Hydromechanical transmission employing lockup clutch
AssigneeInternational Harvester Company
InventorsRichard G. Hennessey, Richard B. Beemer, Harold W. Melles
Life of this patent
Estimating the term…
Abstract
A transmission system particularly usable for transmitting power from an internal combustion engine to the driving wheels of a vehicle such as a tractor includes a multiple ratio mechanical range transmission coupled to an infinitely variable ratio hydromechanical transmission via a manually operable master clutch. A high slip fluid coupling is used to couple the hydromechanical transmission to the engine, and an electronically controlled lockup clutch locks the impeller of the fluid coupling to the output turbine when the speed of the engine exceeds a first predetermined speed, and maintains the coupling locked until the speed of the engine drops below a second substantially lower predetermined speed.
Claims14
A rotary power transmission for transmitting to an output shaft rotary power applied to an input shaft from a source of rotary power, said system comprising:
- a fluid coupling having an impeller and an output turbine interposed between said input shaft and said output shaft and operative to transmit power therebetween;
- a master clutch interposed between said input shaft and said output shaft, said master clutch being operative to interrupt the flow of power between said input shaft and said output shaft;
- means including a lockup clutch operable to a first condition of operation to permit relative motion between said impeller and an output turbine, said lockup clutch being operative to a second condition of operation to prevent relative motion between said impeller and said output turbine;
- and
- means including an electronic circuit for altering the condition of operation of said lockup clutch, said altering means responsive to the master clutch being operative to interrupt said power flow, and said altering means also being responsive to the rotary speed of said rotary power source for operating said lockup clutch from said first condition of operation to said second condition of operation when the speed of said rotary power source exceeds a first predetermined level, and vice versa when the master clutch is operative to interrupt said power flow.
A rotary power transmission system for transmitting to an output shaft rotary power applied to an input shaft from a source of rotary power, said system comprising:
- a fluid coupling having an impeller and an output turbine interposed between said input shaft and said output shaft and operative to transmit power therebetween;
- a master clutch interposed between said input shaft and said output shaft, said master clutch being operative to interrupt the flow of power between said input shaft and said output shaft;
- means including a lockup clutch operable to a first condition of operation to permit relative motion between said impeller and output turbine, said lockup clutch being operable to a second condition of operation to prevent relative motion between said impeller and said output turbine;
- and
- means including an electronic circuit for altering the condition of operation of said lockup clutch, said altering means being responsive to the rotary speed of said rotary power source;
- said system characterized wherein said altering means includes means for operating said lockup clutch from said first condition of operation to said second condition of operation when said rotary power source is accelerated to a speed above said first predetermined level and for maintaining said lockup clutch in said second condition of operation until said rotary power source is decelerated to a speed below a second predetermined level below said first predetermined level.
Dependencies are inferred from the claim text.