In a webbing take-up device, a base cartridge receives pressure of gas generated by an MGG, load from a piston that is moved by the pressure of the gas, and reaction force acting on the MGG when gas has been ejected from the MGG. This enables strength retention with respect to the above-described pressure, load, and reaction force to be simplified.

A retractor includes a spool, a torsion bar and a torsion tube rotationally fixed to the spool, and a locking member aligned with the torsion bar. The torsion bar and the torsion tube extend coaxially from the spool to respective first ends, and the torsion bar has a key. The locking member is movable from an unlocked position rotationally disengaged with the torsion bar to a locked position wherein the key rotationally fixes the locking member to the first end of the torsion bar. When the locking member is in the unlocked position, the torsion bar may be plastically deformed to limit the load applied by webbing against an occupant. If sufficient force is applied to the webbing, the locking member moves to the locked position in which both torsion bar and the torsion tube are locked together and, in tandem, limit the load applied by the webbing.

[Object] To provide a seat belt retractor that is capable of generating a more stable load when restricting a load acting on the seat belt and when absorbing energy, and a seat belt apparatus including the same. [Solution] A seat belt retractor 3 includes a frame 11, a seat belt 4, a spool 12 that is rotatably supported by the frame 11 and that retracts the seat belt 4, a lock mechanism 60 that allows rotation of the spool 12 while not in operation and that prevents rotation of the spool 12 in a seat belt withdrawing direction while in operation, and an energy absorption mechanism 20 that restricts a load acting on the seat belt 4 and that absorbs energy of an occupant. In the seat belt retractor 3, the energy absorption mechanism 20 includes a first energy absorption member 21 that absorbs energy through a rotational difference between the spool 12 and the lock mechanism 60, a first energy transmission member 22 that is attached on one end side of the first energy absorption member 21, a second energy transmission member 23 that meshes with the first energy transmission member 22, and a second energy absorption member 24 that absorbs energy through a rotational difference between the second energy transmission member 23 and the spool 12.

In a webbing retractor device, a compression coil spring is suspended between an engagement frame of a V-gear and an engagement surface of a locking base. As a result of the engagement frame being engaged with from an exposed portion side by the compression coil spring that is being held in a holding groove of the locking base so as to be exposed to the exposed portion side, the compression coil spring is suspended between the V-gear and the locking base. Because of this, the compression coil spring can be easily suspended between the V-gear and the locking base.

A serrated portion is formed on an outer peripheral portion of a lock base body of a lock base of a webbing take-up device. Furthermore, a flange portion is formed on the outer peripheral portion of the lock base body. The flange portion is disposed on a vehicle front side with respect to the serrated portion. Triangular grooves of the serrated portion are closed by the flange portion. When the lock base becomes displaced in a vehicle rearward direction and the flange portion comes into abutting contact with a leg plate of a frame, further displacement of the lock base in the vehicle rearward direction is blocked. Due to this, engagement between the serrated portion and ratchet teeth of a ratchet hole in the leg plate can be maintained.

A webbing take-up device includes a spool that is rotated in a pull-out direction by a webbing being pulled out and a lock base that limits pull-out direction rotation of the spool in a vehicle emergency. The webbing take-up device also includes a wire shaped energy absorbing wire that is deformed so as to permit pull-out direction rotation of the spool at or above a force limiter load after the lock base has limited pull-out direction rotation of the spool, a winder section to which one end of the energy absorbing wire is anchored and that is rotated so as to take up the energy absorbing wire, and a wire guide and a lever that press and deform the energy absorbing wire at position offset in the axial direction of the winder section with respect to a location where the energy absorbing wire is anchored to the winder section.

A force-limiting device (4) for a seat belt device having at least two parts (5, 11, 15) controlled with a frequency-dependent, defined movement for energy absorption, wherein the parts (5, 11, 15) that move the parts (5, 11, 15) undergo an undulating movement (Q) directed perpendicular to the feed movement (V) in the course of which the gearings (8, 10, 18, 19) alternatingly engage and disengage. An open spring washer exerts force to move the parts (5, 11, 15) toward one another and can be automatically increased after a preset belt extraction length. The spring washer (6) applies a varying spring force to the parts (5, 11, 15) moving toward one another during the movement.

A webbing take-up device includes a spool, a lock base that restricts pull-out direction rotation of the spool in a vehicle emergency, and a linear energy absorbing wire that deforms so as to permit pull-out direction rotation of the spool at or above a force limiter load when the lock base has restricted pull-out direction rotation of the spool. The webbing take-up device further includes a housing with which the energy absorbing wire engages along a radial direction inside face of the housing, and a winder section provided at a radial direction inside of the housing. The winder section is capable of rotating together as a unit with the spool, and takes up the energy absorbing wire by being rotated. Moreover, a wire guide and a lever are provided between the winder section and the housing. The wire guide and the lever pinch and deform the energy absorbing wire.

A belt reel (14) for a belt retractor (10) has a rotational axis (R) and a reel body (16) that is provided as a reel for a webbing (24) and has a first axial circumferential circle (34). The reel body (16) further includes a radial constriction (32) having a second axial circumferential circle (36), wherein the constriction (32) is arranged centrally on the reel body (16) in the axial direction (A) and wherein the circumference of the second axial circumferential circle (36) amounts to a maximum of 95% of the circumference of the first axial circumferential circle (34). Moreover, a belt retractor (10) comprising such belt reel (14) is described.

A restraint system includes a retractor housing; a spool rotatably coupled to the retractor housing and defining an axis of rotation; an inner torsion bar elongated along the axis of rotation and positioned coaxially in the spool; an outer torsion bar elongated along the axis of rotation, extending coaxially around the inner torsion bar, and positioned coaxially in the spool; an engagement member selectively engageable with the outer torsion bar; and a solenoid operable to move the engagement member into engagement with the outer torsion bar and out of engagement with the outer torsion bar.