JP5274870B2 - Seat belt retractor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a retractor for a seat belt, simplifying a structure of a pretensioner mechanism part. <P>SOLUTION: A stopper screw 16 formed by a steel material or the like is inserted through respective through-holes 127, 128 formed in positions opposed to respective through-holes 114 of a cover plate 57 and a pipe cylinder 62 of a base plate 65, from a cover plate 57 side, and it is screw-fastened to a screw-fastening part 14B of a housing 11. Thereby, the pipe cylinder 62 is mounted to the housing 11 in the state where it is clamped between the cover plate 57 and the base plate 65. A level difference part 117 of the piston 64 pressed-driven by a pressure of a gas generated at collision of the vehicle is abutted on the stopper screw 16 inserted to an opening side end part of a piston storage part 62B to stop movement of the piston 64. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a seat belt retractor for removing looseness of a seat belt in an emergency such as a vehicle collision.

Conventionally, various retractors for seat belts for removing slack of the seat belt in an emergency such as a vehicle collision have been proposed.
For example, a gas generating member, a cylinder portion, a rack that receives the gas pressure of the gas generating member and moves in the cylinder portion, a pinion gear body that rotates in mesh with the rack and that can rotate in conjunction with the winding drum. And a seat belt provided with a pretensioner mechanism portion composed of an upper end portion of the cylinder and a cover body attached to one side plate portion so as to form a movement guide path of the rack that protrudes from the upper end portion of the cylinder portion. There exists a retractor (for example, refer patent document 1).
JP 2003-335217 A (paragraphs (0020) to (0048), FIGS. 1 to 6)

  However, in the retractor for seatbelts described in Patent Document 1 described above, there is a problem that the structure of the movement path of the rack constituting the pretensioner mechanism portion is complicated because it is composed of the cylinder portion and the cover body. . Further, the rack that is pressed and moved by the gas pressure is stopped by contacting the first contact portion formed by cutting and raising the side plate portion and the second contact portion formed at the lower end portion of the cover body. There is a problem that the shape of the side plate portion constituting the housing is complicated, and the shape of the cover body is complicated to increase the manufacturing cost.

  Therefore, the present invention has been made to solve the above-described problems, and an object of the present invention is to provide a seatbelt retractor capable of simplifying the structure of the pretensioner mechanism.

In order to achieve the object, a seatbelt retractor according to claim 1 is supported in a state where a housing having a pair of side wall portions and a pair of side wall portions are rotatably supported and a webbing is wound. In a seat belt retractor comprising: a winding drum biased in a winding direction of a webbing; and a pretensioner mechanism that winds the webbing by rotating the winding drum in the winding direction when a vehicle collides. The pretensioner mechanism has a gas generating member for generating gas, and a rectangular cross-section disposed on the outer surface of one of the pair of side walls with the gas generating member attached to one end. The cylinder has a long cylindrical shape, a pinion gear body that can rotate in conjunction with the winding drum, and is movably accommodated in the cylinder and is pressed by the pressure of the gas. In addition, a rack that meshes with the pinion gear body is formed on a side surface portion, and a piston that rotates the winding drum in the winding direction via the pinion gear body by the pressing drive, and the cylinder on the one side wall portion. A fastening member inserted through a cover plate disposed between the cover plate, a cover-side fixing hole formed in the cover plate, and a pair of through-holes formed opposite to both side surfaces of the other end of the cylinder. If has the piston a predetermined height over the tooth width direction entire width of the rack at the rear side of the wider width than the portion facing the fastening member to the rack-side direction from the tip end portion of the side surface of the rack The fastening member is fastened to the one side wall portion, and the cover plate is attached to the one side wall portion with the cylinder interposed therebetween. With kicked, the piston, when it is pressed driven by the pressure of the gas, the stepped portion is characterized Rukoto is stopped in contact with the said cylinder to said fastening member.

  The seat belt retractor according to claim 2 is the seat belt retractor according to claim 1, wherein the pretensioner mechanism portion is attached to the housing so as to form one side wall portion of the housing. And a block member having one side face locked to the base plate and the other side face locked to the cover plate and arranged to face the cylinder, and the fastening member is the base plate It is inserted into the base plate side fixing hole formed in the above, and is screwed to the housing.

In the seatbelt retractor according to claim 1, the fastening member is inserted through the cover-side fixing hole formed in the cover plate and the pair of through-holes formed opposite to both side surfaces of the other end of the cylinder. The cover plate is attached to the one side wall portion with the cylinder interposed therebetween by fastening to the one side wall portion. Further, when the piston is driven to be pressed by the gas pressure, the fastening member comes into contact with the stepped portion notched at a predetermined height at the tip, and stops in the cylinder.

Thereby, a cylinder and a cover plate can be attached to one side wall part with a simple structure, and the simplification of the structure of the pretensioner mechanism part can be achieved. In addition, it is possible to configure the movement path of the piston only with the long cylindrical cylinder. Further, the fastening member inserted into the other end of the cylinder can stop the movement of the piston driven by the pressure of the gas generated at the time of a vehicle collision or the like, thereby further improving the structure of the pretensioner mechanism. Simplification can be achieved. In addition, the fastening member can be disposed by being inserted from the front end of the cylinder to the position below the stepped portion, and the length of the cylinder can be shortened to reduce the size of the seat belt retractor. It becomes possible. Further, the length of the rack can be increased by the height of the stepped portion, and the effective length of the rack that meshes with the pinion gear body of the piston can be ensured.

  In the seatbelt retractor according to claim 2, after the cover plate and the base rate are integrated through a block member disposed to face the cylinder, the cover plate, the cylinder, and the base rate are connected by a fastening member. By attaching to the housing, it is possible to configure one side wall portion of the housing, and to simplify the structure for attaching the pretensioner mechanism portion to the housing.

  DETAILED DESCRIPTION Hereinafter, a seat belt retractor according to an embodiment of the present invention will be described in detail with reference to the drawings based on an embodiment.

[Schematic configuration]
First, a schematic configuration of the seatbelt retractor 1 according to the present embodiment will be described with reference to FIGS. 1 and 2.
FIG. 1 is an external perspective view of a seatbelt retractor 1 according to this embodiment. FIG. 2 is an exploded perspective view of the seat belt retractor 1 for each unit.

As shown in FIGS. 1 and 2, the seat belt retractor 1 is a device for winding up a webbing 3 of a vehicle, and includes a housing unit 5, a winding drum unit 6, a pretensioner unit 7, and a winding. A spring unit 8 and a lock unit 9 are included.
The lock unit 9 is fixed to the side wall 12 of the housing 11 constituting the housing unit 5 as will be described later, and the webbing 3 is pulled out in response to a sudden pull-out of the webbing 3 or a rapid acceleration change of the vehicle. Start operation to stop.

  A pretensioner unit 7 provided with a pretensioner mechanism 17 (see FIG. 6), which will be described later, is substantially omitted from the upper and lower end edges of the side plate portions 13 and 14 facing each other of the substantially U-shaped housing unit 5 in plan view. Each screw 15 and stopper screw 16 are screwed to each screwing portion 13A, 13B, 14A, 14B that extends in the direction perpendicular to the inside and has a screw hole. Thereby, the pretensioner unit 7 constitutes the other side wall portion facing the side wall portion 12 of the housing 11.

In addition, the take-up spring unit 8 is fixed to each outside of the pretensioner unit 7 by each ny latch 8A formed integrally with a spring case 56 (see FIG. 5).
The take-up drum unit 6 around which the webbing 3 is wound is rotatably supported between a lock unit 9 fixed to the side wall 12 of the housing unit 5 and the pretensioner unit 7.

[Schematic configuration of winding drum unit]
Next, a schematic configuration of the winding drum unit 6 will be described with reference to FIGS.
FIG. 3 is a perspective view of the winding drum unit 6. FIG. 4 is a sectional view of the seat belt retractor 1. FIG. 5 is an exploded perspective view of the winding drum unit 6, the pretensioner unit 7 and the winding spring unit 8.

  As shown in FIGS. 2 to 5, the winding drum unit 6 includes a guide drum 21, a drum shaft 22, a torsion bar 23, a wire 24, a wire plate 25, a ratchet gear 26, and a bearing 32. Has been.

  The guide drum 21 is formed of an aluminum material or the like, and is formed in a substantially cylindrical shape in which an end surface portion on the pretensioner unit 7 side is closed. Further, a flange portion 27 extending in the radial direction from the outer peripheral portion and further extending in a substantially right-angled outward direction is formed on the end edge portion on the pretensioner unit 7 side in the axial direction of the guide drum 21. . Further, on the inner peripheral surface of the flange portion 27, a clutch gear 30 to be engaged with each clutch pawl 29 at the time of a vehicle collision is formed as will be described later.

  A cylindrical mounting boss 31 is erected at the center position of the end surface portion of the guide drum 21 on the pretensioner unit 7 side, and a drum shaft 22 formed of steel or the like is fixed by press-fitting or the like. Further, on the outer periphery of the mounting boss 31, there is a substantially cylindrical tubular portion 32A formed of a synthetic resin material such as polyacetal, and a bearing 32 in which a proximal end flange portion 32B is connected to the outer periphery of the proximal end portion. It is inserted. The take-up drum unit 6 is rotatably supported by a bearing portion 33A (see FIGS. 6 and 8) of a pinion gear body 33 formed of a steel material or the like constituting the pretensioner unit 7 via the bearing 32. .

  Further, a shaft hole 21A is formed inside the guide drum 21 so that a draft angle is formed so as to gradually become narrower along the central axis, and the flange portion 27 side end portion in the shaft hole 21A is formed. A spline groove into which a spline 23A formed at one end of a torsion bar 23 formed of steel or the like is press-fitted is formed. Thus, the torsion bar 23 is press-fitted and fixed in the guide drum 21 so as not to be relatively rotatable by inserting the spline 23A side of the torsion bar 23 into the shaft hole 21A of the guide drum 21 and press-fitting it until it contacts the flange portion 27. The

  Further, on the lock unit 9 side of the guide drum 21 in the axial center direction, a flange portion 35 extending in the radial direction from the outer peripheral surface slightly inside from the end edge portion is formed. Further, a cylindrical step portion 36 having a slightly smaller outer diameter is formed on the outer side in the axial direction from the flange portion 35. In addition, a pair of protruding pins 37, 37 are erected on the outer end surface portion of the stepped portion 36 at positions facing each other in the radial direction.

Further, a convex portion (see FIG. 31) having a predetermined shape is formed on the outer surface of the flange portion 35 as will be described later, and a wire-like wire 24 made of a metal material such as stainless steel is formed in the shape of the convex portion. In addition, it is mounted on the outer periphery of the base end of the stepped portion 36.
Further, the outer peripheral portion of the flange portion 35 is formed of an aluminum material or the like, and has a substantially oval shape in a side view in which a convex portion 38 into which the wire 24 protruding outward from the flange portion 35 is fitted is formed on the outer peripheral portion of the inner side surface. The wire plate 25 is covered.

  Further, a through hole 40 through which the stepped portion 36 is inserted is formed in the center portion of the wire plate 25, and the outer peripheral portion on the outer side in the axial center direction of the through hole 40 is radially inward from the inner peripheral surface. A pair of fitting convex portions 41 formed so that two convex portions projecting in an arc shape are opposed to each other in the radial direction is provided. Further, four pairs of caulking pins 39 are erected on the outer peripheral portion on the outer side in the axial direction sandwiched between the fitting convex portions 41 of the through hole 40 so as to face each other in the radial direction. In addition, a concave portion 39 </ b> A that is recessed in a semicircular arc shape by a predetermined depth is formed at the base end portion of each caulking pin 39.

