| 摘要 |
PURPOSE:To obtain the highly reliable knock sensor, when a piezoelectric bimorph element is bonded, by adding metallic powder filler in an insulating bonding agent, and performing the bonding so as to ensure the conducting point between the bonding surfaces. CONSTITUTION:In the bimorph element, electrode layers (c) are provided on both sides and piezoelectric porcelain plates 5a and 5b are bonded at a plane (e). In bonding, the metallic filler (f) is added in the bonding agent such as epoxy resin. Then the metallic filler (f) is distributed in a bonding agent layer (g). When the electrode layers (c) receive external stress, they are charged into opposite polarities to each other. The metallic filler (f) is conducted and the external output is generated. Said bimorph type vibrator is used as a vibrator 5 of the knock sensor. Therefore, electric combining property from the viewpoints of initial characteristics and durability can be ensured, and the highly reliable knock sensor can be obtained. |
