Why do we sometimes use a roller-type one-way clutch to hold a member of the planetary gear set?

Why do we sometimes use a roller-type one-way clutch to hold a member of the planetary gear set?

• A. To save money
• B. To prevent engine braking when decelerating
• C. All of the choices are correct.
• D. To provide a much smoother engagement than a hydraulic clutch

Answer: (B)

One-way clutches in a planetary gear set are used to control torque paths by locking a member in one rotational direction while allowing free rotation in the other. When decelerating, a roller-type one-way clutch can hold a particular gear-set member so the engine isn’t forced to drive the planetary train, which reduces engine braking and lets the vehicle coast more smoothly. This decoupling is the main benefit in this context. It isn’t primarily about saving money, and it isn’t chosen for providing smoother engagement than a hydraulic clutch—the key advantage is minimizing engine braking during deceleration.

One-way clutches in a planetary gear set are used to control torque paths by locking a member in one rotational direction while allowing free rotation in the other. When decelerating, a roller-type one-way clutch can hold a particular gear-set member so the engine isn’t forced to drive the planetary train, which reduces engine braking and lets the vehicle coast more smoothly. This decoupling is the main benefit in this context. It isn’t primarily about saving money, and it isn’t chosen for providing smoother engagement than a hydraulic clutch—the key advantage is minimizing engine braking during deceleration.