Bosch Rexroth R900954493

The 3-way pressure reducing valve type 3 DREP 6.. is direct operated by proportional solenoids. It converts an electrical input signal into a proportional pressure output signal. The proportional solenoids are controllable wet-pin DC solenoids. The solenoids are controlled by external control electronics. Set-up: The valve basically consists of:

• Housing (1) with connection surface

• Control spool (2) with pressure measuring pins (3, 4)

• Solenoids (5, 6) with central thread

Function: The pressure in A or B is set by means of the proportional solenoids. The amount of the pressure depends on the current. The amount of the pressure depends on the current. With de-energized solenoids (5, 6), the control spool (2) is held in the central position by means of the compression springs (8). Ports A and B are connected with T so that the hydraulic fluid can flow off to the tank without obstructions. By energization of a proportional solenoid, e. g. solenoid “b" (5), the pressure measuring pin (4) and with it the control spool (2) are moved to the left. This opens the connection from P to A and B to T via orifice-type cross-sections with progressive flow characteristics. With the surface of the pressure measuring pin (3) the pressure that builds up in channel A acts on the control spool and against the solenoid force. The pressure measuring spool (3) is supported by the solenoid "a". If the pressure exceeds the value set at solenoid “b”, the control spool (2) is pushed back against the solenoid force and connects A with T until the set pressure is achieved again. The pressure is proportional to the solenoid current. When the solenoid is switched off, the control spool (2) is returned into the central position by the compression springs (8). Notice: Regarding valves of version 3DREP 6 C, only one solenoid may be actuated at a time. Type 3DREP 6..2X/..XE.. Notice: The tank line must not be allowed to run empty. With corresponding installation conditions, a preload valve (preload pressure approx. 2 bar) must be installed. Valve with two spool positions (type 3DREP..A...): The function of this valve version basically corresponds to the valve with three spool positions. The 2 spool position valve is, however, only equipped with solenoid "b" (5). Instead of the 2nd proportional solenoid, a plug screw (7) is installed.