JP6061877B2 - Seat belt retractor - Google Patents

Description

  The present invention relates to a seat belt retractor, and more particularly to an improvement of a seat belt retractor provided with a lock mechanism.

  Conventionally, the vehicle has been equipped with an emergency lock mechanism that physically locks the webbing drawer by means of vehicle body acceleration sensing means that responds to sudden acceleration, collision or sudden deceleration of the vehicle, or webbing acceleration sensing means that reacts to rapid withdrawal of the webbing. A retractor for a seat belt that is effectively and safely restrained is known (for example, see Patent Document 1).

Japanese Patent Laid-Open No. 05-193441

  The retractor for seat belts disclosed in Patent Document 1 is a webbing of a spindle by causing a lock dog disposed on a side surface of the spindle to protrude outward in a radial direction and engage with an inner tooth of a frame in an emergency. Prevents rotation in the pull-out direction. Therefore, all the loads acting on the webbing are received by the engagement portion between the lock dog and the inner teeth of the frame. On the other hand, the load acting on the webbing varies depending on the vehicle conditions, and the lock strength required for the lock dog and the inner teeth of the frame is required to be large enough to allow for the maximum load of the webbing. Is done. For this reason, the lock dog, the spindle, and the frame must be formed of a material having high mechanical strength, which may increase the manufacturing cost.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to improve the lock strength between the lock dog and the internal teeth of the frame by using a relatively inexpensive material. It is an object of the present invention to provide a retractor for a seat belt that can be restrained effectively and safely.

In order to achieve the above-described object, the seatbelt retractor according to the present invention is characterized by the following (1) to (4) .
(1) A body part rotatably supported by a frame and wound with a webbing, a pair of flange parts provided on both sides of the body part in the rotational axis direction, and extending from the collar part to the outer side in the rotational axis direction. A spindle having a pair of shaft portions to be taken out ;
An internal tooth provided on the frame; a lock mechanism provided on the spindle and having a lock member that engages with the internal tooth; and locking the rotation of the spindle in the webbing pull-out direction;
A winding device for urging the spindle in the winding direction of the webbing;
A seat belt retractor comprising:
On one end face side in the rotation axis direction of the spindle, a side wall portion for accommodating the lock member is provided between the flange portion and the shaft portion in a substantially disc shape with a predetermined thickness,
The locking member is disposed in one of the pair of semicircles divided into two by a virtual straight line extending in the radial direction through the rotation center of the spindle on the side wall ,
The outer peripheral surface of the side wall portion includes engagement teeth that can be engaged with internal teeth of the frame in at least the other semicircle of the pair of semicircles,
When the lock member is engaged with the internal teeth of the frame, the spindle is displaced in a direction opposite to a portion where the lock member and the internal teeth of the frame engage with respect to the rotation center. A retractor for a seat belt, wherein teeth are engaged with internal teeth of the frame.
(2) The retractor for a seat belt according to (1), wherein the engaging teeth are also extended in the one semicircle.
(3) The retractor for a seat belt according to (1) or (2), wherein a width of the engaging tooth is larger than a thickness of an inner tooth of the frame.
(4) Any one of (1) to (3) , characterized in that a wall portion that prevents axial displacement of the frame with respect to the inner teeth is provided outside the engaging teeth in the rotation axis direction. The retractor for seatbelts described in 1.

According to the seatbelt retractor of the present invention, the lock member is accommodated in a substantially disc shape having a predetermined thickness between the flange portion and the shaft portion on one end surface side in the rotation axis direction of the spindle. side wall portions are mounted on the side wall portion, a pair of semi-circular, which is bisected by the imaginary straight line extending as a radial direction of the rotation center of the spindle, the locking member is disposed in one of the semicircular side walls The outer peripheral surface of the portion includes engagement teeth that can be engaged with the internal teeth of the frame in at least the other semicircle. When the lock member engages with the inner teeth of the frame and prevents the spindle from rotating, the spindle is displaced in the opposite direction to the portion where the lock member and the inner teeth of the frame engage with respect to the center of rotation. Since the load is applied to the inner teeth of the frame, the load acting on the webbing is distributed and received at two locations of the lock member and the inner teeth of the frame, and the engaging teeth and the inner teeth of the frame. The lock strength can be improved even by using a relatively inexpensive material that is not so high in mechanical strength, and the occupant can be restrained effectively and safely in an emergency.

