating member 38 which arises at the time when
the first lock base 34 attempts to rotate in the pull-out direction
in the state in which rotation of the rotating member 38 is
restricted.
[0078] On the other hand, a rod-shaped second deforming portion 40
is formed continuously from the leg plate 18 side end surface of
the portion 26 which is joined to the spool. A second joining
portion 42 is formed coaxially and integrally with the second
deforming portion 40, at the leading end side of the second
deforming portion 40. The second joining portion 42 is connected
coaxially and integrally to a second lock base 46 which structures
a second locking mechanism 44 serving as a switching portion
(second locking portion).
[0079] The second lock base 46 is fit-together by insertion from
the leg plate 18 side end portion of the spool 20, so as to be
coaxial with the spool 20 and able to rotate relative to the spool
20. However, due to the second joining portion 42 being connected
integrally to the second lock base 46 as described above, the
second lock base 46 is basically connected coaxially and integrally
with the spool 20.
[0080] As shown in FIG. 1 and FIG. 2, a pair of pawl accommodating
portions 48 are formed at the second lock base 46. The pawl
accommodating portions 48 are open at portions of the outer
periphery of the second lock base 46. The pawl accommodating
portions 48 open at the end surface of the second lock base 46
which end surface is at the opposite side of the spool 20. Second
lock pawls 50 are accommodated in the pawl accommodating portions
48. Each of the second lock pawls 50 is pivotally-supported so as
to be rotatable around an axis parallel to the axis of the spool
20, by a pawl supporting pin 52 formed within the pawl
accommodating portion 48. The second lock pawls 50 are basically
accommodated in the pawl accommodating portions 48, respectively.
When the second lock pawl 50 rotates in one direction around the
pawl supporting pin 52, the distal end side of the second lock pawl
50 projects-out to the outer side from the open portion at the
outer peripheral portion of the pawl accommodating portion 48.
[0081] On the other hand, a rotating disc 54 is provided at the
side of the second lock base 46 opposite to the side where the
spool 20 is located. The rotating disc 54 basically is
pivotally-supported at the spool 20 so as to be coaxial with the
spool 20 and able to rotate relative to the spool 20. A pair of
guiding pins 56 are formed to project-out from the second lock base
46 side end surface of the rotating disc 54. The guiding pins 56
are provided so as to correspond to the aforementioned second lock
pawls 50.
[0082] Long holes 58 are formed in the second lock pawls 50
respectively, in correspondence with the guiding pins 56. The
guiding pins 56 are disposed in the long holes 58. The widthwise
dimensions of the long holes 58 are slightly larger than the outer
diameters of the guiding pins 56. When the guiding pins 56 rotate
together with the rotating disc 54 in one direction around the
spool 20, the guiding pins 56 push the inner walls of the long
holes 58 and rotate the second lock pawls 50 around the pawl
supporting pins 52.
[0083] A flat-plate-shaped plate 60 is formed to project from the
second lock base 46 side end surface of the rotating disc 54. A
spring accommodating hole 62 which is rectangular is formed in the
second lock base 46 in correspondence with the plate 60. A rotating
disc biasing spring 64 is accommodated within the spring
accommodating hole 62.
[0084] The rotating disc biasing spring 64 is a compression coil
spring. One end of the rotating disc biasing spring 64
press-contacts the inner wall of the spring accommodating hole 62.
The other end of the rotating disc biasing spring 64 press-contacts
the plate 60 which is disposed in the spring accommodating hole 62.
The rotating disc 54 can rotate in one direction around the spool
20, due to the plate 60 receiving the biasing force of the rotating
disc biasing spring 64. When the rotating disc 54 rotates in this
direction, the guiding pins 56 rotate the second lock pawls 50 in
the direction around the pawl supporting pins 52.
[0085] On the other hand, as shown in FIG. 5 and FIG. 6, a
through-hole 66 is formed in the floor portion of the spring
accommodating hole 62. A stopper accommodating hole 70 is formed in
the spool 20 in correspondence with the through-hole 66. The
stopper accommodating hole 70 is parallel to the axial center of
the spool 20. One end of the stopper accommodating hole 70 opens at
the end portion of the spool 20 at the first lock base 34 side. The
other end of the stopper accommodating hole 70 opens at the end
portion of the spool 20 at the second lock base 46 side. The inner
radial dimension of the stopper accommodating hole 70 does not
change from the one end to the other end thereof.
[0086] A stopper wire 74, which serves as a second energy absorbing
member and a controlling portion, is accommodated within the
stopper accommodating hole 70. The stopper wire 74 is formed in the
shape of a rod which is long along the axial direction of the spool
20. One end side of the stopper wire 74 projects-out to the
exterior of the stopper accommodating hole 70 from the open end at
the first lock base 34 side of the stopper accommodating hole
70.
[0087] A wire guiding groove 82 (see FIG. 7A) is formed in
correspondence with the portion of the stopper wire 74 which
projects-out from the spool 20, at least either one of the first
lock base 34 side end portion of the spool 20 and the spool 20 side
end portion of the first lock base 34 (in the present exemplary
embodiment, the wire guiding groove 82 is formed at the end portion
of the spool 20). The wire guiding groove 82 is curved such that
the center of curvature thereof is the central axis of the spool
20. One end side of the stopper wire 74 is disposed within the wire
guiding groove 82, and is curved so as to follow the wire guiding
groove 82.
[0088] Further, the one end portion of the stopper wire 74 is bent
toward the first lock base 34 within the wire guiding groove 82.
The one end portion of the stopper wire 74 is disposed in a wire
anchoring hole 84 which is formed in the first lock base 34 shown
in FIG. 8 as well.
[0089] On the other hand, the other end side of the stopper wire 74
projects-out to the exterior of the spool 20 from the second lock
base 46 side end portion of the stopper accommodating hole 70. The
stopper wire 74 passes through the through-hole 66, and is disposed
within the spring accommodating hole 62 at the side of the plate 60
opposite to the side at which the rotating disc biasing spring 64
is disposed. This other end of the stopper wire 74 interferes with
the plate 60 which attempts to rotate due to the biasing force of
the rotating disc biasing spring 64.
[0090] As shown in FIG. 1 and FIG. 2, a base 86 is connected
integrally to the leg plate 18 at the outer side of the leg plate
18. A circular hole 88 is formed in the base 86, coaxially with the
spool 20. The inner diameter of the circular hole 88 is
sufficiently larger than the second lock base 46, and the second
lock base 46 is passed-through the circular hole 88. A lock ring
90, which serves as a moving member, is pivotally-supported at the
circular hole 88 so as to rotate freely. The lock ring 90 is formed
in a ring shape on the whole. Further, inner ratchets 92 are formed
at the inner peripheral portion of the lock ring 90. When the
second lock pawls 50 rotate in one direction around the pawl
supporting pins 52 and the leading end sides of the second lock
pawls 50 project-out to the outer sides of the pawl accommodating
portions 48, second pawl ratchets 94 at the leading end sides of
the second lock pawls 50 mesh-together with the inner ratchets
92.
