What gear set uses a separate planetary gear set as the input to a Ravigneaux gear set and produces six forward speeds, including two overdrives and one reverse?

What gear set uses a separate planetary gear set as the input to a Ravigneaux gear set and produces six forward speeds, including two overdrives and one reverse?

• A. Wilson
• B. ZF
• C. Simpson
• D. Lepelletier

Answer: (D)

Using a separate planetary gear set as the input to a Ravigneaux gear set is a feature of the Lepelletier arrangement. In this design, power first drives its own planetary stage, and the output from that stage then feeds the Ravigneaux train. The Ravigneaux gearset, a compact arrangement with two suns and two planets on a common carrier, can produce several gear ratios depending on which components are held stationary. By combining the two stages, you get a total of six forward speeds, with two of those gears serving as overdrives (output turning faster than input) and one gear providing reverse when the appropriate elements are locked or driven. This specific two-stage input approach is what distinguishes Lepelletier from other layouts, which is why it matches the description.

Using a separate planetary gear set as the input to a Ravigneaux gear set is a feature of the Lepelletier arrangement. In this design, power first drives its own planetary stage, and the output from that stage then feeds the Ravigneaux train. The Ravigneaux gearset, a compact arrangement with two suns and two planets on a common carrier, can produce several gear ratios depending on which components are held stationary. By combining the two stages, you get a total of six forward speeds, with two of those gears serving as overdrives (output turning faster than input) and one gear providing reverse when the appropriate elements are locked or driven. This specific two-stage input approach is what distinguishes Lepelletier from other layouts, which is why it matches the description.