Viscous fluid clutch

Claim 2

A viscous fluid clutch comprising an input shaft, a clutch plate secured to said shaft, a fluid clutch housing rotatably mounted on said input shaft, a cover member sealed to said housing, a divider wall secured for rotation with said cover member and said housing and mounted between said cover member and said clutch plate so as to form a reservoir chamber with said cover member and an operating chamber with said housing, a first opening formed in said divider wall between said operating chamber and said reservoir chamber, pump means operatively connected to said divider wall for pumping a fluid medium from said operating chamber through said first opening to said reservoir chamber, a second opening formed in said divider wall for at times communicating said fluid medium from said reservoir chamber to said operating chamber, and bimetallic thermostatic valve means for controlling the flow of said fluid medium through said second opening in response to the temperature of the ambient air, said bimetallic thermostatic valve means including a bimetallic strip element secured at one end thereof to said divider wall in said reservoir chamber and extending across the center of said viscous fluid clutch free of any contact intermediate the ends thereof and having a valve portion formed on the other end thereof adjacent said second opening, said bimetallic strip element being preformed so as to remain closed against said second opening until a predetermined ambient temperature is reached in said reservoir chamber in the space radially within the annular surface of said fluid medium therein.

Claim 3

A viscous fluid clutch comprising an input shaft, a clutch plate secured to said shaft, a fluid clutch housing rotatably mounted on said input shaft, a cover member sealed to said housing, a divider wall secured for rotation with said cover member and said housing and mounted between said cover member and said clutch plate so as to form a reservoir chamber with said cover member and an operating chamber with said housing, a first opening formed in said divider wall between said operating chamber and said reservoir chamber, pump means operatively connected to said divider wall for pumping a fluid medium from said operating chamber through said first opening to said reservoir chamber, a second opening formed in said divider wall for at times communicating said fluid medium from said reservoir chamber to said operating chamber, and bimetallic thermostatic valve means for controlling the flow of said fluid medium through said second opening in response to the temperature of the ambient air, said bimetallic thermostatic valve means including a bimetallic strip element secured at one end thereof to said divider wall in said reservoir chamber and extending across the center of said viscous fluid clutch free of any contact intermediate the ends thereof and having a valve portion formed on the other end thereof adjacent said second opening, said bimetallic strip element being preformed so as to remain closed against said second opening until a predetermined ambient temperature is reached in said reservoir chamber in the space radially within the annular surface of said fluid medium therein.

Claim 4

A viscous fluid clutch comprising an input shaft, a clutch plate secured to said shaft, a fluid clutch housing rotatably mounted on said input shaft, a cover member sealed to said housing, a divider wall secured for rotation with said cover member and said housing and mounted between said cover member and said clutch plate so as to form a reservoir chamber with said cover member and an operating chamber with said housing, a first opening formed in said divider wall between said operating chamber and said reservoir chamber, pump means operatively connected to said divider wall for pumping a fluid medium from said operating chamber through said first opening to said reservoir chamber, a second opening formed in said divider wall for at times communicating said fluid medium from said reservoir chamber to said operating chamber, and bimetallic thermostatic valve means for controlling the flow of said fluid medium through said second opening in response to the temperature of the ambient air, said bimetallic thermostatic valve means including a bimetallic strip element secured at one end thereof to said divider wall in said reservoir chamber and extending across the center of said viscous fluid clutch free of any contact intermediate the ends thereof and having a valve portion formed on the other end thereof adjacent said second opening, said bimetallic strip element being preformed so as to remain closed against said second opening until a predetermined ambient temperature is reached in said reservoir chamber in the space radially within the annular surface of said fluid medium therein.

Claim 5

A viscous fluid clutch comprising an input shaft, a first member secured to said shaft a second member Rotatably mounted on said input shaft, a cover member fixed to said second member such that said first member is relatively rotatable between said second member and said cover member, a divider wall secured for rotation with said cover member and said second member and mounted between said cover member and said first member so as to form an annular reservoir chamber with said cover member and an operating chamber with said second member, a pair of oppositely disposed outlet openings formed in said divider wall communicating between said operating chamber and said annular reservoir chamber, oppositely disposed pump means operatively connected to said first and second members circumferentially adjacent each of said oppositely disposed outlet openings for forcing a fluid medium from said operating chamber through said oppositely disposed outlet openings to said annular reservoir chamber, an inlet opening formed in said divider wall for at times permitting said fluid medium to flow from said annular reservoir chamber to said operating chamber, a bimetallic stem member having bent ends formed thereon and being mounted in said annular reservoir chamber with one of said bent ends being secured flatly against said divider wall and having valve means formed on the other bent end thereof adjacent said inlet opening, said stem member extending across said annular reservoir chamber substantially perpendicular to a line between said oppositely disposed pump means and being free of any contact intermediate said bent ends, said bent ends serving to maintain said valve means against said divider wall to close off said inlet opening until a predetermined ambient temperature is reached.