[0091] An outer peripheral groove 96, which is triangular in
cross-portion and serves as an engaged portion, is formed at a
portion of the outer periphery of the lock ring 90. A cam
accommodating hole 98, which communicates with the circular hole
88, is formed in the base 86 in correspondence with the outer
peripheral groove 96. A cam 100, which is shaped as a substantially
rectangular plate and serves as an operating member, is provided at
the inner side of the cam accommodating hole 98. The cam 100 is
supported so as to rotate freely at a supporting shaft 102 which is
formed to project-out from the leg plate 18. The supporting shaft
102 is disposed at the pull-out direction side with respect to the
outer peripheral groove 96 of the lock ring 90. A corner portion
100A, which is at one end side of the cam 100 and serves as an
engaging portion, can engage with a winding direction side surface
96A of the outer peripheral groove 96 of the lock ring 90. Due to
the dead weight of the cam 100, rotational force, in the direction
in which the corner portion 100A separates from the outer
peripheral groove 96 of the lock ring 90, is applied to the cam
100. A shear pin 104, which serves as a positioning portion and is
formed to project-out from the leg plate 18, passes through the cam
100. Rotation of the cam 100 is thereby restricted, and the corner
portion 100A of the cam 100 engages with (abuts) the winding
direction side surface 96A of the outer peripheral groove 96 of the
lock ring 90.
[0092] In the state in which the corner portion 100A of the cam 100
is engaged with the winding direction side surface 96A of the outer
peripheral groove 96 of the lock ring 90, when the lock ring 90
attempts to rotate in the pull-out direction, the corner portion
100A of the cam 100 is pushed in the pull-out direction by the
winding direction side surface 96A of the outer peripheral groove
96 of the lock ring 90, and rotational force, in the direction in
which the corner portion 100A separates from the outer peripheral
groove 96 of the lock ring 90, acts on the cam 100. However, due to
the rotation of the cam 100 being restricted by the shear pin 104,
the shear pin 104 receives the rotational force of the lock ring 90
in the pull-out direction, and rotation of the lock ring 90 in the
pull-out direction is restricted (prevented).
[0093] A cylinder accommodating hole 106 is formed in the base 86,
beneath the cam 100. The cylinder accommodating hole 106
communicates with the aforementioned cam accommodating hole 98. A
tubular cylinder 108 is fixed to the inner side of the cylinder
accommodating hole 106. A piston 110 serving as a driving member is
accommodated in the upper end portion of the cylinder 108. The
upper end of the piston 110 projects-out into the cam accommodating
hole 98.
[0094] A gas generator 112 (micro gas generator) serving as a
driving portion is fixed to the lower end portion of the cylinder
108. The gas generator 112 is disposed at the inner side of a
generator accommodating hole 114 formed in the base 86, and is
fixed to the base 86. Chemical agents, such as an igniting agent
and a gas generating agent and the like, and an igniting device,
which ignites the igniting agent due to an electric ignition signal
being inputted thereto, are accommodated in the gas generator 112.
The igniting device of the gas generator 112 is connected to an
unillustrated ECU (control device).
[0095] The ECU is connected directly or indirectly to both a danger
predicting portion and a physique detecting portion. The danger
predicting portion directly or indirectly detects that the vehicle
has entered a state of rapid deceleration or that the vehicle will
likely enter into a state of rapid deceleration. Other than an
acceleration sensor which senses a state of rapid deceleration of
the vehicle, the danger predicting portion may be, for example, a
distance measuring sensor which detects that the distance to an
obstacle in front of the vehicle has become less than a given
value, or the like. The physique detecting portion directly or
indirectly detects the physique of the vehicle occupant who is
seated in the seat, and is, for example, a load sensor which
detects the load applied to the seat of the vehicle, a belt sensor
which detects that the webbing belt 22 has been pulled-out by
greater than or equal to a given amount from the spool 20, or the
like.
[0096] When the ECU judges, on the basis of the signal from the
danger predicting portion, that the vehicle has entered into a
state of rapid deceleration or that the vehicle will likely enter
into a state of rapid deceleration, and judges that the physique of
the vehicle occupant seated in the seat is less than a reference
value which is determined in advance, the ignition signal is output
from the ECU to the igniting device of the gas generator 112, and
the gas generator 112 is operated.
[0097] When the igniting agent is ignited due to the ignition
signal being input to the igniting device of the gas generator 112,
and further, the igniting agent which is ignited burns the gas
generating agent, gas (a fluid) is generated instantaneously within
the gas generator 112. The pressure of this gas works to push-out
(drive) the piston 110 upward via the cylinder 108. Due to the
piston 110, which is pushed-out toward the upper side of the
cylinder 108, pushing the other end side portion of the cam 100
upward, the cam 100 rotates (operates) in the direction of moving
the corner portion 100A away from the outer peripheral groove 96 of
the lock cylinder 90, while the cam 100 breaks the shear pin
104.
[0098] The side of the base 86 at the side opposite to the leg
plate 18 is covered by a cover (not shown) which is made of resin
and serves as a covering member. The second locking mechanism 44 is
accommodated at the interior of the cover.
[0099] Operation and effects of the present exemplary embodiment
will be described next.
(Operation of First Locking Mechanism 32)
[0100] At the webbing retractor 10, in a state in which the webbing
belt 22 which is pulled-out from the spool 20 is applied to the
body of a vehicle occupant, when, for example, the vehicle enters
into a state of rapid deceleration and the first locking mechanism
32 operates, first, rotation of the rotating member 38 in the
pull-out direction is restricted.
[0101] Then, when the body of the vehicle occupant, which attempts
to move forward due to the inertia at the time of the rapid
deceleration of the vehicle, suddenly pulls the webbing belt 22 and
attempts to rotate the spool 20 in the pull-out direction, the
first lock base 34, which is integrally connected to the spool 20
via the torsion shaft 24, rotates in the pull-out direction.
[0102] Here, in this state, if rotation of the rotating member 38
in the pull-out direction is restricted as described above,
relative rotation arises between the first lock base 34 and the
rotating member 38, and the first lock pawl 36 approaches the first
lock base 34.
[0103] In this way, the ratchet teeth of the first lock pawl 36
mesh-together with the ratchet teeth of the first lock base 34.
Rotation of the first lock base 34 in the pull-out direction, and
eventually, rotation of the spool 20 in the pull-out direction, is
restricted, and pulling-out of the webbing belt 22 from the spool
20 is restricted. In this way, the body of the vehicle occupant,
which attempts to move forward, can be reliably restrained by the
webbing belt 22.
