In 4/2 DCVs, the actuator is often allowed to coast to a stop rather than stopping abruptly.

In 4/2 DCVs, the actuator is often allowed to coast to a stop rather than stopping abruptly.

• A. Increase speed
• B. Coast to a stop
• C. Rapidly fluctuate speed
• D. Abruptly Stop

Answer: (B)

The key idea is how a simple 4/2 directional control valve controls flow to the actuator. In this arrangement, one end of the actuator is connected to pressure while the other end is vented, and there isn’t a built-in brake or lock to hold position. When you remove drive or switch directions, the fluid on the driving side is no longer pressurized in the same way, and the actuator loses its driving force. The stored energy from motion dissipates through friction and small amounts of leakage, so the piston slows gradually rather than stopping instantly. This is why the actuator is described as coasting to a stop. If you wanted an abrupt stop, you’d need some form of braking or locking mechanism (like a center-off position that blocks motion or a brake, or a circuit designed to trap pressure on one side). The straightforward behavior of a 4/2 valve is to cut off drive pressure and let the load decelerate, which matches the coast-to-a-stop behavior.

The key idea is how a simple 4/2 directional control valve controls flow to the actuator. In this arrangement, one end of the actuator is connected to pressure while the other end is vented, and there isn’t a built-in brake or lock to hold position. When you remove drive or switch directions, the fluid on the driving side is no longer pressurized in the same way, and the actuator loses its driving force. The stored energy from motion dissipates through friction and small amounts of leakage, so the piston slows gradually rather than stopping instantly. This is why the actuator is described as coasting to a stop.

If you wanted an abrupt stop, you’d need some form of braking or locking mechanism (like a center-off position that blocks motion or a brake, or a circuit designed to trap pressure on one side). The straightforward behavior of a 4/2 valve is to cut off drive pressure and let the load decelerate, which matches the coast-to-a-stop behavior.