Pretensioner device

• US 20030122362A1
• Filed: 11/12/2002
• Published: 07/03/2003
• Est. Priority Date: 11/13/2001
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Tokai RIKA Denki Seisakusho
• Original Assignee: Kabushiki Kaisha Tokai RIKA Denki Seisakusho
• Inventors: Aihara, Kazuhiko, Ukita, Masaru
• Granted Patent: US 6,877,776 B2
• Time in Patent Office: Days
• US Class Current: 280/806
• CPC Class Codes: B60R 22/1952 Transmission of tensioning power by cable; Return motion locking means therefor

Abstract

A pretensioner device in which, at a time of rapid deceleration of a vehicle such as a collision, a gas generator generates gas and the pretensioner device moves a piston in a direction of tensing a webbing. When, due to delayed detection by an acceleration sensor, the gas generator operates after a stretch-out load has been applied to a wire, high-pressure and high-temperature gas within a gas chamber contacts a guard pipe, which is formed of a material having a high thermal conductivity and is disposed within the gas chamber, and is cooled, and passes through a clearance and a pin hole communicating regions to a front and rear of the piston, and is discharged into a cylinder.

Claims

1. A pretensioner device comprising:

a connecting member, one end portion of the connecting member being connected to one of an anchor plate, to which one end portion of a webbing for restraining a vehicle occupant is fixed, and a buckle, which holds a tongue plate through which an intermediate portion of the webbing is inserted;

a piston connected to another end portion of the connecting member;

a cylinder formed in a tubular shape corresponding to the piston, and accommodating the piston such that the piston is movable toward one side in an axial direction;

a gas chamber which communicates with another side of the cylinder, and through which an intermediate portion of the connecting member is inserted;

an entrance portion provided at a side of the gas chamber opposite to a side at which the cylinder is provided, an intermediate portion of the connecting member being slidably inserted through the entrance portion; and

a gas generating device provided so as to be able to supply gas to the gas chamber, and generating gas by being ignited,

and, in a predetermined case, the pretensioner device ignites the gas generating device, and due to pressure of gas supplied into the cylinder from the gas chamber, the pretensioner device moves the piston toward the one side of the cylinder and tenses the webbing in a direction of restraining a vehicle occupant,

wherein a protecting member, at least a portion of which is formed from a material having high thermal conductivity, is disposed within the gas chamber.

2. The pretensioner device of claim 1, wherein the protecting member is formed in a tubular shape, and the connecting member is inserted through the protecting member at an interior of the gas chamber.

3. The pretensioner device of claim 1, wherein the connecting member is a wire, and the piston includes a substantially cylindrical wire holding portion, and the other end portion of the wire is fixed and held in a state of being inserted in the wire holding portion.

4. The pretensioner device of claim 1, wherein the gas generating device includes a gas generator and a control device which can control ignition, and the gas generator includes an ignition device, and the ignition device is electrically connected to the control device.

5. The pretensioner device of claim 1, wherein the protecting member includes a guard pipe, and the guard pipe includes a cylindrical pipe portion, a flange portion provided at one end of the pipe portion substantially coaxially with the pipe portion, and a plurality of through holes provided in the flange portion.

6. The pretensioner device of claim 2, wherein the pretensioner device includes a sealing member through which the connecting member is slidably inserted and which seals an interior of the entrance portion from an exterior, and

the protecting member is fixed to and disposed in the gas chamber while pressing the sealing member between the protecting member and an inner surface of the entrance portion.

7. The pretensioner device of claim 5, wherein a longitudinal dimension of the pipe portion of the guard pipe substantially corresponds to a longitudinal dimension of the gas chamber, and the pipe portion includes an outer diameter which is smaller than an inner diameter of the gas chamber, and an inner diameter which is larger than the connecting member.

8. The pretensioner device of claim 5, wherein the pipe portion of the guard pipe is formed of the material having high thermal conductivity.

