JP2019218012A - Seat belt retractor - Google Patents

Abstract

To provide a seat belt retractor with a pretensioner, which secures torsional amount of a torsion bar during an EA operation.SOLUTION: A spool 20 is rotated while twisting a torsion bar 70 even after slack of a webbing is removed according to the operation of a pretensioner 60, and the webbing is drawn. With this drawing, a second pawl 110 is projected and is engaged with a sawtooth 17a, a carrier 90 is stopped, and a sun gear 82 is rotated and thrust-moved through a planet gear 101. A pawl wall 28 is moved through a push rod 28, a stopper pawl 25 is engaged with a sawtooth 15a, and the spool 20 is stopped.SELECTED DRAWING: Figure 17

Description

  The present invention relates to a seatbelt retractor with a pretensioner used for a vehicle such as an automobile, and more particularly to a seatbelt retractor in which a torsion bar is incorporated in a spool.

  As a seat belt retractor with a pretensioner, a seat in which a torsion bar is inserted into an inner hole of a spool, one end of the torsion bar can be fixed to the spool, and the other end of the torsion bar can be locked to a frame of the seat belt retractor. Belt retractors are known (Patent Documents 1 and 2). In an emergency such as a vehicle collision, the spool is driven to rotate by the pretensioner to wind up the webbing. Thereafter, when a force in the webbing unwinding direction is applied to the spool, the torsion bar is twisted, the spool is gradually rotated, and the webbing is gradually pulled out. Thereby, a part of the kinetic energy applied to the occupant's body is absorbed by the torsion bar torsion, and the impact is reduced.

  Patent Literature 1 describes that the amount of torsion of a torsion bar is limited by movement of a stopper screwed to the torsion bar.

JP-A-11-222100 JP 2017-154525 A

  In the seatbelt retractor with a pretensioner disclosed in Patent Document 1, the torsion bar is twisted when the pretensioner is operated, and the position of the stopper is shifted, so that the amount of twist of the torsion bar may be restricted.

  An object of the present invention is to provide a seat belt retractor with a pretensioner that ensures a torsion amount of a torsion bar during EA operation.

A seat belt retractor of the present invention includes a frame supporting a spool and a locking base,
Winding the webbing, the cylindrical spool having a first inner hole,
The locking base, which is disposed coaxially adjacent to the spool on one side in the axial direction of the spool, has a second inner hole, is connected to the spool by a torsion bar, and has an external thread on an outer peripheral surface. When,
A first inner hole of the spool and a second inner hole of the locking base, the base end of the locking base being non-rotatably connected to the spool, and the distal end of the locking base being non-rotatably connected to the locking base; The torsion bar that is torsionally deformed when a tensile force of a predetermined value or more is applied to the webbing in a locked state,
A pretensioner for rotating the locking base in a webbing winding direction,
A gear in which a female screw on the inner peripheral surface is screwed to the male screw of the locking base,
When the locking base is rotated by the pretensioner drive and the spool stops rotating, the gear rotates integrally with the locking base, the spool rotates by the EA operation, and the locking base stops rotating. When the gear is a seat belt retractor, wherein the gear is screwed along the locking base,
The seat belt retractor further comprises:
A stopper pawl provided on the other end side in the axial direction of the spool and engaged with saw teeth provided on the frame to prevent rotation of the spool in the webbing pull-out direction,
Holding means for holding the stopper pawl in a disengaged position with the saw tooth;
And holding release means for releasing the holding by the holding means and engaging the stopper pawl with the saw teeth when the gear is screwed a predetermined distance.

  In one aspect of the present invention, the holding means includes a pawl wall mounted on the spool so as to be axially movable, a peripheral wall portion provided on the pawl wall and holding the stopper pawl, A push rod held so as to be movable in a direction parallel to the axis of the spool. When the gear is screwed, the gear moves the pawl wall via the push rod, and the peripheral wall The holding of the stopper pawl by the portion is released.

  In one aspect of the present invention, the stopper pawl has a base end rotatably supported with respect to the spool, and a spring for urging the distal end of the stopper pawl toward an engagement position with the saw tooth. Is provided.

