R900617676 4WRZE10E85-7X/6EG24N9ETK31/A1D3M Rexroth proportional directional valve

Key Differences & Selection Guide

1. Q: What is the difference between 4WRZE (this valve) and 4WREE (previous valves)?

   A:​ The 4WRZE​ is a pilot-operated (2-stage)​ valve. It uses a small pilot valve to control a larger main stage, allowing for higher flows (up to ~170 L/min) compared to direct-operated 4WREE valves. It is more powerful but has a slower response time.

2. Q: What does the "E-spool" mean?

   A:​ The E-spool​ is a zero-overlap spool​ (similar to a servo spool). It provides high linearity and is used in applications requiring precise speed control without the "dead zone" characteristic of overlap spools (W/W1).

3. Q: What is the purpose of the /D3 suffix?

   A:​ The /D3​ suffix indicates that the valve is equipped with an integrated pressure reducing valve (ZDR 6). This valve regulates the pilot pressure supplied to the main stage, which can be used to limit the maximum force or speed of the actuator for safety or control purposes.

4. Q: Does this valve have LVDT feedback?

   A:​ No.​ Unlike the 4WREE valves you inquired about earlier, this standard 4WRZE model does not​ have LVDT feedback for the main spool position. It operates in open-loop for the main stage (though the pilot stage is closed-loop). For closed-loop control of the main stage, you would need a model with an "L" in the spool designation (e.g., E1..L).

5. Q: What is the critical installation note?

   A:​ Ensure the T-port backpressure is below 210 bar. The pilot stage relies on internal drain (T port), so excessive backpressure can cause malfunction. Maintain high oil cleanliness (recommended NAS 1638 Class 8 or better).