BOTH ROTARY TYPE DUPLEX INSCRIPTION GEAR PUMP

摘要

PROBLEM TO BE SOLVED: To provide a compact-sized both rotary type duplex inscription gear pump capable of changing-over between low pressure and high pressure.SOLUTION: This invention is made such that a middle flange 12 is arranged between the first pump 10 constituted by the first inner gear 6 and the first outer gear 8 and the second pump 11 constituted by the second inner gear and the second outer gear, the middle flange 12 stores a spool valve 13 changing-over a low pressure high flow rate operation for merging hydraulic oil discharged by the first pump 10 with hydraulic oil discharged by the second pump 11 and a high pressure low flow rate operation for guiding hydraulic oil discharged by the first pump 10 to a suction side of the second pump 11 and further increasing pressure by the second pump 11; excessive state or lacked state adjusting valve 14 for adjusting excessive state or lacked state of hydraulic oil; and flow passages.