| 摘要 |
<p>A spark plug for an internal combustion engine is reduced in diameter (reduced in size) and has sufficient durability achieved by suppressing a sharp rise in the resistance value of a resistive element. A spark plug (1) is provided with an insulator (2) having a shaft hole (4), a main body fitting (3) provided on the outer periphery of the insulator (2), a center electrode (5) inserted in the front end side of the shaft hole (4), a terminal electrode (6) inserted in the rear end side of the shaft hole (4), and a ground electrode (35). A circular column-like resistive element (7) is provided at a position which is in the shaft hole (4) and between the center electrode (5) and the terminal electrode (6), and the center electrode (5) and the terminal electrode (6) are electrically connected to each other. The resistive element (7) consists of a resistive element composition mainly composed of carbon black (53) as an electrically conductive material, glass powder (51), and ceramic particles (54). The maximum particle diameter of the ceramic particles (54) is smaller than or equal to 0.5 µm.</p> |