(Operation of Torsion Shaft 24)
[0104] In the state in which the rotation of the first lock base 34
is restricted by the first lock pawl 36 as described above, if the
body of the vehicle occupant pulls the webbing belt 22 by an even
greater force and the rotational force of the spool 20 in the
pull-out direction, which is based on this pulling force, exceeds
the mechanical strength of the first deforming portion 28, the
first deforming portion 28 twists while the first joining portion
30 remains connected to the first lock base 34, and the spool 20
rotates in the pull-out direction by the amount of this
twisting.
[0105] Accordingly, the webbing belt 22 is pulled-out from the
spool 20 by the amount of rotation of the spool 20 in the pull-out
direction. In this way, the force by which the webbing belt 22
restrains the vehicle occupant weakens slightly, and the energy
provided for pulling the webbing belt 22 is absorbed by the amount
of the aforementioned twisting deformation.
(Operation of Stopper Wire 74)
[0106] As described above, the rotation of the spool 20 in the
pull-out direction with respect to the first lock base 34 is the
rotation of the first lock base 34 in the winding direction
relative to the spool 20. When the first lock base 34 rotates
relative to the spool 20 in the winding direction in this way, the
stopper wire 74 is pulled while being guided by the wire guiding
groove 82 of the first lock base 34, in a state in which one end of
the stopper wire 74 remains disposed in the wire anchoring hole 84
formed in the first lock base 34.
[0107] However, the longitudinal direction of the stopper wire 74
runs along the axial direction of the spool 20 at the inner side of
the stopper accommodating hole 70, whereas the direction in which
the first lock base 34 pulls the stopper wire 74 is the winding
direction. Therefore, as shown in FIG. 7B, the stopper wire 74
which is pulled by the first lock base 34 follows the wire guiding
groove 82, while being strongly rubbed at the edge of the first
lock base 34 side open end of the stopper accommodating hole 70,
and the stopper wire 74 is deformed such that the longitudinal
direction thereof becomes the longitudinal direction of the wire
guiding groove 82, i.e., the peripheral direction of rotation of
the spool 20.
[0108] Due also to the stopper wire 74 being pulled and deformed in
this way, the force by which the webbing belt 22 restrains the
vehicle occupant weakens slightly, and the energy provided for
pulling the webbing belt 22 is absorbed by the amount of
deformation of the stopper wire 74. The energy absorption amount
corresponding to the amount of deformation of the stopper wire 74
is superposed on the energy absorption amount corresponding to the
amount of twisting of the first deforming portion 28, and the
energy provided for pulling the webbing belt 22 can be absorbed
effectively.
(Operation of Second Locking Mechanism 44)
[0109] When the stopper wire 74 moves at the inner side of the
stopper accommodating hole 70 toward the first lock base 34 side as
described above, the other end side of the stopper wire 74 which is
disposed in the spring accommodating hole 62 passes-through the
through-hole 66 and comes out from the spring accommodating hole
62, and is pulled into the stopper accommodating hole 70 from the
lock base 46 side end portion of the stopper accommodating hole 70.
When the stopper wire 74 is pulled-out from the spring
accommodating hole 62 in this way, the interference of the stopper
wire 74 with respect to the plate 60 is released. The plate 60, at
which interference from the stopper wire 74 is released, receives
the biasing force of the rotating disc biasing spring 64 and
rotates within the spring accommodating hole 62.
[0110] Because the plate 60 is integral with the rotating disc 54,
due to the plate 60 rotating by the biasing force of the rotating
disc biasing spring 64, the rotating disc 54 rotates in the winding
direction with respect to the second lock base 46. When the
rotating disc 54 rotates in the winding direction with respect to
the second lock base 46, the guiding pins 56 push the inner walls
of the long holes 58, and cause the second lock pawls 50 to rotate
in one direction around the pawl supporting pins 52.
[0111] When the second lock pawls 50 rotate in this way, the
leading ends of the second lock pawls 50 project-out to the
exterior of the second lock base 46, and the second lock pawl
ratchets 94 of the leading ends of the second lock pawls 50
mesh-together with the inner ratchet 92 of the lock ring 90 (see
FIG. 3).
[0112] The spool 20, at which the webbing belt 22 is being pulled,
attempts to rotate in the pull-out direction. Therefore, the second
lock pawls 50 attempt to rotate in the pull-out direction together
with the second lock base 46.
[0113] Accordingly, the rotating force of the second lock base 46
in the pull-out direction is transmitted to the lock ring 90 which
the second pawls 50 are meshed with, and the lock ring 90 attempts
to rotate in the pull-out direction. In this state, if the corner
portion 100A of the cam 100 is engaged with the winding direction
side surface 96A of the outer peripheral groove 96 of the lock ring
90, rotation of the lock ring 90 in the pull-out direction is
restricted by the cam 100.
[0114] When rotation of the lock ring 90 in the pull-out direction
is restricted, rotation of the second lock base 46 in the pull-out
direction also is restricted. In this state, when the rotational
force in the pull-out direction of the spool 20, which is based on
the pulling force at the time when the body of the vehicle occupant
pulls the webbing belt 22, exceeds the sum of the mechanical
strength of the first deforming portion 28 and the mechanical
strength of the second deforming portion 40, the second deforming
portion 40 as well as the first deforming portion 28 are twisted,
in a state in which the second joining portion 42 remains connected
to the second lock base 46. The spool 20 rotates in the pull-out
direction by the amount of this twisting.
[0115] Accordingly, the webbing belt 22 is pulled-out from the
spool 20 by the amount of rotation of the spool 20 in the pull-out
direction. In this way, the force by which the webbing belt 22
restrains the vehicle occupant weakens slightly, and the energy
provided for pulling the webbing belt 22 is absorbed by
aforementioned amount of twisting deformation. Therefore, energy
absorption by the twisting deformation of the first deforming
portion 28 and the second deforming portion 40 arises, and the
limit load by the torsion shaft 24 is made to be a high load.
[0116] On the other hand, as shown in FIG. 4, before the first
locking mechanism 32 operates, when the vehicle enters a state of
rapid deceleration or a state immediately before rapid
deceleration, and the ECU judges, on the basis of the signal from
the physique detecting portion, that the physique of the vehicle
occupant seated in the seat is less than the predetermined
reference value, and the ignition signal is thereby output from the
ECU, the gas generator 112 operates. When the gas generator 112
operates, the piston 110 is pushed toward the upper side of the
cylinder 108 and pushes the other end side portion of the cam 100
upward. The cam 100 thereby rotates while breaking the shear pin
104, and the corner portion 100A of the cam 100 is separated from
the outer peripheral groove 96 of the lock ring 90.
[0117] In this state, when the rotating force of the spool 20 in
the pull-out direction is transmitted to the lock ring 90 via the
second lock base 46 and the second lock pawls 50, the lock ring 90
rotates in the pull-out direction together with the spool 20.
