US 5,992,594 AGranted

Fluid friction clutch

AssigneeBehr GmbH & Co.

InventorsMax Herrle, Werner Hummel, Gerold Schultheiss

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Abstract

Known fluid friction clutches, which are electromagnetically controlled from either an engine side or a driving side, require very strong and space-consuming coils in order to produce magnetic forces which are sufficient to control valve levers which, on the side of the clutch away from the coil, open or close a connection opening between a storage chamber and a working chamber. To address this problem, the magnet coil is placed as close as possible to the clutch housing and, by way of inserted flux guiding rings, achieve a magnetic shunt of the lines of magnetic flux such that the coil does not have to be overdimensioned. The flux guiding rings extend to just in front of an armature of the valve lever and, with small radial air gaps, to the housing of the coil. The rings can otherwise be arranged opposite the rotatable shaft made of a magnetic material. Such clutches are appropriate for use as fan clutches of vehicle engines.

Claims20

Dependent claims

Fluid friction clutch comprising:

a primary disk,
a live shaft to which the primary disk is fastened which consists of a magnetically active material,
an output clutch housing, which surrounds the primary disk, having a working chamber which is formed between the primary disk and the output clutch housing,
a valve plate having an armature situated in an area of the shaft so that a shearing fluid can enter from a storage chamber as a function of a position of said valve plate, said valve plate opening and closing a connection opening between the storage chamber and the working chamber, and
a stationary electromagnetic coil by which the valve plate can be adjusted against a spring effect into an opened position or a closed position by a magnetic force caused by the stationary electromagnet coil, said stationary electromagnetic coil being arranged on a driven side of the shaft,
wherein the primary disk or at least its hub placed on the shaft is constructed as a magnetic insulator and is provided with a magnetic flux guiding ring which extends into the proximity of the armature of the valve plate and rests against a bearing for the clutch housing which is placed onto the hub and forms a magnetic shunt with the electromagnet coil.

3 more elements

Dependencies are inferred from the claim text.