Machine element or mechanism – Rotary member or shaft indexing – e.g. – tool or work turret – Preselected indexed position
Patent
1989-12-26
1991-07-09
Herrmann, Allan D.
Machine element or mechanism
Rotary member or shaft indexing, e.g., tool or work turret
Preselected indexed position
74877, F16H 6106, F16H 5946
Patent
active
050294946
ABSTRACT:
In an automatic transmission, clutch-to-clutch powered downshifting is controlled by filling the on-coming clutch at a low pressure while ramping down the off-going clutch pressure until turbine speed is pulled up due to off-going clutch slippage, and then increasing the off-going pressure stepwise to compensate the change from static to dynamic coefficients of friction. Then the on-coming pressure is gradually ramped up and a closed-loop profile control period starts wherein the slip of the on-coming clutch is measured and controlled to a slip profile by controlling the off-going clutch pressure. When synchronization of the on-coming clutch is first detected, a closed-loop sync control period starts wherein the off-going pressure is controlled to minimize the slip and the on-coming pressure is ramped up at a steeper rate to begin clutch engagement during the sync control period.
REFERENCES:
patent: 4653351 (1987-03-01), Downs et al.
patent: 4796490 (1989-01-01), Butts et al.
patent: 4858499 (1989-08-01), Ito et al.
patent: 4887491 (1989-12-01), Holbrook et al.
patent: 4938102 (1990-07-01), Leising et al.
patent: 4942787 (1990-07-01), Aoki et al.
Hunter Joseph H.
Lentz Carl A.
General Motors Corporation
Herrmann Allan D.
Navarre Mark A.
Ta Khoi Q.
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