  The ratchet gear 26 has a disk shape formed of a steel material or the like, and is formed with a cylindrical extension portion 42 extending from the outer peripheral portion to the same height as the step portion 36 in the axial direction. A ratchet gear portion 45 with which the pawl 43 (see FIG. 9) engages in the event of a vehicle collision or a vehicle emergency is formed on the outer peripheral surface of the extending portion 42 as will be described later. Further, an anti-rotation flange 46 extending in the radial direction from the outer peripheral portion is formed at the end edge portion of the extending portion 42 on the axial direction guide drum 21 side, and further, a circularly inward in the radial direction is formed on the outer peripheral portion. A pair of fitting recesses 46B formed so that two recesses recessed in an arc shape face each other in the radial direction are provided (see FIG. 5). In addition, on the outer surface in the axial direction facing each caulking pin 39 of the non-rotating flange 46, each recess 46A is formed in a semicircular arc shape and is recessed by a predetermined depth.

  Further, through holes 47 into which the respective protruding pins 37 are fitted are formed at positions facing the respective protruding pins 37 of the ratchet gear 26. In addition, around each through-hole 47, a concave portion 47A that is recessed by a predetermined depth is formed. A shaft portion 48 is erected on the outer center position of the ratchet gear 26. A spline 48 </ b> A is formed on the outer peripheral surface of the shaft portion 48. The winding drum unit 6 is rotatably supported by the lock unit 9 via the shaft portion 48.

  A cylindrical fixed boss 49 is provided upright at the center of the inner surface of the ratchet gear 26. A spline 23 B formed on the other end side of the torsion bar 23 is formed on the inner peripheral surface of the fixed boss 49. Spline grooves into which are inserted are formed. The outer diameter of the spline 23B formed on the other end side of the torsion bar 23 is substantially the same as the outer diameter of the spline 23A formed on one end side of the torsion bar 23.

  Therefore, first, each fitting recess 46 </ b> B of the rotation prevention flange 46 of the ratchet gear 26 is fitted into each fitting projection 41 of the wire plate 25. Thereafter, each crimping pin 39 is crimped so as to spread inside the recess 39A of the base end portion and the recess 46A of the detent flange 46 formed at the opposite position. Then, the wire 24 is mounted on the outer surface of the flange portion 35 of the guide drum 21 (see FIG. 31). Subsequently, the wire plate 25 and the ratchet gear 26 are covered on the outside, and the protruding pins 37 of the guide drum 21 are inserted into the through holes 47 of the ratchet gear 26, while the torsion bar 23 and the like are inserted into the fixed boss 49. The spline 23B formed on the end side is inserted. Thereafter, each projecting pin 37 is crimped so as to spread inside a recess 47 </ b> A formed around the through hole 47.

  As a result, the ratchet gear 26 and the wire plate 25 are fixed so as not to rotate relative to each other, and the ratchet gear 26 and the wire plate 25 rotate relative to the guide drum 21 via the torsion bar 23 and the protruding pins 37. Fixed to impossible. The webbing 3 is wound around the outer peripheral surface between the flange portion 27 of the guide drum 21 and the flange portion 35 and the wire plate 25.

[Schematic configuration of winding spring unit]
Next, a schematic configuration of the winding spring unit 8 will be described with reference to FIGS. 2, 4, and 5.
As shown in FIGS. 2, 4, and 5, the winding spring unit 8 includes a winding attachment biasing mechanism 55 including a spiral spring, a spring case 56 that accommodates the winding attachment biasing mechanism 55, and a spring shaft 58. It is configured. And it fixes to each through-hole 51 of the cover plate 57 which comprises the outer surface of the pretensioner unit 7 formed with a steel material etc. via each ny latch 8A provided in three places of the spring case 56. FIG. The leading end of the drum shaft 22 of the winding drum unit 6 is coupled to a spiral spring via a spring shaft 58 in the spring case 56, and the winding drum unit 6 is always moved in the winding direction of the webbing 3 by the urging force of the spiral spring. The structure is energized.

[Schematic configuration of pretensioner unit]
Next, a schematic configuration of the pretensioner unit 7 will be described with reference to FIGS. 2 and 4 to 8.
FIG. 6 is a perspective view of the pretensioner unit 7 as seen from the side of the mounting surface to the housing unit 5. FIG. 7 is a partially cutaway side view of the pretensioner unit 7. FIG. 8 is an exploded perspective view of the pretensioner unit 7 of FIG.

  As shown in FIGS. 2, 4 to 8, the pretensioner unit 7 is a forced lock that rotates the pretensioner mechanism 17 and a pawl 43 (see FIG. 9) pivotally supported on the side wall 12 of the housing unit 5. And a mechanism 53.

[Pretensioner mechanism]
As shown in FIGS. 5 to 8, the pretensioner mechanism 17 operates the gas generating member 61 at the time of a vehicle collision or the like, and uses the pressure of this gas via the flange portion 27 of the winding drum unit 6 to perform the winding. This is a mechanism for rotating the take-up drum unit 6 in the winding direction of the webbing 3.

  Here, the pretensioner mechanism 17 is formed on the gas generating member 61, the pipe cylinder 62, the seal plate 63 and the piston 64 that move in the pipe cylinder 62 under the gas pressure of the gas generating member 61, and the piston 64. The pinion gear body 33 that meshes with the rack and rotates, a base plate 65 to which the pipe cylinder 62 is attached, and a substantially rectangular parallelepiped shape disposed on the base plate 65 in contact with the side surface of the pipe cylinder 62 on the pinion gear body 33 side. The base block body 66 and a clutch mechanism 68 disposed on the outer surface of the base plate 65 are configured.

  The pinion gear body 33 has a substantially cylindrical shape made of steel or the like, and a pinion gear portion 71 that meshes with a rack formed on the piston 64 is formed on the outer periphery thereof. Further, a cylindrical support portion 72 extending outward from the end portion of the pinion gear portion 71 on the axial direction cover plate 57 side is formed. The support portion 72 is formed to have a length substantially equal to the thickness dimension of the cover plate 57 with the valley diameter of the pinion gear portion 71 as the outer diameter.

  In addition, a flange portion 73 projecting in the radial direction is formed at the end portion of the pinion gear portion 71 on the side of the axial base plate 65. Further, a boss portion 74 is formed which is formed in a substantially cylindrical shape outward from the flange portion 73 and into which the drum shaft 22 of the winding drum unit 6 is inserted and in which a bearing portion 33A into which the bearing 32 is inserted is formed. In addition, on the outer peripheral surface of the boss portion 74, three splines each having an outer diameter of the base end portion are formed at intervals of about 120 degrees of the central angle.

  The clutch mechanism 68 is formed of a substantially annular pawl base 76 made of steel or the like, three clutch pawls 29 made of steel or the like, and a synthetic resin such as polyacetal. Thus, it is comprised from the pawl base 76 and the substantially annular pawl guide 77 which clamps each clutch pawl 29 (refer FIG. 21 etc.).

  Further, on the inner peripheral surface of the pawl base 76, three spline grooves into which the splines formed on the boss portions 74 of the pinion gear body 33 are press-fitted are formed at intervals of about 120 degrees of central angles. Further, the inner peripheral diameter of the pawl guide 77 is formed larger than the spline groove of the pawl base 76, and the positioning projections 77A project at equal angles at three locations on the outer side surface of the pawl guide 77. Has been.

  Then, each positioning protrusion 77A protruding from the outer side surface portion of the pawl guide 77 of the clutch mechanism 68 is fitted into each positioning hole 81 of the base plate 65 so that the clutch mechanism 68 is placed on the outer surface of the base plate 65. Deploy. Subsequently, as shown in FIG. 8, after the boss portion 74 of the pinion gear body 33 is fitted into the through hole 83 formed in the substantially central portion of the base plate 65, each spline formed in the boss portion 74 is moved to the clutch mechanism 68. Are press-fitted and fixed in each spline groove of the pawl base 76. Thereby, the clutch mechanism 68 and the pinion gear body 33 are disposed and fixed to the base plate 65, and the pinion gear portion 71 of the pinion gear body 33 is always positioned and fixed at the position shown in FIG.

  The base block body 66 is made of a synthetic resin such as polyacetal. The gear housing 85 is formed so as to be recessed in a semi-circular shape in plan view from the side edge on the inner side of the base block body 66 and formed in a ring shape with a bottom surface protruding outward. The flange portion 73 of the pinion gear body 33 is inserted into the through hole 82 in the bottom surface portion. Further, each positioning boss 79 protruding from the side surface portion of the base block body 66 on the base plate 65 side is fitted into each positioning hole 80 of the base plate 65, and the base block body 66 is arranged on the inner surface of the base plate 65. .

  Also, an elastic locking piece 66A extending from the outer side surface portion of the base block body 66 to the base plate 65 side and formed to be elastically deformable in the outer direction, and the base plate 65 from the lower side surface portion of the base block body 66. The elastic locking pieces 66 </ b> B that extend to the side and are elastically deformable in the outward direction are locked to the side end portions of the base plate 65. As a result, the base block body 66 is disposed on the base plate 65.

  The inner diameter of the through hole 83 formed in the substantially central portion of the base plate 65 is formed to a diameter that can support the outer diameter of the base end portion of the boss portion 74 of the pinion gear body 33, and rotates on one end side of the pinion gear body 33. It is configured to be possible to support. Further, the height of the gear housing 85 is formed to be substantially equal to the sum of the heights of the pinion gear 71 and the flange 73 of the pinion gear body 33.

[Forced locking mechanism]
Here, the forced lock mechanism 53 disposed in the base block body 66 will be described with reference to FIGS.
As shown in FIG. 7, the base block body 66 is formed with a recess 86 in which the forced lock mechanism 53 is disposed. A block biasing spring 87A that biases the gear side arm 89 toward the rotation lever 88, a gear side arm 89, and a biasing spring 90 that biases the gear side arm 89 toward the rotation lever 88 side are disposed. As shown in FIG. 6, the gear side arm 89 is connected to the connecting shaft 91 constituting the forced lock mechanism 53 and the mechanical side arm 92 from the outside of the base plate 65.

  The rotary lever 88 is formed of a synthetic resin such as polyacetal, an aluminum material, or the like, is formed in a substantially square shape, and has a through hole in a bent portion. As shown in FIG. 7, the rotary lever 88 is rotatable on a boss 93 erected on the bottom surface portion of the recess 86 of the base block body 66 so that one end side thereof faces the pinion gear portion 71 of the pinion gear body 33. It is supported.

  The push block 87 is made of a synthetic resin such as polyacetal. As shown in FIG. 7, the push block 87 has one end positioned near the teeth of the pinion gear portion 71 of the pinion gear body 33 and the other end thereof by the positioning protrusion 94 erected on the bottom surface portion of the recess 86. It is positioned so as to be located in the vicinity of the rotary lever 88. The push block 87 is urged toward the rotating lever 88 by a block urging spring 87A, thereby preventing rattling.

  Therefore, when the pinion gear body 33 rotates as will be described later, the rotation lever 88 can be rotated outward (counterclockwise in FIG. 7) by the push block 87 pushed by the teeth of the pinion gear portion 71. It is configured (see FIG. 11). Further, the push block 87 is prevented from returning to the pinion gear body 33 side by the block urging spring 87A.

  Further, the gear side arm 89 is formed of a synthetic resin such as polyacetal, an aluminum material, and the like, and is formed in a substantially flat plate shape, and at one end side far from the rotation lever 88 on the side surface portion on the base block body 66 side, A boss 95 that is inserted through a through hole 96 formed in the bottom surface of the recess 86 of the base block body 66 is provided upright. Further, a groove portion 97 having a predetermined depth through which the one end side bent portion of the connecting shaft 91 is inserted is formed on a side surface portion where the boss 95 of the gear side arm 89 is erected.

  As shown in FIGS. 6 and 8, the gear side arm 89 is formed with a stepped portion 98 on the upper surface of the distal end portion on the rotating lever 88 side so that the other end side of the rotating lever 88 contacts. The gear-side arm 89 is rotatably supported on the rotating lever 88 side by inserting a boss 95 into a through hole 96 formed in the bottom surface of the recess 86. Further, the gear side arm 89 is urged by the urging spring 90 on the lower surface of the other tip portion facing the stepped portion 98 toward the rotation lever 88 (in the upward direction in FIG. 7). Is in contact with the other end of the rotary lever 88.

