Webbing take-up device

Patent metadata

Field	Value
Publication number	US-11091121-B2
Application number	US-201916412602-A
Country	US
Kind code	B2
Filing date	May 15, 2019
Priority date	Jul 23, 2018
Publication date	Aug 17, 2021
Grant date	Aug 17, 2021

Abstract

The rotatable locking section engages with the fixed locking section resulting in pull-out direction rotation of the spool being locked. The webbing take-up device includes a permanent magnet and an electromagnet that restrict displacement of the rotatable locking section toward the fixed locking section, and that are actuated in a vehicle emergency so as to displace the rotatable locking section toward the fixed locking section. A restricting force of the rotatable locking section by the permanent magnet and the electromagnet is set such that the rotatable locking section is displaced toward the fixed locking section by an inertial force that spins the rotatable locking section about its own center of rotation when the electromagnet is deactivated and the spool has been rotated in the pull-out direction with an angular acceleration greater than a predetermined angular acceleration.

First claim

What is claimed is:

1. A webbing take-up device comprising:
a spool that takes up a webbing worn by an occupant and that is rotated in a pull-out direction by the webbing being pulled out;
a rotatable locking section that is provided so as to be rotatable as a unit together with the spool and so as to be displaceable in a rotation-radial direction of the spool;
a fixed locking section that is provided at an outer side of the rotatable locking section in the rotation-radial direction of the spool, and that the rotatable locking section engages with resulting in pull-out direction rotation of the spool being locked;
a restricting section that restricts displacement of the rotatable locking section toward the fixed locking section; and
a displacement section that is actuated in a vehicle emergency so as to displace the rotatable locking section toward the fixed locking section against the restriction of displacement of the rotatable locking section by the restricting section,
a restricting force of the rotatable locking section by the restricting section being set such that the rotatable locking section is displaced toward the fixed locking section by an inertial force that spins the rotatable locking section about its own center of rotation when the displacement section is deactivated and the spool has been rotated in the pull-out direction with an angular acceleration greater than a predetermined angular acceleration, wherein
the rotatable locking section is not displaced toward the fixed locking section when the displacement section is deactivated and the spool has been rotated in the pull-out direction with an angular acceleration equal to or less than the predetermined angular acceleration.

2. The webbing take-up device of claim 1 , wherein:
the restricting section and the displacement section include:
a permanent magnet fixed to the rotatable locking section, and
an electromagnet formed from a magnetic material and including a core disposed opposite the permanent magnet and a coil disposed around the core;

displacement of the rotatable locking section toward the fixed locking section is restricted by a magnetic force of the permanent magnet attracting the core; and
the rotatable locking section is displaced toward the fixed locking section by a current being passed through the coil in one direction such that a magnetic force of repulsion from the permanent magnet is generated in the core.

3. The webbing take-up device of claim 2 , wherein displacement of the rotatable locking section toward the fixed locking section is restricted by a current being passed through the coil in another direction such that a magnetic force pulling on the permanent magnet is generated in the core.

4. The webbing take-up device of claim 3 , wherein:
current is passed through the coil in the other direction when the webbing is being pulled out from the spool as an occupant attempts to put on the webbing; and
current stops being passed through the coil in a state in which the webbing is being worn by the occupant.

5. The webbing take-up device of claim 2 , wherein:
the core includes a shaft upper portion disposed on a rotation axis of the spool and is provided so as to be capable of rotating as a unit with the spool; and
the coil is disposed around the shaft upper portion.

6. The webbing take-up device of claim 2 , wherein:
the rotatable locking section is displaced as far as a position where the rotatable locking section is capable of abutting the fixed locking section when current is being passed through the coil in the one direction; and
engagement of the rotatable locking section and the fixed locking section with each other is completed by the spool being rotated in the pull-out direction in an abutted state of the rotatable locking section against the fixed locking section.

7. The webbing take-up device of claim 1 , wherein:
the fixed locking section includes a leading end portion that abuts the rotatable locking section at a rotation-radial direction inner side portion of the spool and a terminal portion that abuts the rotatable locking section at a rotation-radial direction outer side portion of the spool; and
a hardness of the leading end portion is lower than a hardness of the terminal portion.

8. The webbing take-up device of claim 7 , wherein:
the fixed locking section includes a first fixed locking section and a second fixed locking section adjacent to each other in a rotation axis direction of the spool;
the terminal portion is provided at the first fixed locking section; and
the leading end portion is provided at the second fixed locking section.

9. The webbing take-up device of claim 1 , wherein:
the restricting section includes a biasing member that biases the rotatable locking section toward an opposite side from the fixed locking section;
the displacement section includes an electromagnet including a coil and a moving member that moves when a current is passed through the coil; and
a current being passed through the coil in one direction moves the moving member such that the rotatable locking section is pressed directly or indirectly by the moving member and the rotatable locking section is displaced toward the fixed locking section.

10. The webbing take-up device of claim 1 , wherein:
the rotatable locking section includes a first rotatable locking section and a second rotatable locking section disposed adjacent to the first rotatable locking section in a rotation axis direction of the spool;
the second rotatable locking section is displaceable toward the outer side with respect to the first rotatable locking section in the rotation-radial direction of the spool; and
the second rotatable locking section is displaced toward the outer side with respect to the first rotatable locking section in the rotation-radial direction of the spool, and the second rotatable locking section engages with the fixed locking section before the first rotatable locking section engages with the fixed locking section.

11. A webbing take-up device comprising:
a spool that takes up a webbing worn by an occupant and that is rotated in a pull-out direction by the webbing being pulled out;
a rotatable locking section that is provided so as to be rotatable as a unit together with the spool and so as to be displaceable in a rotation-radial direction of the spool;
a fixed locking section that is provided at an outer side of the rotatable locking section in the rotation-radial direction of the spool, and that the rotatable locking section engages with resulting in pull-out direction rotation of the spool being locked;
a restricting section that restricts displacement of the rotatable locking section toward the fixed locking section; and
a displacement section that is actuated in a vehicle emergency so as to displace the rotatable locking section toward the fixed locking section against the restriction of displacement of the rotatable locking section by the restricting section,
a restricting force of the rotatable locking section by the restricting section being set such that the rotatable locking section is displaced toward the fixed locking section by an inertial force that spins the rotatable locking section about its own center of rotation when the displacement section is deactivated and the spool has been rotated in the pull-out direction with an angular acceleration greater than a predetermined angular acceleration, wherein:
the restricting section and the displacement section include:
a permanent magnet fixed to the rotatable locking section, and
an electromagnet formed from a magnetic material and including a core disposed opposite the permanent magnet and a coil disposed ar

Assignees

• Toyota Motor Co Ltd

Inventors

• Yamamoto Kazuhito

Classifications

• B60R22/343

  with electrically actuated locking means {(B60R22/3405 takes precedence)} · CPC title

• B60R2022/4473

  using an electric retraction device · CPC title

• B60R22/36 Primary

  self-locking in an emergency ({B60R22/3405} , B60R22/343 take precedence) · CPC title

• B60R22/38 Primary

  responsive only to belt movement · CPC title

• 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