Internal combustion engine fan drive

Claim 2

A fan drive for an internal combustion engine including a fan and an engine drive, said fan drive comprising a clutch which when engaged couples said engine drive to said fan and when disengaged uncouples said engine drive from said fan, said clutch including at least two parts forming a pressure chamber, at least one of said two parts being rotatable, feed and return liquid passage means connected to said chamber and adapted to be connected to a source of liquid under pressure, first valve means connected in said feed passage means for controlling the communication of liquid pressure between the source and said pressure chamber, said first valve means having an open position where said pressure chamber receives substantially the full pressure of said source and a closed position where said passage means is closed and pressure is locked in said chamber, and second valve means on said rotatable part for releasing pressure in said chamber to said return passage after said first valve means is moved to said closed position, said clutch being actuated when said first valve means is open and liquid pressure appears in said chamber, said second valve means including a member that responds to centrifugal force and to liquid pressure and having a closed position and an open position, and said pressure chamber being bounded by seals which enable leakage of liquid under pressure from said chamber when said first valve and said second valve are in said closed positions, and said seals leaking said liquid under pressure when said first valve is closed and thereby causing said second valve to open and sald clutch to slowly disengage.

Claim 3

A fan drive according to claim 1, wherein said second valve means comprises a passage formed through said rotatable part, said passage having one end thereof communicating with said chamber and said one end having a tapered surface forming a valve seat, said second valve means further including a movable ball which is engageable with said valve seat and rotates with said rotatable part.

Claim 4

A fan drive according to claim 2, wherein said two parts are both rotatable and said ball is between said two parts.

Claim 5

A fan drive according to claim 2, wherein said two parts are spaced a distance apart which is less than the diameter of said ball, whereby said ball is prevented from moving out of said tapered end of said passage.

Claim 6

A fan drive for an internal combustion engine including an engine drive, a fan, and an engine lubricating system including a pump having a high pressure outlet and a low pressure return, said fan drive comprising a non rotatable mounting shaft adapted to be secured to the engine, a fan hub rotatably mounted on said shaft, housing means rotatably mounted on said shaft and on said hub, said housing means including drive means adapted to be connected to be rotatably driven by the engine, clutch means including first clutch parts attached to said housing means and second clutch parts attached to said hub, said first and second clutch parts being relatively movable between engaged and disengaged positions, said clutch means further including a clutch piston mounted within said housing means adjacent said clutch parts, said housing means and said piston forming a pressure chamber therebetween, said chamber being bounded by seals which enable leakage of lubricant from said chamber, a control passage formed in shaft and connected to said chamber and adapted to be connected to said outlet, a control valve connected to said control passage to control the flow of lubricant to said passage and to said chamber, said control valve having an open position where it enables the flow of lubricant to said chamber and a closed position where it blocks the flow of lubricant to and from said chamber, lubricant pressure in said chamber forcing said piston to engage said first and second clutch parts and engage said clutch means, and a pressure-speed responsive valve formed on one of said housing means and said piston, said pressure-speed responsive valve being connected between said chamber and said return and being closed to lubricant flow at high pressure and being open to lubricant flow at reduced pressure, and said seals leaking said lubricant under pressure when said control valve is in said closed position and thereby reducing said pressure and causing said pressure-speed responsive valve to open and said clutch means to slowly disengage.

Claim 7

A fan drive for an internal combustion engine including an engine drive, a fan, and an engine lubricating system including a pump having a high pressure outlet and a low pressure return, said fan drive comprising a non rotatable mounting shaft adapted to be secured to the engine, a fan hub rotatably mounted on said shaft, housing means rotatably mounted on said shaft and on said hub, said housing means including drive means adapted to be connected to be rotatably driven by the engine, clutch means including first clutch parts attached to said housing means and second clutch parts attached to said hub, said first and second clutch parts being relatively movable between engaged and disengaged positions, said clutch means further including a clutch piston mounted within said housing means adjacent said clutch parts, said housing means and said piston forming a pressure chamber therebetween, said chamber being bounded by seals which enable leakage of lubricant from said chamber, a control passage formed in shaft and connected to said chamber and adapted to be connected to said outlet, a control valve connected to said control passage to control the flow of lubricant to said passage and to said chamber, said control valve having an open position where it enables the flow of lubricant to said chamber and a closed position where it blocks the flow of lubricant to and from said chamber, lubricant pressure in said chamber forcing said piston to engage said first and second clutch parts and engage said clutch means, and a pressure-speed responsive valve formed on one of said housing means and said piston, said pressure-speed responsive valve being connected between said chamber and said return and being closed to lubricant flow at high pressure and being open to lubricant flow at reduced pressure, and said seals leaking said lubricant under pressure when said control valve is in said closed position and thereby reducing said pressure and causing said pressure-speed responsive valve to open and said clutch means to slowly disengage.

