Granted Patent B2

US 7,285,069 · App. 11/238,394 · Granted Oct 23, 2007

Abstract

Claims (27)

1. A powertrain having a multi-speed transmission comprising:

an input shaft;

an output shaft;

a transmission housing;

a first planetary gearset having first, second and third members;

a second planetary gearset having first, second and third members;

a third planetary gearset having first, second and third members;

a fourth planetary gearset having first, second and third members;

seven torque-transmitting mechanisms;

said first member of said first planetary gearset being continuously connected with said transmission housing;

said second member of said first planetary gearset being connected with a first of said torque-transmitting mechanisms;

said third member of said first planetary gearset being continuously interconnected with said input shaft and with said first member of said second planetary gearset;

said second member of said second planetary gearset being selectively connectible with said second member of said first planetary gearset through said first torque-transmitting mechanism and selectively connectible with said input shaft through a second of said torque-transmitting mechanisms and continuously connected with said first member of said fourth planetary gearset;

said third member of said second planetary gearset being selectively connectible with said housing through a third of said torque-transmitting mechanisms;

said first member of said third planetary gearset being continuously connected with said second member of said fourth planetary gearset and selectively connectible with said transmission housing through a fourth of said torque-transmitting mechanisms;

said second member of said third planetary gearset being continuously connected with said output shaft;

said third member of said third planetary gearset being continuously connected with said third member of said fourth planetary gearset and selectively connectible with said input shaft through a fifth of said torque-transmitting mechanisms, and selectively connectible with said transmission housing through a sixth of said torque-transmitting mechanisms;

said second member of said second planetary gearset and said first member of said fourth planetary gearset being selectively connectible with said transmission housing through a seventh of said torque-transmitting mechanisms; and

said torque-transmitting mechanisms being selectively connectible in combinations of two to establish a reverse speed ratio and eight forward speed ratios between said input shaft and said output shaft.

2. The powertrain having a multi-speed power transmission defined in claim 1 , further wherein:

said torque-transmitting mechanisms are also operable to establish two additional reverse speed ratios through said planetary gearset between said input shaft and said output shaft.

3. The powertrain having a multi-speed power transmission defined in claim 2 , further wherein:

said reverse speed ratios range from lowest to highest and a single transition interchange is provided between the lowest of said reverse speed ratios and the lowest of said first forward speed ratio, a single transition shift is provided between the intermediate of said reverse speed ratios and the next lowest forward speed ratio, and a single transition shift is provided between the highest of said reverse speed ratios and the third lowest of said forward speed ratios.

4. The powertrain having a multi-speed power transmission defined in claim 3 , further wherein:

the sixth of said torque-transmitting mechanisms is engaged for all three of said reverse speed ratios and is disengaged for all of said forward speed ratios.

5. The powertrain having a multi-speed power transmission defined in claim 1 , further wherein:

said fourth torque-transmitting mechanism is engaged for the four lowest forward speed ratios, and the fifth torque-transmitting mechanism is engaged for the five highest of said forward speed ratios.

Assignments (13)