  In one aspect of the present invention, the push rod is inserted into a rod insertion hole provided in the spool, and one end of the push rod protrudes from the one end surface of the spool.

In one aspect of the invention, the gear is a sun gear,
The locking base includes a flange portion, a cylindrical shaft portion having the inner hole protruding from a central portion of the flange portion, and a male member provided on an outer peripheral surface of the shaft portion on a tip end side in a protruding direction. A screw, and a receiving portion provided on the shaft portion for receiving a force from the pretensioner,
A female screw on the inner peripheral surface of the sun gear is screwed to the male screw,
The spool has an internal gear,
A planet gear is arranged between the internal gear and the sun gear,
When the spool rotates and the locking base stops rotating, the planetary gear is stopped from revolving and the rotational force of the internal gear is transmitted to the sun gear.

In one aspect of the present invention, the frame includes a front wall, a left side wall extending forward from a left side of the front wall, a first right side wall extending forward from a right side of the front wall, A second right side wall extending forward from the front wall on the left side of the first right side wall,
An opening is provided in the first right side wall and the second right side wall, and a second saw tooth is provided on an inner periphery of the opening of the second right side wall,
As the revolving stop means, a carrier for engaging the second saw tooth and stopping the revolving of the planet gear is provided.

  In one aspect of the present invention, the spool has a tubular portion around which webbing is wound, the first inner hole provided from one end of the tubular portion, and a flange that expands from the one end of the tubular portion. An annular wall projecting from the outer peripheral edge of the flange toward the locking base and surrounding the flange is provided, and the internal gear is provided on an inner peripheral surface of the annular wall.

  In one aspect of the present invention, the tip of the shaft portion of the locking base is in contact with the one end of the spool.

In one aspect of the present invention, the carrier is in the shape of an annular disk that goes around the shaft portion,
The planet gear is rotatably attached to the carrier,
A second pawl is provided on the outer periphery of the carrier, the second pawl engaging with the second saw tooth of the second right side wall to prevent the carrier from rotating in the webbing pull-out direction.

  In one aspect of the present invention, the engagement between the second pawl and the second saw tooth allows the carrier to rotate in the webbing winding direction.

  In one aspect of the present invention, the second pawl has a base end rotatably supported by the carrier and biases the distal end of the second pawl in a direction protruding from the outer peripheral surface of the carrier. A spring is provided.

  In one aspect of the present invention, a convex wall for pressing the second pawl is provided protruding from the annular wall of the spool, and the second pawl is moved by moving the convex wall from the second pawl pressing position. Project from the outer peripheral surface of the carrier.

  In one aspect of the present invention, a projection protruding toward the annular portion is provided on a tip side of the second pawl, and the projection wall is arranged to press the projection.

In one aspect of the present invention, a non-circular portion is provided on a base end side of the shaft portion of the locking base, and a paddle wheel is provided on the non-circular portion as the receiving portion,
When the power transmission member from the pretensioner moves along the outer peripheral surface of the paddle wheel, the locking base, torsion bar, and spool rotate in the webbing winding direction.

  In one aspect of the present invention, the sun gear is located at a base end side of the shaft portion among the external threads on the outer peripheral surface of the shaft portion before the vehicle collision, and the spool is moved by the EA operation. When the locking base is rotated and the rotation of the locking base is stopped, the torsion bar is screwed toward the distal end side of the shaft portion by the torsion of the torsion bar.

In one aspect of the present invention, a plurality of the planet gears are provided at equally spaced positions in the circumferential direction of the carrier,
An annular link plate is arranged on the opposite side of the carrier with the planet gear therebetween,
A pin for rotatably attaching the planet gear to the carrier is fitted in a pin insertion hole of the link plate.

In one aspect of the present invention, a first saw tooth is provided on an inner periphery of an opening of the first right side wall of the frame,
A first pawl that engages the first saw tooth when an acceleration equal to or greater than a predetermined value is detected is provided.

