Which gear in the Simpson set uses a compound power flow that involves both the front and rear planetary gear sets?

Which gear in the Simpson set uses a compound power flow that involves both the front and rear planetary gear sets?

• A. First gear
• B. Second gear
• C. Third gear
• D. Fourth gear

Answer: (A)

The main idea tested is how a Simpson gear set can create a compound power flow by engaging both the front and rear planetary gear sets, and which gear uses that path. In the lowest gear, the clutching arrangement routes power so it flows through the front planetary gear set and then continues through the rear planetary gear set as part of the same path. This makes the reduction a compound one, giving very high torque at a low speed. In the higher gears, the clutches reconfigure so that power goes through only one of the planetary sets, or the outputs are taken from a single stage, so there isn’t a compound flow involving both sets. Therefore, the gear that uses this compound path through both front and rear planetary gear sets is the first gear.

The main idea tested is how a Simpson gear set can create a compound power flow by engaging both the front and rear planetary gear sets, and which gear uses that path. In the lowest gear, the clutching arrangement routes power so it flows through the front planetary gear set and then continues through the rear planetary gear set as part of the same path. This makes the reduction a compound one, giving very high torque at a low speed. In the higher gears, the clutches reconfigure so that power goes through only one of the planetary sets, or the outputs are taken from a single stage, so there isn’t a compound flow involving both sets. Therefore, the gear that uses this compound path through both front and rear planetary gear sets is the first gear.