Seat-Belt Pretensioner Arrangement

• US 20080023246A1
• Filed: 10/05/2007
• Published: 01/31/2008
• Est. Priority Date: 04/07/2005
• Status: Active Grant

• Current Assignee: Autoliv AB (Autoliv Incorporated)
• Original Assignee: Autoliv AB (Autoliv Incorporated)
• Inventors: Gillet, Christophe
• Granted Patent: US 7,643,920 B2
• Time in Patent Office: Days
• US Class Current: 180/268
• CPC Class Codes: B60R 2021/01272 Belt tensioners
• CPC Class Codes: B60R 2021/01313 monitoring the vehicle steering system or the dynamic control system
• CPC Class Codes: B60R 21/0132 responsive to vehicle motion parameters , e.g. to vehicle longitudinal or transversal deceleration or speed value

Abstract

A seat-belt pretensioner arrangement comprises a pretensioner (7) and a control system (3-6) to control the tension applied to a seat-belt by the pretensioner (7). The control system (3-6) controls the pretensioner (7) in response to at least the rate of change of steering angle (ε′). A first processor (4) provides an output indicating a desired level of force to be applied to the seat-belt determined from the steering angle and the velocity of the vehicle. A second processor (5) provides a corresponding output indicative of a desired force level, determined from the rate of change of steering angle (ε′) and the velocity of the vehicle (v_x). A selector (6) selects the highest of the two force levels, and provides an appropriate signal to the pretensioner (7).

Claims

1. A seat-belt pretensioner arrangement, the arrangement comprising a pretensioner for tensioning a seat-belt for restraining an occupant of a motor vehicle, a steering angle sensor for measuring the steering angle of a steering wheel, a velocity sensor for measuring the longitudinal velocity of the vehicle, and a control system, the control system being configured to provide an output in response to a parameter measured by the steering angle sensor to control the pretensioner in response to the output, the control system further configured to cause the pretensioner to increase the tension in the seat-belt in response to the output exceeding a first threshold, the first threshold being related to the longitudinal vehicle speed measured by the velocity sensor.

2. An arrangement according to claim 1 wherein the control system is configured to cause the pretensioner to increase the tension in the seat-belt in response to the output being a function of the rate of change of steering angle.

3. An arrangement according claim 1 wherein the control system is configured to activate the pretensioner in response to the output as a function of a change in the steering angle.

5. An arrangement according to claim 1 in which the control system includes a first processor receiving input signals from the steering angle sensor and the longitudinal velocity sensor and a second processor is provided receiving input signals from a differentiator which differentiates a signal from the steering angle sensor with respect to time and the velocity sensor, each of the processors producing one of a plurality of the outputs, each representing a desired seat-belt tension in response to the input signals, the output signals being generated when successive predetermined thresholds have been passed, the outputs of the processors being processed by a selector which selects the higher of the two output signals from the processors and which, in response to the higher signal, controls the pretensioner to provide a desired degree of tension in the seat-belt.

6. An arrangement according to claim 5 wherein the selector is configured to control the pretensioner to maintain the highest force level selected until a predetermined period of time has elapsed after the outputs of both processors have fallen to a level indicating that none of the thresholds are being exceeded.

7. An arrangement according to claim 1 wherein the pretensioner comprises a retractor on which part of the seat-belt is wound and a mechanism to apply tension to the seat-belt.

4. An arrangement according to claim I wherein the control system is configured such that the control system output reaches a second threshold of the steering angle which decreases with increasing vehicle speed and wherein the pretensioner causes a greater tension to be applied to the seat-belt a compared with the increased tension in response to the first threshold.

8. A seat-belt pretensioner arrangement, the arrangement comprising a pretensioner and a control system, the control system incorporating a first processor receiving a steering angle input signal from a steering angle sensor and a vehicle speed input signal from a longitudinal vehicle speed sensor and a second processor receiving a differential input signal from a differentiator which differentiates the steering angle signal with respect to time and the speed sensor, each processor producing one of a plurality of outputs representing of desired seat-belt tension, the output signals being generated when successive predetermined thresholds have been passed, the outputs of the processors being passed to a selector which selects the higher of the two output signals from the processors and which, in response to the higher signal, controls the pretensioner to provide a desired degree of tension in the seat-belt.