  In one aspect of the present invention, the engagement between the first pawl and the first saw tooth prevents rotation of the locking base in a webbing pull-out direction, and allows rotation of the locking base in a webbing winding direction.

  In the seat belt retractor of the present invention, in a state before an emergency such as a vehicle collision or the like (hereinafter, referred to as a vehicle collision), the spool, the torsion bar, and the locking base rotate integrally, so that the webbing can be pulled out and taken up. Done.

  At the time of a vehicle collision, the pretensioner operates, and the locking base, the torsion bar, and the spool rotate in the webbing winding direction, and the slack of the webbing is eliminated. Even after the slack of the webbing has been eliminated, the pretensioner further applies a force in the winding direction to the torsion bar, so that the torsion bar slightly twists in the winding direction, but at this time, the gear rotates together with the locking base, The gear does not advance.

  Thereafter, when the force in the pull-out direction applied from the occupant body to the webbing becomes greater than the force in the winding direction applied from the pretensioner, the locking base is kept in a rotation stopped state by the pressure holding action of the pretensioner, and the spool releases the torsion bar. It rotates while twisting, the webbing is pulled out, and the occupant performs EA (energy absorption).

  Further, the gear is screwed with the rotation of the spool at this time, the gear is screwed to a predetermined position, and the stopper is engaged with the saw tooth of the frame, whereby the spool is stopped.

  In one embodiment of the present invention, when the gear screw advances, the pawl wall is pushed and moved via the push rod, the holding by the pawl wall is released, and the stopper pawl engages with the saw tooth.

  In one embodiment of the present invention, the second pawl projecting from the carrier engages with the second saw tooth on the second right side wall as the spool starts rotating in the pull-out direction. Thus, the rotational force of the spool is transmitted to the sun gear via the planet gear, and the sun gear advances. When the sun gear advances, the push rod is pushed by the sun gear and moves. The pawl wall is pushed and moved via the push rod, the holding by the pawl wall is released, and the stopper pawl is engaged with the saw tooth.

It is an exploded perspective view from the front side of the seat belt retractor according to the embodiment. FIG. 2 is an exploded perspective view of the seatbelt retractor according to the embodiment, as viewed from the back. FIG. 2 is a front view of the seat belt retractor according to the embodiment. FIG. 2 is a left side view of the seat belt retractor according to the embodiment. FIG. 2 is a right side view of the seat belt retractor according to the embodiment. FIG. 6 is a sectional view taken along line VI-VI of FIG. 4. FIG. 7 is a sectional view taken along line VII-VII of FIG. 6. FIG. 7 is a sectional view taken along line VIII-VIII in FIG. 6. FIG. 9 is an enlarged view of a portion IX in FIG. 8. It is XX sectional drawing of FIG. FIG. 7 is a cross-sectional view of the seat belt retractor according to the embodiment at the time when the pretensioner operation is completed. FIG. 12 is a sectional view taken along line XII-XII of FIG. 11. It is sectional drawing of the spool axial line direction of a 3rd pawl. It is sectional drawing at the time of the pawl engagement of FIG. It is a front view of a spool. FIG. 16 is a sectional view taken along line XVI-XVI of FIG. 15. It is sectional drawing of the axial center line direction of a spool. It is the disassembled perspective view seen from the left side of the spool. It is the exploded perspective view seen from the right side of the spool. FIG. 4 is an explanatory diagram illustrating a temporal operation of the seat belt retractor.

  Hereinafter, embodiments will be described with reference to the drawings.

  The seat belt retractor 1 includes a frame 10, a spool 20 rotatably held by the frame 10, a return spring unit (spring spring unit) 30 for urging the spool 20 in a webbing winding direction, and a coaxial shape with the spool 20. And a locking base 40 connected to the spool 20 by a torsion bar 70, a lock activation unit 50 for activating the lock of the spool 20, a pretensioner 60, and a connection between the spool 20 and the locking base 40. The torsion bar 70 and the like inserted into the spool 20 and the locking base 40 are provided.

