Patent ID: 7207207
Filing Date: 2007-04-24
Classification: G01L,G01P

Abstract:
1. A knock sensor comprising: a base including a cylindrical part to be mounted on a vibration generating part, and a flange part provided at a part of the cylindrical part; an annular piezoelectric element fitted to the cylindrical part which converts a knocking vibration of the vibration generating part into an electric signal to detect the knocking vibration, said piezoelectric element having a pair of axial end surfaces; annular electrodes respectively provided to be in contact with both of said surfaces of the piezoelectric element, each of said annular electrodes covering less than the entire respective surfaces of the piezoelectric element; terminal plates disposed to be in contact with the respective electrodes and which extract an output of the piezoelectric element to outside the knock sensor; and a hold unit which holds the piezoelectric element, the electrodes and the terminal plates to the flange part, and a conductive adhesive having an almost equal thickness to the electrodes provided on a respective portion of each of the piezoelectric element surfaces which is not in contact with the electrodes.