| 摘要 |
PROBLEM TO BE SOLVED: To provide a spark plug equipped with built-in pressure sensor free of breakage of its piezoelectric element. SOLUTION: This spark plug equipped with a built-in pressure sensor has an accommodating member 52 penetrated by eight accommodation spaces 52a, and a piezoelectric element 53 is accommodated in each space 52a in such a way that the head protrudes upward. At least in one position between the piezoelectric element 53, a projecting piece 52b belonging to the accommodating member 52 is formed protruding upward. A terminal 54a protruding upward is formed on an electrode plate 54 in its position corresponding to the projecting piece 52b, and if the electrode plate 54 is laid on the oversurface of the accommodating member 52, the projecting piece 52b is accommodated in a notch 54b provided in the electrode plate 54. Therefore, even when pressure is impressed on the electrode plate 54 from above, it will concentrate at the edge 54d of the notch 54b, and there is no possibility that the piezoelectric element 53 is damaged. |