  The frame 10 includes a front wall 11, a left side wall 12 extending forward from a left side of the front wall 11, a first right side wall 13 extending forward from a right side, and a predetermined distance greater than the first right side wall 13. It has a second right side wall 14 extending forward on the left side by a distance, and spool insertion holes 15, 16, 17 and the like provided in each of the side walls 12 to 14, respectively. Saw teeth 15a, 16a, and 17a are provided on the inner peripheral surfaces of the spool insertion holes 15, 16, and 17, respectively. The saw tooth 16a is a first saw tooth, and the saw tooth 17a is a second saw tooth.

  The return spring unit 30 contains a mainspring 32 in a case 31, and one end of the mainspring 32 is connected to a projecting shaft 20 t on the left end side of the spool 20. The return spring unit 30 is attached to the frame left side wall 12 via a spacer 33.

  The lock activation unit 50 has a lock assembly 52 in which a pendulum 51 (FIG. 2) held on the first right side wall 13 of the frame is engaged with the outer peripheral surface. When the rotation angular acceleration of the lock assembly 52 becomes equal to or greater than a predetermined value or when the pendulum 51 engages with the outer peripheral surface of the lock assembly 52, the lock assembly 52 projects the first pawl 43 from the outer peripheral surface of the locking base 40 to form a saw tooth. 16a.

  The lock assembly 52 and the pendulum 51 are covered by a cover 55.

  The lock activation unit 50 has a known structure.

  The pretensioner 60 is for winding the spool 20 with a large torque in the webbing winding direction at the time of a vehicle collision to remove the slack of the webbing. The pretensioner 60 includes a gas generator 61 that generates gas at the time of a vehicle collision, a duct 62, and a power transmission member made of a synthetic resin or the like loaded in the duct 62. The power transmission member is sent to the outer periphery of a paddle wheel 80 described later in the circumferential direction by the gas pressure from the gas generator 61, and the spool 20 rotates in the webbing winding direction. This configuration can be, for example, the one described in Patent Document 2.

  Next, the structures of the spool 20 and the locking base 40 will be described in detail.

  As clearly shown in FIGS. 15 to 19, the spool 20 has a tubular portion 21 around which the webbing is wound, a left flange 22 on the left end side of the tubular portion 21, and a right flange 23 on the right end side.

  An annular wall 24 protrudes from the outer peripheral edge of the right flange 23 to the right, that is, in the direction opposite to the cylindrical portion 21. On the inner peripheral surface of the annular wall 24, a rack (internal gear) 24a is provided over the entire circumference. The annular wall 24 is provided with a convex wall 24b protruding rightward, that is, in a direction opposite to the cylindrical portion 21, from two locations facing each other in the diameter direction. The convex wall 24b extends a predetermined length in the circumferential direction of the annular wall 24.

  A pin 22 a for holding a third pawl (stopper pawl) 25 is protruded from an outer surface of the left flange 22 of the spool 20. As shown in FIGS. 13 and 14, the third pawl 25 has a small hole 25a on the base end side fitted into the pin 22a. The distal end side of the third pawl 25 is urged by a spring 26 in a direction protruding from the outer periphery of the left flange 22.

  A pawl wall 27 is attached to the left flange 22 via a C-shaped ring-shaped bearing ring 27A. The pawl wall 27 has a fan shape, and a small hole 27a into which the protruding shaft 20t of the spool 20 is inserted is provided in a main part of the fan. On the outer peripheral edge of the panel wall 27, a peripheral wall portion 27b for holding the pawl 25 (see FIG. 13) is provided. A notch 27c is provided in the peripheral wall 27b.

  In this embodiment, the cylindrical portion 21 of the spool 20 is provided with a rod insertion hole 28a penetrating in a direction parallel to the axis, and the push rod 28 is inserted into the rod insertion hole 28a. The length of the push rod 28 is slightly larger than the distance from the left end face of the spool left flange 22 to the right end face of the right flange 23.