It is a front view which shows the external appearance of the retractor for seatbelts. It is a disassembled perspective view of the retractor for seatbelts shown in FIG. (A) is the perspective view which looked at the spindle from one end side, (b) is the perspective view which looked at the spindle from the other end side. It is a side view which shows the steering wheel periphery of the retractor for seatbelts seen from the one side plate side of a frame in the state which removed the system cover. (A) is a side view showing the positional relationship between the spindle, the lock dog, and the internal teeth of the frame in a normal state, and (b) is a cross-sectional view taken along line AA shown in FIG. 5 (a). (A) is a side view showing a state where the spindle is rotated and the lock dog and the inner teeth of the frame are engaged, and (b) is a further rotation of the spindle and the engaging teeth of the spindle and the inner teeth of the frame are engaged. It is a side view which shows a state.

  Hereinafter, an embodiment of a seatbelt retractor according to the present invention will be described in detail with reference to the drawings.

  FIG. 1 is an external view of a seatbelt retractor according to the present invention, and FIG. 2 is an exploded perspective view of the seatbelt retractor shown in FIG. As shown in FIGS. 1 and 2, the seatbelt retractor 10 is made of a metal (for example, aluminum alloy) spindle 20 around which a webbing W (see FIG. 6) is wound, and the spindle 20 is rotatably supported. A metal U-shaped frame 11, a lock mechanism 14 that mechanically locks the webbing drawer, and an outer side of the other side plate 11 B of the frame 11. And a spring type winding device 30 that urges the spindle 20 to rotate in the webbing winding direction.

  The pair of side plates 11 </ b> A and 11 </ b> B of the frame 11 oppose each other across the central portion of the spindle 20 in the axial direction. Further, on the inner periphery of the circular opening of the side plate 11 </ b> A of the frame 11, a large number of internal teeth 12 are formed that mesh with later-described lock dogs 50 of the lock dog 50 and engagement teeth 29 of the spindle 20.

  As shown in FIG. 3, the spindle 20 has a pair of shaft portions extending outward in the axial direction from a body portion 27 around which the webbing is wound and a pair of flange portions 22 provided on both sides in the axial direction of the body portion 27. 21 and 25. In the spindle 20, one shaft portion 21 is fitted into a support hole (not shown) formed inside a boss 95 of a resin system cover 90 via a bush 55 described later, and the other shaft portion 25 is fitted. The resin spring case 31 is fitted into a support hole 36 and is rotatably supported.

  Further, on one end face side of the spindle 20, a substantially disk-shaped side wall portion 23 having a predetermined thickness is provided between the flange portion 22 and the shaft portion 21. The lock dog 50 is housed in a lock dog housing space 24 formed by partially cutting out the side wall portion 23 so as to be displaceable.

  As shown in FIG. 2, the lock mechanism 14 includes internal teeth 12 provided on the frame 11, a metal (for example, iron) lock dog 50 as a lock member, a resin steering wheel 60, and webbing WS lever 71 and WS spring 75 constituting webbing acceleration sensing means 70 for detecting a sudden pull-out and preventing rotation of spindle 20 in the webbing pull-out direction, and a webbing pull-out direction of spindle 20 by sensing a sudden deceleration state of the vehicle. And an acceleration sensor 80 as a vehicle body acceleration sensing means for preventing the rotation of the vehicle, and is covered by a system cover 90 fixed to the frame 11.

  Referring also to FIG. 4, a resin bush 55 and a latch spring 59 interposed between the steering wheel 60 and the bush 55 are accommodated in the system cover 90. The bush 55 has a cap-shaped portion 57 that covers the shaft portion 21 of the spindle 20 that passes through the center hole 61 of the steering wheel 60, and rotates integrally with the spindle 20. The cap-like portion 57 is rotatably fitted in a support hole (not shown) provided in the boss 95 of the system cover 90. Further, the bush 55 is provided with a spring support portion 56 that extends in a radial direction from the cap-shaped portion 57 and supports one end of the latch spring 59.

