JP2014201122A - Retractor for seat belt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the degree of freedom of timing for starting generation of a webbing draw-out load.SOLUTION: A retractor for seat belts comprises a take-up drum 30, a rotation regulation member, e.g. a ratchet gear 61, switchable between a rotatable state and a rotation-restricted state, a relay member, e.g. a torsion bar 38, attached on one end side to one of the take-up drum 30 and the rotation restriction member so as to be incapable of relative rotation and a restriction mechanism 92. The restriction mechanism 92 is arranged between the other of the take-up drum 30 and the rotation regulation member and the other end side of the relay member. In the state where the other of the take-up drum 30 and the rotation regulation member and the relay member are before undergoing a specified amount of relative rotation, the restriction mechanism 92 allows relative rotation between the other of the take-up drum 30 and the rotation regulation member and the relay member. After the other of the take-up drum 30 and the rotation restriction member and the relay member undergo the specified amount of relative rotation, the regulation mechanism restricts the other of the take-up drum 30 and the rotation restriction member and the relay member so as to be incapable of relative rotation.

Description

  The present invention relates to a seatbelt retractor that restrains an occupant by webbing in the event of a vehicle emergency, and more particularly to a technique for adjusting the generation start timing of a webbing extraction load for absorbing impact energy to the occupant by webbing.

  Conventionally, as this type of seat belt retractor, there are those disclosed in Patent Documents 1 to 3.

  Patent Document 1 discloses a bobbin around which a webbing is wound, a locking device that is prevented from rotating in an emergency of a vehicle, a resistance member that engages both the locking device and the bobbin, and a relative rotation between the locking device and the bobbin. A seat belt device including a second energy absorbing mechanism that absorbs impact energy is disclosed. In this seat belt device, in a standby state, play is performed in the engagement state of at least one of the resistance member, the locking device, and the bobbin so that energy absorption by the second energy absorption mechanism is performed after the bobbin rotates by a predetermined amount. Is provided.

  Patent Document 2 discloses that the idle running region in which the winding drum can rotate relative to the locking base until the plastic deformation due to the torsional deformation of the torsion bar is started is the winding drum and the locking base or the second energy absorbing member. And a technology provided between them. The idling period is realized, for example, by inserting a spline portion provided on the locking base into a spline groove portion provided on the plate body and providing an idling rotation region between the spline portion and the spline groove portion. ing.

  In Patent Document 3, an intermediate rotating member provided between the winding drum and the rotation restricting member, one end portion is attached to the intermediate rotating member, and the other end portion is attached to one of the winding drum and the rotation restricting member. Provided on the other of the second shock absorbing member, the winding drum and the rotation restricting member, and when the intermediate rotating member rotates a predetermined amount relative to the other of the winding drum and the rotation restricting member, the winding drum and the rotation restricting member The structure provided with the stopper part which controls rotation of the intermediate | middle rotating member with respect to the other is disclosed.

Japanese Patent Laid-Open No. 2003-19945 JP 2009-45987 A JP 2012-250627 A

  However, the techniques disclosed in Patent Documents 1 to 3 have a problem that the degree of freedom of the start timing of occurrence of the webbing pull-out load is low.

  Accordingly, an object of the present invention is to improve the degree of freedom of the timing for starting the generation of the webbing withdrawal load.

  In order to solve the above-described problem, a retractor for a seat belt according to a first aspect includes a winding drum on which a webbing is wound, a state in which the webbing can be rotated coaxially with a rotation shaft of the winding drum, and the webbing. A rotation restricting member that can be switched in a state in which rotation in the pull-out direction is restricted, and one end side is attached to one of the winding drum and the rotation restricting member so as not to be relatively rotatable, and generates a webbing pull-out load by torsional deformation. A relay member used as a torsion bar; provided between the other of the winding drum and the rotation restricting member and the other end of the relay member; and the other of the winding drum and the rotation restricting member and the relay member Is allowed to rotate relative to the relay member and the other of the winding drum and the rotation restricting member in a state before the relative rotation of the winding drum, and the winding drum. The other and the relay member of finely the rotation restricting member and a restraining mechanism for non-rotatably restrained and the other with the relay member of the winding drum and the rotation restricting member after rotated by a predetermined amount relative.

  A second aspect is a seatbelt retractor according to the first aspect, wherein the restraining mechanism is configured to take up the winding drum according to relative rotation between the winding drum and the other of the rotation regulating member and the relay member. A movable part movable along the rotation axis direction of the drum, and a restriction part for restricting movement of the movable part by a predetermined amount or more, and the restriction part restricts movement of the movable part, A relative rotation exceeding a predetermined amount between the take-up drum and the other of the rotation regulating member and the relay member is regulated.

  The seatbelt retractor according to the third aspect includes a winding drum around which the webbing is wound, a state in which the webbing can be rotated coaxially with a rotation shaft of the winding drum, and rotation in the pull-out direction to the webbing. A rotation restricting member that is switched between a restricted state, a relay member serving as an impact absorbing member, one end of which is attached to one of the take-up drum and the rotation restricting member so as not to be relatively rotatable, the take-up drum, and the A rotation axis direction of the take-up drum is provided between the other of the rotation restricting member and the other end of the relay member, and according to relative rotation between the take-up drum and the other of the rotation restricting member and the relay member. And a restricting part that restricts movement of the movable part by a predetermined amount or more, and the restricting part restricts movement of the movable part, whereby the winding drum and the rotation Regulatory member And a restraining mechanism for restricting relative rotation exceeding a predetermined amount between the winding member and the relay member, and in any part of the portion from the winding drum to the rotation restricting member via the relay member, When the relative rotation of the relay member with the other of the winding drum and the rotation restricting member is restricted by the restraining mechanism, an impact absorbing mechanism for generating a webbing pull-out load by the relay member is incorporated.

  A fourth aspect is a seat belt retractor according to the second or third aspect, wherein the restraining mechanism includes a shaft member and a ring member configured to be externally fitted to the shaft member, Either the shaft member or the ring member is provided on the relay member so as not to rotate relative to the relay member, and the other of the shaft member and the ring member is relative to either the winding drum or the rotation restricting member. The shaft member and the ring member are non-rotatable, and at least one of the shaft member and the ring member is movable as the movable portion along a rotation axis direction of the winding drum, and the shaft member and the ring member are By the relative rotation, the shaft member and the ring member are configured to be relatively movable along the direction of the rotation axis of the winding drum, and the restricting portion is a phase between the shaft member and the ring member. Rotation is provided so as exceeds a predetermined amount, to restrict the relative movement along the rotation axis direction of the winding drum and said ring member and said shaft member.

  A fifth aspect is a seat belt retractor according to the fourth aspect, wherein the shaft member includes a male screw part, and the ring member includes a female screw part capable of screwing the male screw part.

  A sixth aspect is a seat belt retractor according to the fourth or fifth aspect, wherein either one of the shaft member and the ring member is integrally formed with the relay member.

  A seventh aspect is a seatbelt retractor according to any one of the fourth to sixth aspects, wherein either the shaft member or the ring member is formed separately from the relay member. And attached to the relay member.

  An eighth aspect is a seatbelt retractor according to any one of the fourth to seventh aspects, wherein the shaft member and the ring member are rotated by relative rotation of the shaft member and the ring member. The shaft member and the ring member relatively move along the direction of the rotation axis of the winding drum while at least one of the members is plastically deformed.

  A ninth aspect is a seatbelt retractor according to any one of the first to eighth aspects, wherein the winding drum and the rotation regulating member are connected in a non-rotatable state in a standby state, An impact absorbing member that allows relative rotation between the take-up drum and the rotation restricting member while generating a webbing pull-out load when a force in the pull-out direction of the webbing is applied to the take-up drum; Prepare.

  A tenth aspect is a seatbelt retractor according to the ninth aspect, and is set so that the generation of the webbing pull-out load by the relay member starts during the generation of the webbing pull-out load by the shock absorbing member. Is.

  An eleventh aspect is a seatbelt retractor according to the ninth or tenth aspect, wherein the impact absorbing member is pulled out while being deformed by relative rotation between the winding drum and the rotation restricting member. Includes wire.

  According to the first aspect, after the other of the winding drum and the rotation restricting member and the relay member are relatively rotated by a predetermined amount, the other of the winding drum and the rotation restricting member and the relay member are relatively rotated. The relay member serving as a torsion bar is twisted and deformed by being disabled. For this reason, the start timing of the webbing pull-out load generation operation by the relay member as a torsion bar can be delayed, and the degree of freedom of the timing of the webbing pull-out load generation operation can be improved.

  According to the second aspect, when the restriction portion restricts the movement of the movable portion, relative rotation exceeding a predetermined amount between the other of the winding drum and the rotation restriction member and the relay member is restricted. The webbing pull-out load is generated by the shock absorbing mechanism. Here, the restraining mechanism includes a movable part movable along the rotation axis direction of the take-up drum according to relative rotation between the other of the take-up drum and the rotation regulating member and the relay member, and the movable part A restriction portion that restricts movement of a predetermined amount or more, and the restriction portion restricts movement of the movable portion, whereby a predetermined amount of the other of the winding drum and the rotation restriction member and the relay member is set. It is set as the structure which controls the relative rotation which exceeds. For this reason, the webbing pull-out load can be generated after the other of the winding drum and the rotation restricting member and the relay member are relatively rotated one or more times, and the degree of freedom in the timing of the webbing pull-out load generating operation is improved. Can be made.

  According to the third aspect, when the restricting portion restricts movement of the movable portion, relative rotation exceeding a predetermined amount between the other of the winding drum and the rotation restricting member and the relay member is restricted. The webbing pull-out load is generated by the shock absorbing mechanism. Here, the restraining mechanism includes a movable part movable along the rotation axis direction of the take-up drum according to relative rotation between the other of the take-up drum and the rotation regulating member and the relay member, and the movable part A restriction portion that restricts movement of a predetermined amount or more, and the restriction portion restricts movement of the movable portion, whereby a predetermined amount of the other of the winding drum and the rotation restriction member and the relay member is set. It is set as the structure which controls the relative rotation which exceeds. For this reason, the webbing pull-out load can be generated after the other of the winding drum and the rotation restricting member and the relay member are relatively rotated one or more times, and the degree of freedom in the timing of the webbing pull-out load generating operation is improved. Can be made.

  According to the fourth aspect, when the relative rotation between the shaft member and the ring member exceeds a predetermined amount, the restricting portion restricts the relative movement of at least one of the shaft member and the ring member, so that the relative rotation is prevented. The webbing pull-out load can be generated by regulating.

  According to the fifth aspect, by screwing the male screw portion and the female screw portion, the shaft member and the ring member can be relatively moved relative to each other in the rotational axis direction by the relative rotation of the shaft member and the ring member.

  According to the sixth aspect, any one of the shaft member and the ring member and the relay member can be easily manufactured.

  According to the 7th aspect, a relay member and any one of the said shaft member and the said ring member can be formed with the material suitable for each objective. For example, one of the shaft member and the ring member is formed of a relatively hard material so as to be suitable for the function as the restraining mechanism, and the relay member is comparatively suitable for the function as a torsion bar. It can be made of a soft material.

  According to the eighth aspect, when the shaft member and the ring member rotate relative to each other, at least one of the shaft member and the ring member is plastically deformed, so that a webbing extraction load can be generated.

  According to the ninth aspect, various webbing pull-out loads can be generated by the impact absorbing member.

  According to the tenth aspect, it is possible to increase the webbing withdrawal load stepwise by applying the webbing withdrawal load by the relay member to the webbing withdrawal load by the impact absorbing member.

  According to the eleventh aspect, the webbing pull-out load can be generated by the deformation of the wire.

