🔍 Key Concepts

• Trace the flow paths in the 4/3 directional control valve when solenoid A is energized versus when neither solenoid is energized. • Compare the effective areas of the cylinder cap end vs. rod end and how this affects extension vs. retraction speed for the same pump flow. • Note the flow control/check valve combination at the rod end (E–F) and decide in which direction the flow is being throttled and in which direction it is free-flowing.

💭 Think About

• When solenoid A shifts the spool, which cylinder port (C or D) is connected to the pump pressure line and which is connected to return? What does that do to the piston rod motion? • Looking at the center position of the directional valve symbol, is the pump port connected to tank, blocked, or feeding the cylinder? How would that affect pump flow when both solenoids are de‑energized? • If flow is throttled in only one direction through the flow control at the rod end, during which stroke (extend or retract) is the cylinder movement likely to be slower, assuming constant pump output?

✅ Before You Answer

• Verify from the spool symbol which lines are connected in the center position (P to T, P blocked, or all ports blocked). • Verify from the direction of arrows in the flow control/check valve whether controlled flow is toward or away from the rod end of the cylinder. • Confirm that the difference in piston areas alone would normally make one stroke faster than the other, then factor in the added restriction from the flow control.