Seatbelt retractor

Patent metadata

Field	Value
Publication number	US-9688237-B2
Application number	US-201314412077-A
Country	US
Kind code	B2
Filing date	Jul 3, 2013
Priority date	Jul 13, 2012
Publication date	Jun 27, 2017
Grant date	Jun 27, 2017

Abstract

A lock member includes a closed cylindrical portion having lock teeth and a fixation boss provided inside the cylindrical portion and inserted in a fitting hole formed at one end of the take-up drum and facing the take-up drum along an axial direction of the cylindrical portion. A stopper mechanism includes a ring member whose inner peripheral surface is mounted on the fixation boss and whose outer peripheral surface is fitted in the fitting hole so as to prohibit relative rotation with respect to the fitting hole. The ring member is movable relative to the fixation boss in the axial direction of the take-up drum by the relative rotation with respect to the fixation boss. Further, movable area allowed for the ring member to move on the fixation boss axially outward with respect to the take-up drum has an movable end located inside of the closed cylindrical portion.

First claim

The invention claimed is:

1. A seatbelt retractor comprising:
a take-up drum onto which a webbing is wound;
a lock mechanism having a lock member that is arranged near one end of the take-up drum and connected to the take-up drum with relative rotation between the take-up drum and the lock member being prohibited, the lock member being prohibited from rotating in a webbing-pull-out direction in case of emergency, and the take-up drum being allowed a relative rotation with respect to the lock member when force to pull out the webbing exceeds a predetermined value in a state that the lock member is prohibited from rotating in the webbing-pull-out direction;
an energy absorption mechanism arranged between the take-up drum and the lock member and configured to absorb energy by allowing the relative rotation between the take-up drum and the lock member; and
a stopper mechanism configured to stop the relative rotation between the take-up drum and the lock member when the take-up drum is rotated a predetermined number of times relative to the lock member,
wherein the lock member includes:
a cylindrical portion having lock teeth on an outer periphery thereof and having an inner bottom surface that (i) closes the cylindrical portion, (ii) faces the take-up drum, and (iii) is concentric with the take-up drum; and
a fixation boss provided at the inner bottom surface to face the take-up drum along an axial direction of the closed cylindrical portion, the fixation boss being concentric with the take-up drum and inserted in a fitting hole formed at the one end of the take-up drum and in a stepped portion that is located within the closed cylindrical portion and configured to project from the one end of the take-up drum in an axial direction of the take-up drum,

wherein the stopper mechanism includes a ring member that (i) is externally fitted and screwed to the fixation boss so as to be allowed relative rotation with respect to the fixation boss, (ii) has an outer peripheral surface fitted in the fitting hole so as to prohibit relative rotation of the ring member and allow the ring member to move in the axial direction of the take-up drum with respect to the fitting hole, and (iii) is movable toward a base end of the fixation boss in the axial direction of the take-up drum by the relative rotation with respect to the fixation boss,
wherein when the take-up drum is rotated the predetermined number of times relative to the lock member, the ring member comes into contact with the base end of the fixation boss and is prevented from moving so as to stop the relative rotation between the take-up drum and the lock member, and
wherein the base end portion of the fixation boss, including a surface of the base end portion that comes into contact with the ring member, is inside the closed cylindrical portion in the axial direction of the take-up drum and is located radially inward of the lock teeth of the closed cylindrical portion.

2. The seatbelt retractor according to claim 1 ,
wherein the lock member includes:
a ratchet gear member that has the closed cylindrical portion; and
a fixation member being fixed to the ratchet gear member so as to prohibit relative rotation with respect to the ratchet gear member and having the fixation boss on a center portion thereof facing to the take-up drum.

3. The seatbelt retractor according to claim 2 ,
wherein the ratchet gear member has a connecting portion provided inside of the closed cylindrical portion and including a through hole, and
wherein the fixation member is attached to the connecting portion so that the fixation member is fitted in at least a part of the through hole.

4. The seatbelt retractor according to claim 3 ,
wherein the connecting portion includes a plurality of mounting pieces extended radially inward from the inner peripheral surface of the closed cylindrical portion,
wherein the fixation member includes a brim-like portion configured to project radially outward from the base end portion of the fixation boss with respect to rotational axis of the take-up drum, and
wherein the brim-like portion includes a plurality of concave portions at a radially outer peripheral portion so that the plurality of mounting pieces are fitted in the plurality of concave portions, and
wherein the brim-like portion is attached to the connecting portion so that the plurality of mounting pieces are fitted in the plurality of concave portions and the fixation member is attached to the ratchet gear member so as to prohibit relative rotation therebetween.

5. The seatbelt retractor according to claim 4 ,
wherein the ratchet gear member includes a plurality of pins arranged so as to erect on the connecting portion,
wherein the fixation member includes a plurality of notch portions formed on an outer peripheral portion of the brim-like portion so that the plurality of pins are fitted in the plurality of notch portions,
wherein heads of the plurality of pins are configured to project from the plurality of notch portions when the plurality of pins are fitted in the plurality of notch portions, and
wherein, the fixation member is fixedly attached to the ratchet gear member by causing the heads of the plurality pins to get plastically deformed and cover at least a part of the brim-like portion after the plurality of pins are fitted in the plurality of notch portions.

6. The seatbelt retractor according to claim 4 ,
wherein the brim-like portion is provided on the fixation member at an edge portion located at an axially opposite side with respect to the take-up drum, and
wherein the brim-like portion is attached to the connecting portion so that a surface of the brim-like portion constitutes at least a part of a surface of the ratchet gear facing an opposite side with respect to the take-up drum.

7. The seatbelt retractor according to claim 2 , wherein the fixation member is made from material of which strength is higher than strength of material used for the ratchet gear member.

8. The seatbelt retractor according to claim 1 , wherein the fitting hole has a deepest position in the axial direction of the take-up drum at a location near a flange portion that is extended radially outward from an outer periphery of the one end of the take-up drum.

9. The seatbelt retractor according to claim 1 , wherein the energy absorption mechanism includes a torsion bar that is inserted and fitted inside the take-up drum in such a manner that one axial end of the torsion bar is fixed to the other end of the take-up drum so as to prohibit relative rotation with respect to the take-up drum and the other axial end of the torsion bar is fixed to the fixation boss so as to prohibit relative rotation with respect to the fixation boss, the torsion bar absorbing energy in a form of torsional deformation caused by relative rotation between the take-up drum and the lock member.

Assignees

• Ashimori Ind Co Ltd

Inventors

• Ijiri Takayoshi

Classifications

• B60R22/46

  {Reels} with means to tension the belt in an emergency {by forced winding up}(electrical circuits for triggering safety arrangements B60R21/01 {; tensioners using reels only guiding the belt during normal use, e.g. splitted reels B60R22/195}) · CPC title

• B60R22/341 Primary

  comprising energy-absorbing means · CPC title

• B60R22/405 Primary

  responsive to belt movement and vehicle movement · CPC title

• B60R2022/3402

  Retractor casings; Mounting thereof · CPC title