PRECISE PRESSURE REGULATOR FOR A VARIABLE OUTPUT PUMP

摘要

E PRESSURE REGULATOR FOR A VARIABLE OUTPUT PUMP A precise pressure regulator (42) includes a housing (44) defining a bore (46) having pressure (50) and relief zones (56), a pressure port communicating with the pressure zone, a relief port I communicating with the relief zone, and a control port (60). A follower (78) is slid able and a spool is rotatable in the bore. The spool defines a first passage for communicating the pressure zone with the control port and a second passage for communicating the control port with the relief zone. A spring biases the follower in one direction tending to block the first passage. Pressure in the pressure zone biases the follower in the opposite direction tending to block the second passage. A step motor rotates the spool in discrete steps to precisely control its position, which position determines the level at which pressure is regulated.