Accordingly, in this state, twisting occurs at the first deforming
portion 28, but twisting does not occur at the second deforming
portion 40. Therefore, only energy absorption due to twisting
deformation of the first deforming portion 28 arises, and the limit
load by the torsion shaft 24 is made to be a low load.
[0118] Namely, in the present exemplary embodiment, by controlling
the gas generator 112, it is possible to selectively switch to a
mode (high load mode) which causes deformation at the second
deforming portion 40, and a mode (low load mode) which does not
cause deformation at the second deforming portion 40. In this way,
appropriate energy absorption corresponding to the physique of the
vehicle occupant to which the webbing belt 22 is applied, or the
like, is possible.
[0119] When the gas generator 112 is not operated, the cam 100 is
engaged with the outer peripheral groove 96 of the lock ring 90,
and the limit load by the torsion shaft 24 is made to be a high
load. On the other hand, when the gas generator 112 is operated,
the cam 100 is moved apart from the outer peripheral groove 96 of
the lock ring 90, and the limit load by the torsion shaft 24 is
made to be a low load.
[0120] In this way, the cam 100 is, due to the operation of the gas
generator 112, changed from a state of being engaged with the outer
peripheral groove 96 of the lock ring 90 (the high load mode) to a
state of being separated from the outer peripheral groove 96 of the
lock ring 90 (the low load mode). Therefore, as compared with a
case in which the cam 100 is changed by operation of the gas
generator 112 from a state of being separated from the outer
peripheral groove 96 of the lock ring 90 (the low load mode) to a
state of being engaged with the outer peripheral groove 96 of the
lock ring 90 (the high load mode), the structure can be simplified,
and the limit load by the torsion shaft 24 can be made to be a high
load at an early stage, and, even if operation of the gas generator
112 is late, the amount of movement of the vehicle occupant can be
suppressed because the limit load by the torsion shaft 24 is
maintained at a high load. Further, because the cam 100 is changed
from the state of being engaged with the outer peripheral groove 96
of the lock ring 90 to the state of being separated from the outer
peripheral groove 96 of the lock ring 90, the precision of
assembling the cam 100 with respect to the outer peripheral groove
96 of the lock ring 90 is good, and there is no loss of driving
force between the lock ring 90 and the cam 100. Therefore,
excessive force is not needed at the cam 100, and the operation of
the cam 100 can be made to be stable.
[0121] Here, the second locking mechanism 44 is structured such
that only the cam 100 is interposed between the lock ring 90 and
the piston 110 which is driven by the gas generator 112. Therefore,
the number of parts of the second locking mechanism 44 can be
reduced, and the structure of the second locking mechanism 44 can
be made to be simple. In this way, the work of assembling the
second locking mechanism 44 can be made to be easy, and costs can
be reduced.
[0122] Further, the cam 100 is engaged with the outer peripheral
groove 96 of the lock ring 90 at one position (the corner portion
100A). Therefore, the aligning of the cam 100 with respect to the
outer peripheral groove 96 of the lock ring 90 can be made to be
simple, the precision of assembling the cam 100 with respect to the
outer peripheral groove 96 of the lock ring 90 can easily be
improved, and the cam 100 can appropriately restrict rotation of
the lock ring 90 in the pull-out direction.
[0123] As compared with the position where the cam 100 engages the
lock ring 90 (the position of the corner portion 100A), the
position where the cam 100 is supported (the position of the
supporting shaft 102) is disposed at the lock ring 90 pull-out
direction side. Therefore, in order for the corner portion 100A of
the cam 100 to engage with the outer peripheral groove 96 of the
lock ring 90 and prevent rotation of the lock ring 90 in the
pull-out direction, there is no need to form an engaging portion of
the cam 100 which engages with the outer peripheral groove 96 of
the lock ring 90 (i.e., the corner portion 100A) in a shape which
is inclined toward the winding direction of the lock ring 90. The
shape of this engaging portion of the cam 100 can be made to be
simple, and the strength of the engaging portion of the cam 100 can
be made to be high. Further, because the load from the outer
peripheral groove 96 of the lock ring 90 can be received at the
supporting shaft 102 as well, the engagement of the cam 100 with
the lock ring 90 can be stabilized.
[0124] Moreover, after the gas generator 112 is operated and the
corner portion 100A of the cam 100 is moved apart from the outer
peripheral groove 96 of the lock ring 90, even if the corner
portion 100A of the cam 100 again engages with the winding
direction side surface 96A of the outer peripheral groove 96 of the
lock ring 90, the corner portion 100A of the cam 100 is pushed by
the winding direction side surface 96A of the outer peripheral
groove 96 of the lock ring 90, and is moved away from the outer
peripheral groove 96 of the lock ring 90. Therefore, it is possible
to prevent rotation of the lock ring 90 in the pull-out direction
from being restricted unnecessarily after the gas generator 112 is
operated.
[0125] Note that the present exemplary embodiment is a structure in
which rotation of the cam 100 is restricted by the shear pin 104,
but may be a structure in which rotation of the cam 100 is not
restricted by the shear pin 104. In this case, when the lock ring
90 rotates in the pull-out direction and the corner portion 100A of
the cam 100 is pushed by the winding direction side surface 96A of
the outer peripheral groove 96 of the lock ring 90, rotational
force in the direction in which the corner portion 100A approaches
the lock ring 90 acts on the cam 100. Moreover, it is preferable to
utilize a structure in which rotational force in the direction of
the corner portion 100A approaching the outer peripheral groove 96
of the lock ring 90 is applied due to the dead weight of the cam
100 itself, or a structure in which a positioning portion, which
prevents rotation of the cam 100 at usual times of the vehicle and
whose prevention of the rotation of the cam 100 is released at
times of rapid deceleration of the vehicle, is provided at the
cover or the like.
[0126] Further, the present exemplary embodiment may be structured
such that the state, in which the corner portion 100A of the cam
100 is separated from the outer peripheral groove 96 of the lock
ring 90, is maintained by maintaining the state in which the
interior of the cylinder 108 is made to be high pressure due to the
gas generated by the gas generator 112 and the piston 110 is
pushed-out toward the upper side of the cylinder 108. In this way,
after the gas generator 112 is operated, the corner portion 100A of
the cam 100 can reliably be prevented from engaging with the
winding direction side surface 96A of the outer peripheral groove
96 of the lock ring 90, and it is possible to reliably prevent
rotation of the lock ring 90 in the pull-out direction from being
restricted unnecessarily.
Second Exemplary Embodiment
[0127] A second exemplary embodiment of the present invention will
be described next by using FIG. 9 through FIG. 12.
[0128] A webbing retractor 200 relating to the present exemplary
embodiment has a structure which is substantially similar to that
of the first exemplary embodiment, but differs with respect to the
following points.
