PURPOSE: To obtain a highly reliable knocking detector which can be assembled easily and exhibits good detection characteristics uniformly among products.
CONSTITUTION: At the time of assembling, a diaphragm 4 can be positioned accurately by fitting the central hole thereof on a cylindrical protrusion 18 of housing 3 and a piezoelectric element 5, previously bonded to the diaphragm 4, can be secured to the cylindrical protrusion 18 while being positioned accurately there. The diaphragm 4 is then inserted, at the inner end part thereof, into the stepped part of cylindrical protrusion 18 and secured thereto by ring projection welding. Vibration of engine block 2 is transmitted through the fixing bolt part 12 of a knocking detector 1 and the cylindrical protrusion 18 to the diaphragm 4 and piezoelectric element 5 which then generates a voltage signal corresponding to the stress being applied to the piezoelectric element 5 from the diaphragm 4. The voltage signal is delivered to the outside through a joint terminal 31, a lead wire 32 and a terminal 14.
YAMAGUCHI KIMIAKI
SANO YOSHIHIKO
Next Patent: VIBRATION LEVEL GAUGE EMPLOYING DIGITAL SIGNAL PROCESSING