US 4,064,980 AGranted

Dual speed viscous fluid coupling

AssigneeEaton Corporation

InventorThomas H. Tinholt

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Abstract

A viscous fluid coupling is provided of the type driven by a prime mover, the speed of which varies over a wide range. The coupling includes an output member defining two fluid chambers, with an input member being rotatably disposed in each of the fluid chambers, and the two input members being driven by the prime mover at different rotational speeds. At lower prime mover speeds, viscous fluid is pumped into the fluid chamber containing the higher speed ratio input member to provide a higher ratio of output speed to prime mover speed. At higher prime mover speeds, viscous fluid is pumped into the fluid chamber containing the lower speed ratio input member to provide a lower ratio of output speed to prime mover speed. Utilizing the disclosed fluid coupling as a drive for a radiator cooling fan results in more cooling at low engine speeds, but less wasted power at higher engine speeds.

Claims11

Dependent claims

A viscous fluid coupling adapted to be driven by a prime mover, the fluid coupling comprising:

a. an output coupling member rotatable about an axis and defining a low speed fluid chamber and a high speed fluid chamber;
b. a first input coupling member rotatably disposed within said low speed fluid chamber;
c. a second input coupling member rotatably disposed within said high speed fluid chamber;
d. means for transmitting a given motion of the prime mover into a rotational speed X of said first input coupling member and into a rotational speed Y of said second input coupling member, said rotational speed X being greater than said rotational speed Y for any given motion of the prime mover;
e. first means for providing a quantity of viscous fluid in said low speed fluid chamber below a certain speed of the prime mover to transmit torque from said first input coupling member to drive said output coupling member at a rotational speed A which is less than X but greater than Y;
and
f. second means for providing a quantity of viscous fluid in said high speed fluid chamber above said certain speed of the prime mover to transmit torque from said second input coupling member to drive said output coupling member at a rotational speed B which is less than said rotational speed Y.

4 more elements

Dependencies are inferred from the claim text.