To balance the intake ratio of an operating fluid between a pump chamber on the drive gear side and a pump chamber on the driven gear side.
This internal gear type gear pump apparatus comprises: a drive gear 1 having external teeth 11; a driven gear 2 having internal teeth 21 meshed with the external teeth 11 of the drive gear 1; a housing 3 accommodating the respective gears 1, 2; and a partition part 4 provided to fill a clearance formed between the external teeth 11 of the drive gear 1 and the internal teeth 21 of the driven gear 2. Out of intake ports for supplying the operating fluid to the respective pump chambers 15, 25 formed at the respective tooth parts 11, 21 of the drive gear 1 and driven gear 2, an intake port aperture part 51 to the pump chamber 15 formed between the respective tooth parts 11 of the drive gear 1 is formed to be open longer in a pump rotating direction than an intake port aperture part 52 to the pump chamber 25 formed between the respective tooth parts 21 of the driven gear 2.
KATO TOSHIYA
ITO ATSUSHI
OWAKI MASAAKI
