MULTIFUNCTIONAL SOUNDING BODY

摘要

PROBLEM TO BE SOLVED: To provide shock resistance by making a motion restriction member touch a casing and a magnetic circuit when they make a relational change exceeding a prescribed value. SOLUTION: A resin formed casing 1 has motion restriction members 1c and 1d to which an upper case 1a and a lower base 1b are overlapped and fixed and which protrude to the inner side of a cylindrical main body. A ring- like space whose cross section is of U shape is formed in the intermediate part of the motion restriction members 1c and 1d. A yoke 4a is integrally formed on a soft metallic material and has a motion restriction member 4f protruded outward in an outer peripheral part. The yoke 4a is not fixed to the casing 1, is supported so that it does not touch the casing 1 by a flat supporting spring 5 and it can vibrate in a vertical (center axis) direction. When an impact or a shock is given so that a magnetic circuit 4 is excessively displaced in any direction against the casing 1, the motion restriction member 4f touches the motion restriction member 1c (1d) of a casing side and the maximum quantity of displacement is restricted.