To provide a pump device consisting of two hydraulic pumps having different characteristics, capable of reducing the energy loss of the whole pump device and complementing a shortage in the discharge amount of a working oil when the operation of one of the pumps is started.
The pump device consists of two hydraulic pumps, one being a vane pump 1 of variable displacement type and the other being a gear pump 2 excellent in the initial period discharge characteristic, and a shuttle valve 3 is installed between the discharge port 11 of the vane pump 1 and the discharge port 21 of the gear pump 2. When the operation of the vane pump 1 is going to rise, part of the discharge oil from the gear pump 2 is fed into a back pressure groove 13 in the vane pump 1 through the shuttle valve 3, and the pressure oil fed into the groove 13 is introduced to a slit bottom 153 in which vanes 15 are accommodated.
KATO TOSHIYA
TAKAGI HIDEJI
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