[0129] As shown in FIG. 9 and FIG. 10, at the webbing retractor 200
relating to the present exemplary embodiment, a stopper placement
hole 202, which is shaped as a rectangular plate and serves as an
engaged portion, is formed at a portion of the outer periphery of
the lock ring 90. The lower end of the stopper placement hole 202
is open from the outer periphery of the lock ring 90. A stopper
accommodating hole 204, which communicates with the circular hole
88, is formed at the base 86 so as to correspond to the stopper
placement hole 202. A stopper 206, which is shaped substantially as
a rectangular plate and serves as an operating member, is
accommodated at the inner side of the stopper placement hole 202.
The stopper 206 is engaged with (placed at) the lock ring 90. The
stopper 206 projects-out from the outer periphery of the lock ring
90 into the stopper accommodating hole 204, and abuts a pull-out
direction side surface 204A of the stopper accommodating hole 204.
A shear pin placement recess 208, which is rectangular in
cross-portion, is formed at the upper portion of the stopper 206. A
solid-cylindrical shear pin 210 is formed at the outer peripheral
surface of the stopper placement hole 202. Due to the bottom
surface of the shear pin placement recess 208 being abutted with
the shear pin 210, the entire stopper 206 is prevented from being
accommodated completely within the stopper placement hole 202. The
stopper 206 is prevented from falling out from the stopper
placement hole 202 by a shear pin (not shown) which serves as a
positioning portion and is formed to project-out from the leg plate
18. Note that the stopper 206 may be prevented from falling out
from the stopper placement hole 202 by, for example, being
press-fit into the inner side of the stopper placement hole 202 as
a positioning portion, or the like.
[0130] In the state in which the stopper 206 projects-out from the
outer periphery of the lock ring 90 and is abutted with the
pull-out direction side surface 204A of the stopper accommodating
hole 204, when the lock ring 90 attempts to rotate in the pull-out
direction, the pull-out direction side surface 204A of the stopper
accommodating hole 204 receives the rotational force of the lock
ring 90 in the pull-out direction via the stopper 206, such that
rotation of the lock ring 90 in the pull-out direction is
restricted (prevented).
[0131] The cylinder accommodating hole 106 of the base 86
communicates with the stopper accommodating hole 204. The upper end
of the piston 110, which is accommodated at the upper end portion
of the cylinder 108 which is fixed to the inner side of the
cylinder accommodating hole 106, projects-out into the stopper
accommodating hole 204 and is disposed below the stopper 206.
[0132] When the gas generator 112 is operated and the piston 110 is
pushed-out toward the upper side of the cylinder 108, due to the
piston 110 pushing the stopper 206 upward, the entire stopper 206
is completely accommodated (operated) within the stopper placement
hole 202 while breaking the shear pin 210 and the shear pin which
is formed to project-out from the leg plate 18.
[0133] As shown in FIG. 11, in the state in which the vehicle
enters a state of rapid deceleration, and the second lock pawls 50
mesh-together with the lock ring 90, and the lock ring 90 attempts
to rotate in the pull-out direction via the spool 20, the second
lock base 46 and the second lock pawls 50, if the stopper 206
projects-out from the outer periphery of the lock ring 90 and is
abutted with the pull-out direction side surface 204A of the
stopper accommodating hole 204, rotation of the lock ring 90 in the
pull-out direction is restricted by the stopper 206. Therefore,
energy absorption due to twisting deformation of the first
deforming portion 28 and the second deforming portion 40 arises,
and the limit load by the torsion shaft 24 is made to be a high
load.
[0134] On the other hand, as shown in FIG. 12, before the first
locking mechanism 32 operates, when the vehicle enters into a state
of rapid deceleration or a state immediately before rapid
deceleration and the gas generator 112 is operated, due to the
piston 110 being pushed-out toward the upper side of the cylinder
108 and the piston 110 pushing the stopper 206 upward, the entire
stopper 206 is completely accommodated within the stopper placement
hole 202 while breaking the shear pin 210 and the shear pin which
is formed to project-out from the leg plate 18. In this state, if
rotational force in the pull-out direction is transmitted to the
lock ring 90 via the spool 20, the second lock base 46 and the
second lock pawls 50, the lock ring 90 rotates in the pull-out
direction. Therefore, only energy absorption due to twisting
deformation of the first deforming portion 28 arises, and the limit
load by the torsion shaft 24 is made to be a low load.
[0135] Here, the second locking mechanism 44 is structured such
that only the stopper 206 is interposed between the lock ring 90
and the piston 110 which is driven by the gas generator 112.
Therefore, the number of parts of the second locking mechanism 44
can be reduced, and the structure of the second locking mechanism
44 can be made to be simple. In this way, the work of assembling
the second locking mechanism 44 can be made to be easy, and costs
can be reduced.
[0136] Further, the stopper 206 is engaged with the stopper
placement hole 202 of the lock ring 90 at one position (the upper
portion). Therefore, the aligning of the stopper 206 with respect
to the lock ring 90 can be made to be simple, the precision of
assembling the stopper 206 with respect to the stopper placement
hole 202 of the lock ring 90 can easily be improved, and the
stopper 206 can appropriately restrict rotation of the lock ring 90
in the pull-out direction.
[0137] The stopper 206 is partially accommodated in the stopper
placement hole 202 of the lock ring 90, and projects-out from the
outer periphery of the lock ring 90 and is abutted with the
pull-out direction side surface 204A of the stopper accommodating
hole 204. Therefore, the shape of the stopper 206 for preventing
rotation of the lock ring 90 in the pull-out direction can be made
to be simple, and the strength of the stopper 206 can be made to be
high.
[0138] Further, after the gas generator 112 is operated, the
stopper 206 is prevented by the piston 110 from projecting-out from
the outer periphery of the lock ring 90 by maintaining the state in
which interior of the cylinder 108 is made to be high pressure due
to the gas generated by the gas generator 112 and the piston 110 is
pushed-out toward the upper side of the cylinder 108. Therefore,
after the gas generator 112 is operated, the stopper 206 can
reliably be prevented from abutting the pull-out direction side
surface 204A of the stopper accommodating hole 204, and it is
possible to reliably prevent rotation of the lock ring 90 in the
pull-out direction from being restricted unnecessarily.
Third Exemplary Embodiment
[0139] A third exemplary embodiment of the present invention will
be described next by using FIG. 13 through FIG. 16.
[0140] A webbing retractor 300 relating to the present exemplary
embodiment has a structure which is substantially similar to that
of the first exemplary embodiment, but differs with respect to the
following points.
[0141] As shown in FIG. 13 and FIG. 14, in the webbing retractor
300 relating to the present exemplary embodiment, the winding
direction side surface 96A of the outer peripheral groove 96 at the
outer periphery of the lock ring 90 is disposed horizontally. A
piston accommodating hole 302, which communicates with the circular
hole 88, is formed in the base 86 so as to correspond to the outer
peripheral groove 96.