1 is a perspective view showing an overall configuration of a seatbelt retractor according to an embodiment. It is the perspective view which decomposed | disassembled the seatbelt retractor by the functional unit. It is a disassembled perspective view of the seatbelt retractor. It is a disassembled perspective view of the seatbelt retractor. It is a perspective view which shows the state which decomposed | disassembled the pretensioner mechanism from the retractor for seatbelts. It is explanatory drawing which shows the internal structure of a pretensioner mechanism. It is explanatory drawing which shows operation | movement of a lock pawl. It is explanatory drawing which shows operation | movement of a lock pawl. It is explanatory drawing which shows a webbing sensitive part schematically. It is a disassembled perspective view which shows the extraction load generation | occurrence | production mechanism part in the seatbelt retractor. It is a disassembled perspective view which shows the extraction load generation | occurrence | production mechanism part in the seatbelt retractor. It is a fragmentary sectional view along the axial direction of the extraction load generation mechanism part. It is explanatory drawing which shows operation | movement of a wire type load generation mechanism. It is explanatory drawing which shows operation | movement of a wire type load generation mechanism. It is a perspective view which shows a torsion bar and a restraint mechanism. It is sectional drawing which shows a torsion bar and a restraint mechanism. It is an exploded sectional view showing a restraint mechanism. It is a figure which shows the example of a drawing load generation | occurrence | production characteristic. It is sectional drawing which shows a 1st modification. It is a perspective view which shows a 2nd modification. It is sectional drawing which shows the modification same as the above. It is sectional drawing which shows a 3rd modification. It is a disassembled perspective view which shows a 4th modification. It is a disassembled perspective view which shows the modification same as the above. It is sectional drawing which shows the modification same as the above.

<Overall configuration>
Hereinafter, the retractor 10 for seatbelts which concerns on embodiment is demonstrated. FIG. 1 is a perspective view showing the overall configuration of the seat belt retractor 10, FIG. 2 is a perspective view of the seat belt retractor 10 disassembled in functional units, and FIGS. 3 and 4 further illustrate the seat belt retractor 10. It is the perspective view disassembled finely. FIG. 3 mainly shows the winding drum 30 and parts assembled to one end side thereof, and FIG. 4 mainly shows the parts assembled to the other end side of the winding drum 30.

  The seat belt retractor 10 is applied to a seat belt device provided in a seat of a vehicle or the like. The seat belt retractor 10 is incorporated in a lower part of the center pillar of the vehicle and accommodates a webbing 12 serving as a seat belt so that the seat belt can be pulled out and taken up in a normal state. The seatbelt retractor 10 restricts the withdrawal of the webbing 12 to effectively restrain the occupant when the vehicle is accelerating (including when decelerating). In particular, in the event of an emergency such as a vehicle collision or sudden deceleration, the seat belt retractor 10 winds the webbing 12 so as to remove the slack, and then reduces the impact applied to the occupant. It is configured to gradually pay out.

  That is, the seat belt retractor 10 includes a housing 20, a take-up drum 30, a pretensioner mechanism 40, a take-up mechanism 100, and a lock mechanism 60. A pull-out load generating mechanism is provided between the winding drum 30 and the lock mechanism 60. Here, the pull-out load generation mechanism includes a wire-type pull-out load generation mechanism 80 and a torsion bar-type pull-out load generation mechanism 90. The take-up drum 30 is accommodated in the housing 20, and a pretensioner mechanism 40 is incorporated on one end side (right side in FIG. 1) of the take-up drum 30 and the other end side (left side in FIG. 1) of the take-up drum 30. The winding mechanism 100 and the lock mechanism 60 are incorporated in the above. The winding mechanism 100 is configured to urge the winding drum 30 in the winding direction of the webbing 12. In the normal state, the winding drum 30 is biased in the winding direction of the webbing 12 by the biasing force of the winding mechanism 100, and the webbing 12 is pulled out against the biasing force of the winding mechanism 100. When the pulling force of the webbing 12 is released, the webbing 12 is wound around the winding drum 30 by the urging force of the winding mechanism 100. Further, when the lock mechanism 60 is in a non-normal state such as when the vehicle is decelerated (including an emergency such as when the vehicle collides or suddenly decelerates), the winding drum 30 rotates in the pull-out direction of the webbing 12. Configured to regulate. Further, the pretensioner mechanism 40 is configured to rotate the take-up drum 30 in the take-up direction of the webbing 12 in a vehicle emergency or the like. After the operation of the lock mechanism 60 and after the pretensioner mechanism 40 rotates the take-up drum 30 in the take-up direction of the webbing 12 in the event of a vehicle emergency or the like, the pull-out load generating mechanism extends the webbing 12. The winding drum 30 is allowed to rotate and generates a pulling load that becomes a resistance when the webbing 12 is pulled out. Thus, it plays a role of relieving an impact of an occupant trying to move forward by a sudden deceleration. End.

<Housing and winding drum>
The housing 20 is a member formed of a metal plate or the like, and a pair of side plate portions 21 and 22 provided opposite to each other, and a plurality of connection plate portions 23 that connect edges of the side plate portions 21 and 22 to each other. , 24. The side plate portions 21 and 22 are formed with openings 21h and 22h that allow the end of the winding drum 30 to face the outside. Further, the connecting plate portion 23 has a portion 23a extending to a position between the other edge portions (upper edge portion in FIG. 1) of the side plate portions 21 and 22, and the webbing 12 is externally attached to this portion 23a. An opening 23ah for drawing out is formed. Here, a resin guide member 23b in which a slit-like opening through which the webbing 12 can be inserted is formed in the opening 23ah. Further, a screw fixing piece 23c in which a screw hole for attaching the seat belt retractor 10 to a vehicle body or the like is formed in the portion 23a of the connecting plate portion 23.

  The pretensioner mechanism 40 is attached to the outer surface of the one side plate portion 21 while the winding drum 30 is disposed between the pair of side plate portions 21 and 22, and the lock mechanism 60 is attached to the outer surface of the other side plate portion 22. Is installed.

  The winding drum 30 is a member that is rotatably disposed in the housing 20 in a state where the webbing 12 is wound. Specifically, the take-up drum 30 is made of aluminum or the like, and extends in the radial direction from the cylindrical take-up drum main body 31 and both axial ends of the take-up drum main body 31 in the axial direction. The flange portions 32 and 34 are formed. The webbing 12 is wound around the winding drum body 31 between the flange portions 32 and 34.

  Further, the winding drum 30 is formed with a shaft hole portion 36 along its central axis. The shaft hole 36 is non-penetrating on one end side of the winding drum 30 and is open on the other end side of the winding drum 30. A torsion bar 38 is inserted into the shaft hole portion 36. One end portion 38 a of the torsion bar 38 protrudes from the flange portion 34 on the other end side of the winding drum 30, and is coupled to a ratchet gear 61 (described later) of the lock mechanism 60 so as not to be relatively rotatable. Further, the other end 38 b of the torsion bar 38 is connected to the winding drum 30 through a restraining mechanism 92 described in detail later in the shaft hole 36.

<Pretensioner mechanism>
FIG. 5 is a perspective view showing a state in which the pretensioner mechanism 40 is disassembled from the seat belt retractor 10, and FIG. 6 is an explanatory view showing the internal structure of the pretensioner mechanism 40. As shown in FIGS. 1 to 3, 5, and 6, the pretensioner mechanism 40 rotates the take-up drum 30 in the take-up direction of the webbing 12 in an emergency such as a vehicle collision, thereby causing the webbing 12 to rotate. It is a mechanism for removing slack. Thus, in the event of an emergency such as a vehicle collision, the occupant can be firmly restrained on the seat by removing the slack of the webbing 12.

  More specifically, the pretensioner mechanism 40 includes a gas generation member 41, a pipe cylinder 42, a piston 43, a pinion gear 45, and a clutch mechanism 50.

  The gas generating member 41 has a gas generating agent such as explosive, and is configured to generate gas by igniting the gas generating agent in accordance with the output of an impact detection sensor or the like.

  The pipe cylinder 42 is formed as an L-shaped cylinder member in which a gas introduction part 42b is connected to one end of a linear piston guide cylinder part 42a. The gas generating member 41 is attached to the gas introducing portion 42b. Therefore, the gas generated by the gas generating member 41 is introduced into the piston guide cylinder portion 42a from the gas introduction portion 42b side (lower side in FIG. 6 and the like) of the pipe cylinder 42. In addition, an opening 42ah is formed in the longitudinal intermediate portion of one side portion of the piston guide cylinder portion 42a. A part of a pinion gear tooth 45a of a pinion gear 45 described later is disposed in the opening 42ah.

  The pipe cylinder 42 is sandwiched between the base plate 48a on the side plate portion 21 side and the outer cover plate 48b, and the tapping screw PIN1 or the like is sandwiched between the base block 49 and the cover plate 48b. It is attached and fixed to the outer surface of the side plate part 21 by using.

  In addition, a pretensioner mechanism 40 is attached to the housing 20 at the upper end of the piston guide cylinder 42a, and a through-hole through which a stopper pin PIN2 that functions as a piston 43, a pipe cylinder 42, and a rotation stopper can be inserted. 42c is formed.

  The piston 43 is a member formed of a steel material or the like, and has a long shape as a whole. Rack teeth 43 a that mesh with the pinion gear teeth 45 a of the pinion gear 45 are formed on one side of the piston 43. Further, one end surface (the lower end surface in FIG. 6 and the like) of the piston 43 is formed into a circular end surface corresponding to the cross-sectional shape of the piston guide cylinder portion 42a. A seal plate 42s formed of an elastomer such as rubber is attached to the circular end surface.

  In the standby state before the pretensioner mechanism 40 is operated, the piston 43 is inserted and arranged on the back side of the piston guide cylinder portion 42a until the rack teeth 43a are in a non-engagement state with the pinion gear teeth 45a.

  The pinion gear 45 is a columnar member formed of a steel material or the like, and pinion gear teeth 45a that can mesh with the rack teeth 43a are formed on the outer peripheral portion thereof. A cylindrical support portion 45b is formed so as to extend outward from the pinion gear teeth 45a. The support portion 45b is rotatably fitted in a support hole 48h formed in a cover plate 48b attached to the outer surface side of the side plate portion 21. In this state where the support portion 45b is fitted in the support hole 48h, a part of the pinion gear teeth 45a is disposed in the opening portion 42ah of the piston guide cylinder portion 42a through the opening portion 42ah. When the piston 43 moves upward from the standby state, the rack teeth 43a mesh with the pinion gear teeth 45a, and the pinion gear 45 rotates.

  The rotation of the pinion gear 45 is transmitted to the winding drum 30 through the clutch mechanism 50 (see FIG. 3).

  That is, a boss portion 45 d that protrudes along the axial direction is formed at the end portion on the side plate portion 21 side in the axial direction of the pinion gear 45. The boss portion 45d is formed in a non-circular cross section (here, a spline shape having a plurality of protrusions). The boss portion 45d is disposed so as to protrude toward the winding drum through an opening formed in the base plate 48a.

  Further, the clutch mechanism 50 is in a state in which the winding drum 30 is freely rotated with respect to the pinion gear 45 in a normal state (a state in which the rotation transmission path between the two is cut off), and the rotation of the pinion gear 45 in the operation of the pretensioner mechanism 40. Can be switched between a state in which the rotation is transmitted to the winding drum 30 (a state in which a rotation transmission path between the two is established).

  That is, the clutch mechanism 50 includes a pawl base 51 made of steel or the like, a plurality (three in this case) of clutch pawls 52 made of steel or the like, and a pawl guide 53 made of resin or the like. I have.

  A fitting hole 51h into which the boss portion 45d is fitted is formed at the center portion of the pawl base 51. The boss portion 45d is fitted into the main fitting hole 51h, so that the pawl base 51 is connected to the pinion gear 45. Mounted relative to non-rotatable. That is, the pinion gear 45 and the pawl base 51 have a relationship of rotating together. Further, in this manner, the bearing 54 is fitted into the boss portion 45d in a state where the boss portion 45d is fitted into the fitting hole 51h. A shaft portion 32 b formed at the center of the other side surface of the winding drum 30 is inserted into the bearing 54.

