Gear pump

A gear pump comprising:

• a pump body;
• a pump cover;
• an outer rotor having a plurality of internal teeth;
• and
• an inner rotor having external teeth meshed with the internal teeth and driven to be rotated, wherein
• a rotor installation chamber is defined by the pump body and the pump cover,
• the outer rotor and the inner rotor are disposed in the rotor installation chamber, and gear chambers are defined between the internal teeth of the outer rotor and the external teeth of the inner rotor,
• a suction port groove that forms a suction port and a discharge port groove that forms a discharge port are formed in at least one of the pump body and the pump cover,
• a narrowing portion is formed at a portion of a radially outer side wall portion of the suction port groove, the portion being close to a terminal end wall portion of the suction port groove, the narrowing portion bulging toward a radially inner side wall portion of the suction port groove to narrow a groove width in a radial direction, and
• a pressurizing region is formed between the narrowing portion and the terminal end wall portion, the pressurizing region pressurizing oil in the gear chamber that is defined between the internal tooth and the external tooth located at a position on the suction port groove side and closest to the terminal end wall portion.