Rotary magnetic control for a viscous fluid coupling

Claim 2

A viscous fluid clutch comprising: first and second members mounted for relative rotation about a common axis and defining cooperating shear surfaces forming an operating chamber therebetween; a return passageway operative to direct viscous fluid from said operating chamber to a storage chamber as a function of relative rotation between said members; valve means operable to frictionally engage one of said members to effect modulation of fluid flowing within said return passageway, said valve means comprising a valving element carried by one of said members for limited relative rotational displacement with respect thereto; and means operative to limit said relative rotational displacement of said valving element between a first limit of travel in which viscous fluid flow through said return passageway is substantially unobstructed, and a second limit of travel in which said return passageway is substantially closed.

Claim 3

The viscous clutch of claim 1, wherein said valve means is carried by one of said members and frictionally engages the other of said members.

Claim 4

The visous clutch of claim 1, wherein said valving element is disposed concentrically with respect to said first and second members.

Claim 5

The viscous clutch of claim 1, further comprising biasing means operative to urge said valving element into said first limit of travel.

Claim 6

The viscous clutch of claim 1, further comprising actuator means operative to axially displace said valving element to effect said engagement.

Claim 7

The viscous clutch of claim 5, wherein said actuator means comprises an electromagnet operative to establish a magnetic circuit which passes through ferrous metal within said valving element.

Claim 8

The viscous clutch of claim 6, wherein said electromagnet comprises an inductor disposed concentrically about said axis which is electrically energized as a function of the temperature of a fluid associated with said clutch.

Claim 9

The viscous clutch of claim 1, further comprising a pump operative to receive viscous fluid from said operating chamber and direct said fluid to said storage chamber as a function of relative rotation between said first and second members.

Claim 10

The viscous clutch of claim 1, further comprising at least one drain port for fluidly interconnecting said fluid storage chamber and said operating chamber, and means operative to obstruct said port when said valving element is in said first limit of travel and to open said port when said valving element is in said second limit of travel.

Claim 11

A viscous fluid clutch comprising: a first member secured for rotation with a shaft; a second member rotatably disposed on said shaft relative to said first member; shear surfaces disposed on said first and second members and forming an operating chamber therebetween; a fluid storage chamber disposed adjacent said operating chamber; a pump operative to displace fluid from said operating chamber to said storage chamber through a return passageway as a function of relative rotation between said members; at least one drain port interconnecting said chambers for selective fluid communication therebetween; valve means operable to frictionally engage one of said members to effect modulation of fluid flowing within said return passageway, said valve means carried by one of said members and frictionally engaging the other of said members, said valve means comprising a valving element carried by one of said members for limited relative rotational displacement with respect thereto; and means operative to limit said relative rotational displacement of said valving element between a first limit of travel in which viscous fluid flow through said return passageway is substantially unobstructed, and a second limit of travel in which said return passageway is substantially closed.

Claim 12

A viscous fluid clutch comprising: a first member secured for rotation with a shaft; a second member rotatably disposed on said shaft relative to said first member; shear surfaces disposed on said first and second members and forming an operating chamber therebetween; a fluid storage chamber disposed adjacent said operating chamber; a pump operative to displace fluid from said operating chamber to said storage chamber through a return passageway as a function of relative rotation between said members; at least one drain port interconnecting said chambers for selective fluid communication therebetween; valve means operable to frictionally engage one of said members to effect modulation of fluid flowing within said return passageway, said valve means carried by one of said members and frictionally engaging the other of said members, said valve means comprising a valving element carried by one of said members for limited relative rotational displacement with respect thereto; and means operative to limit said relative rotational displacement of said valving element between a first limit of travel in which viscous fluid flow through said return passageway is substantially unobstructed, and a second limit of travel in which said return passageway is substantially closed.

Claim 13

The viscous clutch of claim 10, wherein said valving element is disposed concentrically with respect to said first and second members.

Claim 14

The viscous clutch of claim 1, further comprising biasing means operative to urge said valving element into said first limit of travel.

Claim 15

The viscous clutch of claim 1, further comprising actuator means operative to axially displace said valving element to effect said engagement.

Claim 16

The viscous clutch of claim 13, wherein said actuator means comprises an electromagnet operative to establish a magnetic circuit which passes through ferrous metal within said valving element.

Claim 17

The viscous clutch of claim 14, wherein said electromagnet comprises an inductor disposed concentrically about said axis which is electrically energized as a function of the temperature of a fluid associated with said clutch.

Claim 18

The viscous clutch of claims 1 or 13, wherein said actuator means is operative to axially displace said valving element between a first, nonengaging position and a second, frictionally engaging position.

Claim 19

The viscous clutch of claim 16, further comprising additional biasing means operative to urge said valving element into said first position.

Claim 20

The viscous clutch of claim 17, wherein said additional biasing means is further operative to compensate for relative misallignment of said first and second members.