Abstract: A speed limiting accessory drive for use with an engine in a vehicle. A speed limiting drive pulley (16) is affixed to a crankshaft (14) via a hub (42) and includes a pulley member (24) which drives the accessory belt (18). A Clutch assembly (36) is operatively located between the hub and pulley member, with a piston (54) or bellows biased against and engaging the clutch assembly. Oil located throughout the clutch assembly is acted on by centrifugal force when the drive pulley is rotating and acts to push against the biases of the piston. This allows the clutch to slip at high engine speeds, thus limiting the speed of the pulley member. A heat compensating mechanism acts to counter the pushing force of the oil if the temperature of the oil rises too high due to the clutch slippage, thereby reducing clutch slip.

Abstract: A speed limiting accessory drive and crankshaft damper for use with an engine in a vehicle. A speed limiting drive pulley (16) is affixed to a crankshaft (14) via a hub (42) and includes a pulley member (24) which drives the accessory belt (18). A damper mass (40) is elastically attached to the hub via damper springs (44). A Clutch assembly (36) is operatively located between the damper mass and pulley member, with a piston (54) or bellows biased against and engaging the clutch assembly. Oil located throughout the clutch assembly is acted on by centrifugal force when the drive pulley is rotating and acts to push against the biases of the piston. This allows the clutch to slip at high engine speeds, thus limiting the speed of the pulley member. A heat compensating mechanism acts to counter the pushing force of the oil if the temperature of the oil rises too high due to the clutch slippage, thereby reducing clutch slip.

Abstract: A bifilar type pendulum automotive engine vibrational damper has at least one pendulum with an inner curved cam follower surface that is alternately engaged and disengaged from a pin type cam fixed on the pendulum carrier during low engine crankshaft operating speeds, such as during engine start up or shut-down, to force the pendulum to follow a path close to the path defined by the swinging arcuate movement of the pendulum during operation at normal engine crankshaft operating speeds, a minimal radial clearance being provided between the pendulum's curved surface and pin during the normal crankshaft operating speeds to reduce the impact of metal to metal contact between the pendulum and rollers or pendulum and carrier and resultant noise when the pendulum alternately falls inwardly against the carrier in response to gravity and then is forced outwardly due to centrifugal force.