Which compound gear set uses a planetary gear set in front of a Ravigneaux gear set?
a. Simple gear set
b. Simpson gear set
c. Ravigneaux gear set
d. Lapelletier gear set
The Correct Answer and Explanation is :
The correct answer is d. Lapelletier gear set.
Explanation:
A Lapelletier gear set (also known as the Lepelletier or Lepelletier planetary gear set) is a type of compound gear set used in automatic transmissions, where a planetary gear set is placed in front of a Ravigneaux gear set.
- Planetary gear sets typically consist of three main components: the sun gear, the planet gears (attached to the planet carrier), and the ring gear. Planetary gear sets are used for various applications, such as speed reduction or torque multiplication.
- The Ravigneaux gear set is a specific type of compound planetary gear set that includes two sun gears and a single set of planet gears. This setup allows for more gear ratios within a smaller space, making it a popular choice for automatic transmissions. It provides a higher level of versatility, including multiple forward gears and a reverse gear.
A Lapelletier gear set utilizes a combination of a planetary gear set followed by a Ravigneaux gear set in its configuration. By placing the planetary gear set first, followed by the Ravigneaux gear set, it achieves even more complex gear ratio combinations. This configuration is often used to increase the efficiency of a transmission, providing more gear ratios for smoother transitions and better overall performance in automatic transmission systems.
Key Differences Between the Options:
- Simple gear set: Refers to a single, basic set of gears (not compound) that doesn’t involve any arrangement like the planetary or Ravigneaux gear sets.
- Simpson gear set: Uses a combination of multiple gears but doesn’t involve the exact arrangement of a planetary gear set in front of a Ravigneaux gear set.
- Ravigneaux gear set: A compound gear set on its own, typically involving two sun gears and one set of planets, but does not involve a planetary set in front of it.
Thus, the Lapelletier gear set is the correct answer, as it uniquely incorporates a planetary gear set in front of a Ravigneaux gear set to provide multiple gear ratios efficiently.