| 摘要 |
PROBLEM TO BE SOLVED: To prevent a core from falling and reduce a measuring error by integrally forming a bobbin at the lower end of a guide sleeve and moving up and down in the bobbin with a cylindrical part of a tappet as the a core. SOLUTION: A top cylindrical tappet 8 is fitted from above so as to cover a spring retainer 4 and the upper end of a valve spring 7 the upper end part of a shaft 1a of a valve 1. Then, a cylindrical part 8a of the tappet 8 is fitted sliding up and down in a guide sleeve 10 press-fitted into a through hole 9. When a lower end of the cylindrical part 8a of the tappet 8 approaches inside the bobbin 11 with a primary coil of a sensor coil 12 excited by a high frequency voltage, an output voltage proportional to the cylindrical part 8a is obtained at a secondary coil. Displacement of the tappet 8 (i.e., displacement of the valve 1 moving integrally with the tappet 8) can be measured by applying the output voltage to an external measuring device body through a lead wire 13.
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