| 摘要 |
PURPOSE:To prevent the breakdown of a vibrator due to external pressure, by filling a cavity part with a hardening resin. CONSTITUTION:A thread pat 17a is formed around a body part 17 of an ultrasonic wave sensor 12. A cavity part 18 is formed in the inside. A PZT vibrator 22 is arranged at a cap 20 at one end of the cavity part 18. The inside of the cavity 18 is filled with a packing material 26. In the material 26, tungsten powder 27 is mixed in epoxy resin 28 and the like. Since the body 17 forming the cavity part 18 and the vibrator 22 form a unitary body, its pressure tightness is improved.
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