  Therefore, when the rotating lever 88 rotates counterclockwise in FIG. 7, the other end side of the rotating lever 88 is separated from the tip end portion of the gear side arm 89, and the gear side arm is biased by the biasing spring 90. Thus, it is configured to be rotatable in the outer direction (the counterclockwise direction in FIG. 7).

  The connecting shaft 91 is formed of a wire material such as a steel material, and is bent at a substantially right angle so that both ends face each other with a shift of about 90 degrees. Also. The length of the straight portion of the connecting shaft 91 is slightly longer than the width of the side plate portions 13 and 14 of the housing unit 5 (see FIG. 9).

  Further, as shown in FIG. 8, a groove 101 through which the one-end bent portion of the connection shaft 91 is inserted extends from the outer peripheral portion in the through hole 96 formed in the bottom surface portion of the concave portion 86 of the base block body 66. ing. Further, a through hole 102 through which the one end side bent portion of the connecting shaft 91 is inserted is formed in a portion of the base plate 65 facing the gear side arm 89.

  Therefore, the one end side bent portion of the connecting shaft 91 passes through the through hole 102 of the base plate 65, the through hole 96 and the groove 101 of the base block body 66, and the gear side disposed in the recess 86 of the base block body 66. The arm 89 is inserted into the groove 97.

  The mechanical arm 92 is formed of a synthetic resin such as polyacetal, aluminum, or the like, and is formed in a substantially flat and generally fan-shaped, and is formed on the outer surface of the edge on the central angle side. A boss 106 that is rotatably fitted in a through hole 105 (see FIG. 10) formed in the side wall portion 12 (see FIG. 9) of the housing unit 5 is provided upright. Further, a boss 92 </ b> A that is inserted into the notch 138 is erected on the outer side surface on the side wall 12 side of the outer peripheral edge of the mechanical arm 92. A groove 107 having a predetermined depth is formed on the inner side surface of the mechanical arm 92 along the center line.

  Therefore, as shown in FIG. 6, by inserting the other end side bent portion of the connection shaft 91 into the groove portion 107 of the mechanical side arm 92, the mechanical side arm 92 is arranged on the central angle side of the mechanical side arm 92. The shaft is attached to the other end of the connecting shaft 91 so that the axis of the boss 106 erected on the outer surface of the end edge portion and the axis of the connecting shaft 91 are substantially straight.

  When the pretensioner unit 7 is attached to the housing unit 5 as described later, the boss 106 of the mechanical side arm 92 is rotatably fitted in the through hole 105 formed in the side wall portion 12 (see FIG. 10). Further, the boss 92 </ b> A of the mechanical side arm 92 is inserted into a notch 138 formed in the side wall portion 12 and is rotatably attached to the inside of the side wall portion 12.

[Pretensioner mechanism]
Next, the configuration and attachment of the pipe cylinder 62 constituting the pretensioner mechanism 17 will be described with reference to FIGS.
As shown in FIGS. 5 to 8, the pipe cylinder 62 is formed in a substantially L shape with a steel pipe material or the like. Then, one end side (the lower bent portion in FIG. 7) is formed with a substantially cylindrical storage portion 62 </ b> A to store the gas generating member 61. The gas generating member 61 includes explosives, and is configured to ignite the explosives according to an ignition signal from a control unit (not shown) and generate gas by combustion of the gas generating agent.

  Further, the other end side (the upper bent portion in FIG. 7) of the pipe cylinder 62 is formed with a piston housing portion 62B having a substantially rectangular cross section, and a notch portion 111 is formed at a portion facing the pinion gear body 33, and the base plate When arranged on 65, the pinion gear portion 71 of the pinion gear body 33 is configured to fit into the notch 111. In addition, a bent portion 112 that is bent at a substantially right angle from the base plate 65 is fitted into the side surface portion on the base block body 66 side at the upper end portion of the piston housing portion 62B, so that the pipe cylinder 62 is prevented from coming off in the vertical direction. A functioning notch 113 is formed. In addition, a pair of opposing through-holes 114 that can be fitted with a stopper screw 16 that functions as a retaining member for the piston 64 and is attached to the housing unit 5 on both side surfaces of the lateral side of the notch 113 are provided. Is formed.

  As shown in FIGS. 7 and 8, the seal plate 63 is formed in a substantially rectangular plate shape that can be inserted from the upper end side of the piston housing portion 62B with a rubber material or the like. The seal plate 63 is formed with a pair of protrusions 63A that extend upward from both end edges in the longitudinal direction and protrude inward over the entire width of each upper end. A gas vent hole 63 </ b> B is formed at the center of the seal plate 63.

  The piston 64 is formed of a steel material or the like, has a substantially rectangular cross section that can be inserted from the upper end side of the piston housing portion 62B, and has a long shape as a whole. Further, in the lower end portion of the piston 64, insertion grooves 64A into which the projections 63 of the seal plate 63 are fitted from the lateral direction are formed. In addition, a communication hole 64C having a small diameter is formed in the lower end surface of the piston 64 so as to communicate with the through hole 64B formed in the side surface portion of the piston 64 from the lower end surface.

  Then, the respective projections 63A of the seal plate 63 are slid from the lateral sides into the respective insertion grooves 64 of the piston 64, and are then press-fitted from the upper end side of the piston housing portion 62B to the back side with the seal plate 63 facing away. Further, the gas vent hole 63B of the seal plate 6 communicates with the through hole 64B via the communication hole 64C of the piston 64.

  Accordingly, in this state, the seal plate 63 is pressed by the pressure of the gas generated by the gas generating member 61, and the piston 64 moves to the upper end side opening (upper end in FIG. 7) of the piston housing portion 62B. Further, when the webbing 3 is pulled out again as described later, when the piston 64 is lowered downward by the reverse rotation of the pinion gear body 33, the gas vent hole 63B of the seal plate 63, the communication hole 64C of the piston 64, and the through hole The gas in the pipe cylinder 62 is released through 64B, and the piston 64 is smoothly lowered.

  A rack 116 that meshes with the pinion gear portion 71 of the pinion gear body 33 is formed on the side surface of the piston 64 on the pinion gear body 33 side. Further, a stepped portion 117 capable of contacting the stopper screw 16 is formed on the back surface of the front end portion (the upper end portion in FIG. 7) of the rack 116. Further, as shown in FIG. 7, in a normal state until the gas generating member 61 is operated, the piston 64 is retracted to the back side of the piston housing part 62B, and the tip of the rack 116 is not engaged with the pinion gear part 71. It is located to become.

  Then, as shown in FIG. 7, the protruding portions that protrude outward from both side edge portions of the gear storage portion 85 of the base block body 66 are formed inside the notch portion 111 of the piston storage portion 62 </ b> B configured as described above. 109, the bent portion 112 of the base plate 65 is inserted into the notch 113 formed at the upper end of the piston accommodating portion 62B, and the pipe cylinder 62 is disposed on the base plate 65. At this time, the rack stop pin 108 erected on the base block body 66 and having a substantially U-shaped cross section is inserted into the gear groove at the upper end of the rack 116, and the vertical movement of the piston 64 is restricted. Further, the tip end portion of the piston 64 is located in the vicinity of the pinion gear portion 71 of the pinion gear body 33 and is in a non-meshing state.

  As a result, the piston accommodating portion 62B of the pipe cylinder 62 is separated from each rib 110 having a substantially triangular cross-section standing on the side surface portion of the base block body 66 and the portion facing the pinion gear body 33 on the side edge of the base plate 65. Both side surface portions are supported by the back support portions 118A and 118B extending substantially at right angles. Each of the back support portions 118A and 118B extends so as to be slightly higher than the piston housing portion 62B, and is formed at a side end portion of the cover plate 57 facing the back support portions 118A and 118B. The through holes 119A and 119B are formed to be insertable.

  Further, the side edge portions of the through holes 119A and 119B facing the outer side surfaces of the back support portions 118A and 118B have a predetermined height (for example, a height of about 1 mm) in the inner direction (left side direction in FIG. 8). There is a depression. Thereby, when each back support part 118A, 118B is inserted in each through-hole 119A, 119B, the inner surface of each through-hole 119A, 119B is surely contacted with the outer surface of each back support part 118A, 118B. It is configured to touch.

  Then, in a state in which the base block body 66, the forced lock mechanism 53, the pipe cylinder 62, and the like are arranged on the base plate 65, the positioning bosses 121 that protrude from the side surface portion on the cover plate 57 side of the base block body 66 are covered with the cover. The cover plate 57 is disposed on the upper side of the base block body 66, the forced lock mechanism 53, the pipe cylinder 62 and the like by being fitted into the positioning holes 122 of the plate 57. At the same time, the cylindrical support portion 72 of the pinion gear body 33 is fitted into the support hole 125 formed in the substantially central portion of the cover plate 57.

  Further, the back support portions 118A and 118B extending substantially at right angles from the side edge portions of the base plate 65 are passed through the through-holes formed at the side edge portions of the cover plate 57 facing the back support portions 118A and 118B. The holes 119A and 119B are inserted. An elastic locking piece 66C that extends from the outer side surface of the base block body 66 toward the cover plate 57 and is elastically deformable in the outer direction, and a cover from the upper side surface of the base block body 66. Elastic locking pieces 66 </ b> D that extend toward the plate 57 side and are formed so as to be elastically deformable in the outward direction are respectively locked to the side end portions of the cover plate 57.

  Accordingly, the cover plate 57 is disposed and fixed to the base block body 65, and the pipe cylinder 62 is attached between the cover plate 57 and the base plate 65. Further, the support portion 72 formed at the end of the pinion gear body 33 is rotatably supported by the support hole 125 of the cover plate 57. Therefore, as shown in FIG. 4, the base end portion of the boss portion 74 and the support portion 72 formed at both ends of the pinion gear body 33 are respectively formed by the through hole 83 of the base plate 65 and the support hole 125 of the cover plate 57. It is rotatably supported.

  Further, the through holes 114 of the pipe cylinder 62, the through holes 127 formed at positions facing the through holes 114 of the cover plate 57, and the screw holes formed at positions facing the through holes 114 of the base plate 65. 141B (see FIG. 9) is arranged on the same axis. As a result, the stopper screw 16 formed of a steel material or the like can be inserted and fixed from the cover plate 57 side to the base plate 65 side.

  Accordingly, the pipe cylinder 62 is sandwiched between the cover plate 57 and the base plate 65, and both side surface portions are sandwiched between the base block body 66 and the backrest portions 118A and 118B. Further, the upper end side opening of the piston accommodating portion 62 </ b> B of the pipe cylinder 62 is covered with a cover portion 131 that extends substantially at a right angle from the upper end portion of the cover plate 57. Further, when the seal plate 63 is pressed by the pressure of the gas generated by the gas generating member 61 and the piston 64 moves to the upper end side opening (upper end in FIG. 7) of the piston housing portion 62B, the piston The 64 stepped portions 117 can be brought into contact with the stopper screws 16 inserted through the respective through holes 114 and stopped.

[Schematic configuration of housing unit]
Next, a schematic configuration of the housing unit 5 will be described with reference to FIGS. 9 and 10.
FIG. 9 is an exploded perspective view of the housing unit 5. FIG. 10 is a side view of the seatbelt retractor 1 with the lock unit 9 removed.
As shown in FIGS. 9 and 10, the housing unit 5 includes a housing 11, a bracket 133, a protector 135, a pawl 43, and a pawl rivet 136.