[0142] The cylinder accommodating hole 106 of the base 86
communicates with the piston accommodating hole 302. The piston
110, which is partially accommodated at the upper end portion of
the cylinder 108 which is fixed to the inner side of the cylinder
accommodating hole 106, functions also as an operating member, and
projects-out into the piston accommodating hole 302. The piston 110
is formed substantially in the shape of a sideways T-shaped plate,
and the upper end of the piston 110 engages with (abuts) the
winding direction side surface 96A of the outer peripheral groove
96 of the lock ring 90. The piston 110 is positioned by a
positioning portion (e.g., a positioning projection which is formed
at the cover).
[0143] In the state in which the upper end of the piston 110 is
engaged with the winding direction side surface 96A of the outer
peripheral groove 96 of the lock ring 90, if the lock ring 90
attempts to rotate in the pull-out direction, the piston 110
receives the rotational force of the lock ring 90 in the pull-out
direction, and rotation of the lock ring 90 in the pull-out
direction is restricted (prevented).
[0144] When the gas generator 112 is operated, the piston 110 is
pushed-out toward the lateral side of the upper end portion of the
cylinder 108 while breaking the positioning portion (i.e., is
driven and operated), and the engagement of the upper end of the
piston 110 with the winding direction side surface 96A of the outer
peripheral groove 96 of the lock ring 90 is released.
[0145] As shown in FIG. 15, in the state in which the vehicle
enters a state of rapid deceleration, and the second lock pawls 50
mesh-together with the lock ring 90, and the lock ring 90 attempts
to rotate in the pull-out direction via the spool 20, the second
lock base 46 and the second lock pawls 50, if the upper end of the
piston 110 is engaged with the winding direction side surface 96A
of the outer peripheral groove 96 of the lock ring 90, rotation of
the lock ring 90 in the pull-out direction is restricted by the
piston 110. Therefore, energy absorption due to twisting
deformation of the first deforming portion 28 and the second
deforming portion 40 arises, and the limit load by the torsion
shaft 24 is made to be a high load.
[0146] On the other hand, as shown in FIG. 16, before the first
locking mechanism 32 operates, when the vehicle enters into a state
of rapid deceleration or a state immediately before rapid
deceleration and the gas generator 112 is operated, the piston 110
is pushed-out toward the lateral side of the upper end portion of
the cylinder 108 while breaking the positioning portion, and the
engagement of the upper end of the piston 110 with the winding
direction side surface 96A of the outer peripheral groove 96 of the
lock ring 90 is released. In this state, if rotational force in the
pull-out direction is transmitted to the lock ring 90 via the spool
20, the second lock base 46 and the second lock pawls 50, the lock
ring 90 rotates in the pull-out direction. Therefore, only energy
absorption due to twisting deformation of the first deforming
portion 28 arises, and the limit load by the torsion shaft 24 is
made to be a low load.
[0147] Here, the second locking mechanism 44 is structured such
that nothing is interposed between the lock ring 90 and the piston
110 which is driven by the gas generator 112. Therefore, the number
of parts of the second locking mechanism 44 can be reduced, and the
structure of the second locking mechanism 44 can be made to be
simple. In this way, the work of assembling the second locking
mechanism 44 can be made to be easy, and costs can be reduced.
[0148] Further, the piston 110 is engaged with the outer peripheral
groove 96 of the lock ring 90 at one position (the upper end).
Therefore, the aligning of the upper end of the piston 110 with
respect to the winding direction side surface 96A of the outer
peripheral groove 96 of the lock ring 90 can be made to be simple,
the precision of assembling the piston 110 with respect to the
winding direction side surface 96A of the outer peripheral groove
96 of the lock ring 90 can easily be improved, and the piston 110
can appropriately restrict rotation of the lock ring 90 in the
pull-out direction.
[0149] The piston 110 partially projects-out from the upper end
portion of the cylinder 108, and the upper end of the piston 110 is
engaged with the winding direction side surface 96A of the outer
peripheral groove 96 of the lock ring 90. Therefore, the shape of
the piston 110 for preventing rotation of the lock ring 90 in the
pull-out direction can be made to be simple, and the strength of
the piston 110 can be made to be high.
[0150] Further, after the gas generator 112 is operated, the state,
in which the interior of the cylinder 108 is made to be high
pressure due to the gas generated by the gas generator 112 and the
piston 110 is pushed-out toward the lateral side of the upper end
portion of the cylinder 108, is maintained. Therefore, after the
gas generator 112 is operated, the piston 110 can reliably be
prevented from engaging with the winding direction side surface 96A
of the outer peripheral groove 96 of the lock ring 90, and it is
possible to reliably prevent rotation of the lock ring 90 in the
pull-out direction from being restricted unnecessarily.
Fourth Exemplary Embodiment
[0151] A fourth exemplary embodiment of the present invention will
be described next by using FIG. 17 through FIG. 20.
[0152] A webbing retractor 400 relating to the present exemplary
embodiment has a structure which is substantially similar to that
of the first exemplary embodiment, but differs with respect to the
following points.
[0153] As shown in FIG. 17 and FIG. 18, at the webbing retractor
400 relating to the present exemplary embodiment, a stopper portion
placement hole 402, which is substantially hemispherical and serves
as an engaged portion, is formed at a portion of the outer
periphery of the lock ring 90. The lower end of the stopper portion
placement hole 402 is open from the outer periphery of the lock
ring 90. A stopper portion accommodating hole 404, which is
pillar-shaped and communicates with the circular hole 88, is formed
at the base 86 so as to correspond to the stopper portion placement
hole 402.
[0154] The cylinder accommodating hole 106 of the base 86
communicates with the stopper portion accommodating hole 404. The
piston 110, which is accommodated at the upper end portion of the
cylinder 108 which is fixed to the inner side of the cylinder
accommodating hole 106, is structured by a stopper portion 406,
which is shaped as a shaft and is at the upper side, and a piston
portion 408, which is shaped as a plate and is at the lower side,
being formed integrally. The piston 110 functions also as an
operating member. The stopper portion 406 projects-out upwardly
from the piston portion 408. The stopper portion 406 passes through
the top wall of the cylinder 108, and the upper end of the stopper
portion 406 is engaged with (inserted in) the stopper portion
placement hole 402 of the lock ring 90 via the stopper portion
accommodating hole 404. The piston 110 (the piston portion 408) is
positioned by a positioning portion (e.g., a positioning projection
which is formed at the cylinder 108), and downward movement of the
piston 110 within the cylinder 108 is restricted.
[0155] In the state in which the upper end of the stopper portion
406 of the piston 110 is engaged with the stopper portion placement
hole 402 of the lock ring 90, if the lock ring 90 attempts to
rotate in the pull-out direction, the stopper portion 406 receives
the rotational force of the lock ring 90 in the pull-out direction,
and rotation of the lock ring 90 in the pull-out direction is
restricted (prevented).