9. The pretensioner device of claim 6, wherein the cylinder includes an opening, and the pretensioner device further includes, between a side end portion of the opening of the cylinder and the buckle, a block-shaped base cartridge which holds the cylinder, and the sealing member is disposed at the base cartridge.

10. The pretensioner device of claim 8, wherein the flange portion of the guard pipe also is formed of the material having high thermal conductivity.

11. The pretensioner device of claim 9, wherein the entrance portion includes a guide hole, and the sealing member includes packing which seals a region between the gas chamber and the guide hole.

12. The pretensioner device of claim 11, wherein the packing is formed in a substantially cylindrical shape and of a material having elasticity, and the packing includes an inner diameter which is larger than the connecting member.

13. The pretensioner device of claim 11, wherein the pretensioner device further includes, between the gas chamber and the guide hole, a packing chamber which is provided coaxially with the gas chamber and the guide hole, and the packing chamber includes a diameter of a magnitude between a diameter of the gas chamber and a diameter of the guide hole, and the packing is disposed within the packing chamber, and the packing is pressed in a longitudinal axial direction by the pipe portion of the guard pipe at a side opposite to the flange portion.

14. A pretensioner device comprising:

a connecting member, one end portion of the connecting member being connected to one of an anchor plate, to which one end portion of a webbing for restraining a vehicle occupant is fixed, and a buckle, which holds a tongue plate through which an intermediate portion of the webbing is inserted;

a piston connected to another end portion of the connecting member;

a cylinder formed in a tubular shape corresponding to the piston, and accommodating the piston such that the piston is movable toward one side in an axial direction;

a gas generating device provided so as to be able to supply gas, and generating gas upon being ignited;

a gas chamber which communicates with another side of the cylinder and through which an intermediate portion of the connecting member is inserted, and when the gas generating device operates, gas is supplied to the gas chamber;

an entrance portion provided at a side of the gas chamber opposite a side at which the cylinder is provided, and an intermediate portion of the connecting member is slidably inserted through the entrance portion, and a region between the connecting member and the entrance portion is sealed by a sealing member; and

a gas discharging portion communicating a region ahead of the piston and a region behind the piston,

wherein, in a predetermined case, the pretensioner device operates the gas generating device, and due to pressure of gas supplied into the cylinder from the gas chamber, the pretensioner device moves the piston toward the one side of the cylinder and tenses the webbing in a direction of restraining a vehicle occupant.

15. The pretensioner device of claim 14, wherein the connecting member is a wire, and the piston includes a substantially cylindrical wire holding portion, and the other end portion of the wire is fixed and held in a state of being inserted in the wire holding portion.

16. The pretensioner device of claim 14, wherein the piston includes a substantially cylindrical sealing portion at one end of the piston, a reduced diameter portion adjacent to the sealing portion, a taper portion adjacent to the reduced diameter portion and whose diameter gradually increases, and a holding portion adjacent to the taper portion and holding the connecting member, and a boundary between the taper portion and the holding portion is formed in a form of a step, and the holding portion includes a pin hole, and the gas discharging portion includes the pin hole.

17. The pretensioner device of claim 14, wherein the gas generating device includes a gas generator and a control device which can control ignition, and the gas generator includes an ignition device, and the ignition device is electrically connected to the control device.

18. The pretensioner device of claim 14, wherein the entrance portion includes a guide hole, and the sealing member includes packing which seals a region between the gas chamber and the guide hole.

19. The pretensioner device of claim 14, wherein the cylinder includes an opening, and the pretensioner device further includes, between a side end portion of the opening of the cylinder and the buckle, a block-shaped base cartridge which holds the cylinder, and the sealing member is disposed at the base cartridge.

20. The pretensioner device of claim 16, wherein a clearance can be formed between the taper portion and the connecting member and between the sealing portion and the connecting member, and the gas discharging portion includes the clearance.

21. The pretensioner device of claim 18, wherein the packing is formed in a substantially cylindrical shape and of a material having elasticity, and the packing includes an inner diameter which is larger than the connecting member.