Magnetic crash sensor

• US 20050093540A1
• Filed: 09/20/2004
• Published: 05/05/2005
• Est. Priority Date: 09/19/2003
• Status: Active Grant

• Current Assignee: Joyson Safety Systems Acquisition, LLC
• Original Assignee: TK Holdings Incorporated (Ningbo Junsheng Investment Group Co., Ltd.)
• Inventors: Watson, William Todd, Cech, Leonard S., Bomya, Timothy J., Merrick, William D.
• Granted Patent: US 7,209,844 B2
• Time in Patent Office: Days
• US Class Current: 324/239
• CPC Class Codes: B60R 21/0136 responsive to actual contact with an obstacle , e.g. to vehicle deformation, bumper displacement or bumper velocity relative to the vehicle monitoring crash strength in combination with passenger seat detection B60R21/01558

Abstract

A first magnetic field generated by a first coil operatively associated with a first portion of a vehicle interacts with at least one conductive element operatively associated with or at least a part of a second portion of the vehicle so as to generate an eddy current in the conductive element, which affects the magnetic field sensed by a magnetic sensor. A conductive element operatively coupled to a portion of the vehicle susceptible to a crash, e.g. a bumper or a door, provides for sensing a crash with the signal from the magnetic sensor. In another aspect, a second magnetic field is generated in the frame of a vehicle by a second coil wherein the frame is adapted so that the reluctance of the associated magnetic circuit is responsive to a crash. Signals from the first or second coils may be used to sense the associated magnetic fields.

Claims

1. A magnetic crash sensor, comprising:

a. at least one first coil operatively associated with a first portion of a vehicle;

b. a first signal source operatively associated with said at least one first coil, wherein a first signal from said first signal source is operatively coupled to said at least one first coil so as to cause said at least one first coil to generate a first magnetic field;

c. at least one conductive element operatively associated with or at least a part of a second portion of said vehicle, wherein said at least one conductive element is located so that said first magnetic field generated by said at least one first coil induces at least one eddy current in said at least one conductive; and

d. at least one first magnetic sensor adapted to generate a second signal responsive to said first magnetic field from said at least one first coil responsive to an influence by said at least one eddy current induced in said at least one conductive element by said first magnetic field.

2. A magnetic crash sensor as recited in claim 1, wherein said first portion of said vehicle comprises a front cross beam of said vehicle.

3. A magnetic crash sensor as recited in claim 2, wherein at least one said first coil is located proximate to a central portion of said front cross beam of said vehicle.

4. A magnetic crash sensor as recited in claim 1, wherein said signal source comprises a first oscillator.

5. A magnetic crash sensor as recited in claim 1, wherein said at least one conductive element comprises a metal sheet, film or coating of paramagnetic or diamagnetic material that is relatively highly conductive.

6. A magnetic crash sensor as recited in claim 1, wherein said at least one conductive element is operatively coupled to or a part of a portion of said vehicle that is susceptible to deformation responsive to a crash.

7. A magnetic crash sensor as recited in claim 6, wherein said at least one conductive element is operatively coupled to or at least a part of a bumper of said vehicle.

8. A magnetic crash sensor as recited in claim 1, wherein at least one said first magnetic sensor comprises a corresponding at least one said first coil, and said second signal is responsive to a self-impedance of said corresponding at least one said first coil.

9. A magnetic crash sensor as recited in claim 1, wherein at least one said first magnetic sensor comprises a coil, a Hall-effect sensor or a giant magnetoresistive (GMR) sensor.

10. A magnetic crash sensor as recited in claim 1, wherein said at least one first magnetic sensor is displaced from said at least one first coil.

11. A magnetic crash sensor as recited in claim 10, wherein said at least one first magnetic sensor comprises a plurality of first magnetic sensors that are relatively distal with respect to said at least one first coil.

12. A magnetic crash sensor as recited in claim 1, further comprising a safety restraint system, wherein said safety restraint system is actuated responsive to a signal from said at least one first magnetic sensor.

13. A magnetic crash sensor as recited in claim 1, further comprising:

a. at least one second coil operatively associated with a third portion of a vehicle;

b. a second signal source operatively associated with said at least one second coil, wherein a second signal from said second signal source is operatively coupled to said at least one second coil so as to cause said at least one second coil to generate a second magnetic field within a frame of said vehicle; and

c. at least one second magnetic sensor adapted to generate a second signal responsive to said second magnetic field within said frame of said vehicle.