  Each pawl pawl 52 is supported by the pawl base 51 so that the posture can be changed between an accommodation posture and a locking posture. The stowed posture is a posture in which the entire clutch pawl 52 is accommodated in the outer peripheral edge portion of the pawl base 51, and the locking posture is a posture in which the tip end portion of the clutch pawl 52 protrudes outward from the outer peripheral edge portion of the pawl base 51. is there.

  The pawl guide 53 is an annular member, and is disposed at a position facing the pawl base 51 with each clutch pawl 52 interposed therebetween. A positioning protrusion (not shown) is provided on the outer side surface of the pawl guide 53. The positioning protrusion is fitted into the positioning hole 48e of the base plate 48a, so that the pawl guide 53 is in a standby state. Is fixedly attached to the base plate 48a in a non-rotatable state. Further, on the surface of the pawl guide 53 on the pawl base 51 side, a posture changing projection 53 a is projected corresponding to each clutch pawl 52. Then, when the pawl base 51 and the pawl guide 53 are rotated relative to each other by the operation of the pretensioner mechanism 40, each clutch pawl 52 comes into contact with the posture changing projection 53a so that the posture is changed from the housed posture to the locked posture. It has become.

  Further, when each clutch pawl 52 changes its position to the locked position, it engages with the winding drum 30. More specifically, an annular recess 32h in which the clutch mechanism 50 can be disposed is formed on one side surface of the winding drum 30 (see FIG. 5). A clutch gear 32a is formed on the peripheral wall of the annular recess 32h, and the tip of the clutch pawl 52 can be engaged with the clutch gear 32a. When the clutch pawl 52 is changed to the locked posture as described above, the tip end portion of the clutch pawl 52 is engaged with the clutch gear 32a, whereby the pawl base 51 rotates the winding drum 30. . The engagement between the clutch pawl 52 and the clutch gear 32a is an engagement structure in only one direction that rotates the winding drum 30 in the winding direction of the webbing 12.

  The operation of the pretensioner mechanism 40 will be described.

  That is, when gas is generated from the gas generating member 41 in the standby state (see FIG. 6), the piston 43 is pushed by the pressure of the generated gas. As a result, the piston 43 moves toward the upper side of the piston guide cylinder portion 42a, and the pinion gear 45 having the pinion gear teeth 45a meshed with the rack teeth 43a rotates (left rotation in FIG. 6).

  Then, the pawl base 51 rotates together with the pinion gear 45. At this time, since the pawl base 51 rotates relative to the pawl guide 53, the attitude changing projection 53a formed on the pawl guide 53 comes into contact with the clutch pawl 52, and the clutch pawl 52 is locked. To change the posture. Thereby, the clutch pawl 52 is engaged with the clutch gear 32 a of the winding drum 30. As a result, the force to move the piston 43 upward is transmitted to the take-up drum 30 via the pinion gear 45, the pawl base 51, the clutch pawl 52, and the clutch gear 32a, and the take-up drum 30 takes up the take-up of the webbing 12. The webbing 12 is wound around the winding drum 30 by being rotationally driven in the direction.

  Since the posture changing projection 53a formed on the pawl guide 53 is maintained in contact with the clutch pawl 52, a force to rotate the pawl guide 53 is also applied. When the positioning protrusion formed on the pawl guide 53 is broken by this force, the pawl guide 53 rotates with the pawl base 51.

  When the piston 43 moves until it comes into contact with the stopper pin PIN2, the winding operation of the webbing 12 is finished.

  When gas generation is stopped from the gas generating member 41 and the gas is extracted through the gas vent hole 42h, the piston can move in the opposite direction. Accordingly, when the webbing 12 is pulled in the pull-out direction by the movement of the occupant due to the impact and the winding drum 30 is rotated in the pull-out direction of the webbing 12, the pinion gear 45 is in the direction opposite to that when the pretensioner mechanism 40 is operated. In addition, the piston 43 is rotated through the clutch mechanism 50, and the piston 43 is pushed back in the direction opposite to the operation direction. When the piston 43 is pushed back to a position where the engagement between the rack teeth 43 a of the piston 43 and the pinion gear teeth 45 a of the pinion gear 45 is disengaged, the pinion gear 45 is disengaged from the piston 43, so that the take-up drum 30 is in relation to the piston 43. It will be able to rotate freely. As described above, the pretensioner mechanism 40 is in a state in which the rotation of the webbing 12 in the pull-out direction is suppressed as much as possible after the operation.

  The configuration of the pretensioner mechanism is not limited to the above configuration. The structure may be such that the winding drum is rotated by pulling a wire or the like by the gas pressure generated by the gas generating agent, or the winding drum is rotated by driving a motor or the like. In short, the pretensioner mechanism may be configured to be able to rotate the winding drum at a timing when an emergency state such as a vehicle collision is detected.

<Lock mechanism>
2 to 4 and 7 to 9, the lock mechanism 60 allows rotation of the one end 38 a of the torsion bar 38 in the normal state, and moves the webbing 12 in the drawing direction in the non-normal state. It is comprised so that rotation of the one end part 38a of the torsion bar 38 may be controlled.

  In the present embodiment, the lock mechanism 60 is configured to restrict the rotation of the one end portion 38a of the torsion bar 38 when the webbing 12 is suddenly pulled out and when the vehicle is suddenly accelerated or decelerated.

  That is, the lock mechanism 60 includes a ratchet gear 61, a lock pawl 64, a lock-side clutch 66, a lock cover 68, a webbing sensitive part 70, and an acceleration sensitive part 74 (see FIGS. 3 and 4). ). Then, according to the sensitive operation of the webbing sensitive part 70 or the acceleration sensitive part 74, the lock side clutch 66 moves the lock pawl 64 to engage with the ratchet gear 61, thereby restricting the rotation of the ratchet gear 61 and the take-up drum 30. To do.

  That is, a ratchet gear 61 is attached to one end 38 a of the torsion bar 38. The ratchet gear 61 is disposed adjacent to the other side surface of the take-up drum 30 and rotates in conjunction with the take-up drum 30 in a normal state and is stopped by the lock mechanism 60 in a vehicle emergency or the like. Is done. That is, the ratchet gear 61 is switched between a state in which the ratchet gear 61 can rotate coaxially with the rotation shaft of the winding drum 30 and a state in which the rotation of the webbing 12 in the pull-out direction is restricted. It is a rotation restricting member.

  More specifically, the ratchet gear 61 is a member formed of a steel material or the like, and includes a disc-shaped ratchet gear main body portion 61a and a shaft portion 61c protruding from one main surface side of the ratchet gear main body portion 61a. It has. Ratchet gear teeth 61b with which the lock pawl 64 can be engaged are formed on the outer periphery of the ratchet gear main body 61a. The ratchet gear main body 61a is formed (slightly) smaller than the opening 22h formed in the side plate portion 22, and is rotatably disposed in the opening 22h. The shaft portion 61c is fitted into a lock rotation member 71 described later.

  Further, a fitting hole 62a into which the one end 38a of the torsion bar 38 can be fitted is formed at the center of the other main surface of the ratchet gear main body 61a (see FIG. 10). Here, a cylindrical portion 62 projects from the central portion of the other main surface of the ratchet gear main body portion 61a, and the inner peripheral portion of the cylindrical portion 62 corresponds to the one end portion 38a of the torsion bar 38 (here, Is formed in a fitting hole 62a formed in a gear shape (see FIG. 10). Then, the one end 38a of the torsion bar 38 is fitted into the fitting hole 62a, so that the one end 38a of the torsion bar 38 and the ratchet gear 61 are attached to each other so as not to be relatively rotatable.

  The other main surface of the ratchet gear main body 61a is formed with a portion for incorporating the wire-type pull-out load generating mechanism 80, which will be described later.

  7 and 8 are explanatory views showing the operation of the lock pawl 64. As shown in FIGS. 2, 4, 7 and 8, the lock pawl 64 is a member formed of a steel material or the like. The lock pawl 64 is formed in an elongated member (here, an oval member), and an engagement tooth 64a that can be engaged with the ratchet gear tooth 61b is formed on one end side thereof. The lock pawl 64 is attached to the side plate portion 22 at an outer peripheral position of the take-up drum 30 attached to the housing 20 so that the posture can be changed between an engagement posture and a non-engagement posture via a pin member 64c. . The engagement posture is a position where the engagement teeth 64a are engaged with the ratchet gear teeth 61b, and the non-engagement posture is a position where the engagement teeth 64a are separated from the ratchet gear teeth 61b. Further, a connecting pin 64b protrudes from the outward face of one end of the lock pawl 64. The connecting pin 64b passes through a recess 22ha formed by cutting out a part of the peripheral edge of the opening 22h. And projecting to the outer surface side of the side plate portion 22.

  The lock pawl 64 is provided with a return spring (not shown) as a biasing member that biases the lock pawl 64 to the non-engagement position. One end portion of the return spring is fixed to the housing 20 and the other end portion of the return spring is fixed to one end portion of the lock pawl 64, and the lock pawl 64 is biased to the non-engagement position by the biasing force of the return spring. ing.

  In the normal state, the lock pawl 64 is maintained in the non-engagement posture by the urging force of the return spring (see FIG. 7). When the lock pawl 64 is changed to the engagement posture by a lock side clutch 66 described later, the engagement teeth 64a of the lock pawl 64 are engaged with the ratchet gear teeth 61b of the ratchet gear 61, and the ratchet gear 61 and The rotation of the winding drum 30 is restricted (see FIG. 8). When the force for changing the posture of the lock pawl 64 to the engaged posture is released, the posture of the lock pawl 64 is changed to the non-engaged posture by the biasing force of the return spring, and the ratchet gear 61 and the winding drum 30 are moved to the webbing 12. Can be pulled out and wound.

  The lock side clutch 66 and the lock cover 68 are members formed of resin or the like.

  The lock cover 68 has a clutch housing portion 68a and an acceleration sensitive portion housing portion 68b. The clutch housing portion 68a is formed in a case shape that can house the lock-side clutch 66 rotatably within a certain range and has a housing space that opens to the side plate portion 22 side. The acceleration sensitive portion accommodating portion 68b is formed in a case shape that can accommodate the acceleration sensitive portion 74 and has a space communicating with the inner space of the clutch accommodating portion 68a. Then, the clutch housing portion 68a is disposed at a position corresponding to the outer surface of the flange portion 34 on the other side of the take-up drum 30, and the lock cover 68 is disposed with the acceleration sensitive portion housing portion 68b disposed below the clutch housing portion 68a. It is attached to the outer surface of the side plate part 22. The lock cover 68 may be attached by fitting a protrusion formed on the lock cover 68 into the side plate portion 22, or other pinning or screwing.

  The lock-side clutch 66 includes a disk-shaped plate portion 66p, and an inner peripheral wall portion 66a (see FIG. 9) and an outer peripheral wall portion 67 (see FIG. 4) formed on one main surface of the plate portion 66p. .

  An insertion hole 66ah through which a shaft protrusion 71p, which will be described later, can be inserted is formed in the central portion of the plate portion 66p. The lock-side clutch 66 is fixed within the clutch housing portion 68a of the lock cover 68 (here, a slight amount). It is accommodated rotatably within a certain range of rotation.

  The inner peripheral wall portion 66a is formed at a position surrounding the insertion hole 66ah, and an inner tooth 66b on which an end engaging portion 73a of an inertia arm 73 described later can be locked is formed on the inner peripheral surface. (See FIG. 9).

  The outer peripheral wall portion 67 is formed so as to surround the inner peripheral wall portion 66a with a space therebetween. A part of the outer peripheral wall part 67 is formed with a connection hole 67h into which the connection pin 64b of the lock pawl 64 can be fitted. Then, the lock-side clutch 66 rotates in both forward and reverse directions within the fixed rotation range, whereby the lock pawl 64 is changed in posture between the engagement posture and the non-engagement posture. Since the lock pawl 64 is biased toward the non-engagement posture by the biasing force of the return spring, the lock-side clutch 66 is rotated to a rotational posture corresponding to the non-engagement posture of the lock pawl 64 by this biasing force. It is energized.

