Method for downsizing a safety device for a motor vehicle

• US 8,794,672 B2
• Filed: 04/04/2011
• Issued: 08/05/2014
• Est. Priority Date: 04/09/2010
• Status: Active Grant

• Current Assignee: Volkswagen AG
• Original Assignee: Volkswagen AG
• Inventors: Dramlitsch, Thomas
• Primary Examiner(s): Dickson, Paul N
• Assistant Examiner(s): GOODEN JR, BARRY J
• Application Number:
  US13/638,971
• Publication Number:
  US 20130092778A1
• Time in Patent Office: 1,219 Days
• Field of Search: 280/730.2, 280/739, 280/743.2, 280/805, 280/806, 297/470, 297/478
• US Class Current: 280/805
• CPC Class Codes: B60R 2022/288 with means to adjust or regulate the amount of energy to be absorbed
• CPC Class Codes: B60R 22/36 self-locking in an emergency B60R22/3405 , B60R22/343 take precedence
• CPC Class Codes: B60R 22/41 with additional means for preventing locking during unwinding under predetermined conditions

Abstract

A method of downscaling the travel-time-function of a reference body of mass m_t in a spring-mass system with a spring providing a spring force when the spring-mass system is exposed to an acceleration field with an acceleration which moves the reference body against the spring force according to the travel-time-function is provided. In this method, the downscaling is done by coupling the reference body of mass m_t to additional masses m_r which are kinematically linked together in such a way that they do not react to acceleration field.

Claims

1. Method of establishing belt pull-out with a specified travel-time-function in a vehicle occupant restraint system during an accident exposing a vehicle to an acceleration field, in which the vehicle occupant restraint system comprises a seat belt, a spring-mass system with a reference body of mass m_t which is exposed to the acceleration field and which can be moved against a spring force by an acceleration of the acceleration field, and a blocking and releasing device for blocking and releasing the belt pull-out of the seat belt, wherein a travel-time-function of the reference body when moving against the spring force mechanically establishes a travel-time-function of the belt pull-out via the blocking and releasing device of the vehicle occupant restraint system, characterized in that, when establishing the belt pull-out with the specified travel-time-function, the travel-time-function of the reference body is scaled down by downscaling the travel-time-function of the reference body of mass m_t in the spring-mass system with a spring providing the spring force when the spring-mass system is exposed to the acceleration field with the acceleration which moves the reference body against the spring force yielding the travel-time-function, wherein the downscaling is done by coupling the reference body of mass m_t to additional masses m_r which are kinematically linked together in such a way that the additional masses m_r do not react to the acceleration field.

2. Method according to claim 1, characterized in that the additional masses m_r are rotating masses having rotational inertias.

3. Method according to claim 2, characterized in that the mass m_t of the reference body is smaller than the additional masses m_r.

4. Method according to claim 1, characterized in that a transmission is used between a motion of the reference body and the belt pull-out.

5. Method according to claim 4, characterized in that a transmission increases the travel-time-function of the belt pull-out resulting from the travel-time-function of the reference mass at least by a factor of (m_t+m_r)/m_t.

6. Vehicle occupant restraint system, comprising:

a seat belt which provides, in an accident, a belt pull-out according to a specified travel-time-function of the belt pull-out;

a spring mass device with a spring providing a defined spring force and a reference body m_t which can move against the spring force in an acceleration field yielding a travel-time-function of the reference body; and

a blocking and releasing device for blocking and releasing the belt pull-out of the seat belt, wherein

the spring-mass device is linked to the blocking and releasing device so as to mechanically establish the travel-time-function of the reference body, characterized in that the spring mass device comprises additional masses m_r which are kinematically linked together in such a way that the additional masses do not react to the acceleration field and which are coupled to the reference body of mass m_t.

7. Vehicle occupant restraint system according to claim 6, characterized in that the additional masses m_r are rotating masses having rotational inertias.

8. Vehicle occupant restraint system according to claim 7, characterized in that the mass m_t of the reference body is smaller than the additional masses m_r.

9. Vehicle occupant restraint system according to claim 6, characterized by a transmission between the spring-mass device and the belt pull-out.

10. Vehicle occupant restraint system according to claim 9, characterized in that that the transmission increases the travel-time-function of the belt pull-out resulting from the travel-time-function of the reference mass at least by a factor of (m_t+m_r)/m_t.

11. Vehicle occupant restraint system according to claim 6, characterized in that the additional masses m_r are provided in form of gearwheels.

12. Vehicle occupant restraint system according to claim 6, characterized in that the additional masses m_r, are provided in form of flywheels.

13. Vehicle occupant restraint system according to claim 12, characterized in that the flywheels are coupled to the reference body by a band, a belt or a chain wrapped around the flywheels and connected to the reference mass.

14. Vehicle occupant restraint system according to claim 12, characterized in that a radius at which the reference body is coupled to the flywheels is smaller than the radius of the flywheels.

15. Vehicle occupant restraint system according to claim 12, characterized in a transmission between the reference body and the flywheels.

16. Vehicle occupant restraint system according to claim 15, characterized in that the transmission has a transmission ratio of greater than 2.