| 摘要 |
PROBLEM TO BE SOLVED: To obtain an alarm unit which can prevent water from entering the inside of a case. SOLUTION: A sound guide to dissipate the sound generated from a sounder 2 to the outside has a center sound guide 16 that is open nearly in the middle of the sounder 2 and an external circumferential sound guide 17 that is meandered in an S-shape toward the external circumference. An exit side opening 17a of the external circumferential sound guide 17 is provided with a buffer wall 18 extended to the inside of the external circumferential sound guide 17, and a 1st recessed part 19 and a 2nd recessed part 20 obtained by forming a recess to a bottom face of the external circumferential sound guide 17 are provided on the way of the external circumferential sound guide 17. Thus, even when water intrudes from the exit of the external circumferential sound guide 17, the intruded water strikes on the buffer wall 18 to reduce its speed and to lose its energy, then the intruded water is easily pooled in the 1st recessed part 19 or the 2nd recessed part 20. As a result, even when water intrudes to the inside of the external circumferential sound guide 17, further flooding to the inside of a case from the external circumferential sound guide 17 through the center sound guide 16 can be suppressed.
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