  Moreover, the other part of the outer peripheral wall portion 67 is provided with a lock arm support shaft portion 67b that supports a lock arm 78, which will be described later, so that the posture can be changed (see FIG. 4). Here, the lock arm 78 is a long member having an engagement portion 78a that can be engaged with the external teeth 71b of the lock rotation member 71 (see FIG. 4). The base end portion of the lock arm 78 is pivotally supported by the lock arm support shaft portion 67b so that the posture can be changed between an engaged posture and a non-engaged posture. The engagement posture of the lock arm 78 is a posture in which the engagement portion 78a is moved to the inner peripheral side and engaged with the outer teeth 71b of the lock rotation member 71 (see the position shown in FIG. 9). The alignment posture is a posture in which the engaging portion 78a is moved to the outer peripheral side and retracted from the external teeth 71b.

  FIG. 9 is an explanatory view schematically showing the webbing sensitive part 70. As shown in FIGS. 4 and 9, the webbing sensitive part 70 is a part for restricting the rotation of the winding drum 30 when the webbing 12 is suddenly pulled out, and includes a lock rotating member 71 and a coil spring as an urging member. 72 and an inertial arm 73.

  The lock rotation member 71 is a member formed of resin or the like, and is formed into a circular member in which a peripheral wall portion 71a is formed on one main surface of the disk portion. The peripheral wall portion 71 a is set to have a diameter that can be disposed between the inner peripheral wall portion 66 a and the outer peripheral wall portion 67, and the peripheral wall portion 71 a is disposed between the inner peripheral wall portion 66 a and the outer peripheral wall portion 67. In the installed state, it can be rotated. External teeth 71b that can engage with the engaging portions 78a of the lock arm 78 are formed on the outer peripheral portion of the peripheral wall portion 71a.

  In addition, a fitting hole (not shown) in which the shaft portion 61 c of the ratchet gear 61 can be fitted is formed in the central portion of the lock rotating member 71. Then, the shaft portion 61c is fitted into the fitting hole. Further, a shaft projecting portion 71p projects from the center portion of the lock rotating member 71 and on the opposite side of the opening of the fitting hole. The fitting hole is formed to a depth that reaches the inside of the shaft projection 71p. Therefore, as will be described later, the shaft portion 61c fitted into the fitting hole plays a role of reinforcing the shaft projection 71p. .

  In this fitted state, a protruding portion (not shown) provided on the ratchet gear 61 side of the lock rotating member 71 is fitted into a rotation stop recess 61 h formed in the ratchet gear 61. Thereby, the ratchet gear 61 and the lock | rock rotation member 71 are in the state which cannot be rotated relatively.

  The inertia arm 73 is a member made of resin or the like, and is formed in an arc shape along the inner side of the outer peripheral edge of the lock rotation member 71. One end portion of the inertia arm 73 is formed in a tip engagement portion 73a that can engage with the internal teeth 66b of the inner peripheral wall portion 66a. The inertia arm 73 is rotatably supported at a position off the center of the lock rotation member 71 via a support shaft portion 71c, and the non-engagement in which the tip engagement portion 73a is moved to a position from the inner periphery. The posture can be changed between the stopping posture (see the solid line in FIG. 9) and the engaging posture (see the dotted line in FIG. 9) in which the tip engaging portion 73a is moved to a position from the outer periphery. In addition, a coil spring 72 as a biasing member that biases the inertial arm 73 to a non-engagement posture is interposed between the other end of the inertial arm 73 and the stop piece 71f of the lock rotation member 71 in a compressed state. . In the normal state, the inertial arm 73 is biased toward the retracted posture by the biasing force of the coil spring 72. In this state, when the webbing 12 is pulled out and the take-up drum 30 is rotated and the lock rotating member 71 is rotated accordingly (rotation in the pulling direction of the webbing 12), the inertial arm 73 is brought into a locked posture by inertial force. The force to change is applied. At this time, if the webbing 12 is pulled out suddenly, the inertial force increases, and the inertial arm 73 changes its posture to the engaged posture against the urging force of the coil spring 72. As a result, the distal end engaging portion 73a of the inertial arm 73 engages with the internal teeth 66b to rotate the lock-side clutch 66.

  Further, in this state, when the force pulling the webbing 12 is released, the winding drum 30 and the lock rotating member 71 are slightly rewound, and the engagement between the tip engaging portion 73a and the internal teeth 66b is released. . As a result, the lock-side clutch 66 returns to the original rotational position.

  As shown in FIG. 4, the acceleration sensing unit 74 is a part for restricting the rotation of the winding drum 30 when the vehicle suddenly accelerates, and includes a sphere 75, a relay transmission lever 76, and a lock arm 78. ing. The rapid acceleration of the vehicle includes a case where the acceleration is “minus”, that is, a time when the vehicle is decelerated, and of course includes a case where the vehicle is suddenly decelerated due to a vehicle collision.

  The sphere 75 is a metal sphere or the like, and is supported in a mounting shape by the sphere support portion 75b. The sphere support portion 75 b has a portion that supports only a portion smaller than the lower half of the sphere 75. Therefore, when a large inertial force acts on the sphere 75, the sphere 75 is displaced upward in an attempt to escape from the sphere support portion 75b.

  The relay transmission lever 76 has a dish-like portion 76a covering the upper portion of the sphere 75, and is supported above the sphere 75 so that the posture can be changed by a support column portion 75c protruding from the sphere support portion 75b. Yes. When the sphere 75 is within the sphere support portion 75 b, the relay transmission lever 76 is placed on the sphere 75. From this state, when the sphere 75 is displaced upward so as to be detached from the sphere support portion 75b, the relay transmission lever 76 is also lifted upward.

  The spherical body 75, the spherical body support portion 75b, and the relay transmission lever 76 are accommodated in the acceleration sensitive portion accommodating portion 68b of the lock cover 68. In this state, the opening on the side plate portion 22 side of the acceleration sensitive portion accommodating portion 68 b is closed by the lid portion 77.

  In this state, the relay transmission lever 76 is disposed at a position where it can come into contact with the lock arm 78 through a portion between the acceleration sensitive portion accommodating portion 68 b and the lid portion 77. When the relay transmission lever 76 is lifted upward, the engaging portion 78a of the lock arm 78 is lifted upward by the relay transmission lever 76, and the posture of the lock arm 78 is changed to the engagement posture. Since the rotation range of the lock side clutch 66 is very small here, it is possible to maintain the state where the relay transmission lever 76 lifts the lock arm 78 within the rotation range.

  In the normal state, the sphere 75 is in a predetermined position of the sphere support portion 75b, and the lock arm 78 is also maintained in the non-engagement posture by its own weight. In this state, when the vehicle is rapidly accelerated (decelerated), the sphere 75 is displaced from the predetermined position of the sphere support 75b and displaced upward. Then, the relay transmission lever 76 is lifted upward, and the posture of the lock arm 78 is also changed to the engagement position. Then, the engagement portion 78 a of the lock arm 78 engages with the external teeth 71 b of the peripheral wall portion 71 a of the lock rotation member 71. Then, the rotational force of the lock rotating member 71 is transmitted to the lock side clutch 66 through the lock arm 78, and the lock side clutch 66 is rotated. Note that after the lock-side clutch 66 is rotated until the lock pawl 64 engages with the ratchet gear teeth 61b, the state where the relay transmission lever 76 lifts the lock arm 78 may be maintained or released. Good.

  In the above state, when the vehicle is in a stable state (stopped or constant speed state), the sphere 75 is placed in a predetermined position of the sphere support portion 75b, and the relay transmission lever 76 and the lock arm 78 are returned to the original positions below. You can move.

  The operation of the lock mechanism 60 will be described.

  First, when the webbing 12 is suddenly pulled out, the inertial arm 73 is changed to a locked posture by an inertial force, and the tip engaging portion 73a is engaged with the internal teeth 66b to rotate the lock-side clutch 66. . Then, the posture of the lock pawl 64 is changed to the engagement posture, and the engagement teeth 64a of the lock pawl 64 are engaged with the ratchet gear teeth 61b of the ratchet gear 61, thereby restricting the rotation of the ratchet gear 61 and the winding drum 30. . As a result, the rotation of the one end 38a of the torsion bar 38 is restricted, and the withdrawal of the webbing 12 is restricted.

  In this state, when the force of pulling out the webbing 12 is released and the winding drum 30 is slightly rewound, the posture of the lock pawl 64 is changed to the non-engagement posture by the urging force of the return spring, and the return spring The lock-side clutch 66 also returns to the original rotational posture using the urging force. Further, the posture of the inertial arm 73 is also changed to the non-locking posture by the biasing force of the coil spring 72. Thereby, the rotation restriction of the one end portion 38a of the torsion bar 38 is released, and the ratchet gear 61 and the winding drum 30 return to the normal state, and the webbing 12 can be pulled out and wound. That is, the torsion bar 38 is used as an impact absorbing member that couples the winding drum 30 and the ratchet gear 61 as the rotation restricting member so as not to be relatively rotatable in a state where the webbing 12 is pulled out in a pulling direction smaller than a predetermined load. ing. Here, the predetermined load is a load range generated by a normal use state of the seatbelt retractor 10 (that is, a load generated by pulling out the webbing 12 manually and pulling out the webbing 12 by deceleration assumed in normal traveling). ) And a load range caused by an emergency state such as a vehicle collision.

  Further, when the vehicle is suddenly accelerated due to a vehicle collision or sudden deceleration, the sphere 75 is displaced from the predetermined position of the sphere support 75b and displaced upward. Then, the relay transmission lever 76 is lifted upward, and the posture of the lock arm 78 is also changed to the engagement position by the relay transmission lever 76. As a result, the engagement portion 78 a of the lock arm 78 is engaged with the external teeth 71 b of the peripheral wall portion 71 a of the lock rotation member 71, and the rotational force of the lock rotation member 71 is transmitted to the lock side clutch 66 via the lock arm 78. Then, the lock side clutch 66 rotates.

  Then, similarly to the above, the lock pawl 64 is changed to the engagement posture, the engagement teeth 64 a of the lock pawl 64 are engaged with the ratchet gear teeth 61 b of the ratchet gear 61, and the ratchet gear 61 and the winding drum 30. Regulate the rotation of As a result, the rotation of the one end 38a of the torsion bar 38 is restricted, and the withdrawal of the webbing 12 is restricted.

  In this state, when the vehicle is in a stable state (stopped or in a constant speed state), the sphere 75 is placed in a predetermined position of the sphere support portion 75b, and the relay transmission lever 76 and the lock arm 78 can be returned to their original positions below. It becomes like this. At the same time, when the force for pulling out the webbing 12 is released and the take-up drum 30 is slightly rewound, the lock pawl 64 is changed to the disengaged posture by the urging force of the return spring and the urging force of the return spring is changed. Utilizing this, the lock side clutch 66 also returns to the original rotational posture. At the same time, the relay transmission lever 76 and the lock arm 78 return to their original positions below due to their own weight. As a result, the ratchet gear 61 and the winding drum 30 return to the normal state, and the webbing 12 can be pulled out and wound.

  With this lock mechanism 60, the rotation of the ratchet gear 61 can be restricted at least in an emergency state so that the operation of the pull-out load generating mechanism described below can be started.

  Here, an example has been described in which the lock mechanism 60 restricts (stops) the rotation of the one end portion 38a of the torsion bar 38 when the webbing 12 is suddenly pulled out and when the vehicle is suddenly accelerated. Alternatively, the rotation of the one end 38a of the torsion bar 38 may be restricted by another mechanism. That is, the lock mechanism 60 may be configured to restrict the rotation of the one end portion 38a of the torsion bar 38 at least in an emergency state in which the webbing 12 is pulled out and the shock should be absorbed.

<Winding mechanism>
As shown in FIG. 4, the winding mechanism 100 is configured to constantly urge the winding drum 30 in the winding direction. Here, the winding mechanism 100 is provided outside the lock mechanism 60 and includes a spiral spring 102, a stopper 104, and a spring cover 106.

