Winding – tensioning – or guiding – Reeling device – With spring motor
Reexamination Certificate
2002-11-13
2004-12-28
Matecki, Kathy (Department: 3654)
Winding, tensioning, or guiding
Reeling device
With spring motor
Reexamination Certificate
active
06834821
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a webbing retractor which, at the time a vehicle rapidly decelerates and by using a locking device, temporarily locks rotation in a webbing pull-out direction of a spool on which a webbing for restraining a vehicle occupant is taken-up in a roll form by urging force, and which, in this state, permits a predetermined amount of rotation of the spool in the webbing pull-out direction due to load of a predetermined value or more being applied from the vehicle occupant to the webbing.
2. Description of the Related Art
Generally, a three-point-type seat belt device is structured so as to include a webbing for restraining a vehicle occupant, an anchor plate, a webbing retractor, a shoulder anchor, a tongue plate, and a buckle device. The anchor plate fixes one end portion of the webbing to the floor of the vehicle. The webbing retractor is a device which is disposed at the lower end portion of the center pillar of the vehicle and which takes-up the other end portion of the webbing in a roll form by urging force. The shoulder anchor is disposed at the upper portion of the center pillar, and an intermediate portion of the webbing is movably inserted through the shoulder anchor. An intermediate portion of the webbing passes through the tongue plate. The buckle device stands upright at the side of a seat of the vehicle, and the tongue plate engages therewith.
Various types of the above-described webbing retractor have been proposed. In one type, when the vehicle rapidly decelerates, the webbing retractor temporarily stops rotation of the spool in the webbing pull-out direction. Thereafter, due to a load of a predetermined value or more being applied to the webbing from the vehicle occupant, a torsion bar, which is provided integrally with and coaxially with the axially central portion of the spool, is twisted. The spool is thereby rotated by a predetermined amount in the webbing pull-out direction. In this way, the load which the vehicle occupant receives from the webbing which is in a locked state can be lessened. This mechanism is called a “force limiter mechanism”.
In a webbing retractor equipped with this type of a force limiter mechanism, a locking assembly, which locks rotation of the torsion bar in the webbing pull-out direction at the time when the vehicle rapidly decelerates, must be coaxially fixed to the axially central portion of the spool shaft. Thus, conventionally, the locking assembly was fixed to the spool by inserting a stopper, which was made of resin and formed in a substantial U shape, into the spool in a direction orthogonal to the axis of the spool, and by plastically deforming the stopper.
In recent years, structures have been proposed in which the load, at the time when the spool can rotate again by a predetermined amount in the webbing pull-out direction due to an increase in the webbing tensile force after the rotation of the spool in the webbing pull-out direction has been stopped at the time when the vehicle rapidly decelerates (this load is the force limiter load and hereinafter will be abbreviated as “FL load”), is set to be two stages. Namely, in the initial stage of the time when the vehicle rapidly decelerates, the FL load is maintained high, and the energy absorption efficiency is high. Thereafter, by reducing the FL load, the load which the vehicle occupant receives from the webbing is reduced.
When the above-described fixing structure is applied to a webbing retractor which is equipped with a force limiter mechanism which is this two-stage FL load type, a large load in the thrusting direction arises. Thus, there is the possibility that the conventional resin stopper will not be able to withstand this load, and the locking assembly will spring out in the axial direction. Accordingly, this springing-out of the locking assembly must be suppressed by forming the stopper of metal. However, if the stopper is formed of metal, press-fitting of the stopper into the spool by plastic deformation is not possible, and therefore, noise arises at the time of ordinary operation of the webbing retractor.
SUMMARY OF THE INVENTION
In view of the aforementioned, an object of the present invention is to provide a webbing retractor which can prevent the generation of noise at the time of ordinary operation, which noise is caused by a stopper member being insufficiently pressed-in, and which can more strongly fix a locking device to a spool.
An aspect of the present invention is a webbing retractor comprising: a spool taking up a webbing, for restraining a vehicle occupant, in a roll form by urging force; an energy absorbing member permitting a predetermined amount of rotation of the spool in a webbing pull-out direction; a locking device stopping rotation of the energy absorbing member at a time of rapid deceleration of a vehicle; and a stopper member which, when installed, applies both press-in load in a thrusting direction and press-in load in a radial direction, between one portion of the locking device and the spool. The energy absorbing member is connected coaxially to the spool, and usually rotates integrally with the spool. In a state in which rotation of the energy absorbing member in the webbing pull-out direction is impeded, the energy absorbing member deforms due to a load of a predetermined value or more being applied to the energy absorbing member via the spool, and the energy absorbing member permits a predetermined amount of rotation of the spool in the webbing pull-out direction. One portion of the locking device is inserted coaxially between the energy absorbing member and the spool. The stopper member is a member which is installed by being inserted between the outer peripheral surface of one portion of the locking device and the inner peripheral surface of the spool, from a direction orthogonal to the axis.
In the webbing retractor relating to the present invention, the stopper member may have a terminal end portion which is formed by being bent back and which, in an installed state, applies elastic restoring force in the radial direction between one portion of the locking device and the spool.
In the webbing retractor relating to the present invention, a protruding portion may be formed at the terminal end portion of the stopper member, and the protruding portion protrudes in a widthwise direction of the terminal end portion, and at a time of installation, due to the protruding portion being pushed relatively from a spool side, the protruding portion elastically deforms and applies elastic restoring force in the thrusting direction between one portion of the locking device and the spool.
Further, in the webbing retractor relating to the present invention, a portion of the stopper member which opposes the terminal end portion may, in an installed state, be pressed so as to contact and be trained along the outer peripheral surface of one portion of the locking device.
In the webbing retractor relating to the present invention, a projecting portion, which projects in a direction opposite to the direction in which the terminal end portion is bent back, may be formed at the portion which is pressed into contact in this way. Moreover, an interference portion, which, in the installed state of the stopper member, interferes with the projecting portion and hinders movement of the stopper member in the direction opposite to the direction of insertion, may be formed at the spool.
In the webbing retractor relating to the present invention, in addition to any of the above-described structures, a resistance imparting device may be provided between the spool and the locking device. The resistance imparting device usually rotates integrally with the spool without imparting rotational resistance to the spool. After locking by the locking device, in an initial stage of rotation of the spool in a webbing pull-out direction, the resistance imparting device imparts resistance to the rotation of the spool in the webbing pull-out direction, and thereafter, cancels the state of imparting re
Aihara Kazuhiko
Asagiri Katsuki
Kitazawa Yasuho
Nagata Tomonori
Kabushiki Kaisha Tokai-Rika-Denki-Seisakusho
Kim Sang
Matecki Kathy
Nixon & Peabody LLP
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