| 摘要 |
PURPOSE:To prevent a screw shaft of a rotary shaft from wedging into a valve needle by connecting resistances of pressure sensitive electricity conductive rubber washers arranged on both end surfaces of a flange or on both end surfaces of a valve frame to a bridge circuit. CONSTITUTION:Pressure sensitive electricity conductive rubber washers 15, 16, 25 and 26 are fitted on both end surfaces of a flange 11 of a stator frame 10 of an electric motor 8 or on both end surfaces of a valve frame 1. Bolts 12 for connecting the stator frame 10 to the valve frame 1 are passed through the rubber washers, with the bolts insulated from the rubber washers, and tightened with nuts 14. The resistances of the respective washers are connected to a bridge circuit. When a valve needle reaches a forward end, the rubber washers on one of the both end surfaces are compressed to reduce their resistances while the resistances of the rubber washers on the other side increase. This is detected with the bridge circuit to stop the electric motor 8. When the valve needle reaches a backward end, on the other hand, the electric motor 8 is similarly stopped by the bridge circuit.
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