There are two symmetrical circular arc grooves milled on the oil pressure distribution shaft, and there is a section of circular arc surface (the outer circular surface of the shaft) between the two grooves that has not been milled off, which is used for sealing and opening the oil pressure, as well as the suction area. During the rotation of the oil distribution shaft, two grooves alternate with the suction and pressure ports on the pump body. The oil distribution principle is similar to the end face oil distribution mentioned above, except that one is sealed with an end face (flat or spherical) and the other is sealed with a cylindrical fan-shaped circular surface. In order to balance the radial force on the gear pump shaft, a balance groove is also provided on the oil distribution shaft, which belongs to the clearance sealing type of oil distribution.