  The stopper 104 is fixed to the tip end portion of the shaft projecting portion 71p protruding outside the lock mechanism 60 in a non-rotating state, and is fixed to the innermost peripheral end portion of the spiral spring 102. The spiral spring 102 is accommodated in a spring cover 106 attached to the outer surface of the lock mechanism 60 in a state of being disposed outside the lock mechanism 60. The outer end of the spiral spring 102 within the spring cover 106 is fixed at a fixed position within the spring cover 106.

  Then, the one-way rotational biasing force of the spiral spring 102 constantly biases the winding drum 30 in the winding direction with respect to the winding drum 30 via the lock rotating member 71, the ratchet gear 61 and the torsion bar 38. Acts as a force.

<Drawing load generation mechanism>
10 and 11 are exploded perspective views showing the extraction load generation mechanism portion of the seatbelt retractor 10, and FIG. 12 is a partial cross-sectional view along the axial direction of the extraction load generation mechanism portion.

  The seat belt retractor 10 includes a pull-out load generating mechanism that generates a pull-out load that becomes a resistance to the webbing 12 when the webbing 12 is pulled out after the operation of the lock mechanism 60 is started. The pull-out load generating mechanism can be regarded as a mechanism that absorbs an impact applied to the occupant from the webbing 12 by the pull-out load. Here, the pull-out load generation mechanism includes a wire-type pull-out load generation mechanism 80 and a torsion bar-type pull-out load generation mechanism 90.

  The wire-type pull-out load generating mechanism 80 is a mechanism that generates a pull-out load of the webbing 12 by the pull-out resistance of the wire 86. The torsion bar type pull-out load generation mechanism 90 is a mechanism that generates a pull-out load of the webbing 12 by torsional deformation of the torsion bar 38.

<Wire-type pull-out load generation mechanism>
As shown in FIGS. 3, 10, and 11, the wire-type pull-out load generation mechanism 80 makes the winding drum 30 and the ratchet gear 61 serving as the rotation restricting member relatively unrotatable in the standby state (normal state). When the force is applied to the take-up drum 30 in the pulling-out direction of the webbing 12 due to the impact, an impact that allows relative rotation between the take-up drum 30 and the ratchet gear 61 while generating a pull-out load on the webbing 12. It is an absorption mechanism, and the wire 86 is an impact absorbing member. Here, the wire-type pull-out load generation mechanism 80 is configured to generate a pull-out load of the webbing 12 by pulling out the wire 86 while deforming it by relative rotation between the winding drum 30 and the ratchet gear 61.

  More specifically, a cylindrical portion 37 projects from the side surface on the other end side of the winding drum 30 so as to surround the opening of the shaft hole portion 36. The cylindrical portion 62 of the ratchet gear 61 is coupled to the one end portion 38 a of the torsion bar 38 so as not to be relatively rotatable while being inserted into the main cylindrical portion 37 so as to be relatively rotatable. A concave portion 37 a is formed in a part of the cylindrical portion 37 in the circumferential direction, and one end of the wire 86 is bent and fitted into the concave portion 37 a from the outer peripheral side of the cylindrical portion 37. The portion is attached to the winding drum 30 so as not to rotate relative to the winding drum 30.

  A disc-shaped portion 63 is formed on the outer peripheral portion of the surface of the ratchet gear 61 on the side facing the winding drum 30. An outer peripheral wall portion 63w is formed on the outer peripheral portion of the disk-shaped portion 63 on the surface on the winding drum 30 side so as to surround the cylindrical portion 62 with a space therebetween.

  Further, a drawing path 63p for allowing the wire 86 to be drawn while applying resistance is formed on the surface of the disk-like portion 63 on the winding drum 30 side. Here, the lead-out path 63p is formed on the inner peripheral side of the outer peripheral wall portion 63w by gaps between a plurality of protruding portions 63a, 63b, 63c, 63d, and 63e that protrude along the outer peripheral wall portion 63w. (See FIG. 13). More specifically, the protruding portions 63a, 63c, and 63e are formed on the inner peripheral side of the outer peripheral wall portion 63w at intervals along the circumferential direction. The protruding portions 63a, 63c, and 63e are formed with curved surfaces that are convex toward the outer peripheral side of the disc-shaped portion 63. In addition, the protrusions 63b and 63d are located on the inner peripheral side of the outer peripheral wall 63w and on the outer peripheral side of the protrusions 63a, 63c, and 63e, between the 63a, 63c, and 63e along the circumferential direction of the outer peripheral wall 63w. It is provided so that it may be located in. The protruding portions 63b and 63d are formed with curved surfaces that protrude toward the inner peripheral side of the disk-shaped portion 63. And it becomes convex between the projecting parts 63a, 63c, 63e and the projecting parts 63b, 63d at two locations toward the outer peripheral side of the disk-shaped part 63 (two locations that contact the projecting parts 63a, 63c). A lead-out path 63p that is convex toward the inner peripheral side is formed at one place (a place that contacts the protruding portion 63b) therebetween. Then, when the wire 86 passes through the lead-out path 63p, it is bent and deformed at each convex portion of the lead-out path 63p, whereby a pull-out resistance is given to the wire 86. .

  Further, a gap in which the wire 86 can be disposed is formed between the protruding portions 63b and 63d and the outer peripheral wall portion 63w. Furthermore, a plurality of guide protrusions 63f are provided on the surface of the disk-shaped portion 63 on the winding drum 30 side and on the inner peripheral side of the outer peripheral wall portion 63w in order to guide the wire 86 along an arcuate path. Is formed. And the wire 86 is guided so that it may pass the inner peripheral side of the outer peripheral wall part 63w through the said drawing-out path 63p.

  Of course, the shape of the lead-out path 63p is not limited to the above example, and any shape can be used as long as it can be pulled out while providing resistance to the wire 86 by providing a bent portion or a narrow portion.

  As described above, one end portion of the wire 86 is attached to the cylindrical portion 37 of the winding drum 30 so as not to be relatively rotatable, and the middle portion in the longitudinal direction of the wire 86 and the other end side portion thereof are connected to the drawing path. It is incorporated in the ratchet gear 61 so as to be able to pass through 63p. Then, when the winding drum 30 and the ratchet gear 61 rotate relative to each other, the wire 86 passes through the drawing path 63p and is given a drawing resistance, thereby generating a drawing load of the webbing 12. .

  More specifically, the wire 86 is a linear member formed of a steel material or the like, and one end thereof is bent and is fitted and fixed to the cylindrical portion 37 of the winding drum 30. Moreover, the longitudinal direction intermediate part of the wire 86 is arrange | positioned at the said extraction path 63p in the state bent so that it could arrange | position along the said extraction path 63p. A portion of the wire 86 between the one end portion and the intermediate portion in the longitudinal direction is bent in an annular shape and wound around the outer periphery of the cylindrical portion 37 by about one turn. Further, the other end portion of the wire 86 than the intermediate portion in the longitudinal direction is bent in a spiral shape, and an arcuate path formed between the plurality of guide projections 63f, the outer peripheral wall 63w and the projection. A circle is drawn once or more (here, about once and a half) along the inner peripheral side of the outer peripheral wall 63w through an arcuate path formed between 63b, 63d or the guide projection 63f. Arranged. Then, the winding drum 30 and the ratchet gear 61 are combined so that the cylindrical portion 37 of the winding drum 30 is fitted into the cylindrical portion 62 of the ratchet gear 61, so that one end side of the wire 86 is rotated relative to the winding drum 30. The wire 86 is disposed between the one side surface of the take-up drum 30 and the disc-shaped portion 63 of the ratchet gear 61 in a state where the intermediate portion in the longitudinal direction is disposed in the drawing path 63p. Is done.

  An intermediate member that can rotate within a certain range may be attached to the winding drum side, and one end of the wire may be attached to the intermediate member. Thereby, the drawing start timing of a wire can be delayed. Moreover, the path | route which provides drawing resistance with respect to a wire may be formed in the winding drum side, and the wire may be connected with the ratchet gear side so that relative rotation is impossible. In this case, the intermediate member may be attached to the ratchet gear side.

  The extraction load generation operation of the wire type extraction load generation mechanism 80 will be described.

  First, in the standby state, as shown in FIG. 13, one end of the wire 86 is attached so as not to rotate relative to the take-up drum 30, and the longitudinal intermediate portion and the other end of the wire 86 are connected to the cylindrical portion 37. It is arranged in a spiral around. The longitudinal direction intermediate part of the wire 86 is arrange | positioned in the state bent so that it might wave along the extraction path 63p.

  When sudden acceleration (deceleration) occurs due to a vehicle collision or the like, the pretensioner mechanism 40 rotates the winding drum 30 in the winding direction of the webbing 12, and the lock mechanism 60 ratchets the webbing 12 in the drawing direction. The rotation of the gear 61 is restricted.

  When a vehicle collision or the like occurs, the occupant tries to move forward relative to the vehicle by the inertial force, so that a large pulling force acts on the webbing 12.

  When the winding drum 30 rotates relative to the ratchet gear 61 in the pulling direction of the webbing 12 due to the pulling output of the webbing 12, the longitudinal intermediate portion of the wire 86 is pulled along the pulling path 63p. Then, the longitudinal direction intermediate part and other end part of the wire 86 are pulled out while being given a pulling resistance in the pulling path 63p. As a result, a pull-out load of the webbing 12 is generated. When the wire 86 is completely drawn out from the drawing path 63p, the drawing load generating operation by the wire 86 is completed, and the wire 86 is wound around the cylindrical portion 37 (see FIG. 14).

  In addition, the cross-sectional shape (cross-sectional shape in the surface orthogonal to the longitudinal direction) of the wire 86 is a flat shape in which the wires 86 are in surface contact with each other when the wire 86 is wound so as to be easily wound around the cylindrical portion 37 a plurality of times. The shape is preferred. For example, as the wire 86, a narrow strip may be used.

  Note that the generation period of the pull-out load of the webbing 12 due to the pull-out resistance of the wire 86 depends on the length of the wire 86. That is, if the length dimension of the wire 86 movable along the drawing path 63p is increased, the generation period of the drawing load of the webbing 12 due to the drawing resistance of the wire 86 can be extended. Here, during the period in which the winding drum 30 rotates about a little around two turns with respect to the ratchet gear 61, the pulling load of the webbing 12 is generated by the pulling resistance of the wire 86. What is necessary is just to adjust the length dimension of the wire 86 suitably according to the generation | occurrence | production aspect of the extraction load made preferable.

  Note that the wire-type pull-out load generating mechanism 80 may be omitted. In addition, as an impact absorbing mechanism provided separately from the torsion bar type extraction load generation mechanism 90, a configuration different from the wire type extraction load generation mechanism 80 using the wire 86 may be adopted.

<Torsion bar type load generation mechanism>
FIG. 15 is a perspective view showing the torsion bar 38 and the restraining mechanism 92, FIG. 16 is a cross-sectional view showing the torsion bar 38 and the restraining mechanism 92, and FIG.

  As shown in FIGS. 3, 10 to 12, and 15 to 17, the torsion bar type pull-out load generation mechanism 90 twists and deforms the torsion bar 38 by the relative rotation of the winding drum 30 and the ratchet gear 61. This is a mechanism that generates the pull-out load of the webbing 12 by the force required for the torsional deformation. Here, by providing a restraining mechanism 92 between the winding drum 30 and the torsion bar 38, the torsion bar 38 starts torsional deformation after the start of relative rotation between the winding drum 30 and the ratchet gear 61. Like to do.

  More specifically, the torsion bar 38 as a relay member is a member formed of a metal material or the like that can be torsionally deformed, and is a rod-like shape that can be disposed in the shaft hole portion 36 of the winding drum 30. The outer shape of the shaft hole 36 is smaller than the inner diameter of the shaft hole 36 and is formed into a round bar shape. Further, the length dimension of the torsion bar 38 is smaller than the length dimension of the shaft hole portion 36.

