Pressure mechanical control change valve mechanism

The utility model relates to a pressure mechanical control change valve mechanism, which comprises a direct current motor, a speed reducer, a multi-plunger fuel pump and a pressure control mechanism which are sequentially connected. The output end of a check valve is connected with a P port of a two-position five-way slide valve through an a port of a relief valve, a B port of the two-position five-way slide valve is connected with a pressure sensor, the output end of the two-position five-way slide valve is connected with a link mechanism, the input end of the two-position five-way slide valve is connected with a micro switch, an A port of the two-position five-way slide valve is respectively connected with an a port of a changeover forcing valve and an a port of a reversing decompression valve which are in parallel, one circuit of the pressure sensor is connected with a sidewall contact device, and one circuit of the pressure sensor is connected with an oil cylinder through a throttle valve. The pressure mechanical control change valve mechanism solves the technical problem that the existing control system of an admeasuring apparatus is complex in process, and the change valve of the pressure mechanical control change valve mechanism is reliable in performance, convenient to adjust, convenient to manufacture, and simple in control.