[0156] When the gas generator 112 is operated, the piston 110 (the
piston portion 408) is moved downward within the cylinder 108 while
breaking the stopper portion 406 (i.e., is driven and operated),
and the engagement of the upper end of the piston portion 408 with
the stopper portion placement hole 402 of the lock ring 90 is
released.
[0157] As shown in FIG. 19, in the state in which the vehicle
enters a state of rapid deceleration, and the second lock pawls 50
mesh-together with the lock ring 90, and the lock ring 90 attempts
to rotate in the pull-out direction via the spool 20, the second
lock base 46 and the second lock pawls 50, if the upper end of the
stopper portion 406 of the piston 110 is engaged with the stopper
portion placement hole 402 of the lock ring 90, rotation of the
lock ring 90 in the pull-out direction is restricted by the stopper
portion 406. Therefore, energy absorption due to twisting
deformation of the first deforming portion 28 and the second
deforming portion 40 arises, and the limit load by the torsion
shaft 24 is made to be a high load.
[0158] On the other hand, as shown in FIG. 20, before the first
locking mechanism 32 operates, when the vehicle enters into a state
of rapid deceleration or a state immediately before rapid
deceleration and the gas generator 112 is operated, the piston 110
(the piston portion 408) is moved downward within the cylinder 108
while breaking the positioning portion, and the engagement of the
piston 110 (the upper end of the stopper portion 406) with the
stopper portion placement hole 402 of the lock ring 90 is released.
In this state, if rotational force in the pull-out direction is
transmitted to the lock ring 90 via the spool 20, the second lock
base 46 and the second lock pawls 50, the lock ring 90 rotates in
the pull-out direction. Therefore, only energy absorption due to
twisting deformation of the first deforming portion 28 arises, and
the limit load by the torsion shaft 24 is made to be a low
load.
[0159] Here, the second locking mechanism 44 is structured such
that nothing is interposed between the lock ring 90 and the piston
110 which is driven by the gas generator 112. Therefore, the number
of parts of the second locking mechanism 44 can be reduced, and the
structure of the second locking mechanism 44 can be made to be
simple. In this way, the work of assembling the second locking
mechanism 44 can be made to be easy, and costs can be reduced.
[0160] Further, the stopper portion 406 of the piston 110 is
engaged with the stopper portion placement hole 402 of the lock
ring 90 at one position (the upper end). Therefore, the aligning of
the piston 110 (the stopper portion 406) with respect to the
stopper portion placement hole 402 of the lock ring 90 can be made
to be simple, the precision of assembling the piston 110 (the
stopper portion 406) with respect to the stopper portion placement
hole 402 of the lock ring 90 can easily be improved, and the
stopper portion 406 of the piston 110 can appropriately restrict
rotation of the lock ring 90 in the pull-out direction.
[0161] The upper end of the stopper portion 406 of the piston 110
is engaged with the stopper portion placement hole 402 of the lock
ring 90. Therefore, the shape of the piston 110 (the stopper
portion 406) for preventing rotation of the lock ring 90 in the
pull-out direction can be made to be simple, and the strength of
the piston 110 (the stopper portion 406) can be made to be
high.
[0162] Further, after the gas generator 112 is operated, the state,
in which the interior of the cylinder 108 is made to be high
pressure due to the gas generated by the gas generator 112 and the
piston 110 (the piston portion 408) is moved downward within the
cylinder 108, is maintained. Therefore, after the gas generator 112
is operated, the upper end of the stopper portion 406 of the piston
110 can reliably be prevented from engaging with the stopper
portion placement hole 402 of the lock ring 90, and it is possible
to reliably prevent rotation of the lock ring 90 in the pull-out
direction from being restricted unnecessarily.
Fifth Exemplary Embodiment
[0163] A fifth exemplary embodiment of the present invention will
be described next by using FIG. 21 through FIG. 24.
[0164] A webbing retractor 500 relating to the present exemplary
embodiment has a structure which is substantially similar to that
of the first exemplary embodiment, but differs with respect to the
following points.
[0165] As shown in FIG. 21 and FIG. 22, at the webbing retractor
500 relating to the present exemplary embodiment, a stopper
accommodating hole 502 which communicates with the circular hole 88
is formed in the base 86 so as to correspond to the outer
peripheral groove 96 of the outer periphery of the lock ring 90. A
stopper 504, which is substantially shaped as a rectangular plate
and serves as an operating member, is accommodated within the
stopper accommodating hole 502. A piston accommodating hole 506 is
formed in the base 86, and communicates with the lower end of the
stopper accommodating hole 502.
[0166] The cylinder accommodating hole 106 of the base 86
communicates with the piston accommodating hole 506. The piston
110, which is shaped as an L-shaped plate and is partially
accommodated at the upper end portion of the cylinder 108 which is
fixed to the inner side of the cylinder accommodating hole 106,
projects-out into the stopper accommodating hole 502 and is
disposed beneath the stopper 504. In this way, downward movement of
the stopper 504 is prevented by the piston 110, and the upper end
of the stopper 504 is engaged with (inserted in) the outer
peripheral groove 96 of the lock ring 90.
[0167] In the state in which the upper end of the stopper 504 is
engaged with the outer peripheral groove 96 of the lock ring 90, if
the lock ring 90 attempts to rotate in the pull-out direction, the
stopper 504 receives the rotational force of the lock ring 90 in
the pull-out direction, and rotation of the lock ring 90 in the
pull-out direction is restricted (prevented).
[0168] When the gas generator 112 is operated and the piston 110 is
pushed-out sideways from the upper end portion of the cylinder 108,
the prevention of the downward movement of the stopper 504 by the
piston 110 is released, and the stopper 504 is moved (dropped)
downward (is operated).
[0169] As shown in FIG. 23, in the state in which the vehicle
enters a state of rapid deceleration, and the second lock pawls 50
mesh-together with the lock ring 90, and the lock ring 90 attempts
to rotate in the pull-out direction via the spool 20, the second
lock base 46 and the second lock pawls 50, if the upper end of the
stopper 504 is engaged with the outer peripheral groove 96 of the
lock ring 90, rotation of the lock ring 90 in the pull-out
direction is restricted by the stopper 504. Therefore, energy
absorption due to twisting deformation of the first deforming
portion 28 and the second deforming portion 40 arises, and the
limit load by the torsion shaft 24 is made to be a high load.