Claim 8

A fan drive as in claim 5, and further including bearings for rotatably mounting said hub and said housing means on said shaft, a feed passage formed in said shaft and adapted to be connected to said outlet, said feed passage being connected to supply lubricant to said bearings and to said first and second clutch parts.

Claim 9

A fan drive as in claim 5, wherein said control valve comprises a temperature responsive lubricant control valve adapted to respond to the temperature of the engine.

Claim 10

A fan drive as in claim 5, wherein said pressure-speed responsive valve comprises a member that responds to centrifugal force when it is rotated and to lubricant pressure within said chamber.

Claim 11

A fan drive for an internal combustion engine including an engine drive, a fan, and an engine lubricating system including a high pressure pump outlet and a low pressure pump return, said fan drive comprising clutch means between said engine drive and said fan, said clutch including a pressure chamber and said clutch when engaged coupling said engine drive to said fan and when disengaged uncoupling said engine drive from said fan, seals bounding said pressure chamber and enabling leakage of lubricant from said pressure chamber, said fan drive further including a feed path and a return path therethrough, means for connecting said feed and return paths respectively to said pump outlet and said pump return for continuously circulating lubricant through said feed path and said return path during engine operation, said fan drive further including a control path connected to said pressure chamber, first valve means connected in said control path and having an open position and a closed position, said first valve placing said pressure chamber in lubricant flow communication with the pump outlet when in said open position, and said first valve closing said control path to lubricant flow when in said closed position, and second valve means between said pressure chamber and said return path, said second valve being responsive to lubricant pressure in said pressure chamber and being closed to lubricant flow at high pressure and open to lubricant flow at reduced pressure, the lubricant pressure appearing in said pressure chamber when said first valve is open and the pressure closing said second valve and said seals leaking lubricant from said chamber when said first valve is closed and thereby causing said second valve to open.

Claim 12

A fan drive for an internal combustion engine including an engine drive, a fan, and an engine lubricating system including a high pressure pump outlet and a low pressure pump return, said fan drive comprising clutch means between said engine drive and said fan, said clutch including a pressure chamber and said clutch when engaged coupling said engine drive to said fan and when disengaged uncoupling said engine drive from said fan, seals bounding said pressure chamber and enabling leakage of lubricant from said pressure chamber, said fan drive further including a feed path and a return path therethrough, means for connecting said feed and return paths respectively to said pump outlet and said pump return for continuously circulating lubricant through said feed path and said return path during engine operation, said fan drive further including a control path connected to said pressure chamber, first valve means connected in said control path and having an open position and a closed position, said first valve placing said pressure chamber in lubricant flow communication with the pump outlet when in said open position, and said first valve closing said control path to lubricant flow when in said closed position, and second valve means between said pressure chamber and said return path, said second valve being responsive to lubricant pressure in said pressure chamber and being closed to lubricant flow at high pressure and open to lubricant flow at reduced pressure, the lubricant pressure appearing in said pressure chamber when said first valve is open and the pressure closing said second valve and said seals leaking lubricant from said chamber when said first valve is closed and thereby causing said second valve to open.

Claim 13

A fan drive as in claim 9, wherein said first valve means comprises a temperature responsive solenoid operated fluid valve.

Claim 14

A fan drive as in claim 9, wherein said second valve means includes a member that responds to centrifugal force and to said pressure of the lubricant in the pressure chamber.

Claim 15

A fan drive as in claim 9, and further including mounting means for fastening said fan drive to the engine, first and second coupling means on said mounting means and connected respectively to said pump outlet and pump return and to said feed path and said return path, said feed path and said return path extending through said mounting means, and said control path extending into said mounting means and connecting with said feed path in said mounting means.

Claim 16

A fan drive as in claim 12, wherein said first valve comprises a temperature responsive valve fastened to said mounting means.

Claim 17

A fan drive as in claim 12, wherein said coupling means forms the only connections between said fan drive and said engine lubricating system.