  The housing 11 is made of a steel material or the like and is formed in a substantially U shape in plan view, and a through hole 137 into which the tip of the ratchet gear 26 of the take-up drum unit 6 is inserted is formed in the side wall portion 12 on the back side. Has been. In addition, a notch 138 is formed in a portion of the through hole 137 facing the pawl 43 on the oblique lower side so that the pawl 43 can smoothly rotate. A through hole 139 for rotatably mounting the pawl 43 is formed on the lateral side of the notch 138.

  Further, a semicircular guide portion 140 is formed on the concentric circle of the through hole 139 at the portion of the notch 138 where the pawl 43 abuts. On the other hand, the portion of the pawl 43 that slides in contact with the guide portion 140 has a height substantially equal to the thickness dimension of the side wall portion 12 and is stepped in an arc shape having the same radius of curvature as the side edge of the guide portion 140. The part 43B is formed slightly higher than the thickness dimension of the side wall part 12. Further, a guide pin 43 </ b> A that is inserted into the guide groove 202 </ b> F of the clutch 202 that constitutes the lock unit 9 is erected at the tip of the outer side surface of the pawl 43 as will be described later.

  Further, the side plate portions 13 and 14 facing each other are extended from both side edge portions of the side wall portion 12. In addition, an opening is formed in the central portion of each of the side plate portions 13 and 14 to reduce the weight and improve the efficiency of attaching the webbing 3. In addition, screw fixing portions 13A, 13B, 14A, and 14B that extend in a substantially right-angled inner direction with a predetermined width are formed on the upper and lower end edge portions of the side plate portions 13 and 14, respectively. Further, each screw-fastening portion 13A, 13B, 14A is formed with a screw hole 141A to which each screw 15 is screwed, and the screw-fastening portion 14B has a screw hole 141B to which the stopper screw 16 is screwed. Is formed by burring.

Further, the bracket 133 attached to the upper edge portion of the side plate portion 13 by the rivets 134 is formed of a steel material or the like, and webbing is performed on an extending portion that extends substantially inwardly from the upper edge portion of the side plate portion 13. A horizontally long through-hole 142 from which 3 is pulled out is formed, and a horizontally long frame-shaped protector 135 formed of a synthetic resin such as nylon is fitted therein.
Further, the pawl 43 made of steel or the like can be rotated by a rivet 136 that is rotatably inserted into the through hole 139 from the outside of the side wall portion 12 with the stepped portion 43B being in contact with the guide portion 140. It is fixed. Thus, the side surface of the pawl 43 and the side surface of the ratchet gear 26 are positioned so as to be substantially flush with the outer surface of the side wall portion 12.

  As shown in FIG. 10, when the pretensioner unit 7 is attached to the housing unit 5 with the screws 15 and the stopper screws 16, the mechanical arm 92 attached to the bent portion on the other end side of the connecting shaft 91. The boss 106 is rotatably fitted in the through-hole 105 formed in the side wall portion 12 and is located in the vicinity of the lower side surface portion of the pawl 43 located in the notch 138. Further, a boss 92 </ b> A standing on the outer side surface of the mechanical arm 92 is inserted into the notch 138. Further, the pawl 43 is normally close to the mechanical arm 92 and is not engaged with the ratchet gear 26.

[Description of forced lock mechanism and pawl operation]
Next, the operations of the forced lock mechanism 53 and the pawl 43 that are activated by the operation of the gas generating member 61 of the pretensioner mechanism 17 in the event of a vehicle collision will be described with reference to FIGS.

  FIG. 11 is an explanatory view showing a state in which the piston 64 is in contact with the pinion gear portion 71 of the pinion gear body 33 by the operation of the gas generating member 61 of the pretensioner mechanism 17. FIG. 12 is an explanatory diagram showing the operation of the pawl 43 corresponding to FIG. FIG. 13 is an explanatory view showing a moment when the piston 64 further moves and the lower end portion of the rotation lever 88 is disengaged from the tip end portion of the gear side arm 89. FIG. 14 is an explanatory diagram showing the operation of the pawl 43 corresponding to FIG. FIG. 15 is an explanatory view showing a state where the piston 64 further moves and the lower end portion of the rotation lever 88 is disengaged from the tip end portion of the gear side arm 89. FIG. 16 is an explanatory view showing the operation of the pawl 43 corresponding to FIG.

  As shown in FIG. 11, when the gas generating member 61 of the pretensioner mechanism 17 is actuated at the time of a vehicle collision or the like, the piston 64 in the piston housing portion 62B of the pipe cylinder 62 is moved from the normal state shown in FIG. The rack stop pin 108 is sheared and moved upward (in the direction of the arrow X1) and comes into contact with the teeth of the pinion gear portion 71 of the pinion gear body 33. Thereby, the pinion gear body 33 rotatably supported by the base plate 65 and the cover plate 57 starts to rotate counterclockwise (in the direction of the arrow X2) when viewed from the front.

  Therefore, the clutch mechanism 68 that is integrally fixed to the pinion gear body 33 also starts to rotate. Further, until the teeth of the pinion gear portion 71 come into contact with the end portion on the pinion gear body 33 side of the push block 87 constituting the forced lock mechanism 53 disposed in the recess 86 of the base block body 66, the push block 87 is The base block body 66 is stopped by a positioning protrusion 94 erected on the bottom surface portion. For this reason, since this push block 87 does not push the upper end part of the rotation lever 88, the rotation lever 88 and the gear side arm 89 are located in a normal position.

  Further, as shown in FIG. 12, since the lower end portion of the rotary lever 88 is in contact with the tip end portion of the gear side arm 89, the mechanical side arm 92 connected to the gear side arm 89 via the connecting shaft 91. Does not rotate. Therefore, the pawl 43 is located in a normal state away from the ratchet gear portion 45 of the ratchet gear 26. That is, the pawl 43 is not engaged with the ratchet gear portion 45 of the ratchet gear 26.

  Subsequently, as shown in FIG. 13, when the piston 64 further moves in the pipe cylinder 62 and rotates the pinion gear body 33 in the counterclockwise direction when viewed from the front (in the direction of the arrow X2), the pinion gear body. The clutch mechanism 68 integrally fixed to 33 is further rotated. As a result, each positioning protrusion 77A of the pawl guide 77 constituting the clutch mechanism 68 is sheared from the outer surface of the pawl guide 77, and the clutch mechanism 68 and the pinion gear body 33 are integrated with the movement of the piston 64. And start rotating.

  At the same time, as the piston 64 moves upward, the push block 87 is pushed by the teeth of the pinion gear portion 71 to move outward (in the left direction in FIG. 13), and the bottom surface of the base block body 66. The positioning protrusion 94 erected on the part is sheared. For this reason, the push block 87 is pushed outward by the block urging spring 87A, abuts against the upper end portion of the rotary lever 88, and is pushed outward. As a result, the rotation lever 88 is pushed by the push block 87 and rotates counterclockwise when viewed from the front (in the direction of arrow X3), and the lower end of the rotation lever 88 moves to the tip of the gear side arm 89. To do.

  Further, as shown in FIG. 14, until the lower end portion of the rotation lever 88 is disengaged from the tip end portion of the gear side arm 89, the mechanical side arm 92 connected to the gear side arm 89 via the connection shaft 91 is rotated. do not do. Therefore, the pawl 43 is located in a normal state away from the ratchet gear portion 45 of the ratchet gear 26. That is, the pawl 43 is not engaged with the ratchet gear portion 45 of the ratchet gear 26.

  Thereafter, as shown in FIG. 15, the piston 64 further moves in the pipe cylinder 62 to rotate the pinion gear body 33 in the counterclockwise direction when viewed from the front (in the direction of the arrow X2). Further, since the upper end portion of the rotation lever 88 is further pushed by the push block 87 pushed by the block urging spring 87A, the lower end portion of the rotation lever 88 is disengaged from the tip end portion of the gear side arm 89.

  Therefore, the gear side arm 89 is pressed outward by the biasing spring 90 and rotates in the counterclockwise direction when viewed from the front (in the direction of the arrow X4). The push block 87 is pressed outward by the block urging spring 87A and maintained in a state of being separated from the pinion gear portion 71 of the pinion gear body 33, and the upper end portion of the rotary lever 88 is abutted against the inner wall surface of the recess 86. Keep in contact.

  Further, as shown in FIG. 16, when the lower end portion of the rotating lever 88 is disengaged from the tip end portion of the gear side arm 89, the gear side arm 89 is counterclockwise when viewed from the front (the direction of the arrow X4). ), The connecting shaft 91 in which the one-end bent portion is inserted into the groove portion 97 of the gear side arm 89 is also rotated counterclockwise in the front view (in the direction of the arrow X4) around the axis. To do.

  For this reason, the mechanical side arm 92 has the other end side bent portion of the connecting shaft 91 inserted in the groove portion 107, and therefore, when the gear side arm 89 rotates, it is counterclockwise when viewed from the front (in the direction of the arrow X5). And the pawl 43 is engaged with the ratchet gear portion 45 of the ratchet gear 26. The pawl 43 and the ratchet gear portion 45 of the ratchet gear 26 are configured to mesh with each other so as to prevent the winding drum unit 6 from rotating in the webbing 3 pull-out direction and to allow rotation in the webbing 3 winding direction. ing.

  Accordingly, when the pawl 43 and the ratchet gear portion 45 of the ratchet gear 26 are engaged, a locking operation is performed to prevent the winding drum unit 6 from rotating in the webbing 3 pull-out direction, and in the webbing 3 winding direction. Is allowed to rotate. In addition, before the clutch mechanism 68 and the pinion gear body 33 described above start to rotate together, the pawl 43 is in a state in which the rotation of the winding drum unit 6 in the webbing 3 pull-out direction can be suppressed.

  Further, after the operation of the pretensioner mechanism 17 and after the rotation of the pinion gear body 33 is stopped, the state in which the lower end portion of the rotation lever 88 is detached from the distal end portion of the gear side arm 89 is maintained as shown in FIG. The That is, after the pretensioner mechanism 17 is operated, the engagement between the pawl 43 and the ratchet gear portion 45 of the ratchet gear 26 is maintained. For this reason, the ratchet gear 26 and the wire plate 25 of the winding drum unit 6 are prevented from rotating in the direction in which the webbing 3 is pulled out.

  Next, the pretensioner operation that operates in the event of a vehicle collision will be described with reference to FIGS.

[Configuration around the pretensioner unit]
FIG. 17 is a partial cross-sectional view showing a configuration in which the retractor 1 for the seat belt is connected to the take-up drum unit 6 and the take-up spring unit 8 with the pretensioner unit 7 interposed therebetween, and the cross-sectional view of FIG. It is the figure seen from.

  As shown in FIG. 17, the guide drum 21 is coaxially connected to the winding spring unit 8 via the drum shaft 22. The guide drum 21 is always urged in the winding direction of the webbing 3 by the winding spring unit 8.

  In the pretensioner unit 7, the clutch mechanism 68 that protrudes from the base plate 65 is housed in the drum recess 21 </ b> B of the guide drum 21. The bearing 32 is slidably provided between the guide drum 21 and the pinion gear body 33. The bearing 32 includes a cylindrical portion 32A having a cylindrical shape, and a proximal end flange portion 32B continuously provided at one end of the cylindrical portion 32A and extending in the outer diameter direction, and the guide drum 21 and the pinion gear body. 33 is slidably mounted between the two.

  Specifically, the outer surface of the mounting boss 31 of the guide drum 21 and the bottom surface of the drum recess 21B provided on the outer surface, the inner surface of the cylindrical portion 32A of the bearing 32 and the lower surface of the proximal flange portion 32B. And slidably contact each other. Further, the outer side surface of the cylindrical portion 32A and the upper side surface of the base end flange portion 32B of the bearing 32 are slidably in contact with the inner side surface and the distal end portion of the pinion gear body 33.

  In the pretensioner unit 7, the pinion gear body 33 and the clutch mechanism 68 are configured to slidably contact the guide drum 21 via the bearings 32. As a result, during normal use, the rotation of the guide drum 21 when the webbing 3 is pulled out and taken up can be freely performed without being restricted by the pinion gear body 33 and the clutch mechanism 68 of the pretensioner unit 7.

