German Rexroth proportional directional valves in stock

Brand

REXROTH/German Rexroth

Rexroth proportional directional valve working principle: 2-position 4-way and 3-position 4-way Rexroth proportional directional valves are directly controlled, plate-type structures; operated by a proportional solenoid with a central thread, the coil of which can be disassembled independently. The solenoid can be controlled by an external amplifier (WRE type) or a built-in amplifier (WREE type).

Example model: 4WREE10E75-2X/G24K31/A1V

4WRE → Direct-controlled proportional directional valve, plate-type structure

E → With built-in amplifier (if E is not available, an external amplifier can be connected)

10 → 10-way valve (also available in 6-way, etc.)

E → Functional symbol (also E1-, V, W, W1-, EA, WA, etc.)

75 → Rated flow rate (NS10) at a differential pressure of 10 bar: 75 L/min

(Also available: (NS6)08, 16, 32; (NS10)25, 50, 75, etc.)

2X → 20 to 29 series (20 to 29: installation and connection dimensions unchanged)

G24 → 24V DC power supply

K31 → With socket conforming to E DIN 43 563-AM6-3, without plug. Plug must be ordered separately. (K4 refers to socket conforming to DIN 43 650-AM2, without plug)

A1 → WREE type A1 or F1 interface: setpoint input ±10 V (F1 = setpoint, input 4 to 20mA)

V → Fluororubber rectangular seal. Hydraulic oil conforming to DIN 51 524 standard (HL, HLP)

Affiliate/Distributor of Rexroth proportional valves, Bosch directional control valves @ Rexroth proportional directional valves, 2-position 4-way and 3-position 4-way proportional directional direct control valves, valve core with displacement feedback

Model 4WRE and 4WREE

6 and 10 mm diameter

2X series

Maximum working pressure 315 ba

Maximum flow rate 80 L/min (NS6)

Maximum flow rate 180 L/min (NS6)

Rexroth proportional directional valve order numbers and models are as follows:

R961004665 REGULATOR4WREE6-22/A1*BG

R961003549 GERAETESATZDW40E-D.W4WREE6.-2X

R901161258 4WREE6E32-2X/G24K31/A1V-204

R901073856 HOUSING4WREE10.-22/

R901028415 4WREE10R3-75-2X/G24K31/A1V

R900625643 DECKEL4WRE10.A-12/

R900624754 GEHAEUSE4WRE10.-14/GGG4

R900617766 4WREE6WA16-2X/G24K31/F1V

R900617482 4WREE6E1-16-2X/G24K31/F1V

R90617269 4WREE10V75-2X/G24K31/F1V

R900617253 4WREEM6E32J-2X/G24K34/B6V-687

R900582331 4WRE10E16-1X/24K4/M

R900576935 4WRE10E32-1X/24K4/M-402

R900551280 4WRE6W1-08-1X/24K4/M

R900549113 4WRE10E1-32-1X/24K4/M

R900540589 KOLBEN4WRE6W1-16-1X/BG

R900487026 4WRE6W32-1X/24Z4/M

R900461236 4WRE10W1-16-1X/24K4/M

R901136691 4WREQ6Q5-08-2X/V5C-24PF60

R901135153 4WREE6V08-2X=G24K31/F1V-876

R901135118 4WREE10W75-2X/G24K31/A1V-280

R901132085 4WREQ6Q5-32-2X/V4A-24PF60

R901131081 4WREQ6V08-2X/V8F-24CA60

R901131077 4WREQ10V25-2X/V8F-24CA60

R901130450 4WREE10W1-75-2X/G24K31/A1V-660

Rexroth proportional directional valve working principle

Rexroth proportional directional valve structure The main valve of a servo valve is generally a spool valve, similar to a directional control valve. However, the spool is not switched by an electromagnet, but by the hydraulic pressure output from the pilot valve. This is similar to an electro-hydraulic directional control valve, except that the pilot valve of an electro-hydraulic directional control valve is an electromagnetic valve, while the pilot valve of a servo valve is a nozzle-flange valve or jet valve with better dynamic characteristics.

In other words, the main valve of a servo valve is controlled by the output pressure of the pilot valve, which comes from the inlet (p) of the servo valve. If the pressure at port p is insufficient, the pilot valve cannot output enough pressure to actuate the main valve spool.

We know that when the load is zero, if the four-way spool valve is open, the pressure at port p = the pressure at port t + the pressure loss at the valve port (ignoring other pressure losses in the oil circuit). If the pressure loss at the valve port is very small, and the pressure at port t is zero, then the pressure at port p is insufficient to supply the pilot valve to actuate the main valve spool, and the entire servo valve fails. Therefore, servo valves have relatively small orifices, requiring a certain pressure loss even when fully open to maintain the normal operation of the pre-stage valve.

Servo valves actually have many disadvantages: high energy consumption, prone to failure, poor contamination resistance, high price, etc. Their only advantage is their highest dynamic performance among all hydraulic valves. This single advantage makes them indispensable in many applications with high dynamic performance requirements, such as aircraft and rocket steering, and turbine speed control. For applications with lower dynamic requirements, proportional valves are generally preferred.

Generally speaking, servo systems are mostly closed-loop control, while proportional valves are mostly used for open-loop control. Secondly, proportional valves come in more types, including proportional pressure and flow control valves, offering more flexible control than servo valves. Internally, servo valves are mostly zero-overlap, while proportional valves have a certain dead zone, resulting in lower control accuracy and slower response. However, looking at development trends, especially in proportional directional flow control valves and servo valves, the performance difference between the two is gradually narrowing. Furthermore, proportional valves are significantly cheaper than servo valves and have stronger resistance to contamination.

The main differences between Rexroth proportional directional valves and servo valves are as follows:

1. Different drive devices. The drive device for proportional valves is a proportional solenoid; the drive device for servo valves is a force motor or torque motor;

2. Different performance parameters. 2.1 Servo valves have no dead zone in the neutral position, while proportional valves do. Therefore, their applications differ. Servo valves and servo proportional valves are mainly used in closed-loop control systems, while other proportional valve structures are mainly used in open-loop control systems and closed-loop speed control systems.

2.2 Servo valves have a higher frequency response (response frequency), reaching up to around 200Hz, while proportional valves generally have a maximum frequency of tens of Hz.

2.3 Servo valves have higher requirements for hydraulic fluid, requiring filtration to prevent clogging, while proportional valves have lower requirements.

3. Valve core structure and machining precision differ. Proportional valves use a valve core + valve body structure, with the valve body also serving as the valve sleeve. Servo valves and servo proportional valves use a valve core + valve sleeve structure.

4. Neutral position functions differ. Proportional directional valves have neutral position functions similar to ordinary directional valves, while servo valves only have an O-type neutral position function (E-type for Rexroth products).

5. Rated pressure drop differs.

The performance of a proportional servo valve falls between that of a servo valve and a proportional valve.

A proportional directional valve is a type of proportional valve used to control flow rate and direction.