  The steering wheel 60 is supported by the spindle 20 so as to be relatively rotatable, and operates the lock dog 50 by causing a rotation delay with respect to the spindle 20. The steering wheel 60 is fitted into the spring receiving portion 62 that supports one end of the latch spring 59, the cam hole 63 in which the cam pin 52 of the lock dog 50 is engaged, and the shaft hole 72 of the WS lever 71. It has a convex shaft 64 that is swingably supported, a projecting piece 65 that supports one end of the WS spring 75, and a plurality of engaging claws 66 formed on the outer peripheral surface.

  The spring receiving portion 62, the convex shaft 64, and the protruding piece 65 are formed on the side surface of the steering wheel 60 on the side facing the system cover 90.

  A latch spring 59 is mounted between the spring receiving portion 62 and the spring support portion 56 of the bush 55 to urge the steering wheel 60 counterclockwise with respect to the spindle 20.

  Therefore, the lock dog 50 in which the cam pin 52 is inserted into the cam hole 63 is held in the unlocking direction in which the pawl 51 is separated from the internal teeth 12 by the urging force of the latch spring 59. Further, when the steering wheel 60 rotates clockwise relative to the spindle 20 against the urging force of the latch spring 59 (actually, the spindle 20 rotates), the cam pin 52 enters the cam hole 63. And the claw 51 is moved outward in the radial direction. Then, by engaging the claw 51 that has advanced outward in the radial direction with the internal teeth 12 of the frame 11, the spindle 20 is locked to the internal teeth 12 of the frame 11, and the rotation in the webbing pull-out direction is mechanically locked.

  The system cover 90 is provided with inner teeth 93 that can mesh with the WS lever 71 inside the side plate portion 91 (see FIG. 4).

  The WS lever 71 is made of metal so that it also has a function as an inertial body. The WS lever 71 includes a claw 73 that can be engaged with the internal teeth 93 of the system cover 90 and is fitted to the convex shaft 64 of the steering wheel 60. ing. A WS spring 75 is mounted between the arm 74 on the opposite side of the claw 73 with respect to the shaft hole 72 and the protruding piece 65 of the steering wheel 60 to retract the claw 73 inward (inside of the system cover 90). The WS lever 71 is urged to rotate in a direction away from the teeth 93. Therefore, at normal times, the pawl 73 is held in a non-operating position where it does not engage with the internal teeth 93 of the system cover 90.

  As a result, when the webbing W is guided by the webbing guide 13 and pulled out due to a sudden movement of the occupant, the WS lever 71 is rotated by the inertial force, and the claw 73 of the WS lever 71 is protruded outward, and the system cover It meshes with 90 internal teeth 93. As a result, the webbing acceleration sensing means 70 prevents the steering wheel 60 from rotating in the webbing pull-out direction.

  As shown in FIG. 2, the acceleration sensor 80 includes a sensor holder 81, a ball cover 82 attached to the sensor holder 81, a ball 83 stored in the ball cover 82 and displaced according to horizontal acceleration, And a sensor lever 84, which is housed in a sensor cover 94 of the system cover 90.

  When the ball 83 moves in accordance with the vehicle body acceleration, the acceleration sensor lever 84 swings and the claw 85 is lifted up, and engages with the engagement claw 66 provided on the outer periphery of the steering wheel 60, so that the steering wheel The rotation of the webbing 60 in the pulling direction is prevented.

  As shown in FIG. 2, the winding device 30 includes a spring core 32 formed in a cylindrical shape, a winding spring 33, and a spring cassette 34. The spring cassette 34 includes a spring housing 35 that supports the spring core 32, and a spring case 31 that is fixed to the other side plate 11B of the frame 11 so as to cover the spring housing 35 from the axial direction and the radial direction. The spring core 32 and the winding spring 33 are accommodated.

