Magnetostrictive stress wave sensor
5 Assignments
0 Petitions
Accused Products
Abstract
A shock sensor has a housing with a Terfenol-D type sensing element positioned inside a sensing coil. A permanent biasing magnet is positioned in engagement with the Terfenol-D sensing element, and a spacer engages the Terfenol-D sensing element and extends from the housing. The housing has a beam with one or two mounting holes through which fasteners extend to mount the shock sensor to a structural member. The housing places the spacer in compression against the structural member. In an alternative embodiment a DC current can be supplied to the sensing coil to provide the biasing magnetic field. A high frequency filter separates the shock sensing signal from the applied DC biasing current.
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Citations
24 Claims
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2. (canceled)
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3. (canceled)
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4. (canceled)
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5. (canceled)
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6. A shock wave sensor in an automobile comprising:
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a housing, the housing having a portion providing a mounting surface for attachment to an automobile structural element;
a giant magnetostrictive sensing element mounted to the housing;
a coil mounted to the housing;
a DC power source connected to the coil to form a biasing magnet, the coil being positioned to provide a biasing magnetic field to the giant magnetostrictive sensing;
an electronic filter connected across the coil for sensing a change in magnetic field produced by a shock wave in the giant magnetostrictive sensing element;
a fastener extending between the housing and an automobile structural element to hold the mounting surface of the housing against the automobile structural element, wherein the giant magnetostrictive sensing element is directly, or through a spacer in engagement with and located between the giant magnetostrictive sensing element and the automobile structural element, loaded against the automobile structural element when the portion of the housing providing a mounting surface is held by the fastener against the automobile structural element; and
wherein the housing has a portion that extends between the mounting surface and the giant magnetostrictive sensing element, that resiliently biases the giant magnetostrictive sensing element or the spacer against the automobile structural element thereby compressively loading the giant magnetostrictive sensing element against the spacer or the automotive structural element directly to improve shock wave transmission to the giant magnetostrictive sensing element. - View Dependent Claims (7, 8, 9, 19, 20, 21, 22, 23, 24)
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10. (canceled)
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11. (canceled)
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12. (canceled)
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13. (canceled)
- 14. (canceled)
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15. (canceled)
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16. (canceled)
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17. (canceled)
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18-1. The shock wave sensor of claim 14 wherein the biasing magnet is a high-strength type containing a rare earth metal.
Specification