The invention discloses a first-stage variable pump
control system with a simplified structure. The
system comprises an
oil pump, a pump outlet, a main oil passage and an oil
sump, the
oil pump comprises a pump body, a feedback
pressure control cavity, a variable sliding block, a variable spring, an oil inlet and an oil outlet, the oil
sump is connected to the oil inlet through an oil path, and the oil outlet communicates with the oil
sump through the pump outlet and the main oil passage; an oil through groove or an oil through hole is formed in the position, close to the oil outlet, of the variable sliding block and used for introducing pressure oil of the oil outlet into the feedback
pressure control cavity; when the
oil pressure of the oil outlet is increased, the
oil pressure in the feedback
pressure control cavity is correspondingly increased; and when the
oil pressure reaches a set
variable pressure point, the oil pressure in the feedback pressure control cavity can push the variable sliding block to overcome the elastic force of the variable spring to deflect, so that the output displacement of the
oil pump is reduced, the first-stage displacement is variable, the variable response is more sensitive, an oil circuit can be actively protected if the oil circuit pressure is too high, and therefore a
safety valve mechanism does not need to be designed.