| 摘要 |
PROBLEM TO BE SOLVED: To provide a knock sensor capable of preventing effectively the lowering of sealability performance even at a high temperature, and having excellent durability. SOLUTION: This knock sensor is equipped with a metal cylindrical core bar 2 comprising a collar part 21 provided on one end and a cylindrical cylinder part 23. Seal grooves 3, 3 are provided on the outer periphery of the collar part 21, and seal grooves 4, 4 are provided on the other end. Each section of the seal groove 3 and the seal groove 4 has both groove side wall faces 32, 33, 42, 43 having respectively the tapered width reducing gradually in the axial direction toward a groove mouth. A piezoelectric mechanism 5 is arranged cylindrically on the outer circumferential of the cylinder part 23, and the outer periphery of the piezoelectric mechanism 5 is coated with a coating body 7 formed by molding of a resin. The resin by molding enters the seal grooves 3, 4, and when the temperature of the knock sensor 1 becomes high, the penetration part in the seal grooves 3, 4 is expanded to prevent exfoliation of the joint surface. COPYRIGHT: (C)2004,JPO&NCIPI
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