  FIG. 18 is a plan view of the seatbelt retractor 1 as viewed from the winding spring unit 8 side. In order to explain the relationship between the guide drum 21, the clutch mechanism 68, and the base plate 65, the constituent members of the pretensioner unit 7 excluding the clutch mechanism 68 and the base plate 65, the winding spring unit 8, and the drum shaft 22 are omitted. Yes. Moreover, in order to show the relationship between members, the state (displayed with a dotted line) where part or all of the members was seen through was displayed as needed.

  As shown in FIG. 18, the clutch mechanism 68 is assembled coaxially with the guide drum 21. The clutch mechanism 68 is coaxially connected to the pinion gear body 33 through the opening 65A of the base plate 65, and the inner side surface of the pinion gear body 33 is positioned so as to be rotatable and slidable through the outer surface of the mounting boss 31 and the bearing 32. Because.

  A clutch gear 30 is engraved on the peripheral edge of the guide drum 21 that forms the drum recess 21B toward the axis. As will be described later, the clutch pawl 29 housed in the clutch mechanism 68 protrudes when the pretensioner is operated. The protruding clutch pawl 29 engages with the clutch gear 30 to rotate the guide drum 21 in the winding direction of the webbing 3.

  Further, a positioning protrusion 77A is provided on the surface of the clutch mechanism 68 that contacts the base plate 65, and is engaged with a positioning hole 81 that is opened in the base plate 65. As a result, the clutch mechanism 68 and the base plate 65 are fixed so that they cannot rotate relative to each other during normal operation.

  Further, as will be described later, the positioning protrusion 77A is formed on a pawl guide 77 constituting the clutch mechanism 68. The pawl guide 77 is fixed so as not to rotate relative to the base plate 65 at the initial stage during normal operation and vehicle collision.

  Then, when the piston 64 is pressed and driven when the vehicle collides, and the pinion gear body 33 rotates, the pawl base 76 rotates relative to the pawl guide 77. With this rotational movement, the clutch pawl 29 protrudes in the outer diameter direction. Even after the clutch pawl 29 protrudes, the driving force continues to be applied to the pawl guide 77 as well. If the driving force cannot be resisted, the positioning protrusion 77A is broken. Thereafter, the clutch mechanism 68 integrally rotates the guide drum 21 to wind the webbing 3.

  The mounting boss 31 of the guide drum 21 is provided with an opening 31A coaxially. The drum shaft 22 is press-fitted into the opening 31A.

[Description of mechanism of pretensioner operation]
19 and 20 are perspective views for illustrating a configuration of the winding operation of the webbing 3 at the time of a vehicle collision by the pretensioner unit 7, that is, the configuration of the pretensioner operation. Note that some components are omitted in order to clarify the configuration related to the pretensioner operation. Specifically, among the members constituting the pretensioner unit 7, the clutch mechanism 68, the pinion gear body 33, and the pipe cylinder 62 remain, and the other members are omitted. Here, the base plate 65 is indicated by a dotted line. Further, the winding spring unit 8 is also omitted.

  As shown in FIGS. 19 and 20, the clutch mechanism 68 connected to the pinion gear body 33 with the base plate 65 interposed therebetween is housed in the drum recess 21 </ b> B of the guide drum 21. Thus, the side surface of the clutch mechanism 68 is disposed to face the clutch gear 30 of the guide drum 21. During the pretensioner operation, the pinion gear body 33 rotates according to the gas pressure in the pipe cylinder 62. The clutch pawl 29 housed in the clutch mechanism 68 protrudes from the side surface of the clutch mechanism 68 in the outer diameter direction in accordance with the rotation of the pinion gear body 33 by the pressing drive of the piston 64. The protruding clutch pawl 29 engages with the clutch gear 30 to rotate the guide drum 21 in the winding direction of the webbing 3.

  Here, in FIG. 20, a plurality of clutch pawls 29 are provided. According to FIGS. 21 and 22 to be described later, three clutch pawls 29 are provided and engaged with the clutch gear 30 of the guide drum 21 at three locations. The driving force of the pinion gear body 33 can be evenly transmitted to the guide drum 21 by evenly engaging the clutch gear 30 formed on the peripheral edge of the drum recess 21 </ b> B of the guide drum 21.

[Configuration of clutch mechanism]
21 and 22 are exploded perspective views showing the configuration of the clutch mechanism 68. FIG. FIG. 21 is an exploded perspective view seen from the winding spring unit 8 side, and FIG. 22 is an exploded perspective view seen from the winding drum unit 6 side.

  As shown in FIGS. 21 and 22, the clutch mechanism 68 includes a pawl base 76, a clutch pawl 29, and a pawl guide 77.

  A through hole 29 </ b> A is opened at the base end portion of the clutch pawl 29, and is press-fitted into a cross-shaped projection 77 </ b> B projecting from the pawl guide 77. The length of one side of the cross shape of the cross-shaped protrusion 77B is longer than the diameter of the through hole 29A of the clutch pawl 29, and restricts the rotation of the clutch pawl 29 in the press-fitted state. In this case, a chamfering process is performed on the through hole 29 </ b> A on the surface side facing the pawl guide 77 in the clutch pawl 29. Further, instead of or along with the chamfering of the through-hole 29A, the cross-shaped projection 77B is formed such that the length of one side of the cross shape is short at the tip, or the tip is compared with other parts. It may be formed thin. Thereby, the press-fitting work can be performed smoothly.

  Further, in the clutch pawl 29, a recess 29 </ b> C is provided at an intermediate position between the through hole 29 </ b> A and the engaging tooth 29 </ b> B, and a protrusion 77 </ b> E is provided at a corresponding position of the pawl guide 77. In a state where the pawl guide 77 is press-fitted into the cross-shaped protrusion 77B, the protrusion 77E and the recess 29C are fitted. The arrangement position of the recess 29C and the protrusion 77E has an effect of determining the rotational position of the clutch pawl 29 press-fitted into the cross-shaped protrusion 77B. This is a configuration for positioning the clutch pawl 29 press-fitted into the cross-shaped projection 77B at the storage position. Due to the fitting of the recess 29C and the protrusion 77E and the press-fitting of the through-hole 29A into the cross-shaped protrusion 77B, the clutch pawl 29 does not rotate from the storage position during normal operation, and the engaging teeth 29B protrude outward. There is no.

  Further, a guide portion 77 </ b> C is provided close to each side of the inner side of the pawl guide 77 for each clutch pawl 29. In the initial stage of operation of the pretensioner unit 7, the pawl guide 77 is in a non-rotatable state. This is because the positioning protrusion 77A is engaged with the base plate 65. In this state, the pawl base 76 rotates. The clutch pawl 29 that is pressed by the pawl support block 76B with the rotation moves in the rotational direction while breaking the cross-shaped protrusion 77B and the protrusion 77E. In the moved clutch pawl 29, the side surface on the inner diameter side of the clutch pawl 29 is pressed against the guide portion 77C. Since the pawl base 76 further rotates, the clutch pawl 29 is pressed against the pawl support block 76B and the guide portion 77C. As a result, the clutch pawl 29 is slidably guided in the outer diameter direction by the guide portion 77C and protrudes in the outer diameter direction.

The pawl base 76 is provided with an insertion hole 76A. Here, the protruding length of the cross-shaped protrusion 77B is longer than the thickness of the clutch pawl 29. When the clutch pawl 29 is press-fitted into the cruciform protrusion 77B, the tip of the cruciform protrusion 77B protrudes from the opposite side of the through hole 29A of the clutch pawl 29. When the pawl guide 77 and the pawl base 76 are fitted, a portion of the cross-shaped projection 77B that protrudes from the clutch pawl 29 is fitted into the insertion hole 76A.
Further, a thick pawl support block 76B is provided so as to surround the insertion hole 76A on the outer diameter side of the pawl base 76. The pawl support block 76B is provided to receive a load received by the clutch pawl 29 when the clutch pawl 29 presses and drives the guide drum 21 at the time of a vehicle collision.

  In addition, the clutch pawl 29 is provided with engagement teeth 29 </ b> B that engage with the clutch gear 30 at the tip. In the present embodiment, three clutch pawls 29 are arranged. When the guide drum 21 is pressed and driven when the pretensioner is actuated, it is possible to disperse the load accompanying the pressing and realize efficient pressing performance and load resistance performance.

  In the pawl base 76, a locking block 76C is formed at the outer diameter end of the pawl support block 76B. Further, a recess 76D is opened at one corner of the pawl support block 76B in the vicinity of the locking block 76C.

  The pawl guide 77 is formed with a locking hook 77D that engages with the locking block 76C and a cross-shaped projection 77F that engages with the recess 76D when the pawl base 76 is fitted.

  Here, the engagement between the locking block 76 </ b> C and the locking hook 77 </ b> D is preferably in an engagement state in which the pawl base 76 can rotate relative to the pawl guide 77 in the initial rotation by the pinion gear body 33. As a result, at the initial stage of rotation, the pawl base 76 rotates while the pawl guide 77 is kept non-rotatable, and the clutch pawl 29 protrudes. Further, the cross-shaped projection 77F fitted to the recess 76D is broken in accordance with the rotation of the pawl base 76.

  Here, the pawl base 76 and the clutch pawl 29 are made of metal members, and the pawl guide 77 is made of a resin member. As a result, the protrusion operation of the clutch pawl 29 and the rotation operation integrally with the pawl base 76 of the pawl guide 77 after the protrusion of the clutch pawl 29 and the reverse rotation restricting operation of the pawl base 76 can be performed easily and reliably. .

[Description of pretensioner operation]
Next, the pretensioner operation will be described with reference to FIGS.
FIGS. 23, 25, and 26 show a part of the pipe cylinder 62 as a cross-sectional view and a position of the piston 64 arranged inside to clearly explain a mechanism in which the pretensioner operation is transmitted to the guide drum 21. ing. Further, as an indication excluding the base plate 65 and the pawl guide 77, the engaged state between the clutch pawl 29 and the guide drum 21 is clearly shown.

  24, 27, and 28 are enlarged views of the engagement state between the clutch pawl 29 and the guide drum 21. FIG. In addition, each of the pawl base 76 and the pawl guide 77 is provided.

23 and 24 show a state before the pretensioner operation.
As shown in FIGS. 23 and 24, the piston 64 in the pipe cylinder 62 is disposed at the base position, and the rack 116 carved on the piston 64 is not engaged with the pinion gear body 33. The clutch pawl 29 is maintained in the storage position.

FIG. 25 shows a state where gas generation has started in the pipe cylinder 62. FIG. 27 shows a state corresponding to FIG. 25, and shows a state where the clutch pawl 29 which has started to protrude in the outer diameter direction starts to engage with the clutch gear 30.
As shown in FIG. 25, the piston 64 starts to be pressed toward the tip of the pipe cylinder 62 by the gas pressure. The rack 116 and the pinion gear body 33 are engaged, and the pawl base 76 starts to rotate. As a result, the clutch pawl 29 starts to protrude in the outer diameter direction.

FIG. 26 shows a state in which the piston 64 is continuously driven by gas pressure. FIG. 28 shows a state corresponding to FIG.
As shown in FIG. 26, the rotation of the pinion gear body 33 engaged with the rack 116 is continued. The rotation of the clutch mechanism 68 continues, and the protruding state of the clutch pawl 29 is maintained. Further, as shown in FIG. 28, the clutch pawl 29 completes the protrusion in the outer diameter direction, and the engagement with the clutch gear 30 is completed. Thereby, the engagement between the clutch pawl 29 and the guide drum 21 is completed, and the webbing 3 is wound around the guide drum 21.