  As shown in FIG. 17 and the like, a first inner hole 29 is provided in the cylindrical portion 21 of the spool 20 from the right end side, that is, from the annular wall 24 side to the left end side. A serration portion 29a is provided at the innermost portion, that is, the left end side of the inner hole 29, and a gear-shaped portion 71 of a torsion bar 70 is engaged with the serration portion 29a.

  A locking base 40 is disposed adjacent to the right side of the spool 20 so as to be coaxial with the cylindrical portion 21. The locking base 40 has a flange portion 41, a cylindrical shaft portion 42 connected to a central portion of the flange portion 41, a first pawl 43 provided on the flange portion 41, and the like.

  A serration 42a is provided on the inner peripheral surface on the tip side of the inner hole (second inner hole) of the shaft portion 42, and the gear-shaped portion 72 on the right end of the torsion bar 70 is engaged with the serration portion 42a.

  A hexagonal portion 42b as a non-circular portion is provided on the outer periphery of the base portion (the flange 41 side) of the shaft portion 42 of the locking base 40, and a male screw 42c is provided on the outer peripheral surface on the distal end side. The outer peripheral surface between the male screw 42c and the hexagonal portion 42b is a smooth surface.

  The hexagonal inner hole 80a of the paddle wheel 80 is engaged with the hexagonal portion 42b, and the paddle wheel 80 is mounted on the shaft portion 42 so as not to rotate in the circumferential direction.

  When a power transmission member made of a synthetic resin or the like is supplied from the duct 62 of the pretensioner 60 to the outer peripheral position of the paddle wheel 80, the paddle wheel 80 rotates, and the locking base 40 rotates.

  A female screw 82a on the inner peripheral surface of the center hole of the sun gear 82 is screwed to the male screw 42c. The sun gear 82 is capable of screwing along the male screw 42c.

  The sun gear 82 is arranged in a circular inner hole 91 of the carrier 90 that holds the planet gear 101 and the second pawl 110. The carrier 90 has an annular plate shape, and the inner hole 91 is provided at the center thereof. The carrier 90 is provided with three pin holes 92 at three equally circumferential positions. A planet gear 101 is held in each pin hole 92 via a pin 102. As shown in FIG. 16, the planet gear 101 is engaged with the sun gear 82 and the internal gear 24a.

  At two places on the outer peripheral edge of the carrier 90, there are provided pawl housing portions 93 each formed of a concave portion, and a second pawl 110 is disposed in each of the pawl housing portions 93. The pawl accommodating portion 93 is provided with a small hole 94 into which the pin-shaped shaft portion 111 (FIG. 18) on the base end side of the second pawl 110 is inserted.

  A projection 95 (FIG. 19) is provided near the pawl housing 93, and one end of a loop spring 112 attached to the pawl 110 is locked to the projection 95. The other end of the loop spring 112 is locked on the tip side of the pawl 110. The loop spring 112 is wound around a pin-like projection 113 (FIGS. 9 and 19) of the pawl 110.

  The pawl 110 is urged by a loop spring 113 in a direction in which the tip side protrudes from the outer periphery of the carrier 90.

  Projections 115 (FIGS. 10, 17 to 19) project from the front end of the pawl 110 toward the flange 23.

  The convex wall 24b protruding from the annular wall 24 of the spool 20 is disposed on the outer peripheral side of the projection 115 as shown in FIGS.

  A link plate 120 is arranged between the carrier 90 and the flange 23. The link plate 120 is a ring-shaped plate having an inner hole 121 having a larger diameter than the sun gear 82. The link plate 120 is provided with pin insertion holes 122 at three equally spaced positions in the circumferential direction. The pins 102 fitted in the respective pin insertion holes 122 are inserted through the planet gear 101, inserted into the pin holes 92 of the carrier 90 and fixed. The planet gear 101 is rotatable with respect to the pin 102.

  In the above seat belt retractor, the sun gear 82 is normally screwed to the most proximal side (right side) of the male screw 42c of the locking base 40. Normally, the pawls 25, 43, 110 are not engaged with the saw teeth 15a, 16a, 17a, and the locking base 40, the torsion bar 70, and the spool 20 can rotate integrally. Therefore, the webbing is pulled out and wound up according to the position of the occupant.

