Patent ID: 7294089
Filing Date: 2007-11-13
Classification: F16H

Abstract:
1. A multi-speed automatic transmission comprising: an input; an output; a first power path producing a first ratio of a speed of the input and a speed of a first power path output; a second power path producing a second ratio of a speed of the input and a speed of the second power path output, the second ratio being is less than the first ratio; a double planetary gear unit secured to first, second, third and fourth members, the second member being secured to the output for rotation therewith, the double planetary gear unit further comprising of a second gear unit including a second sun gear secured to the fourth member, second ring gears, one of said second ring gears being secured to the output and second member, second planet pinions meshing with the second sun gear and the second ring gears, and a second carrier rotatably supporting the second planet pinions and secured to the third member; a third gear unit including a third sun gear secured to the second sun gear and the fourth member, a third ring gear, and a third carrier rotatably supporting third planet pinions and secured to the other of the second ring gears; a first clutch being operable to connect the first member to the input through the first power path; a second clutch being operable to connect the fourth member to the input through the first power path; a third clutch being operable to connect the third member to the input through the second power path; a fourth clutch being operable to connect the fourth member to the input through the second power path; and a first brake being operable to hold the fourth member against rotation; and a second brake being operable to hold the third member against rotation.