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US 4,364,259 AGranted
Vibration sensor for an automotive vehicle engine
AssigneeNissan Motor Co., Ltd.
InventorsShigeo Muranaka, Michio Onoda
Life of this patent
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Abstract
A vibration sensor for an automotive vehicle having a piezoelectric element of diaphragm type for detecting mechanical vibrations from an internal combustion engine such as knocking frequency. The piezoelectric element is formed within a holder of plastic or the like and bonded thereto in a manner to accurately regulate the clamping pressure at the element periphery and regulate the vibration area thereof to accurately regulate the resonant frequency of the vibration sensor.
Claims5
A vibration sensor for an automotive vehicle engine comprising:
- (a) a piezoelectric disc, a first disc-shaped metal electrode co-axially affixed to one surface of and having substantially the same diameter as said piezoelectric disc, a second disc-shaped metal electrode co-axially affixed to the other surface of and having a smaller diameter than said piezoelectric disc to increase the diaphragm vibration sensitivity of the vibration sensor;
- (b) a holder for said piezoelectric disc including means for mounting said holder on the vehicle engine, said holder being formed and bonded around the peripheral edge of said piezoelectric disc and being made of a material which contracts during the bonding process to apply sustained compressional force to said piezoelectric disc;
- and
- (c) a pair of protective covers affixed to both sides of said holder, said covers sandwiching and covering said piezoelectric disc and being spaced therefrom to provide cavities adjacent both sides of said piezoelectric disc.
1 more element
Dependencies are inferred from the claim text.