Vibration sensor
AssigneeNissan Motor Co., Ltd.
InventorToshifumi Nishimura
Life of this patent
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Abstract
A vibration sensor for detecting the magnitude of engine vibration and for generating an electric signal corresponding to the vibration incorporates a piezoelectric vibration element. The vibration sensor is used, for example, for detecting the knocking condition of an internal combustion engine. The piezoelectric element is secured onto an internal boss of a sensor housing by a threaded fastener. The fastener effectively secures the piezoelectric element onto the sensor boss so that the connection therebetween is not affected by vibration which could otherwise impair the electrical contact.
Claims52
A vibration sensor comprising:
- a housing having means for attaching said sensor to a vibrating source;
- a vibrator including a piezoelectric element having an electrically conductive member on both plane surfaces thereof to form electrodes thereon and a metal plate made from a metal having a thermal expansion ratio approximately the same as that of said piezoelectric element, said piezoelectric element being responsive to vibration applied thereto and generating an electric signal having potential corresponding to the magnitude of sensed vibration;
- and
- a threaded fastener mounting said vibrator to said housing.
A knocking sensor for detecting knocking condition of an internal combustion engine comprising:
- a sensor housing having an internal space therein and an anchor bolt portion integrally formed therewith, which anchor bolt portion engages a cylinder block of the internal combustion engine;
- a vibrator including a piezoelectric element provided with an electrically conductive member on both planar surfaces thereof to form electrodes thereof and a metal plate made from a metal having a thermal expansion ratio approximately the same as that of said piezoelectric element, which piezoelectric element resonates with a specific frequency of engine vibration generated when the engine is driven in knocking condition, said piezoelectric element generating an electric signal having potential corresponding to the magnitude of vibration applied thereto;
- and
- a threaded fastener engaged to said sensor housing within the internal space of the housing.
A knocking sensor for detecting an internal combustion engine in knocking condition comprising:
- a sensor housing defining an internal chamber therein and having an anchor bolt portion integrally formed therewith and engageable with a cylinder block of the internal combustion engine;
- a vibrator including a piezoelectric element having a thermal expansion ratio of about 1.5.times.10.sup.-6 /.degree.C. and a metal plate made from an alloy having a thermal expansion ratio about 1.2.times.10.sup.-6 /.degree.C., which piezoelectric element resonates with a specific frequency of engine vibration generated when the engine is in knocking condition, said piezoelectric element generating an electric signal having a potential corresponding to the magnitude of vibration applied thereto;
- and
- a threaded fastener engaged to said sensor housing so that it mounts said vibrator onto said sensor housing within the internal chamber of the sensor housing.
Dependencies are inferred from the claim text.