[Description of pretensioner operation (tooth contact state)]
Here, when the clutch pawl 29 protrudes, the operation in the case where the leading end of the clutch pawl 29 hits the leading end of the clutch gear 30 of the guide drum 21 will be described with reference to FIGS.

  FIG. 29 shows a state where one of the three projecting clutch pawls 29 is in contact with the tip of the clutch gear 30 of the guide drum 21. This is a so-called tooth contact state. In this state, the clutch pawl 29 and the guide drum 21 cannot move relative to each other. Since the rotation of the pawl base 76 continues, the clutch pawl 29 that contacts the teeth tends to rotate integrally with the guide drum 21.

  At this time, the clutch pawl 29 is pressed by the guide portion 77C of the pawl guide 77 that is maintained so as not to be relatively rotatable. As the pawl base 76 rotates, the guide portion 77C receives the clutch pawl 29 while being elastically deformed.

  Normally, even if the tip end portion of the clutch pawl 29 and the tip end portion of the clutch gear 30 of the guide drum 21 are in a tooth contact state, the tooth contact state rarely continues. That is, the reaction force between the clutch pawl 29 and the clutch gear 30 due to the elastic deformation of the guide portion 77C acts obliquely with respect to the contact surface. Therefore, when the elastic deformation of the guide portion 77C proceeds, a force acts on the clutch pawl 29 in the rotational direction, and the clutch pawl 29 is pushed back. Accordingly, the tooth contact state can be eliminated, and the clutch pawl 29 and the clutch gear 30 can shift to the engaged state.

  Even when the tooth contact state cannot be resolved, as shown in FIGS. 21 and 22, three clutch pawls 29 are provided and arranged in three directions of the outer diameter direction of the clutch mechanism 68. Even if the clutch pawl 29 in the tooth contact state is not canceled, the protrusion operation of the other clutch pawls 29 is continued and the clutch gear 30 can be engaged. If there is at least one clutch pawl 29 that is not in the tooth contact state, the clutch pawl 29 and the clutch gear 30 can be engaged, and the pretensioner operation can be performed without any problem.

[Energy absorption mechanism]
Next, after the forced lock mechanism 53 or a normal emergency lock mechanism described later is operated, the webbing 3 is pulled out under a predetermined load when the pulling force acting on the webbing 3 exceeds a predetermined value set in advance. An energy absorbing mechanism that absorbs impact energy generated by the occupant will be described with reference to FIGS.

First, the attachment structure of the wire 24 attached between the guide drum 21 and the wire plate 25 will be described with reference to FIGS.
FIG. 30 is a cross-sectional view including the axis of the winding drum unit 6 and the caulking pin 39. 31 is a cross-sectional view taken along arrow X6-X6 in FIG. FIG. 32 is a perspective view of the drum guide 21 as viewed from the wire plate 25 attachment side. FIG. 33 is a partially enlarged view showing a bent path formed in the step portion 36 of the drum guide 21. FIG. 34 is a partially enlarged view showing a bent path of the wire plate 25.

  As shown in FIGS. 30 and 31, the drum shaft 22 is fixed to the center position of the end surface portion of the guide drum 21 constituting the winding drum unit 6 on the pretensioner unit 7 side by press-fitting or the like. A bearing 32 is fitted into the base end portion of the drum shaft 22. Further, a spline 23A of the torsion bar 23 is press-fitted and fixed to the inner side of the shaft hole 21A of the guide drum 21 so as not to be relatively rotatable.

Further, as shown in FIG. 31, a bent portion 24 </ b> A at one end of the wire 24 is fitted and held on the outer peripheral portion of the step portion 36 having a substantially circular shape in front view formed on the outer surface of the flange portion 35 of the guide drum 21. A bent path 145 is integrally formed.
As shown in FIG. 32, the curved path 145 includes a convex portion 147 that is formed in a substantially trapezoidal shape that projects from the outer surface in the axial direction of the flange portion 35 and that faces the lower side in front view, and a convex portion on the outer periphery of the step portion 36. A concave portion 148 that faces 147, a groove portion 149 that is formed obliquely inwardly from the outer peripheral surface of the step portion 36 that is slightly apart from the left end in the front view (left end in FIG. 33), and the concave portion 148 of the step portion 36. And the outer peripheral surface between the groove portion 149.

  Further, as shown in FIG. 33, two opposing ribs 151 are provided on the opposing surfaces of the convex portion 147 and the concave portion 148 along the depth direction of the curved path 145. A pair of ribs 152 is provided on the opposing surface of the groove 149 along the depth direction of the curved path 145. Further, the distance between the opposing ribs 151 and 152 is formed to be smaller than the outer diameter of the wire 24.

  In addition, as shown in FIG. 31, the bent portion 24A at one end of the wire 24 is fitted and fixedly held in the bent path 145 while crushing the ribs 151 and 152. Further, a frontal bent portion 24 </ b> B formed continuously from the bent portion 24 </ b> A of the wire 24 is formed to protrude outward from the outer periphery of the flange portion 35. A bent portion 24 </ b> C formed continuously with the bent portion 24 </ b> B of the wire 24 is formed in an arc shape along the outer peripheral surface of the stepped portion 36.

  In addition, as shown in FIGS. 5, 30, 31, and 34, the inner periphery of the through hole 40 of the wire plate 25 is substantially opposite to the outer periphery of the stepped portion 36, and at the periphery of the through hole 40. Is formed with an accommodating recess 155 that accommodates the wire 24, the flange portion 35, and the convex portion 147. In addition, the accommodation recess 155 is formed so that the diameter of the inner peripheral surface covering the outer periphery of the flange portion 35 is substantially equal to the outer diameter of the flange portion 35.

  Further, a bulging portion 155A that bulges outward in the radial direction to accommodate the bent portion 24B is formed in a portion of the receiving recess 155 that faces the bent portion 24B of the wire 24. Further, a convex portion 38 having a generally chevron shape when viewed from the front is integrally formed on the inner side surface of the bulging portion 155A so as to form a bending path 156 in which the wire 24 is slidably guided. Has been. Further, the radially inner end surface portion of the wire plate 25 of the convex portion 38 is formed in an arc shape along the outer peripheral surface of the step portion 36.

  Therefore, as shown in FIG. 31, to attach the wire 24 to the guide drum 21, first, the spline 23 </ b> A of the torsion bar 23 is press-fitted and fixed to the inner side of the shaft hole 21 </ b> A of the guide drum 21. Subsequently, the bent portion 24 </ b> A of the wire 24 is pushed into the bent path 145 formed in the stepped portion 36, and the bent portion 24 </ b> C is disposed along the outer peripheral surface of the stepped portion 36. Then, the convex portion 38 of the wire plate 25 is inserted into the bent portion 24B of the wire 24, the bent portion 24B of the wire 24 is inserted into the bent path 156, and the peripheral portion of the through hole 40 is applied to the wire 24. In contact therewith, the wire 24, the stepped portion 36 and the convex portion 147 are accommodated in the accommodating concave portion 155.

  Thereafter, as described above, the spline 23B formed on the other end side of the torsion bar 23 is fitted into the fixed boss 49 of the ratchet gear 26, and the protruding pins 37 of the guide drum 21 inserted into the through holes 47 are inserted. Caulking. As a result, the ratchet gear 26 and the wire plate 25 are fixed to the guide drum 21 so as not to rotate relative to each other via the protruding pins 37. Further, the ratchet gear 26 and the wire plate 25 are fixed to the torsion bar 23 so as not to rotate relative to each other by caulking each caulking pin 39 of the wire plate 25.

  Next, in the event of a vehicle collision or the like, when the forced locking mechanism 53 or a normal emergency locking mechanism described later is operated and the pawl 43 meshes with the ratchet gear 26 of the take-up drum unit 6, the webbing of the ratchet gear 26 is performed. 3 is prevented from rotating in the pull-out direction. In this state, when the pulling force acting on the webbing 3 is pulled out beyond a predetermined value set in advance, it is inserted into each through hole 47 of the ratchet gear 26 by the rotational torque acting on the guide drum 21. Each crimped pin 37 is rotated with the guide drum 21 and sheared. At this time, the impact energy is absorbed by the shearing of each of the protruding pins 37 as the “first energy absorbing mechanism”.

  At the same time, when the guide drum 21 is rotated, the spline 23A side press-fitted and fixed to the inner side of the shaft hole 21A of the guide drum 21 of the torsion bar 23 is rotated, and the torsional deformation of the torsion bar 23 is started. With the torsional deformation of the torsion bar 23, the guide drum 21 rotates in the drawing direction of the webbing 3, and the impact energy is absorbed by the torsional deformation of the torsion bar 23 as the "second energy absorbing mechanism".

  At the same time, when the guide drum 21 is rotated, the wire plate 25 and the ratchet gear 26 are fitted by the fitting convex portions 41 and the fitting concave portions 46B. Relative rotation also occurs between the guide drum 21 and the guide drum 21. Accordingly, relative rotation occurs between the wire 24 and the wire plate 25 as the guide drum 21 rotates, and the impact energy is absorbed by the wire 24 as the “third energy absorbing mechanism”.

[Wire drawing operation]
Here, the operation of the wire 24 when absorbing impact energy by the wire 24 will be described with reference to FIGS. 31 and 35 to 38. FIG. 35 to FIG. 38 are diagrams for explaining the operation of pulling out the wire 24.
As shown in FIG. 31, in the initial state of the wire plate 25 and the guide drum 21, one end side in the circumferential direction of the convex portion 141 constituting the curved path 145 is the drawing side end of the convex portion 38 constituting the curved path 156. The end portions of the bent paths 145 and 156 are opposed to each other so as to be substantially straight.

  As shown in FIGS. 35 to 37, when the guide drum 21 rotates in the pulling-out direction of the webbing 3 by pulling out the webbing 3, the wire plate 25 is prevented from rotating, and as the guide drum 21 rotates. The step portion 36 is relatively rotated in the drawing direction X7 of the webbing 3. As a result, the wire 24 in which the bent portion 24A is fixedly held on the bent path 145 of the stepped portion 36 is sequentially moved from the substantially U-shaped bent path 156 formed by the convex portion 38 in the bulged portion 155A. While being crushed, it is pulled out in the direction of arrow X8 and wound around the outer peripheral surface of the stepped portion 36. At this time, the torsion bar 23 is twisted and deformed with the rotation of the guide drum 21 at the same time as the wire 24 is pulled out.

  In addition, when the wire 24 is deformed and passes through the substantially U-shaped bending path 156 when viewed from the front, sliding resistance is generated between the convex portion 38 and the wire 24, and the bending resistance by the wire 24 itself is reduced. The impact energy is absorbed by the wire 24 by the sliding resistance and the drawing resistance due to the bending resistance.

  As shown in FIG. 38, when the other end portion of the wire 24 is detached from the bending path 156 with the rotation of the guide drum 21, the absorbing action of the impact energy by the wire 24 is finished. As the drum 21 rotates, only impact energy is absorbed due to torsional deformation of the torsion bar 23.

  Here, the absorption characteristic of the impact energy by each protrusion pin 37, the wire 24, and the torsion bar 23 is demonstrated based on FIG. FIG. 39 is an absorption characteristic diagram illustrating an example of absorption of impact energy by each of the protruding pins 37, the wire 24, and the torsion bar 23.

  As shown in FIG. 39, the impact energy is absorbed by each of the ejection pins 37 and the torsion bar 23 at the same time from when the webbing 3 starts to be pulled until each of the ejection pins 37 is sheared. Therefore, energy is absorbed by each of the protruding pins 37, the torsion bar 23, and the wire 24 until the protruding pins 37 are sheared after the webbing 3 is started to be pulled out.

  Further, during the period from when the webbing 3 is pulled out and each protruding pin 37 is sheared until the wire 24 is detached from the bending path 156, the impact energy absorbed by the torsional deformation of the torsion bar 23 and the impact energy by the wire 24 are absorbed. Is absorbed at the same time. Further, during the period from when each protruding pin 37 is sheared to when the wire 24 is pulled out from the bending path 156, the energy absorption load is as much as possible along a predetermined load smaller than the maximum load F1 that does not adversely affect the occupant. Can be set.