  One end portion 38 a of the torsion bar 38 is attached to the ratchet gear 61 so as not to be relatively rotatable. Here, one end portion 38a of the torsion bar 38 is formed in a shape (in this case, a spline shape) in which a cross section in a plane orthogonal to the axial direction has a non-circular shape, and the other end portion 38b is formed as a ratchet gear. It is fitted in the fitting hole 62a formed in 61 in a manner in which relative rotation is impossible.

  A restraining mechanism 92 is attached to the other end 38 b of the torsion bar 38. Here, the other end portion 38b of the torsion bar 38 is formed with a fitting hole 38bh having a non-circular cross section in a plane orthogonal to the axial direction, and the following description will be made using this fitting hole 38bh. A restraining mechanism 92 is attached to the head.

  The restraining mechanism 92 is provided between the winding drum 30 and the other end 38b of the torsion bar 38, and in a state before the winding drum 30 and the torsion bar 38 rotate relative to each other by a predetermined amount, The relative rotation with the bar 38 is allowed, and the winding drum 30 and the torsion bar 38 are constrained to be relatively unrotatable after the winding drum 30 and the torsion bar 38 rotate relative to each other by a predetermined amount. .

  That is, the restraining mechanism 92 includes a shaft member 94 and a ring member 96.

  The shaft member 94 is provided at the other end portion 38b of the torsion bar 38 so as not to be relatively rotatable. The ring member 96 is configured to be externally fitted to the shaft member 94 and is provided on the winding drum 30 so as not to be relatively rotatable. Further, the ring member 96 is movable as a movable part along the direction of the rotation axis of the winding drum 30. When the shaft member 94 and the ring member 96 are relatively rotated, the relative rotational motion is converted into a motion for moving the ring member 96 along the rotational axis direction, whereby the ring member 96 is moved in the rotational axis direction. Move to. When the amount of movement of the ring member 96 in the direction of the rotation axis exceeds a predetermined amount, the movement of the ring member 96 is restricted by the shaft member 94 including the restricting portion 94b, and thus relative rotation between the shaft member 94 and the ring member 96 is restricted. The winding drum 30 and the torsion bar 38 are coupled so as not to rotate relative to each other.

  More specifically, the shaft member 94 is formed in a round bar shape. One end portion 94a of the shaft member 94 is formed in a shape having a non-circular cross section in a plane perpendicular to the axial direction, and is not relatively rotatable in the fitting hole 38bh at the other end portion of the torsion bar 38. It is inserted. Moreover, the longitudinal direction intermediate part of the shaft member 94 is formed in the control part 94b whose outer diameter is larger than the both ends. As will be described later, when the relative rotation between the shaft member 94 and the ring member 96 exceeds a predetermined amount, the restricting portion 94b makes a relative movement along the rotation axis direction of the winding drum 30 between the shaft member 94 and the ring member 96. Plays a role in regulating movement. Furthermore, the other end of the shaft member 94 is formed in the male screw portion 94c.

  The ring member 96 is formed in a ring shape that can be fitted onto the male screw portion 94 c of the shaft member 94. As for the outer periphery shape of the ring member 96, the cross-sectional shape in the surface orthogonal to the axial direction is formed in a non-circular shape (here, a spline shape having a plurality of protrusions). Further, the outer peripheral shape of the ring member 96 is fitted in the inner part of the shaft hole portion 36 of the winding drum 30 so that the ring member 96 can be fitted in a state in which the ring member 96 cannot be relatively rotated and moved along the axial direction. A fitting recess 36a having a shape corresponding to is formed (see FIG. 12). Then, the ring member 96 is fitted into the fitting recess 36a on the back side of the shaft hole portion 36 of the winding drum 30 so as not to be relatively rotatable and movable along the axial direction.

  An inner peripheral portion of the ring member 96 is formed in a female screw portion 96a capable of screwing the male screw portion 94c. Accordingly, when the male screw portion 94c of the shaft member 94 is screwed into the female screw portion 96a of the ring member 96, the shaft member 94 and the ring member 96 approach each other along the axial direction when they are rotated relative to each other. It moves relative to the direction or away. Here, by rotating the winding drum 30 relative to the torsion bar 38 in the drawing direction of the webbing 12, the ring member 96 on the winding drum 30 side rotates relative to the shaft member 94 on the torsion bar 38 side. As a result, the ring member 96 moves closer to the shaft member 94.

  The shaft member may be provided on the winding drum side so as not to be relatively rotatable, and the ring member may be provided on the torsion bar so as not to be relatively rotatable. Moreover, the structure which a shaft member moves by the relative rotation of a shaft member and a ring member may be sufficient, and the structure which both a ring member and a shaft member move may be sufficient. In addition, the restricting portion that restricts the movement of at least one of the shaft member and the ring member in the rotation axis direction may be incorporated in at least one of the shaft member and the ring member, or may be incorporated in another portion. Also good. For example, the movement of the ring member may be restricted by moving in a direction away from the shaft member and the ring member contacting the bottom of the shaft hole portion of the winding drum. In this case, the restricting portion is the bottom of the shaft hole portion of the take-up drum (see the fourth modification described later).

  Further, here, when the shaft member 94 and the ring member 96 rotate relative to each other, at least one of the shaft member 94 and the ring member 96 is plastically deformed, and the shaft member 94 and the ring member 96 are moved in the direction of the rotation axis. Relative movement along.

  More specifically, the pitch P1 of the thread of the male thread portion 94c of the shaft member 94 is different from the pitch P2 of the thread groove of the female thread portion 96a of the ring member 96 (see FIGS. 16 and 17). Here, the pitch P2 of the thread groove is set smaller than the pitch P1 of the thread. For this reason, when the male thread portion 94c of the shaft member 94 and the thread groove of the female thread portion 96a of the ring member 96 are screwed together, at least one of them must be plastically deformed. The force required for the plastic deformation is the force required to rotate the male threaded portion 94c of the shaft member 94 and the female threaded portion 96a of the ring member 96, that is, the relative rotation of the winding drum 30 with respect to the torsion bar 38. It will be the power required to make it. This force acts as a force acting as a resistance when the webbing 12 is pulled out, that is, as a part of the drawing load of the webbing 12.

  In order to plastically deform at least one of the shaft member 94 and the ring member 96 when the shaft member 94 and the ring member 96 rotate relative to each other, the pitch of the thread groove and the pitch of the thread are changed as described above. In addition to the configuration, a configuration in which one of the height and the width of the screw thread is larger than one of the depth and the width of the thread groove may be employed. However, when the shaft member 94 and the ring member 96 are relatively rotated, it is not essential to plastically deform at least one of the shaft member 94 and the ring member 96.

  In the standby state, a gap is provided between the restriction portion 94 b of the shaft member 94 and the end portion of the ring member 96 on the shaft member 94 side. The clearance may be equal to or greater than a distance corresponding to one pitch in which the ring member 96 moves along the rotation axis direction when the ring member 96 makes one rotation with respect to the shaft member 94 (for example, a distance of three rotations). preferable. As a result, the winding drum 30 rotates relative to the torsion bar 38 at least once, so that the winding drum 30 and the torsion bar 38 are connected to each other through the restraint mechanism 92 so as not to be relatively rotatable. However, it is not essential that the gap is set in this way.

<Operation>
The operation of the seatbelt retractor 10 will be described focusing on the operation of the pull-out load generating mechanism.

  First, in the standby state, the wire type pull-out load generating mechanism 80 is attached such that one end of the wire 86 is relatively unrotatable with respect to the take-up drum 30 and the middle portion and the other end of the wire 86 are the cylindrical portion 37. Are arranged in a spiral around. Moreover, the longitudinal direction intermediate part of the wire 86 is arrange | positioned along the extraction path 63p.

  In the standby state, as described above, the torsion bar type pull-out load generation mechanism 90 provides a gap between the restriction portion 94b of the shaft member 94 and the end portion of the ring member 96 on the shaft member 94 side. (See FIG. 12). In this state, the ring member 96 is preferably in contact with the bottom of the fitting recess 36 a of the shaft hole 36.

  In this standby state, the winding drum 30 and the ratchet gear 61 are incapable of relative rotation due to the arrangement structure of the wire 86.

  In the standby state, when a sudden acceleration (deceleration) occurs due to a vehicle collision or the like, the winding drum 30 is rotated in the winding direction of the webbing 12 by the pretensioner mechanism 40, and the webbing 12 is rotated by the lock mechanism 60. The rotation of the ratchet gear 61 in the pull-out direction is restricted.

  When a vehicle collision or the like occurs, the occupant tries to move forward relative to the vehicle by the inertial force, so that a large pulling force acts on the webbing 12.

  Then, the longitudinal direction intermediate portion and the other end portion of the wire 86 are pulled out while being provided with a pulling resistance in the pulling path 63p, and accordingly, the winding drum 30 rotates with respect to the ratchet gear 61, and the webbing 12 gradually moves. Withdrawn. The pulling resistance of the wire 86 at this time generates a pulling load that becomes resistance when the webbing 12 is pulled out, and the impact energy is absorbed. That is, in the initial stage, the impact energy is absorbed by the drawing load generated by the drawing resistance of the wire 86. The pull-out load of the webbing 12 due to the pull-out resistance of the wire 86 is continuously generated until the intermediate portion and the other end portion of the wire 86 are completely pulled out after passing through the pull-out path 63p.

  Here, the torsion bar 38 and the shaft member 94 are not rotatable relative to the ratchet gear 61, and the ring member 96 is not rotatable relative to the take-up drum 30. For this reason, when the winding drum 30 rotates with respect to the ratchet gear 61, the ring member 96 rotates relative to the shaft member 94. When the ring member 96 rotates relative to the shaft member 94, the ring member 96 moves closer to the shaft member 94 side, and the ring member 96 comes into contact with the regulating portion 94b of the shaft member 94. As a result, the movement of the ring member 96 relative to the shaft member 94 in the rotational axis direction is restricted, the relative rotation between the shaft member 94 and the ring member 96 is also restricted, and the winding drum 30 and the torsion bar 38 cannot be rotated relative to each other. Be bound. Then, the torsion bar 38 is twisted between the one end portion 38a on the ratchet gear 61 side and the other end portion 38b on the winding drum 30 side of the torsion bar 38. Due to the twist of the torsion bar 38, a pull-out load that becomes resistance when the webbing 12 is pulled out is generated, and the impact energy is absorbed.

  In the initial stage, when the ring member 96 rotates relative to the shaft member 94, at least one of the male screw portion 94c of the shaft member 94 and the female screw portion 96a of the ring member 96 is plastically deformed. The force required to relatively rotate the member 96 also acts as a pull-out load for the webbing 12 in the initial stage.

  The generation start timing of the extraction load by the torsion bar 38 is preferably during the generation of the extraction load by the wire 86. That is, it is preferable that the restricting portion 94b of the shaft member 94 and the ring member 96 come into contact with each other and the torsion bar 38 starts to be twisted before the wire 86 is completely drawn out from the drawing path 63p. This embodiment will be described on the assumption that it is set as described above. As a result, after the above-described initial stage has elapsed, the pull-out load caused by the torsional deformation of the torsion bar 38 and the pull-out load due to the pull-out resistance of the wire 86 are combined to generate the pull-out load of the webbing 12, and the impact energy is absorbed. The

  The timing adjustment is performed by adjusting the length of the wire 86 (for example, sufficiently increasing the length of the wire 86), the size of the gap between the restricting portion 94b of the shaft member 94 and the ring member 96 in the standby state, and their screws. This can be done by appropriately setting the pitch and the like.

  But the drawing load generation end timing by the wire 86 and the drawing load generation start timing by the torsion bar 38 may be simultaneous.

  FIG. 18 is a diagram showing an example of a drawing load generation characteristic. The upper graph shows the extraction load generation characteristics of the entire extraction load generation mechanism, the middle graph shows the extraction load generation characteristics of the wire-type extraction load generation mechanism 80, and the lower graph shows the torsion bar type. The drawing load generating characteristics by the drawing load generating mechanism 90 and the restraining mechanism 92 are shown. The horizontal axis of each graph shows the amount of webbing 12 drawn, and the vertical axis shows the drawing load.