  As described above, in the state before the vehicle collision, the sun gear 82 is located on the rightmost side of the male screw 42c. In this state, the second pawl 110 of the carrier 90 is pressed by the convex wall 24b of the spool 20, as shown in FIGS. 8 to 10, and the spool 20, the torsion bar 70, and the locking base 40 rotate integrally. I do. In this state, since the second pawl 110 is not engaged with the saw tooth 17a and the carrier 90 is free from the second side wall portion 14, the carrier 90 rotates following the revolution of the planet gear 101. I do. Therefore, no rotational force is applied to the sun gear 82 from the planet gear 101, and the sun gear 82 is stopped at the rightmost position shown in FIG.

  At the time of a vehicle collision, the spool 20 rotates in the webbing pull-out direction. Further, the pendulum 51 is engaged with the outer peripheral surface of the lock assembly 52, and the lock activation unit 50 causes the first pawl 43 to protrude from the outer peripheral surface of the locking base 40. The protruding first pawl 43 is engaged with the first saw tooth 16 a of the first right side wall 13.

  Further, at the time of a vehicle collision, the gas generator 61 of the pretensioner 60 is operated, and a strong torque in the webbing winding direction is applied to the locking base 40 via the paddle wheel 80, so that the locking base 40, the torsion bar 70 and the spool 20 are rotated. Rotate together in the webbing winding direction. Thereby, the webbing is wound around the spool 20, and the slack of the webbing is removed.

  In this state, the locking base 40 rotates in the webbing winding direction without being restricted by the sawtooth 16a. Further, since the spool 20 and the locking base 40 rotate integrally at the same speed, the second pawl 110 is kept pressed by the convex wall 24 b of the annular wall 24.

  Accordingly, in this state, the second pawl 110 is not engaged with the saw tooth 17a, and the carrier 90 is free from the second side wall portion 14. Therefore, the carrier 90 rotates following the revolution of the planet gear 101. I do. Therefore, no rotational force is applied to the sun gear 82 from the planet gear 101, and the sun gear 82 is stopped at the rightmost position shown in FIG.

  When the winding of the webbing advances and the slack of the webbing is removed, the winding of the webbing by the spool 20 stops. As described above, even after the slack of the webbing is removed, a force is applied to the torsion bar 70 from the pretensioner 60 in the webbing winding direction, whereby the torsion bar 70 is twisted. The position of the convex wall 24b of the spool 20 is shifted in the circumferential direction from above the projection 115 of the second pawl 110. As a result, the second pawl 110 protrudes from the outer peripheral surface of the carrier 90, but does not engage with the sawtooth 17a of the second right side wall 14, so that at this stage, the rotation of the carrier 90 is not restricted and the planet gear 101 Since no rotational force is applied to the sun gear 82 from above, the sun gear 82 remains at the original position.

  Thereafter, the spool 20 starts rotating in the webbing pull-out direction while twisting the torsion bar 70 by the force in the webbing pull-out direction applied from the webbing to the spool 20 (EA operation). That is, the locking base 40 connected to the spool 20 via the torsion bar 70 is prevented from rotating in the webbing pull-out direction by the pressure-holding action of the pretensioner 60. As a result, the spool 20 rotates while twisting the torsion bar 70, and the webbing is pulled out. The torsional deformation of the torsion bar 70 absorbs the driving energy of the occupant moving forward.

  When the spool 20 rotates in the webbing pull-out direction with the locking base 40 stopped in this way, the carrier 90 rotates in the webbing pull-out direction, so that the second pawl 110 is attached to the saw teeth 17a of the second right side wall 14. Engage. As clearly shown in FIG. 12 and the like, the engagement relationship between the second pawl 110 and the saw teeth 17a also allows the spool 20 to rotate in the webbing take-up direction and prevents the spool 20 from rotating in the webbing pull-out direction. When the second pawl 110 engages with the saw teeth 17a, the carrier 90 stops, the rotation of the spool 20 is transmitted to the sun gear 82 via the planet gear 101, and the sun gear 82 rotates, and as shown in FIG. Screw (thrust movement).

