| 摘要 |
PURPOSE:To execute easily the adjustment and to obtain a good output, by making a ring plate closely adhere to one face or both faces of a metallic plate to which a ring-like piezoelectric element is sticking, and adjusting by size of its diameter so that the resonance frequency accords with the knocking frequency. CONSTITUTION:A piezoelectric resonance type knock sensor consists of a vibration detecting member 4 fitted through a bolt 9 to a supporting plate 2 fixed by a holding cover 3 in a case 1. The detecting member 4 consists of a metallic plate formed by joining a ring-like piezoelectric element 6 to the upper face, a ring plate 7 for adjusting the resonance frequency and an electrode 8 which are placed on its upper face, and a ring plate 7 which is made to press-contact with the lower face, and is fixed to the supporting plate 2 through the bolt 9 and a space nut 10. The resonance frequency is adjusted so as to accord with the knocking frequency by using the ring plate 7 of a large diameter and the ring plate of a small diameter in case when the resonance frequency is made high, and in case when it is made low, respectively. Accordingly, the adjustment is executed easily. |