  The wire-type pull-out load generation mechanism 80 generates a certain pull-out load F1 from a relatively early stage after the start of pulling out the webbing 12. The pull-out load F1 by the wire-type pull-out load generation mechanism 80 is continuously generated to some extent (see the middle graph in FIG. 18).

  In addition, at a relatively early stage after the webbing 12 starts to be pulled out, the pull-out load F2 is also generated by the relative movement of the shaft member 94 and the ring member 96 of the restraining mechanism 92 while being plastically deformed (the lower part of FIG. 18). See the graph).

  Therefore, at a relatively early stage after the webbing 12 is started to be pulled out, the pulling load (F1 + F2) obtained by adding the pulling load F2 by the restraining mechanism 92 to the pulling load F1 by the wire-type pulling load generating mechanism 80 is applied to the webbing 12. Works.

  When the webbing 12 is pulled out to some extent and the restricting portion 94b of the shaft member 94 and the ring member 96 come into contact with each other when the webbing pull-out amount L is reached, the pull-out load F2 by the restraining mechanism 92 is lost, instead. A pull-out load F3 due to torsion of the torsion bar 38 is generated.

  Therefore, at the stage where the webbing 12 is pulled out to a certain extent after the webbing 12 is started to be pulled out, a pulling load (F1 + F3) in which the pulling load F1 by the twist of the torsion bar 38 is added to the pulling load F1 by the wire type pulling load generating mechanism 80. Acts on the webbing 12.

  When the wire 86 is pulled out from the lead-out path 63p, a load for absorbing shock is generated only by the torsional deformation of the torsion bar 38.

  As described above, by delaying the torsional deformation of the torsion bar 38, the pull-out load can be set to be large stepwise so that the pull-out load is relatively small in the initial stage and the pull-out load is increased in the middle.

  The stage at which the torsional deformation of the torsion bar 38 is caused is determined experimentally and empirically so that the impact energy can be absorbed effectively.

  According to the seatbelt retractor 10 configured as described above, the restraining mechanism 92 is provided between the winding drum 30 and the other end portion 38b of the torsion bar 38, and the state before they are relatively rotated by a predetermined amount. Then, the relative rotation between the winding drum 30 and the torsion bar 38 is allowed, and after the relative rotation of the winding drum 30 and the torsion bar 38 by a predetermined amount, the winding drum 30 and the torsion bar 38 are restrained so as not to be relatively rotatable. For this reason, after the winding drum 30 and the torsion bar 38 rotate relative to each other by a predetermined amount, the torsion bar 38 is twisted and deformed. For this reason, it is possible to delay the start timing of the pull-out load generating operation of the webbing 12 due to the torsional deformation of the torsion bar 38, and to improve the degree of freedom of the pull-out load generating operation timing of the webbing 12.

  This point will be described in relation to Patent Document 1 as follows. That is, in the technique disclosed in Patent Document 1, one end portion of the torsion bar is connected to the bobbin so as not to be relatively rotatable, and the other end portion of the torsion bar is connected to the locking device so as not to be relatively rotatable. Simultaneously with the relative rotation of the bobbin with respect to the torsion bar, the impact energy is absorbed. For this reason, there exists a problem that the setting freedom of the timing of webbing extraction load generation operation by a torsion bar is low.

  On the other hand, in the seat belt retractor 10, as described above, the start timing of the pull-out load generating operation of the webbing 12 due to the torsional deformation of the torsion bar 38 is delayed, and the pull-out load generating operation timing of the webbing 12 is delayed. The degree of freedom can be improved.

  From this point of view, the restraining mechanism 92 is not necessarily configured to include the shaft member 94 and the ring member 96. For example, the other end of the torsion bar is formed in a non-circular cross-sectional shape such as a spline shape, and the recess at the back of the shaft hole of the take-up drum rotates the other end of the torsion bar only within a predetermined rotation range. The structure formed in the non-circular cross-sectional shape which accept | permits may be sufficient. In this case, the torsional deformation of the torsion bar can be delayed until the winding drum and the torsion bar rotate once relative. A similar structure may be applied to the coupling portion between the torsion bar and the ratchet gear.

  However, in the seatbelt retractor 10 according to the present embodiment, the restraining mechanism 92 is a movable part that can move along the rotation axis direction of the winding drum 30 in accordance with the relative rotation of the winding drum 30 and the torsion bar 38. And a restricting portion 94b for restricting movement of the ring member 96 by a predetermined amount or more. The restricting portion 94b restricts the relative rotation of the winding drum 30 and the torsion bar 38 beyond a predetermined amount by restricting the movement of the ring member 96.

  More specifically, the restraining mechanism 92 includes a shaft member 94 and a ring member 96 that can be externally fitted to the shaft member 94. The shaft member 94 is provided on the torsion bar 38 so as not to rotate relative to the shaft member 94. The winding drum 30 is provided so as not to be relatively rotatable, and the ring member 96 is movable as a movable portion along the direction of the rotation axis of the winding drum 30. Further, when the shaft member 94 and the ring member 96 are relatively rotated, the shaft member 94 and the ring member 96 are relatively movable along the rotation axis direction. When the relative rotation between the shaft member 94 and the ring member 96 exceeds a predetermined amount, the restricting portion 94b restricts the relative movement of the shaft member 94 and the ring member 96 along the rotation axis direction.

  For this reason, after the winding drum 30 and the torsion bar 38 rotate relative to each other one or more times, the torsion bar 38 and the winding drum 30 are restrained so as not to be relatively rotatable by the restraining mechanism 92, and the webbing 12 by the torsion bar 38 is restrained. A pull-out load can be generated, and the degree of freedom of the pull-out load timing of the webbing 12 can be further improved.

  This point will be described as follows in relation to Patent Documents 1 to 3. That is, in the technique disclosed in Patent Document 1, the start of energy absorption by the second energy absorption mechanism is delayed only within the range of play provided in the engagement state of at least one of the resistance member, the locking device, and the bobbin. Can only do. Further, in the technique disclosed in Patent Document 2, since the winding drum can be rotated relative to the locking base by providing an idle rotation region between the spline portion and the spline groove portion, The energy absorbing operation by the energy absorbing member 2 cannot be greatly delayed. In the technique disclosed in Patent Document 3, when the intermediate rotation member rotates a predetermined amount with respect to the other of the winding drum and the rotation restricting member, the rotation of the intermediate rotating member with respect to the other of the winding drum and the rotation restricting member is restricted. The energy absorbing operation of the second shock absorbing member cannot be greatly delayed. As described above, in Patent Documents 1 to 3, the timing of the webbing extraction load generation operation can only be delayed within the range in which the winding drum rotates once, and the degree of freedom of the timing of the webbing extraction load generation operation is low. There is a problem.

  Therefore, as described above, the restraining mechanism 92 includes a ring member 96 as a movable portion that is movable along the rotation axis direction of the winding drum 30 in accordance with the relative rotation of the winding drum 30 and the torsion bar 38; A restricting portion 94b for restricting movement of the ring member 96 by a predetermined amount or more, and the restricting portion 94b restricts the movement of the ring member 96, so that the relative rotation exceeding the predetermined amount of the winding drum 30 and the torsion bar 38 is achieved. By restricting the torsion bar 38 and the torsion bar 38 to be relatively unrotatable by the restraining mechanism 92 after the take-up drum 30 and the torsion bar 38 are relatively rotated once or more, The pull-out load of the webbing 12 by the bar 38 can be generated, and the degree of freedom in the timing of the pull-out load of the webbing 12 can be further improved.

  From this point of view, the target for which the generation of the pull-out load is delayed by the restraining mechanism 92 is not necessarily the torsion bar 38. The restraining mechanism is interposed between a relay member as various impact absorbing members such as an impact absorbing member using a wire and a take-up drum or a rotation restricting member, and delays the impact absorbing operation by the impact absorbing member by one rotation or more. Can be adopted as. In this case, the restraining mechanism as described above may be provided in any part of the part from the winding drum to the rotation restricting member via the relay member.

  Further, since the shaft member 94 of the restraining mechanism 92 includes a male screw portion 94c and the ring member 96 includes a female screw portion 96a into which the male screw portion 94c can be screwed, the shaft member is engaged with the male screw portion 94c and the female screw portion 96a. As a result of relative rotation of 94 and the ring member 96, they can be moved more reliably in the direction of the rotation axis.

  In the above embodiment, the shaft member 94 formed separately from the torsion bar 38 is attached to the torsion bar 38. For this reason, the torsion bar 38 and the shaft member 94 can be formed of materials suitable for the respective purposes. For example, the shaft member 94 is formed of a relatively hard material so as to be suitable for the function of suppressing the relative rotation between the winding drum 30 and the torsion bar 38 as the restraining mechanism 92, and the torsion bar 38 has an appropriate torsional deformation. Can be made of a relatively soft material.

  Further, since the shaft member 94 and the ring member 96 are relatively rotated, at least one of them is plastically deformed, and the shaft member 94 and the ring member 96 are relatively moved along the rotation axis direction. The pull-out load of the webbing 12 can also be generated by relative rotation between the ring 94 and the ring member 96.

  The seat belt retractor 10 connects the take-up drum 30 and the torsion bar 38 so that they cannot rotate relative to each other in a standby state, and when the force in the pull-out direction of the webbing 12 due to impact is applied to the take-up drum 30, Since a wire-type pull-out load generating mechanism 80 as an impact absorbing member that allows relative rotation between the winding drum 30 and the ratchet gear 61 while generating a load is provided, a wider variety of webbing pull-out loads can be generated. Can do.

  Note that the wire-type pull-out load generating mechanism 80 is not always necessary. Even in this case, for example, at a relatively early stage after the webbing 12 starts to be pulled out, a pulling load is generated by the relative movement of the shaft member 94 and the ring member 96 of the restraining mechanism 92 while being plastically deformed. After a certain period of time has elapsed from the start of drawing out the webbing 12, it is possible to generate a drawing load characteristic in which the drawing load increases stepwise by generating a drawing load due to torsional deformation of the torsion bar 38.

  Further, since the generation of the pull-out load of the webbing 12 by the torsion bar 38 is set while the pull-out load of the webbing 12 by the wire-type pull-out load generation mechanism 80 is generated, the pull-out by the wire-type pull-out load generation mechanism 80 is started. The pull-out load of the webbing 12 can be increased stepwise by applying a pull-out load by the torsion bar 38 to the load.

  Further, since the wire-type pull-out load generating mechanism 80 includes the wire 86 that is pulled out while being deformed by the relative rotation between the winding drum 30 and the ratchet gear 61, the pull-out load of the webbing 12 is generated by the deformation of the wire 86. be able to. In particular, by setting the wire 86 to be long, a stable extraction load can be generated over a relatively long period.

{Modifications}
Based on the above embodiment, various modifications will be described.

  First, in the said embodiment, the shaft member 94 and the torsion bar 38 were demonstrated in the example formed separately.

  However, as in the first modification shown in FIG. 19, the shaft member portion 194 corresponding to the shaft member 94 and the torsion bar portion 138 corresponding to the torsion bar 38 appropriately press and cut the rod-shaped member. May be integrally formed. Thereby, the shaft member portion 194 and the torsion bar portion 138 can be easily manufactured.

  Of course, when the positional relationship between the shaft member and the ring member is reversed, the ring member may be integrally formed with the torsion bar.

  In the above-described embodiment, an example in which the male thread portion 94c is formed on the shaft member 94 and the female thread portion 96a is formed on the ring member 96 has been described. However, such a configuration is not necessarily required.