  A support hole 36 that rotatably supports the shaft portion 25 is formed on the inner wall surface of the spring case 31 at a position facing the shaft portion 25 on the other end side of the spindle 20.

  The spring core 32 includes a cylindrical spring fixing portion 41 and a flange portion 42 that is formed to protrude radially outward from one axial end portion of the spring fixing portion 41. Three leaf springs 46 extending in the circumferential direction in a cantilever shape are formed integrally with the flange 42 in the middle of the flange 42 in the radial direction. A middle portion in the longitudinal direction (circumferential direction) of the leaf spring 46 protrudes toward the spring fixing portion 41 and is curved.

  The spring core 32 is disposed between the spindle 20 and the wall portion 38 of the spring housing 35 and is fitted to the spindle 20 so as to be integrally rotatable. The spring core 32 presses the spindle 20 in the axial direction by the elastic force of the leaf spring 46 to absorb the axial play and is positioned in the axial direction.

  The winding spring 33 is obtained by winding a strip-shaped spring material in a spiral shape. The outer peripheral end is fixed to the spring housing 35, and the inner peripheral end 33 a is fixed to the spring fixing portion 41 of the spring core 32. It is fixed and accommodated in the spring housing 35, and always urges the spindle 20 in the winding direction.

  Here, as shown in FIGS. 3 and 5A, the lock dog accommodating space 24 of the spindle 20 is a substantially fan-shaped recess formed in the side wall portion 23 when viewed from the axial direction. Further, the side plate portion 28 forming the recess is cut out so that the claw 51 and the cam pin 52 of the lock dog 50 accommodated in the lock dog accommodating space 24 can be exposed.

  When the spindle 20 is divided into a pair of semicircles by a virtual straight line L obtained by extending a straight line connecting the circumferential end B of the lock dog housing space 24 of the side wall 23 and the rotation center O of the spindle 20, On the other hand, the lock dog 50 accommodated in the lock dog accommodation space 24 is disposed in the semicircle C1 on the lock dog accommodation space 24 side. On the other hand, a plurality of engaging teeth 29 that can mesh with the inner teeth 12 of the frame 11 are formed on the outer peripheral surface 23a of the side wall portion 23 in the semicircle C2 on the opposite side of the virtual dog L to the lock dog accommodating space 24. Is formed.

  The engaging teeth 29 are arranged at substantially the same circumferential interval (phase interval) as the adjacent inner teeth 12. The engaging teeth 29 are also extended in the semicircle C1 on the lock dog accommodating space 24 side with respect to the virtual straight line L. Moreover, although the shape of each engagement tooth 29 is arbitrary, in this embodiment, it is formed by the long side which goes to the circumferential direction, and the short side which goes to a radial direction.

  Further, the engagement teeth 29 do not need to have the height of the meshing portion as much as the lock dog 50, and it is sufficient that the engagement teeth 29 have a height that can mesh with the internal teeth 12 at a minimum. Specifically, the height of the engaging teeth 29 varies depending on the shape of the internal teeth 12, but may be lower than the height of the internal teeth 12 or may be higher than the height of the internal teeth 12. The engaging teeth 29 may have any wall height that can receive a force in the rotational direction when engaged.

  As shown in FIG. 5B, the width w of the engaging tooth 29 is larger than the thickness t of the inner tooth 12 of the frame 11, and even if there is an axial backlash of the spindle 20 with respect to the frame 11, The engaging teeth 29 and the inner teeth 12 of the frame 11 can be reliably engaged with each other. Further, a wall portion 23b is formed on the outer side in the axial direction of the engaging tooth 29, and even if an axial shift occurs between the inner tooth 12 of the frame 11 and the engaging tooth 29, each other Engagement can be reliably maintained.

  Hereinafter, the operation of the seatbelt retractor 10 of the present embodiment will be described. In the seat belt retractor 10 of the present embodiment, when the webbing W is pulled out through the webbing guide 13 at a normal speed, the shaft portions 21 and 25 at both ends are supported by the resin system cover 90 and the spring case 31. The spindle 20 rotates to allow the wound webbing W to be pulled out (see FIG. 5A).