Claim 6

A viscous fluid clutch comprising an input shaft, a first member secured to said shaft a second member Rotatably mounted on said input shaft, a cover member fixed to said second member such that said first member is relatively rotatable between said second member and said cover member, a divider wall secured for rotation with said cover member and said second member and mounted between said cover member and said first member so as to form an annular reservoir chamber with said cover member and an operating chamber with said second member, a pair of oppositely disposed outlet openings formed in said divider wall communicating between said operating chamber and said annular reservoir chamber, oppositely disposed pump means operatively connected to said first and second members circumferentially adjacent each of said oppositely disposed outlet openings for forcing a fluid medium from said operating chamber through said oppositely disposed outlet openings to said annular reservoir chamber, an inlet opening formed in said divider wall for at times permitting said fluid medium to flow from said annular reservoir chamber to said operating chamber, a bimetallic stem member having bent ends formed thereon and being mounted in said annular reservoir chamber with one of said bent ends being secured flatly against said divider wall and having valve means formed on the other bent end thereof adjacent said inlet opening, said stem member extending across said annular reservoir chamber substantially perpendicular to a line between said oppositely disposed pump means and being free of any contact intermediate said bent ends, said bent ends serving to maintain said valve means against said divider wall to close off said inlet opening until a predetermined ambient temperature is reached.

Claim 7

A viscous fluid clutch comprising first and second relatively rotatable drive members, said first drive member including front and rear walls and defining a fluid cavity therebetween, said front wall having first and second pairs of oppositely disposed radial pockets formed therein at substantially right angles to each other, a divider wall sealed between said front and rear walls in said fluid cavity and dividing said fluid cavity into first and second chambers, said second drive member being rotatable in said first chamber, said second drive member and said rear wall having opposed spaced parallel surfaces defining a fluid shear space therebetween and cooperable with a fluid medium in said shear space to provide a shear-type fluid drive therebetween, first and second openings formed in said divider wall for providing communication between said first and second chambers, said first and second openings being located adjacent said first pair of oppositely disposed pockets, a dam element formed on said divider wall in said first chamber adjacent each of said first and second openings for causing said fluid medium to flow through said first and second openings from said first chamber to said second chamber for varying the volume of fluid medium in said shear space to vary the torque transmitted between said first and second drive members, a third opening formed in said divider wall for at times communicating said fluid medium from said second chamber to said first chamber, a temperature-responsive valve operatively connected with said third opening for controlling the flow of said fluid medium through said third opening from said second chamber to said shear space in said first chamber to further vary the torque transmitted between said first and second drive members, said temperature-responsive valve having a stem portion extending from a location adjacent said third opening across said second chamber on a line transverse to a line between said first and second openings and secured at the end thereof to said divider wall, said valve end and said secured end being located in said second pair of oppositely disposed pockets.

Claim 8

A viscous fluid clutch comprising first and second relatively rotatable drive members, said first drive member including front and rear walls and defining a fluid cavity therebetween, said front wall having first and second pairs of oppositely disposed radial pockets formed therein at substantially right angles to each other, a divider wall sealed between said front and rear walls in said fluid cavity and dividing said fluid cavity into first and second chambers, said second drive member being rotatable in said first chamber, said second drive member and said rear wall having opposed spaced parallel surfaces defining a fluid shear space therebetween and cooperable with a fluid medium in said shear space to provide a shear-type fluid drive therebetween, first and second openings formed in said divider wall for providing communication between said first and second chambers, said first and second openings being located adjacent said first pair of oppositely disposed pockets, a dam element formed on said divider wall in said first chamber adjacent each of said first and second openings for causing said fluid medium to flow through said first and second openings from said first chamber to said second chamber for varying the volume of fluid medium in said shear space to vary the torque transmitted between said first and second drive members, a third opening formed in said divider wall for at times communicating said fluid medium from said second chamber to said first chamber, a temperature-responsive valve operatively connected with said third opening for controlling the flow of said fluid medium through said third opening from said second chamber to said shear space in said first chamber to further vary the torque transmitted between said first and second drive members, said temperature-responsive valve having a stem portion extending from a location adjacent said third opening across said second chamber on a line transverse to a line between said first and second openings and secured at the end thereof to said divider wall, said valve end and said secured end being located in said second pair of oppositely disposed pockets.