  When the sun gear 82 is screwed leftward, the sun gear 82 abuts on the right end of the push rod 28, and is then pushed by the sun gear 82 which is screwed, and the push rod 28 moves leftward. The left end of the push rod 28 pushes the pawl wall 27 and moves it to the left. As a result, the peripheral wall portion 27b is disengaged from the third pawl 25, and as shown in FIG. Prevent rotation to Thereby, the forward movement of the occupant stops.

  FIG. 20 shows the change over time of the belt (webbing) tension, the rotation of the spool and the locking base, and the movement of the sun gear during the operation of the seat belt retractor. In the figure, PT indicates pretension, and T / B indicates a torsion bar.

  The above embodiment is an example of the present invention, and the present invention may be applied to other modes.

Reference Signs List 1 seat belt retractor 10 frame 11 front wall 12 left side wall 13 first right side wall 14 second right side wall 15a, 16a, 17a saw tooth 20 spool 22 left flange 23 right flange 24 annular wall 24a internal gear 24b convex wall 25 third pawl 26 Spring 29 Inner hole 30 Return spring unit 40 Locking base 41 Flange part 42 Shaft part 42c Male screw 43 First pawl 50 Lock activation unit 52 Lock assembly 60 Pretensioner 70 Torsion bar 80 Paddle wheel 82 Sun gear 90 Carrier 101 Planet gear 110 Second Paul 120 Link Plate

Claims (18)