14. A magnetic crash sensor as recited in claim 13, wherein said second signal is different from said first signal.

15. A magnetic crash sensor as recited in claim 13, further comprising a safety restraint system, wherein said safety restraint system is actuated responsive to a signal from said at least one first magnetic sensor, said safety restraint system is actuated responsive to a signal from said at least one second magnetic sensor, and said signal from said at least one first magnetic sensor is used to provide safing for said signal from said at least one second magnetic sensor.

16. A magnetic crash sensor as recited in claim 6, wherein said at least one first coil is operatively associated with a first portion of a door of said vehicle, and said at least one conductive element is operatively associated with or at least a part of a second portion of said door of said vehicle.

17. A magnetic crash sensor as recited in claim 16, wherein at least one said conductive element is operatively associated with or at least a part of an outer skin of said door of said vehicle.

18. A magnetic crash sensor as recited in claim 17, wherein at least one said conductive element is operatively associated with or at least a part of a door beam of said door of said vehicle.

19. A magnetic crash sensor as recited in claim 16, wherein at least one said conductive element is operatively associated with or at least a part of a door beam of said door of said vehicle.

20. A magnetic crash sensor as recited in claim 16, further comprising at least one accelerometer operatively coupled to said vehicle, wherein a detection of a crash is responsive to a signal from said at least one first magnetic sensor and is responsive to a signal from said accelerometer.

21. A magnetic crash sensor as recited in claim 20, wherein said accelerometer is operatively coupled to a structural element of said vehicle proximate to said door of said vehicle.

22. A magnetic crash sensor, comprising:

a. at least one second coil operatively associated with a third portion of a vehicle;

b. a second signal source operatively associated with said at least one second coil, wherein a second signal from said second signal source is operatively coupled to said at least one second coil so as to cause said at least one second coil to generate a second magnetic field within a frame of said vehicle;

c. at least one second magnetic sensor adapted to generate a second signal responsive to said second magnetic field within said frame of said vehicle, wherein said frame of said vehicle comprises at least one substantially non-magnetic element in series with a magnetic circuit of said frame, said substantially non-magnetic structural element is susceptible to deformation responsive to a crash, a deformation of said substantially non-magnetic element affects a reluctance of said magnetic circuit of said frame and said reluctance of said magnetic circuit of said frame affects said second magnetic field sensed by said at least one second magnetic sensor.

23. A magnetic crash sensor as recited in claim 22, wherein said third portion of said vehicle comprises a front cross beam of said vehicle, and at least one said second coil is located around said front cross beam of said vehicle.

24. A magnetic crash sensor as recited in claim 22, wherein said signal source comprises a second oscillator.

25. A magnetic crash sensor as recited in claim 22, wherein at least one said first magnetic sensor comprises a corresponding at least one said second coil, and said second signal is responsive to a self-impedance of said corresponding at least one said second coil.

26. A magnetic crash sensor as recited in claim 22, wherein at least one said second magnetic sensor comprises a coil, a Hall-effect sensor or a giant magnetoresistive (GMR) sensor.

27. A magnetic crash sensor as recited in claim 22, wherein said at least one second magnetic sensor is displaced from said at least one second coil.

28. A magnetic crash sensor as recited in claim 22, wherein said at least one second magnetic sensor is operatively associated with at least one side rail of said frame of said vehicle.

29. A magnetic crash sensor as recited in claim 22, further comprising a safety restraint system, wherein said safety restraint system is actuated responsive to a signal from said at least one second magnetic sensor.

30. A method of sensing a crash, comprising:

a. generating at least one magnetic field in a vehicle;

b. operatively associating at least one conductive element with a portion of a vehicle that is susceptible to a crash;

c. generating at least one eddy current in said conductive element responsive to said at least one magnetic field; and

d. sensing a magnetic field responsive to said at least one eddy current;

31. A method of providing for sensing a crash, comprising:

a. providing for generating at least one magnetic field in a frame of a vehicle;

b. providing for sensing said at least one magnetic field in said frame of said vehicle, wherein said at least one magnetic field extends along a magnetic circuit containing at least a portion of said frame of said vehicle; and

c. adapting said frame of said vehicle so that a reluctance of said magnetic circuit is responsive to a crash.