Fluid coupling

Claim 2

A fluid coupling comprising relatively rotatable first and second coupling members, said first coupling member defining a chamber in which said second coupling member is located, said first and second coupling members having spaced opposed surface portions defining a shear space therebetween and cooperable with a fluid shear medium within said shear space to provide a sheartype fluid drive therebetween, one of said coupling members defining a reservoir chamber for the fluid shear medium, and means for varying the volume of the fluid shear medium in the shear space dependent on the temperature of the fluid shear medium comprising means on one of said coupling members defining at least one pumping groove communicating said shear space with said reservoir chamber and operable to pump fluid from said shear space into said reservoir chamber to decrease the volume of fluid in the shear space when the fluid viscosity is within a predetermined range, said coupling members being rotatable in the same direction at different rotational speeds, said pumping groove being located on the slower of said coupling members and creating a pressure head on the viscous fluid to urge the fluid from the shear space toward said reservoir chamber when the viscosity is within the predetermined range due to a relatively low ambient temperature.

Claim 3

A fluid coupling as defined in claim 1 wherein the flow of fluid from said reservoir chamber into the shear space is effected by centrifugal force acting on the fluid.

Claim 4

A fluid coupling as defined in claim 1 wherein the slower of said coupling members is the output member which is driven by the other of said coupling members.

Claim 5

A fluid coupling as defined in claim 1 wherein said volume varying means pumps fluid from said shear space with a pressure head which increases as the temperature of tehe fluid decreases and which pressure head decreases as the temperature of the fluid increases.

Claim 6

A fluid coupling as defined in claim 1 wherein a surface is provided adjacent to said vane means on said one coupling mamber which is spaced from an adjacent surface of the other coupling member and through which the fluid flows from the reservoir into the shear space.

Claim 7

A fluid coupling as defined in claim 1 wherein said one coupling member defines a chamber and said other coupling member is located in said chamber and divides said chamber into two chamber portions, one of said chamber portions comprising a reservoir chamber and being in communication with the other chamber portion through said vane means, and passage means in said other coupling member for directing fluid from said reservoir chamber into said shear space upon a decrease in viscosity of the fluid to a predetermined level.

Claim 8

A fluid coupling comprising relatively rotatable first and second coupling members, said first coupling member defining a chamber in which said second coupling member is located, said second coupling member dividing said chamber into two chamber portions, said first and second coupling members having spaced opposed surface portions defining a shear space therebetween and cooperable with a fluid shear medium within said shear space to provide a shear-type fluid drive therebetween, one of said chamber portions comprising a reservoir chamber for the fluid shear medium, means for varying the volume of the fluid shear medium in the shear space dependent on the temperature of the fluid shear medium comprising vane means on one of said coupling members defining a passage communicating said shear space with said reservoir chamber and operable to pump fluid from said shear space into said reservoir chamber to decrease the volume of fluid in the shear space, means on said second coupling member isolating said two chamber portions from free flow of fluid therebetween to thereby provide for said decrease in volume of fluid in the shear space, and surfaces of said first and second coupling members defining a passage for fluid flow from the reservoIr chamber into said shear space due to centrifugal force acting in opposition to the action of said vane means to increase the volume of fluid in said shear space.

Claim 9

A fluid coupling comprising relatively rotatable first and second coupling members, said first coupling member defining a chamber in which said second coupling member is located, said second coupling member dividing said chamber into two chamber portions, said first and second coupling members having spaced opposed surface portions defining a shear space therebetween and cooperable with a fluid shear medium within said shear space to provide a shear-type fluid drive therebetween, one of said chamber portions comprising a reservoir chamber for the fluid shear medium, means for varying the volume of the fluid shear medium in the shear space dependent on the temperature of the fluid shear medium comprising vane means on one of said coupling members defining a passage communicating said shear space with said reservoir chamber and operable to pump fluid from said shear space into said reservoir chamber to decrease the volume of fluid in the shear space, means on said second coupling member isolating said two chamber portions from free flow of fluid therebetween to thereby provide for said decrease in volume of fluid in the shear space, and surfaces of said first and second coupling members defining a passage for fluid flow from the reservoIr chamber into said shear space due to centrifugal force acting in opposition to the action of said vane means to increase the volume of fluid in said shear space.

Claim 10

A fluid coupling as defined in claim 7 wherein said vane means comprises a series of vane formed in the output coupling member and which extend angularly so as not to intersect the axis of rotation of the coupling members.