  Further, when the wire 24 is detached from the bending path 156, the impact energy absorbing action by the wire 24 is finished, and thereafter only the impact energy is absorbed by the torsional deformation of the torsion bar 23 as the guide drum 21 rotates. It becomes.

Accordingly, by pushing the bent portion 24A of the wire 24 into the bent path 145, the wire 24 is fixed and held by the ribs 151 and 152, so that the structure can be simplified and the assembly work of the wire 24 can be made more efficient. it can.
Further, the absorption of impact energy at the time of a vehicle collision or the like is performed by absorbing the energy absorption in the initial stage immediately after the start of the absorption of the impact energy by the protruding pins 37, the torsion bar 23 and the wire 24, and thereafter the wire 24 and the torsion bar 23. Therefore, it is possible to perform the process more efficiently.

  The webbing forced locking mechanism 53 described above is a locking mechanism that operates in the event of a vehicle collision or the like. That is, the lock mechanism prevents the occupant from moving earlier than the normal emergency lock mechanism described later operates after the webbing winding operation is completed in the pretensioner operation in an emergency such as a vehicle collision. This is a lock mechanism that operates immediately after the impact of a vehicle collision.

  In the seatbelt retractor 1 according to the present embodiment, in addition to the forced lock mechanism 53, two types of lock mechanisms are provided. They are a webbing sensitive lock mechanism that operates when a webbing is suddenly pulled out, and a vehicle body sensitive lock mechanism that operates in response to acceleration caused by a vehicle swinging or tilting. In the following description, these two types of locking mechanisms will be referred to as emergency locking mechanisms and will be described below in order to clearly distinguish them from the forced locking mechanism 53.

[Schematic configuration of emergency lock mechanism]
FIG. 40 is an exploded perspective view showing the configuration of the lock unit 9 that provides the emergency lock mechanism. FIG. 4 shows a cross-sectional view.

  As shown in FIGS. 40 and 4, the lock unit 9 is a unit that performs operations of the webbing sensitive lock mechanism and the vehicle body sensitive lock mechanism. A mechanism block 201, a clutch 202, a pilot arm 203, a return spring 204, a vehicle sensor 205, a locking gear 206, a sensor spring 207, a lock arm 208, an inertia mass 209, and a mechanism cover 210 are configured.

  A rib 202 </ b> A is provided on the outer peripheral edge of the clutch 202. By engaging with the engaging portion 201A of the mechanism block 201, the clutch 202 is rotatably attached to the mechanism block 201. At this time, the return spring 204 is held between the mechanism block 201 and the protruding holding portions 201B and 202B of the clutch 202, which are opposed to each other at the upper end of the lock unit 9, and the clutch 202 is attached to a predetermined position. Rush.

  The mechanism block 201 is open at the center. The opening shape has a substantially inverted bowl shape. Among these, the large-diameter opening has a diameter larger than the diameter of the ratchet gear 26 and smaller than the diameter of the clutch 202. As a result, the rear surface of the clutch 202 and the ratchet gear 26 are disposed close to and opposed to each other in the large-diameter opening. A connection portion between the small diameter opening and the large diameter opening provides a movable region of the pawl 43. A pawl 43 pivotally supported on the housing 11 by a pawl rivet 136 is disposed. The pawl 43 is engaged with the ratchet gear portion 45 of the ratchet gear 26 by the rotation of the pawl 43 to the large-diameter opening.

  In the mechanism block 201, a sensor placement portion 201C is provided on the opposite side of the small-diameter opening, and the vehicle sensor 205 is placed on the ball sensor 205C with the vehicle sensor lever 205A facing upward. The

  The clutch 202 has an opening 202C at the center. The shaft portion 48 of the ratchet gear 26 disposed in proximity is loosely fitted. Clutch teeth 202D are erected in an annular shape on the front surface of the clutch 202 in the direction coaxial with the opening 202C and toward the axial center.

  A mounting pin 202E and a guide groove 202F are provided in a substantially lower central portion of the clutch 202. The mounting pin 202E is provided on the front side, and the pilot arm 203 is pivotally supported so as to be rotatable. The pilot arm 203 is pushed and pushed up by the vehicle sensor lever 205A. The guide groove 202F is provided on the back side, and the guide pin 43A of the pawl 43 is loosely fitted. The guide groove 202F is formed to approach the axial center of the opening 202C toward the left. Accordingly, the pawl 43 is guided so as to approach the ratchet gear 26 as the clutch 202 rotates counterclockwise.

  Further, a guide block 202G extends from the mounting pin 202E to the lower left. The guide block 202G is provided to face the lever base 205B of the vehicle sensor 205. It has a taper structure that extends downward as it extends leftward from the mounting pin 202E. The tip is an area having a certain width.

  The locking gear 206 has an annular groove 206 </ b> D that accommodates a clutch tooth 202 </ b> D erected on the clutch 202 in an annular shape on the back side thereof. The locking gear 206 is disposed in contact with or close to the clutch 202 so that the groove 206D surrounds the clutch teeth 202D. The shaft portion 48 in which the opening 202C is loosely fitted is press-fitted coaxially with the locking gear 206. The ratchet gear 26 and the locking gear 206 are fixed coaxially.

  At one corner of the locking gear 206 on the outer peripheral end side, an opening 206C is provided through the groove 206D. A shaft support pin 206B is provided in the vicinity of the opening 206C. The lock arm 208 is pivotally supported by the pivot pin 206B so that the tip end portion of the lock arm 208 can rotate from the opening 206C toward the outer groove 206D. Further, the lock arm 208 is connected to the locking gear 206 by a sensor spring 207, and is urged so that the tip portion does not protrude from the opening 206C during normal operation. During the locking operation by the webbing sensitive lock mechanism, the lock arm 208 projects into the groove 206D through the opening 206C, and the tip of the lock arm 208 engages with the clutch teeth 202D.

  Locking gear teeth 206A are formed on the outer peripheral edge of the locking gear 206 in the outer diameter direction. The locking gear 206 is disposed on the clutch 202 so that the locking gear teeth 206 </ b> A are close to the pilot arm 203. During the locking operation by the vehicle body sensitive locking mechanism, the pilot arm 203 is pushed up by the vehicle sensor lever 205A of the vehicle sensor 205, and the tip of the pilot arm 203 is engaged with the locking gear teeth 206A.

  An inertia mass 209 is rotatably attached to the front surface of the locking gear 206. The inertia mass 209 has a guide opening 209A. A guide pin 208A protruding from the lock arm 208 is loosely fitted into the guide opening 209A. The inertia mass 209 is a member that generates a delay in inertia with respect to a sudden webbing withdrawal, and is formed of a metal member. Although one guide opening 209A may be functionally provided, a dummy guide opening 209A is provided at a point-symmetrical position at the center point of the inertia mass 209 for the purpose of generating inertial delay.

  The front surface of the lock unit 9 is covered with a mechanism cover 210. The mechanism cover 210 is provided with a ny latch 210A. The ny latch 210A has the same configuration as the ny latch 8A. The lock unit 9 is fixed to the housing 11 by the ny latch 210A through the opening 201D of the mechanism block 201.

  The lock unit 9 is made of a resin member except the inertia mass 209, the return spring 204, the sensor spring 207, and the metal ball of the vehicle sensor 205, and the coefficient of friction between the members when they are in contact with each other is It is a small thing.

  Next, the operation of the normal lock mechanism will be described with reference to FIGS. In the figure, the drawing direction of the webbing is the illustrated direction. The counterclockwise rotation direction is the webbing pull-out direction. In the following description, the operation related to the locking operation will be mainly described, and description of other portions will be omitted as appropriate. Further, for the explanation of the operation, a part of the drawing is cut out and displayed as necessary. The operation of the pawl 43 is common in both the webbing sensitive lock mechanism and the vehicle body sensitive lock mechanism. For this reason, in the following description, about the part which shows the relationship between the pawl 43 and the ratchet gear 26, the part is displayed as a notch state.

[Description of webbing-sensitive locking mechanism]
41 to 43 are operation explanatory views of the webbing sensitive lock mechanism. In the webbing sensitive lock mechanism, in addition to the portion indicating the relationship between the pawl 43 and the ratchet gear 26, the portion indicating the relationship between the lock arm 208 and the clutch teeth 202D and the portion of the sensor spring 207 are cut out and displayed. Yes.

  When the acceleration in the pulling direction applied to the webbing exceeds a predetermined value, the sensor spring 207 cannot maintain the initial position of the inertia mass 209. That is, an inertia delay occurs in the inertia mass 209, and the locking gear 206 rotates counterclockwise with respect to the inertia mass 209.

  As a result, the guide pin 208A of the lock arm 208 is guided by the guide opening 209A of the inertia mass 209, and the distal end of the lock arm 208 rotates in the outer diameter direction and engages with the clutch teeth 202D. This state is shown in FIG.

  When the webbing continues to be pulled out even after the lock arm 208 is engaged with the clutch teeth 202D, the counterclockwise rotational force is continuously applied to the locking gear 206 fixed coaxially with the ratchet gear 26. Since the lock arm 208 is engaged with the clutch teeth 202D, the clutch 202 is also rotated counterclockwise.

  As a result, the guide pin 43A of the pawl 43 is guided into the guide groove 202F of the clutch 202, and the pawl 43 rotates toward the ratchet gear 26. This state is shown in FIG.

  As the pawl 43 continues to rotate and engages with the ratchet gear 26, the rotation of the ratchet gear 26 is locked. The rotation of the guide drum 21 is locked, and the webbing drawer is locked. This state is shown in FIG.

  In the state of FIG. 43, the return spring 204 is maintained in a compressed state. Accordingly, when the pulling force applied to the webbing is relaxed and the guide drum 21 rotates in the winding direction, the clutch 202 is rotated clockwise by the urging force of the compressed return spring 204. As a result, the guide pin 43A of the pawl 43 is guided in the reverse direction through the guide groove 202F of the clutch 202, and the pawl 43 is separated from the ratchet gear 26. The locked state is released.

[Explanation of body-sensitive locking mechanism]
44 to 46 are operation explanatory views of the vehicle body sensitive locking mechanism. In the vehicle body sensitive locking mechanism, a portion indicating the relationship between the pawl 43 and the ratchet gear 26 is cut out and displayed.

  When the acceleration due to the shake or tilt of the vehicle body exceeds a predetermined value, the ball sensor 205C of the vehicle sensor 205 cannot maintain the predetermined position, and the vehicle sensor lever 205A pushes up the pilot arm 203.

  Thereby, the front-end | tip part of the pilot arm 203 engages with the locking gear teeth 206A. This state is shown in FIG.

  When the engagement state between the pilot arm 203 and the locking gear teeth 206 </ b> A continues, the counterclockwise rotational force applied to the locking gear 206 causes the clutch 202 on which the pilot arm 203 is pivotally supported via the pilot arm 203. Turn counterclockwise.

  As a result, the guide pin 43A of the pawl 43 is guided into the guide groove 202F of the clutch 202, and the pawl 43 rotates toward the ratchet gear 26. This state is shown in FIG.

  As the pawl 43 continues to rotate and engages with the ratchet gear 26, the rotation of the ratchet gear 26 is locked. The rotation of the guide drum 21 is locked, and the webbing drawer is locked. This state is shown in FIG.

  Similar to the webbing sensitive lock mechanism, when the webbing 3 is wound up, the clutch 202 rotates clockwise and the engagement between the pawl 43 and the ratchet gear 26 is released. The ball sensor 205C returns to the initial state when the acceleration of the vehicle is lost.