A frame supporting the spool and the locking base,
Winding the webbing, the cylindrical spool having a first inner hole,
The locking base, which is disposed coaxially adjacent to the spool on one side in the axial direction of the spool, has a second inner hole, is connected to the spool by a torsion bar, and has an external thread on an outer peripheral surface. When,
A first inner hole of the spool and a second inner hole of the locking base, the base end being non-rotatably connected to the spool, and the distal end being non-rotatably connected to the locking base; The torsion bar that is torsionally deformed when a tensile force of a predetermined value or more is applied to the webbing in a locked state,
A pretensioner for rotating the locking base in a webbing winding direction,
A gear in which a female screw on the inner peripheral surface is screwed to the male screw of the locking base,
When the locking base is rotated by the pretensioner drive and the spool stops rotating, the gear rotates integrally with the locking base, the spool rotates by the EA operation, and the locking base stops rotating. When the gear is a seat belt retractor, wherein the gear is screwed along the locking base,
The seat belt retractor further comprises:
A stopper pawl provided on the other end side in the axial direction of the spool and engaged with saw teeth provided on the frame to prevent rotation of the spool in the webbing pull-out direction,
Holding means for holding the stopper pawl in a disengaged position with the saw tooth;
A seat belt retractor comprising: holding release means for releasing the holding by the holding means and engaging the stopper pawl with the saw teeth when the gear is screwed a predetermined distance. The holding means,
A pawl wall mounted on the spool so as to be axially movable,
A peripheral wall portion provided on the pawl wall for holding the stopper pawl;
The spool includes a push rod held movably in a direction parallel to an axis of the spool,
2. The seat belt retractor according to claim 1, wherein when the gear is screwed, the gear moves the pawl wall via the push rod, and the holding of the stopper pawl by the peripheral wall portion is released. The stopper pawl has a base end rotatably supported with respect to the spool,
3. The seat belt retractor according to claim 2, wherein a spring is provided for urging the distal end side of the stopper pawl toward an engagement position with the saw tooth.   4. The seat belt retractor according to claim 2, wherein the push rod is inserted into a rod insertion hole provided in the spool, and one end of the push rod protrudes from the one end surface of the spool. 5. The gear is a sun gear,
The locking base includes a flange portion, a cylindrical shaft portion having the inner hole protruding from a central portion of the flange portion, and a male member provided on an outer peripheral surface of the shaft portion on a tip end side in a protruding direction. A screw, and a receiving portion provided on the shaft portion for receiving a force from the pretensioner,
A female screw on the inner peripheral surface of the sun gear is screwed to the male screw,
The spool has an internal gear,
A planet gear is arranged between the internal gear and the sun gear,
A revolving stop means for stopping the revolution of the planet gear when the spool rotates and the locking base stops rotating, and transmitting the torque of the internal gear to the sun gear. Item 5. The seat belt retractor according to any one of items 1 to 4. The frame includes a front wall, a left side wall extending forward from a left side of the front wall, a first right side wall extending forward from a right side of the front wall, and a left side of the first right side wall. And a second right side wall extending forward from the front wall.
An opening is provided in the first right side wall and the second right side wall, and a second saw tooth is provided on an inner periphery of the opening of the second right side wall,
The seat belt retractor according to claim 5, wherein a carrier is provided as the revolving stop means for engaging the second saw tooth and stopping the revolving motion of the planet gear.   The spool has a tubular portion around which webbing is wound, the first inner hole provided from one end side of the tubular portion, a flange expanding from the one end side of the tubular portion, and an outer peripheral edge of the flange. 7. The seat belt retractor according to claim 6, further comprising an annular wall projecting toward the locking base and surrounding the flange, and the internal gear provided on an inner peripheral surface of the annular wall.   The seat belt retractor according to claim 7, wherein a tip of a shaft portion of the locking base is in contact with the one end of the spool. The carrier is in the shape of an annular disk that goes around the shaft portion,
The planet gear is rotatably attached to the carrier,
A second pawl is provided on an outer periphery of the carrier, the second pawl engaging with the second saw tooth of the second right side wall to prevent the carrier from rotating in a webbing pull-out direction. 8. The seat belt retractor according to any one of 8 above.   The seat belt retractor according to claim 9, wherein the engagement between the second pawl and the second saw tooth allows the carrier to rotate in a webbing winding direction.   The second pawl has a base end rotatably supported by the carrier, and a spring provided to urge the distal end of the second pawl in a direction protruding from an outer peripheral surface of the carrier. The seat belt retractor according to claim 9 or 10, wherein:   A convex wall for pressing the second pawl is protruded from the annular wall of the spool, and the second pawl moves from the outer surface of the carrier by moving the convex wall from the second pawl pressing position. The seat belt retractor of claim 11, wherein the seat belt retracts.   13. The seat belt retractor according to claim 12, wherein a protrusion protruding toward the annular portion is provided on a distal end side of the second pawl, and the protrusion wall is arranged to press the protrusion. A non-circular portion is provided on a base end side of the shaft portion of the locking base, and a paddle wheel is provided on the non-circular portion as the receiving portion,
The power transmission member from the pretensioner moves along the outer peripheral surface of the paddle wheel, whereby the locking base, torsion bar, and spool rotate in the webbing winding direction. The seat belt retractor according to any one of the preceding claims.   In the state before the vehicle collision, the sun gear is located on the proximal end side of the shaft portion among the external threads on the outer peripheral surface of the shaft portion, the spool rotates by the EA operation, and the locking base is The seat belt retractor according to any one of claims 6 to 14, wherein when the rotation is stopped, the torsion bar is screwed toward the distal end side of the shaft portion by the torsion of the torsion bar. A plurality of the planet gears are provided at equally spaced positions in the circumferential direction of the carrier,
An annular link plate is arranged on the opposite side of the carrier with the planet gear therebetween,
The seat belt retractor according to any one of claims 6 to 15, wherein a pin for rotatably attaching the planet gear to the carrier is fitted in a pin insertion hole of the link plate. A first saw tooth is provided on an inner periphery of an opening of the first right side wall of the frame,
The seat belt retractor according to any one of claims 6 to 15, further comprising a first pawl that engages with the first saw tooth when acceleration equal to or greater than a predetermined value is detected.   18. The seat belt retractor according to claim 17, wherein the engagement between the first pawl and the first saw blade prevents rotation of the locking base in a webbing pull-out direction and allows rotation of the locking base in a webbing winding direction.

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