R900553670 Bosch Rexroth: The Industry Standard Solenoid Valve
The R900553670 is one of the most widely installed hydraulic valves in the world. It is a 4WE 6 D6X/EG24N9K4 directional control valve, featuring a 24V DC solenoid. This unit is the «workhorse» for controlling hydraulic cylinders and motors in machine tools, presses, and mobile hydraulics. The solenoid (electromagnet) acts directly on the control spool, shifting it to manage the flow of hydraulic fluid between the pump (P), tank (T), and actuator ports (A/B). Its wet-pin DC solenoid design allows for long service life and smooth switching characteristics, minimizing hydraulic shock (water hammer) in the system.
Key Technical Characteristics
- Size: NG6 / CETOP 3.
- Actuation: Solenoid (Wet-pin, DC).
- Voltage: 24 VDC.
- Spool: Symbol D (4/2 Way).
- Flow Capacity: Up to 80 l/min.
- Electrical Connection: 3-pin + PE (Connector sold separately usually).
- Seals: NBR (Nitrile Butadiene Rubber).
Maintenance & Troubleshooting
Lifecycle State: Active. Diagnosis: The most common failure mode is a burnt coil. You can check the coil resistance with a multimeter; an infinite reading means an open circuit. The coil can be replaced without opening the hydraulic circuit (Material No. usually R900021389 for the coil alone). Installation Advice: Torque the four mounting screws to exactly 9 Nm. Over-tightening can distort the valve body and cause the spool to jam. Compatibility: This valve integrates easily into automated lines managed by Siemens LOGO! or any 24V PLC. It features a concealed manual override (N9) which allows maintenance technicians to manually shift the valve during power outages or commissioning.
| Feature | Specification |
|---|---|
| Switching Time (ON) | 25 – 45 ms |
| Switching Time (OFF) | 10 – 25 ms |
| Protection Class | IP65 (with connector) |
| Duty Cycle | 100% (Continuous) |
Pro-Tip
Always verify the backpressure in the T-line. While the P, A, and B ports handle 350 bar, the T-port limit is lower (210 bar). Excessive backpressure can affect the shifting performance of the solenoid.
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