re29178 - Bosch Rexroth

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2/10 Bosch Rexroth AG Hydraulics DRE(M); DRE(M)E RE 29178/04.05 Ordering code Without maximum pressure relief function = No code With maximum pressure relief function = M For external control electronics = No code With integrated electronics (OBE) = E Size 32 = 30 Component series 40 to 49 = 4X (40 to 49: unchanged installation and connection dimensions) Pressure stage 50 bar = 50 100 bar = 100 200 bar = 200 315 bar = 315 Pilot oil drain always external, separate, and at zero pressure to tank = Y With check valve between A and B = No code Without check valve = M Preferred types Type Material no. DREE 30-4X/50YMG24K31M R900954516 DREE 30 -4X/100YMG24K31M R900954513 DREE 30-4X/200YMG24K31M R900954514 DREE 30-4X/315YMG24K31M R900954515 Symbols A Y B A Y B DRE 30 4X Y G24 * A Y B A Y B A Y B A Y B Further details in clear text Seal material M = NBR seals, suitable for mineral oil (HL, HLP) to DIN 51524 V = FKM seals suitable for phosphate ester (HFD-R) Electrical connection for DRE; DREM: K4 = Without cable socket, with component plug to DIN EN 175301-803 Cable socket – separate order see page 6 For DREE; DREME K31 = Without cable socket, with component plug to DIN EN 175201-804 Cable socket – separate order see page 6 Supply voltage of control electronics G24 = 24 V DC DRE 30-4X/...YM… DREM 30-4X/...YM… DRE 30-4X/...Y… DREM 30-4X/...Y… A Y DREE 30-4X/...YM… DREME 30-4X/...YM… DREE 30-4X/...Y… DREME 30-4X/...Y… B A Y B
RE 29178/04.05 DRE(M); DRE(M)E Hydraulics Bosch Rexroth AG 3/10 Function, section Valves of types DRE and DREM are pilot operated pressure reducing valves. They are used for reducing an operating pressure. These valves basically consist of a pilot control valve (1) with proportional solenoid (2), a main valve (3) with main spool insert (4) and optionally a check valve (5). Type DRE... The pressure in channel A is adjusted by a proportional solenoid (2) in relation to a current. At the rest position – no pressure in channel B – the spring (11) holds the main spool (4) in the initial position. The connection from channel B to A is open. The pressure in channel A acts on the bottom side of the main spool in the direction of closing, and the pressure of the pilot control valve on the spring side of the main spool in the direction of opening from channel B to A. The pilot oil is taken from channel B and flows through the bore (6) to the constant-flow control valve (9) that keeps the pilot oil flow constant independently of the pressure drop between channel A and B. The pilot oil flows from the constant-flow control valve (9) through bores (7) via the valve seat (10), passes the valve poppet (8) and is directed into the Y channel to the tank. The pressure desired in channel A is pre-selected on the associated amplifier. The proportional solenoid pushes the valve 9 6 11 12 7 1 10 8 2 X X 13 A B Y Type DRE. 30-4X/.Y.G24K4… (with check valve) 3 4 5 poppet (8) against the valve seat (10) and limits the pressure in the spring chamber (12) to the set value. At the control position of the main spool (4), the hydraulic fluid flows from channel B to A and generates pressure in channel A (setting of the pilot control valve plus spring (11)). When the set pressure is reached in A, a balance of forces is achieved on the main spool. When the actuator connected to port A is not moving (e.g. cylinder piston at end position), and a lower pressure is set in channel A via the proportional solenoid (2), the main spool (4) closes the connection from B to A and at the same time opens the connection from channel A to the spring chamber (12) of the main spool (4). At this position, the compressed volume in channel A can expand via the pilot control valve (1) and port Y. A check valve (5) can optionally be installed to allow a free return flow from channel A to B. The reduced pressure in channel A can be checked by means of a pressure gauge port (13). Type DREM... For the hydraulic protection against impermissibly high electrical control currents on the proportional solenoid, which inevitably result in high pressures in port A, a spring-loaded pressure relief valve can optionally be installed as maximum pressure relief feature (14). 14 X-X A B 5
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re29178 - Bosch Rexroth

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