[0170] On the other hand, as shown in FIG. 24, before the first
locking mechanism 32 operates, when the vehicle enters into a state
of rapid deceleration or a state immediately before rapid
deceleration and the gas generator 112 is operated, due to the
piston 110 being pushed-out sideways from the upper end portion of
the cylinder 108, the prevention of the downward movement of the
stopper 504 by the piston 110 is released, and the stopper 504 is
moved downward, and the engagement of the upper end of the stopper
504 with the outer peripheral groove 96 of the lock ring 90 is
released. In this state, if rotational force in the pull-out
direction is transmitted to the lock ring 90 via the spool 20, the
second lock base 46 and the second lock pawls 50, the lock ring 90
rotates in the pull-out direction. Therefore, only energy
absorption due to twisting deformation of the first deforming
portion 28 arises, and the limit load by the torsion shaft 24 is
made to be a low load.
[0171] Here, the second locking mechanism 44 is structured such
that only the stopper 504 is interposed between the lock ring 90
and the piston 110 which is driven by the gas generator 112.
Therefore, the number of parts of the second locking mechanism 44
can be reduced, and the structure of the second locking mechanism
44 can be made to be simple. In this way, the work of assembling
the second locking mechanism 44 can be made to be easy, and costs
can be reduced.
[0172] Further, the stopper 504 is engaged with the outer
peripheral groove 96 of the lock ring 90 at one position (the upper
end). Therefore, the aligning of the stopper 504 with respect to
the outer peripheral groove 96 of the lock ring 90 can be made to
be simple, the precision of assembling the stopper 504 with respect
to the outer peripheral groove 96 of the lock ring 90 can easily be
improved, and the stopper 504 can appropriately restrict rotation
of the lock ring 90 in the pull-out direction.
[0173] The upper end of the stopper 504 is engaged with the outer
peripheral groove 96 of the lock ring 90. Therefore, the shape of
the upper end of the stopper 504 for preventing rotation of the
lock ring 90 in the pull-out direction can be made to be simple,
and the strength of the stopper 504 can be made to be high.
Sixth Exemplary Embodiment
[0174] A sixth exemplary embodiment of the present invention will
be described next by using FIG. 25 through FIG. 28.
[0175] A webbing retractor 600 relating to the present exemplary
embodiment has a structure which is substantially similar to that
of the first exemplary embodiment, but differs with respect to the
following points.
[0176] As shown in FIG. 25 and FIG. 26, at the webbing retractor
600 relating to the present exemplary embodiment, a stopper shaft
accommodating hole 602 which communicates with the circular hole 88
is formed in the base 86 so as to correspond to the outer
peripheral groove 96 of the outer periphery of the lock ring 90,
and a stopper main body accommodating hole 604, which communicates
with the lower end of the stopper shaft accommodating hole 602, is
formed. A stopper 606 serving as an operating member is
accommodated within the stopper shaft accommodating hole 602 and
the stopper main body accommodating hole 604. The stopper 606 is
structured by the lower end of a shaft-shaped stopper shaft 608
being fixed to the upper end of a rectangular-plate-shaped stopper
main body 610. The stopper shaft 608 and the stopper main body 610
are accommodated in the stopper shaft accommodating hole 602 and
the stopper main body accommodating hole 604, respectively. The
upper end of the stopper shaft 608 is thereby engaged with
(inserted in) the outer peripheral groove 96 of the lock ring
90.
[0177] In the state in which the upper end of the stopper shaft 608
is engaged with the outer peripheral groove 96 of the lock ring 90,
if the lock ring 90 attempts to rotate in the pull-out direction,
the stopper 606 receives the rotational force of the lock ring 90
in the pull-out direction, and rotation of the lock ring 90 in the
pull-out direction is restricted (prevented).
[0178] The cylinder accommodating hole 106 of the base 86
communicates with the side portion of the stopper main body
accommodating hole 604. The piston 110, which is accommodated in
one end of the cylinder 108 which is fixed to the inner side of the
cylinder accommodating hole 106, is disposed at the lateral side of
the stopper main body 610.
[0179] When the gas generator 112 is operated and the piston 110 is
pushed-out sideways from one end of the cylinder 108, the stopper
main body 610 is moved sideways by the piston 110, the stopper
shaft 608 and the stopper main body 610 are separated, and the
stopper shaft 608 is moved (dropped) downward (the stopper 606 is
operated).
[0180] As shown in FIG. 27, in the state in which the vehicle
enters a state of rapid deceleration, and the second lock pawls 50
mesh-together with the lock ring 90, and the lock ring 90 attempts
to rotate in the pull-out direction via the spool 20, the second
lock base 46 and the second lock pawls 50, if the upper end of the
stopper shaft 608 is engaged with the outer peripheral groove 96 of
the lock ring 90, rotation of the lock ring 90 in the pull-out
direction is restricted by the stopper 606. Therefore, energy
absorption due to twisting deformation of the first deforming
portion 28 and the second deforming portion 40 arises, and the
limit load by the torsion shaft 24 is made to be a high load.
[0181] On the other hand, as shown in FIG. 28, before the first
locking mechanism 32 operates, when the vehicle enters into a state
of rapid deceleration or a state immediately before rapid
deceleration and the gas generator 112 is operated, due to the
piston 110 being pushed-out sideways from one end of the cylinder
108, the stopper main body 610 is moved sideways by the piston 110,
the stopper shaft 608 and the stopper main body 610 are separated,
the stopper shaft 608 is moved downward, and the engagement of the
upper end of the stopper shaft 608 with the outer peripheral groove
96 of the lock ring 90 is released. In this state, if rotational
force in the pull-out direction is transmitted to the lock ring 90
via the spool 20, the second lock base 46 and the second lock pawls
50, the lock ring 90 rotates in the pull-out direction. Therefore,
only energy absorption due to twisting deformation of the first
deforming portion 28 arises, and the limit load by the torsion
shaft 24 is made to be a low load.
[0182] Here, the second locking mechanism 44 is structured such
that only the stopper 606 is interposed between the lock ring 90
and the piston 110 which is driven by the gas generator 112.
Therefore, the number of parts of the second locking mechanism 44
can be reduced, and the structure of the second locking mechanism
44 can be made to be simple. In this way, the work of assembling
the second locking mechanism 44 can be made to be easy, and costs
can be reduced.
[0183] Further, the stopper shaft 608 of the stopper 606 is engaged
with the outer peripheral groove 96 of the lock ring 90 at one
position (the upper end). Therefore, the aligning of the stopper
606 (the stopper shaft 608) with respect to the outer peripheral
groove 96 of the lock ring 90 can be made to be simple, the
precision of assembling the stopper 606 (the stopper shaft 608)
with respect to the outer peripheral groove 96 of the lock ring 90
can easily be improved, and the stopper 606 can appropriately
restrict rotation of the lock ring 90 in the pull-out
direction.
[0184] The upper end of the stopper shaft 608 is engaged with the
outer peripheral groove 96 of the lock ring 90. Therefore, the
shape of the stopper 606 (the upper end of the stopper shaft 608)
for preventing rotation of the lock ring 90 in the pull-out
direction can be made to be simple, and the strength of the stopper
606 (the upper end of the stopper shaft 608) can be made to be
high.
* * * * *