  Here, the guide block 202G is a swing restricting member that prevents the vehicle sensor lever 205A from being lifted by the acceleration of the vehicle body when the locked state is released and the clutch 202 rotates clockwise to return to the normal position. Thus, the tip of the pilot arm 203 and the vehicle sensor lever 205A of the vehicle sensor 205 are in contact with each other so that the return of the clutch 202 is not restricted.

  In the locked state, the lower end portion of the wide area of the guide block 202G is in contact with the lever base portion 205B of the vehicle sensor 205. In this state, if the width of the wide area is set so that the tip position of the vehicle sensor lever 205A is maintained below the movable locus of the lower end portion of the pilot arm 203, the clutch 202 rotates clockwise. Also when returning, the vehicle sensor lever 205A and the tip of the pilot arm 203 do not come into contact with each other. As the clutch 202 rotates in the clockwise direction, the lower end portion of the guide block 202G that comes into contact with the lever base portion 205B has a taper structure, and the width is gradually reduced. As a result, when the clutch 202 rotates clockwise and returns to the normal position when returning from the locked state, the tip of the pilot arm 203 comes into contact with the vehicle sensor lever 205A to restrict the return operation of the clutch 202. There is no end. Further, in a normal operation state, the lever base 205B does not contact the guide block 202G, and the swing of the vehicle sensor 205 due to the acceleration of the vehicle body is not restricted by the guide block 202G.

  Here, the winding drum unit 6 is an example of a winding drum. The pretensioner mechanism 17 is an example of a pretensioner mechanism unit. The base plate 65 is an example of one side wall portion. The gas generating member 61 is an example of a gas generating member. The pipe cylinder 62 is an example of a cylinder. The block body 66 is an example of a block member. The stopper screw 16 is an example of a fastening member. The through hole 127 is an example of a cover side fixing hole. The through hole 128 is an example of a base plate side fixing hole.

  Therefore, in the seatbelt retractor 1 according to the present embodiment, the bent portion 112 of the base plate 65 is fitted into the notch 113 formed at the upper end of the piston accommodating portion 62B, and the pipe having a rectangular cross section is formed on the base plate 65. A cylinder 62 is disposed. Further, the piston 64 to which the seal plate 63 is attached at the end portion is press-fitted from the upper end side of the piston housing portion 62B with the seal plate 63 at the back side. Then, a base block body 66 that is locked by the elastic locking pieces 66A and 66B, a forced lock mechanism 53, a pipe cylinder 62, and the like are disposed on the base plate 65, and a cover plate 57 is further disposed on the upper side, The cover plate 57 is locked by the elastic locking pieces 66C and 66D of the base block body 66.

  Subsequently, stopper screws 16 made of steel or the like are inserted into the through holes 127 and 128 formed at positions facing the through holes 114 of the pipe cylinder 62 of the cover plate 57 and the base plate 65 from the cover plate 57 side. The pipe cylinder 62 is attached to the housing 11 in a state of being sandwiched between the cover plate 57 and the base plate 65 by being inserted and screwed to the screwing portion 14B of the housing 11. Then, the stepped portion 117 of the piston 64 that is pressed and driven by the gas pressure generated at the time of a vehicle collision or the like comes into contact with the stopper screw 16 inserted into the opening side end portion of the piston housing portion 62B, and the piston 64 The movement stops.

  Thereby, the pipe cylinder 62 and the cover plate 57 can be attached to the base plate 65 with a simple configuration, and the structure of the pretensioner mechanism 17 can be simplified. Further, the pipe cylinder 62 can form a moving path of the piston 64 only by the long cylindrical piston housing part 62B having a substantially rectangular cross section. Further, the stopper screw 16 inserted through the opening side end of the piston housing portion 62B can stop the movement of the piston 64 that is pressed and driven by the gas pressure generated at the time of a vehicle collision or the like. It becomes possible to further simplify the structure of the mechanism 17.

  Further, the stepped portion 117 of the piston 64 comes into contact with the stopper screw 16 inserted through the opening side end portion of the piston housing portion 62B and stops in the cylinder. This makes it possible to dispose the stopper screw 16 from the upper end of the piston accommodating portion 62B to the lower position by the height of the stepped portion 117, and shorten the length of the piston accommodating portion 62B to reduce the seat belt. The retractor 1 can be downsized. Further, the length of the rack 116 can be increased by the height of the stepped portion 117, and the effective length of the rack 116 that meshes with the pinion gear portion 71 of the piston 64 can be ensured.

  Further, the pipe cylinder 62 and the block body 66 are arranged on the base plate 65, and the cover plate 57 can be locked to the base plate 65 in advance by the elastic locking pieces 66C and 66D of the block body 66. Then, by attaching the base plate 65 and the like to the housing unit 5 with the screws 15 and the stopper screws 16, it becomes possible to constitute one side wall portion of the housing unit 5, and the pretensioner mechanism 17 is attached to the housing unit 5. It is possible to simplify the structure.

  In addition, this invention is not limited to the said embodiment, Of course, various improvement and deformation | transformation are possible within the range which does not deviate from the summary of this invention.

  For example, instead of the stopper screw 16, a rivet or the like is inserted into the through holes 127 and 128 formed at positions facing the through holes 114 of the pipe cylinder 62 of the cover plate 57 and the base plate 65, and then caulked and fastened. You may do it. Thereby, the pipe cylinder 62 and the cover plate 57 can be attached to the base plate 65 with a simple configuration, and the structure of the pretensioner mechanism 17 can be simplified. In addition, the rivet or the like inserted through the opening side end of the piston storage portion 62B can stop the movement of the piston 64 that is pressed and driven by the gas pressure generated at the time of a vehicle collision or the like. It is possible to further simplify the structure of 17.

1 is an external perspective view of a seatbelt retractor according to the present embodiment. It is the perspective view which decomposed | disassembled the seatbelt retractor for every unit. It is a perspective view of a winding drum unit. It is sectional drawing of the retractor for seatbelts. It is a disassembled perspective view of a winding drum unit, a pretensioner unit, and a winding spring unit. It is the perspective view which looked at the pretensioner unit from the attachment surface side to a housing unit. It is a partially cutaway side view of a pretensioner unit. It is the disassembled perspective view which decomposed | disassembled the pretensioner unit of FIG. It is a disassembled perspective view of a housing unit. It is a side view of the state which removed the lock unit of the retractor for seatbelts. It is explanatory drawing which shows the state which the piston contact | abutted to the pinion gear part of the pinion gear body by the action | operation of the gas generation member of a pretensioner mechanism. It is explanatory drawing which shows the operation | movement of the pawl corresponding to FIG. It is explanatory drawing which shows the moment when a piston moves further and the lower end part of a rotation lever remove | deviates from the front-end | tip part of a gear side arm. It is explanatory drawing which shows the operation | movement of the pawl corresponding to FIG. It is explanatory drawing which shows the state which the piston further moved and the lower end part of the rotation lever removed from the front-end | tip part of a gear side arm. It is explanatory drawing which shows the operation | movement of the pawl corresponding to FIG. It is a fragmentary sectional view which shows connection with a winding drum unit and a winding spring unit on both sides of a pretensioner unit. It is a top view explaining the relationship between a guide drum, a clutch mechanism, and a base plate. It is a perspective view explaining the mechanism of a pretensioner operation. It is a perspective view explaining the mechanism of a pretensioner operation. It is a disassembled perspective view which shows the structure of a clutch mechanism. It is a disassembled perspective view which shows the structure of a clutch mechanism. It is a figure explaining the mechanism which a pretensioner operation | movement transmits to a guide drum (normal time). It is the elements on larger scale (at the time of a rest) which show the engagement state of a clutch pawl and a guide drum. It is a figure explaining the mechanism which a pretensioner operation | movement transmits to a guide drum (at the time of engagement start). It is a figure explaining the mechanism which pretensioner operation | movement transmits to a guide drum (at the time of completion of engagement). It is the elements on larger scale which show the engagement state of a clutch pawl and a guide drum (at the time of the engagement start by pretensioner operation | movement). It is the elements on larger scale which show the engagement state of a clutch pawl and a guide drum (at the time of completion of engagement by pretensioner operation). It is the elements on larger scale which show the state of the tooth contact of a clutch pawl and a clutch gear. It is sectional drawing containing the axial center and winding pin of a winding drum unit. It is X6-X6 arrow sectional drawing of FIG. It is the perspective view which looked at the drum guide from the attachment side of a wire plate. It is a partially expanded view which shows the bending path formed in the level | step-difference part of a drum guide. It is a partially expanded view which shows the bending path of a wire plate. It is operation | movement explanatory drawing which pulls out a wire. It is operation | movement explanatory drawing which pulls out a wire. It is operation | movement explanatory drawing which pulls out a wire. It is operation | movement explanatory drawing which pulls out a wire. It is an absorption characteristic figure which shows an example of absorption of the impact energy by each protrusion pin, a wire, and a torsion bar. It is a disassembled perspective view of a lock unit. It is operation | movement explanatory drawing (at the time of an operation | movement start) of a webbing sensitive type locking mechanism. It is operation | movement explanatory drawing (transition period to a locked state) of a webbing sensitive type locking mechanism. It is operation | movement explanatory drawing (lock state) of a webbing sensitive type locking mechanism. It is operation | movement explanatory drawing (at the time of operation | movement start) of a vehicle body sensitive lock mechanism. It is operation | movement explanatory drawing (transition period to a locked state) of a vehicle body sensitive lock mechanism. It is operation | movement explanatory drawing (lock state) of a vehicle body sensitive lock mechanism.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Retractor for seat belts 3 Webbing 5 Housing unit 6 Winding drum unit 7 Pretensioner unit 8 Winding spring unit 9 Lock unit 11 Housing 12 Side wall part 16 Stopper screw 17 Pretensioner mechanism 26 Ratchet gear 33 Pinion gear body 43 Pawl 45 Ratchet gear part 53 Lock Mechanism 61 Gas Generating Member 62 Pipe Cylinder 64 Piston 68 Clutch Mechanism 87 Push Block 88 Rotating Lever 89 Gear Side Arm 90 Biasing Spring 91 Connection Shaft 92 Mechanical Side Arm 136 Paul Rivet

Claims (2)

A housing having a pair of side wall portions;
A winding drum that is rotatably supported between the pair of side wall portions and biased in a winding direction of the webbing in a state where the webbing is wound;
A pretensioner mechanism that winds the webbing by rotating the winding drum in the winding direction at the time of a vehicle collision;
In the seat belt retractor with
The pretensioner mechanism is
A gas generating member that generates gas;
A cylinder having a rectangular cross section and a long cylindrical shape, the gas generating member being mounted at one end and disposed on the outer surface of one of the pair of side walls,
A pinion gear body that can rotate in conjunction with the winding drum;
A rack that is movably accommodated in the cylinder and is pressed and driven by the pressure of the gas, and a rack that meshes with the pinion gear body is formed on a side surface, and the winding drum is moved through the pinion gear body by the pressing drive. A piston that rotates in the winding direction;
A cover plate disposed across the cylinder on the one side wall;
A fastening member inserted through a cover-side fixing hole formed in the cover plate and a pair of through-holes formed opposite to both side surfaces of the other end of the cylinder;
Have
Forming said piston, are all predetermined height cut over the tooth width direction entire width of the rack at the rack on the back side of the wider width than the portion facing the fastening member to the rack-side direction from the tip end portion of the side surface Has a stepped portion,
When the fastening member is fastened to the one side wall portion and the cover plate is attached to the one side wall portion with the cylinder interposed therebetween, and the piston is pressed and driven by the pressure of the gas, a seatbelt retractor according to claim Rukoto stopped in the cylinder the stepped portion is in contact with the fastening member. The pretensioner mechanism is
A base plate attached to the housing to form one side wall of the housing;
A block member having one side surface locked to the base plate and the other side surface locked to the cover plate and disposed opposite the cylinder;
Have
The seat belt retractor according to claim 1, wherein the fastening member is inserted into a base plate-side fixing hole formed in the base plate and screwed to the housing.

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