  As shown in FIGS. 4 and 6A, when the webbing W is pulled out from the seat belt retractor 10 at a speed higher than a predetermined speed, the WS lever 71 rotating together with the steering wheel 60 is inertial. 5 is rotated clockwise in FIG. 5 against the elastic force of the WS spring 75, and the claw 73 of the WS lever 71 meshes with the internal teeth 93 of the system cover 90 to pull out the webbing of the steering wheel 60. Prevent the rotation of.

  When the webbing W is further pulled out while the steering wheel 60 is stopped and the spindle 20 rotates relative to the steering wheel 60, the lock dog 50 in which the cam pin 52 is fitted in the cam hole 63 of the steering wheel 60. The pawl 51 is pushed outward, meshed with the inner teeth 12 of the frame 11, the rotation of the spindle 20 is locked, the webbing W is prevented from being pulled out, and the occupant is protected.

  When a large acceleration is applied to the vehicle, the ball 83 stored in the ball cover 82 moves to swing the acceleration sensor lever 84 and the claw 85 engages with the engagement claw 66 of the steering wheel 60. The rotation of the steering wheel 60 in the webbing pull-out direction is prevented. Then, when the spindle 20 rotates relative to the steering wheel 60 by pulling out the webbing W, the claw 51 of the lock dog 50 meshes with the internal teeth 12 of the frame 11 to prevent the webbing W from being pulled out. Is done.

  When the rotation of the spindle 20 is blocked by the engagement between the claw 51 of the lock dog 50 and the internal teeth 12 of the frame 11, and further a large force of 1 kN or more acts on the webbing W, for example, as shown in FIG. Thus, the counterclockwise rotational torque about the interference point C between the lock dog 50 and the wall of the lock dog accommodating space 24 acts on the spindle 20. As a result, the resin system cover 90 and the spring case 31 that support the shaft portions 21 and 25 of the spindle 20 are elastically deformed, and the spindle 20 has the lock dog 50 and the internal teeth 12 of the frame 11 with respect to the rotation center O. Is displaced in the opposite direction (arrow D direction) to the region where the engaging teeth engage, and the engaging teeth 29 mesh with the inner teeth 12 of the frame 11.

As described above, the seatbelt retractor 10 of the present embodiment has the claw 51 of the lock dog 50 and the internal teeth 12 of the frame 11 when the force acting on the webbing W is a relatively light load (for example, 1 kN or less). When the webbing W is prevented from being pulled out by the meshing to protect the occupant and a large load (for example, 1 kN or more) is applied, The engaging teeth 29 of the spindle 20 and the inner teeth 12 of the frame 11 are engaged with each other, so that the locking state is obtained at two places and a large locking strength is obtained. In particular, since the short sides of the engaging teeth 29 of the spindle 20 and the inner teeth 12 of the frame 11 are in contact with each other, a large lock strength can be obtained at an early stage.
Further, in the present embodiment, the engaging teeth 29 mesh with the inner teeth 12, so that the concave and convex portions of the engaging teeth 29 and the inner teeth 12 of the frame 11 always mesh with each other without inducing large plastic deformation, and locking performance. Can be further improved. For example, in a structure in which the engagement teeth 29 are not provided and the inner teeth 12 are plastically deformed, scratches and recesses are formed in different parts of the spindle 20 each time the inner teeth 12 come into contact. For this reason, there is a possibility that the locking performance varies, and in the worst case, the internal teeth 12 may slip due to random scratches or recesses, and the locking performance may not be sufficiently exhibited.

