The invention relates to an automotive hydraulic vane pump motor and a switching control hydraulic
system thereof. The pump motor comprises a rear pump cover, an oil-in distribution disc, a
stator, a rotor, an oil-out distribution disc, a front pump cover, a shaft, a vane, an oil inlet and an oil outlet, wherein a static pressure oil chamber is formed in one side wall of a vane slot in the rotor and is communicated with an external hydraulic source through a
signal oil passage; the static pressure oil chamber takes the shape of a groove and has openings which directly face the body of the vane when the vane extends to the maximal position and the minimal position; a vane root oil chamber, which is used for supplying
hydraulic pressure to actuate the vane to extend out, is arranged at the root of the vane; an external switching control hydraulic
system is used for supplying hydraulic oil to the vane root oil chamber; the switching control hydraulic
system comprises an accumulator, a three-position electromagnetic
directional valve and a
reversing valve; one oil port in an output end of the
reversing valve is communicated with the static pressure oil chamber, and the other oil port is connected with the vane root oil chamber; the oil port in an input end of the
reversing valve is connected with
signal oil, and a non-return valve is arranged on the accessed oil passage; oil ports in the output end of the three-position electromagnetic
directional valve are respectively connected with the oil inlet and the oil outlet, and oil ports in the input end of the three-position electromagnetic
directional valve are respectively connected with an
oil tank and the accumulator.