  For example, instead of forming the female thread portion 96a in the ring member 296 corresponding to the ring member 96 as in the second modification shown in FIGS. 20 and 21, the male thread portion 94c is formed on a part of the inner periphery thereof. You may form the protrusion 296c which can move along the extension direction of the groove in a screw groove. In this case, when the ring member 296 and the shaft member 94 rotate relative to each other, the protrusion 296c moves along the thread groove of the male thread portion 94c. As a result, the ring member 296 and the shaft member 94 relatively move along the axial direction, the ring member 296 contacts the restricting portion 94b, and the relative movement in the axial direction between the ring member 296 and the shaft member 94 is restricted. Is done. Thereby, the relative rotation of the ring member 296 and the shaft member 94 becomes impossible, and the winding drum 30 and the torsion bar 38 are restrained so as not to be able to rotate relative to each other. Then, the torsional deformation of the torsion bar 38 starts.

  That is, according to the relative rotation between the winding drum 30 and the torsion bar 38, as a configuration for moving some movable part along the rotation axis direction, a spiral protrusion or a concave groove is formed on one member. A guide portion capable of fitting the protrusion into the other member or a guide protrusion capable of fitting into the concave groove is formed, and the guide portion or the guide protrusion is helically formed by relative rotation between the one member and the other member. By moving, the structure which moves one member and the other member along a rotating shaft direction is employable.

  In the above embodiment, the example in which the restraining mechanism 92 is interposed between the torsion bar 38 and the take-up drum 30 has been described. For example, as in the third modification shown in FIG. 22, the restraining mechanism 92 may be interposed between the torsion bar 338 corresponding to the torsion bar 38 and the ratchet gear 361 corresponding to the ratchet gear 61.

  That is, in this modification, one end (the left end in FIG. 22) of the torsion bar 338 is connected to the inner part of the shaft member 94 of the winding drum 30 so as not to be relatively rotatable. Further, a restraining mechanism 92 is provided at the other end of the torsion bar 338 (the right end in FIG. 22). Here, the constraining mechanism 92 has the same configuration as that described in the above embodiment.

  The shaft member 94 of the restraining mechanism 92 is connected to the other end of the torsion bar 338 so as not to be relatively rotatable. Further, the inner peripheral portion of the cylindrical portion 362 at the central portion of the ratchet gear 361 on the winding drum 30 side is formed in a concave shape in which the ring member 296 cannot be relatively rotated and can be moved along the rotation axis direction. Yes. A ring member 96 is fitted into the cylindrical portion 362 so as not to be relatively rotatable and movable along the rotation axis direction.

  According to the third modification, when the winding drum 30 and the ratchet gear 361 rotate relative to each other, the shaft member 94 and the ring member 96 relatively rotate as in the above embodiment, and the shaft member 94 and the ring member 96 Moves along the direction of the rotation axis. Then, when the ring member 96 comes into contact with the restricting portion 94b of the ring member 96, the relative rotation between the shaft member 94 and the ring member 96 is restricted, and the torsional deformation of the torsion bar 38 starts.

  Also in this modification, the positions of the shaft member 94 and the ring member 96 may be interchanged.

  Moreover, in the said embodiment and 3rd modification, the ring member 96 which is a member provided in the winding drum 30 or the ratchet gear 361 side among the shaft member 94 and the ring member 96 of the restraint mechanism 92 is followed along a rotating shaft direction. However, such a configuration is not necessarily required.

  For example, in the fourth modification shown in FIGS. 23 to 25, one end portion of the torsion bar 438 corresponding to the torsion bar 38 is relatively unrotatable in the inner portion of the shaft hole portion 36 of the winding drum 30 and in the direction of the rotation axis. It is connected so that movement is possible along. A shaft member 494 corresponding to the shaft member 94 is integrally formed at the other end of the torsion bar 438. The shaft member 494 is formed with a male screw portion 494c. Note that the torsion bar 438 and the shaft member 494 may be formed separately and joined later.

  In addition, a ring member 496 corresponding to the ring member 96 is integrally formed in the central portion of the ratchet gear 461 corresponding to the ratchet gear 61 on the winding drum 30 side instead of the cylindrical portion 62. A female screw portion 496a capable of screwing the male screw portion 494c is formed on the inner peripheral portion of the ring member 496.

  In this modification, a gap is provided between one end of the torsion bar 438 and the bottom surface of the shaft hole 36 of the winding drum 30 in the standby state. When the shaft member 494 and the ring member 496 rotate relative to each other by the relative rotation of the torsion bar 438 on the winding drum 30 side and the ring member 496 on the ratchet gear 461 side, the shaft member 494 and the shaft member 494 are integrally formed. The torsion bar 438 thus moved moves in the direction away from the ring member 496 along the rotation axis direction. When one end of the torsion bar 438 comes into contact with the bottom surface of the shaft hole 36 of the winding drum 30, further movement of the shaft member 494 and the torsion bar 438 is restricted. That is, in the present modification, the bottom surface of the shaft hole portion 36 of the torsion bar 438 functions as a restricting portion 494b that restricts the movement of the shaft member 494 and the torsion bar 438 in the rotation axis direction. Therefore, the member that regulates the movement of the shaft member or the ring member does not need to directly abut against the shaft member or the ring member to regulate the movement thereof. The structure which controls the movement of a member may be sufficient.

  When the movement of the shaft member 494 and the torsion bar 438 is restricted, the relative rotation between the shaft member 494 and the ring member 496 is restricted. As a result, one end of the torsion bar 438 is connected to the take-up drum 30 in a relatively non-rotatable manner, and the other end of the torsion bar 438 is connected to the ratchet gear 461 through the restraint mechanism 492 in a relatively non-rotatable state. The torsion bar 438 is torsionally deformed by the relative rotation of the winding drum 30 with respect to the ratchet gear 461. As a result, similarly to the above-described embodiment, the pull-out load of the webbing 12 can be generated at a timing delayed from the start of relative rotation of the winding drum 30 with respect to the ratchet gear 461.

  Of course, also in this modification, the shaft member 494 and the ring member 496 may be provided in an opposite positional relationship. Further, even when the restraining mechanism is provided between the torsion bar and the take-up drum, as in the present modification, the shaft member and the ring member are moved away from each other by relative rotation, The torsion bars may be brought into contact with the ratchet gear side to restrict their relative rotation.

  Further, when the shaft member 494 and the ring member 496 rotate relative to each other, the shaft member 494 and the torsion bar 438 formed integrally with the shaft member 494 move in a direction close to the ring member 496 along the rotation axis direction. May be. In this case, when the shaft member 494 comes into contact with the ratchet gear 461 provided with the ring member 496, further movement of the shaft member 494 and the torsion bar 438 is restricted, and the relative rotation between the torsion bar 438 and the ratchet gear 461 is performed. Is regulated.

  In addition, each structure demonstrated in the said embodiment and each modification can be suitably combined unless it mutually contradicts.

  As described above, the present invention has been described in detail. However, the above description is illustrative in all aspects, and the present invention is not limited thereto. It is understood that countless variations that are not illustrated can be envisaged without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 10 Seat belt retractor 12 Webbing 20 Housing 30 Winding drum 36 Shaft hole part 36a Insertion recessed part 38, 338, 438 Torsion bar 38a One end part of torsion bar 38b Other end part of torsion bar 38bh Fitting hole 61,361,461 Ratchet gear 62, 362 Tube portion 62a Fitting hole 63p Pull-out path 80 Wire-type pull-out load generation mechanism 86 Wire 90 Torsion bar-type pull-out load generation mechanism 92, 492 Restraint mechanism 94, 494 Shaft member 94b, 494b Restriction section 94c, 494c Male thread Portions 96, 296 Ring member 96a Female thread portion 138 Torsion bar portion 194 Shaft member portion

Claims (11)

A winding drum wound with webbing;
A rotation restricting member that can be switched between a state that is rotatable on the same axis as the rotation axis of the winding drum and a state in which rotation in the pull-out direction to the webbing is restricted;
One end side is attached to one of the winding drum and the rotation regulating member so as not to be relatively rotatable, and a relay member used as a torsion bar for generating a webbing pull-out load by torsional deformation;
Provided between the other of the winding drum and the rotation restricting member and the other end of the relay member, and before the other of the winding drum and the rotation restricting member and the relay member are relatively rotated by a predetermined amount. In the state, the other of the winding drum and the rotation restricting member and the relay member are allowed to rotate relative to each other, and the other of the winding drum and the rotation restricting member and the relay member are relatively rotated by a predetermined amount. A restraint mechanism for restraining the other of the winding drum and the rotation restricting member and the relay member from being relatively unrotatable;
A seat belt retractor comprising: The retractor for a seat belt according to claim 1,
The restraining mechanism includes a movable part movable along the rotation axis direction of the take-up drum according to relative rotation between the other of the take-up drum and the rotation restricting member and the relay member, and a position of the movable part. A restricting part that restricts movement beyond a fixed amount, and the restricting part restricts movement of the movable part, so that the other of the winding drum and the rotation restricting member and the relay member exceed a predetermined amount. Seatbelt retractor that regulates rotation. A winding drum wound with webbing;
A rotation restricting member that can be switched between a state that is rotatable on the same axis as the rotation axis of the winding drum and a state in which rotation in the pull-out direction to the webbing is restricted;
A relay member as an impact absorbing member, one end of which is attached to one of the winding drum and the rotation restricting member so as not to be relatively rotatable;
The winding drum is provided between the other of the winding drum and the rotation restricting member and the other end of the relay member, and the winding according to relative rotation between the other of the winding drum and the rotation restricting member and the relay member. A movable part movable along the rotation axis direction of the take-up drum, and a restriction part for restricting movement of the movable part by a predetermined amount or more, and the restriction part restricts movement of the movable part, A restraining mechanism that restricts relative rotation exceeding a predetermined amount between the winding drum and the other of the rotation regulating member and the relay member;
With
Relative rotation between the relay member and the other of the winding drum and the rotation restricting member is caused by the restraining mechanism at any part of the portion from the winding drum to the rotation restricting member via the relay member. A seat belt retractor incorporating an impact absorbing mechanism that generates a webbing pull-out load by the relay member when regulated. A retractor for a seat belt according to claim 2 or claim 3,
The restraint mechanism includes a shaft member and a ring member configured to be externally fitted to the shaft member,
One of the shaft member and the ring member is provided on the relay member so as not to rotate relative to the relay member, and the other of the shaft member and the ring member is either the winding drum or the rotation regulating member. Provided so that it cannot rotate relative to the
At least one of the shaft member and the ring member is movable as the movable part along the rotation axis direction of the winding drum,
The shaft member and the ring member are relatively rotated so that the shaft member and the ring member are configured to be relatively movable along the rotation axis direction of the winding drum,
When the relative rotation between the shaft member and the ring member exceeds a predetermined amount, the restricting portion restricts relative movement of the shaft member and the ring member along the rotation axis direction of the winding drum. A retractor for a seat belt provided. The retractor for a seat belt according to claim 4,
The seat member includes a male screw portion, and the ring member includes a female screw portion capable of screwing the male screw portion. The retractor for a seat belt according to claim 4 or 5,
A retractor for a seat belt, wherein either one of the shaft member and the ring member is integrally formed with the relay member. It is a retractor for seatbelts as described in any one of Claims 4-6,
A retractor for a seat belt, wherein either one of the shaft member and the ring member is formed separately from the relay member and attached to the relay member. A retractor for a seat belt according to any one of claims 4 to 7,
When the shaft member and the ring member rotate relative to each other, at least one of the shaft member and the ring member is plastically deformed, and the shaft member and the ring member are moved in the direction of the rotation axis of the winding drum. A seat belt retractor that moves relative to each other. It is a retractor for seatbelts as described in any one of Claims 1-8,
In the standby state, the winding drum and the rotation restricting member are connected so as not to be relatively rotatable. When a force in the pulling-out direction of the webbing is applied to the winding drum, a webbing pull-out load is generated. The seatbelt retractor further comprising an impact absorbing member that allows relative rotation between the winding drum and the rotation restricting member. The seatbelt retractor according to claim 9,
A seatbelt retractor configured to start generation of a webbing pull-out load by the relay member while a webbing pull-out load is generated by the impact absorbing member. The retractor for a seat belt according to claim 9 or 10,
The impact absorbing member is a seat belt retractor including a wire that is drawn while being deformed by relative rotation between the winding drum and the rotation restricting member.

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