  As described above, according to the seatbelt retractor 10 of the present embodiment, the end of the spindle 20 in the rotation axis direction is divided into two by the virtual straight line L that extends in the radial direction through the rotation center O of the spindle 20. Among the pair of semicircles, the lock dog 50 is disposed in one semicircle, and at least the other semicircle includes engagement teeth 29 that can engage with the internal teeth 12 of the frame 11. When the lock dog 50 engages with the internal teeth 12 of the frame 11 and prevents the spindle 20 from rotating, the part where the lock dog 50 and the internal teeth 12 of the frame 11 engage with the spindle 20 with respect to the rotation center O Since the engaging teeth 29 are engaged with the inner teeth 12 of the frame 11 by being displaced in the opposite direction, the load acting on the webbing W is affected by the lock dog 50, the inner teeth 12 of the frame 11, and the engaging teeth 29. And the inner teeth 12 of the frame 11 can be received in a distributed manner, and the lock strength can be improved even by using a relatively inexpensive material that is not so high in mechanical strength. It can be restrained safely.

  Further, if the engaging teeth 29 are extended in one semicircle, the engaging teeth 29 and the inner teeth 12 of the frame 11 can be more reliably engaged.

  Further, since the width W of the engaging tooth 29 is larger than the thickness t of the inner tooth 12 of the frame 11, the engaging tooth 29 and the inner tooth of the frame 11 even if there is a backlash in the axial direction of the spindle 20 with respect to the frame 11. 12 can be reliably meshed with each other.

  Furthermore, since the lock dog 50 and the engagement tooth 29 are disposed on the side wall 23 on the same axial end side of the spindle 20, the engagement tooth 29 is formed without increasing the size of the spindle 20. can do.

  Further, since the wall portion 23 b is provided on the outer side in the axial direction of the engagement tooth 29, even if an axial deviation occurs between the inner tooth 12 of the frame 11 and the engagement tooth 29, each other. Can be reliably maintained.

In addition, this invention is not limited to embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably.
In the present embodiment, the spindle 20 is divided into a pair of semicircles by a virtual straight line L obtained by extending a straight line connecting the circumferential end B of the lock dog housing space 24 of the side wall 23 and the rotation center O of the spindle 20. However, the virtual straight line L forming the semicircle is not limited thereto, and one semicircle may be formed by the virtual straight line L passing through the rotation center O so as to include the opening of the lock dog accommodating space 24.

DESCRIPTION OF SYMBOLS 10 Seatbelt retractor 11 Frame 12 Frame internal teeth 14 Lock mechanism 20 Spindle 23 Side wall part 23b Wall part 29 Engagement tooth 30 Winding device 50 Lock dog
L Virtual straight line O Spindle rotation center t Internal tooth thickness w Arc groove width

Claims (4)

A barrel portion rotatably supported by the frame and wound with webbing, a pair of flange portions provided on both sides of the barrel portion in the rotation axis direction, and a pair extending outward from the flange portion in the rotation axis direction A spindle with a shaft portion of
An internal tooth provided on the frame; a lock mechanism provided on the spindle and having a lock member that engages with the internal tooth; and locking the rotation of the spindle in the webbing pull-out direction;
A winding device for urging the spindle in the winding direction of the webbing;
A seat belt retractor comprising:
On one end face side in the rotation axis direction of the spindle, a side wall portion for accommodating the lock member is provided between the flange portion and the shaft portion in a substantially disc shape with a predetermined thickness,
The locking member is disposed in one of the pair of semicircles divided into two by a virtual straight line extending in the radial direction through the rotation center of the spindle on the side wall ,
The outer peripheral surface of the side wall portion includes engagement teeth that can be engaged with internal teeth of the frame in at least the other semicircle of the pair of semicircles,
When the lock member is engaged with the internal teeth of the frame, the spindle is displaced in a direction opposite to a portion where the lock member and the internal teeth of the frame engage with respect to the rotation center. A retractor for a seat belt, wherein teeth are engaged with internal teeth of the frame.   The retractor for a seat belt according to claim 1, wherein the engaging teeth are also extended in the one semicircle.   The seatbelt retractor according to claim 1 or 2, wherein a width of the engagement tooth is larger than a thickness of an inner tooth of the frame. The rotary shaft outwardly of said engaging teeth, according to any one of claims 1 to 3, characterized in that the wall portion to prevent axial displacement between the inner teeth of the frame are provided Seat belt retractor.

Images