US 5,626,215 AGranted

Speed limiting accessory drive

AssigneeFord Motor Company

InventorsAlvin H. Berger, Roy E. Diehl, Anthony Verduce

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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.

Claims15

Dependent claims

A speed limiting accessory drive, adapted to be rotationally driven by a crankshaft of an engine and drive engine accessories, which limits the maximum speed at which the accessories are driven, the speed limiting accessory drive comprising:

a hub member adapted to be rotationally fixed to the crankshaft;
a housing mounted about and rotatable relative to the hub, the housing including a cavity;
a pulley member mounted on and rotationally fixed relative to the housing;
a wet clutch assembly, mounted radially outward within the housing cavity, including a plurality of friction discs and a plurality of separator plates interleaved with the friction discs, with the friction discs being rotationally fixed relative to the hub and the separator plates being rotationally fixed relative to the housing;
a front cover mounted to the housing for sealing the cavity in the housing;
biasing means, located in the cavity and rotationally fixed relative to the housing, for exerting a first force on the clutch assembly to press the separator plates into contact with the friction discs;
fluid, filling the cavity in the housing, whereby the pulley member will be driven at crankshaft speed for low crankshaft rotational speeds, and the fluid will exert a second force on the biasing means opposite the first force to allow clutch slip at a maximum pulley rotational speed for high crankshaft rotational speeds;
and
temperature compensating means for creating a third force on the biasing means in the direction of the first force as the temperature of the biasing means rises.

6 more elements

a hub member adapted to be rotationally fixed to the crankshaft;
a housing mounted about and rotatable relative to the hub, the housing including a cavity;
a pulley member mounted on and rotationally fixed relative to the housing;
a wet clutch assembly, mounted radially outward within the housing cavity, including a plurality of friction discs and a plurality of separator plates interleaved with the friction discs, with the friction discs being rotationally fixed relative to the hub and the separator plates being rotationally fixed relative to the housing;
a front cover mounted to the housing for sealing the cavity in the housing;
a piston, located in the cavity adjacent to the clutch assembly and rotationally fixed relative to the housing, and a compressed spring located between the piston and housing, for exerting a first force on the clutch assembly to press the separator plates into contact with the friction discs;
fluid, filling the cavity in the housing, whereby the pulley member will be driven at crankshaft speed for low crankshaft rotational speeds, and the fluid will exert a second force on the piston opposite the first force to allow clutch slip at a maximum pulley rotational speed for high crankshaft rotational speeds;
and
temperature compensating means for creating a third force on the piston in the direction of the first force as the temperature of the piston rises.

6 more elements

Dependencies are inferred from the claim text.