Centrifugal spark-advance control device

摘要

Disclosed is a centrifugal spark-advance control device for an ignition system of an internal combustion engine, comprising: a base plate which rotates at a speed corresponding to the rotational speed of the engine; a timing plate which is rotatably supported on the base plate; a spring for biasing the timing plate in a certain direction; a centrifugal weight which is pivoted to the base plate at a point spaced from the center of gravity of the centrifugal weight and which is provided with a cam surface for rotatably driving the timing plate in an opposite direction against the biasing force of the spring by cooperating with a corresponding cam follower surface provided in the timing plate; a spark generating device coupled to the timing plate for generating ignition sparks in synchronism with the rotational angle of the timing plate; a mass member attached to the timing plate by way of an elastic member. Since the mass member is elastically supported by the timing plate, undesirable vibration of the timing plate is minimized by the action of a dynamic damper provided by the mass member and the accuracy in ignition timing is assured.