Double-valve automatic grinding device

The utility model provides a double-valve automatic grinding device which comprises a shell, a spring pre-tightening knob, a spring pre-tightening screw, an upper piston, a spring, a lower piston, two guide rods, a rotary mechanism and a support frame. A hollow cavity is arranged in the shell, the shell is fixed onto the support frame, an air inlet hole and an air exhaust hole are formed in the bottom of the shell, the upper piston, the spring and the lower piston are positioned in the shell, the spring pre-tightening screw penetrates the top of the shell, one end of the spring pre-tightening screw is connected with the spring pre-tightening knob, the other end of the spring pre-tightening screw is connected with the upper piston, one end of the spring is connected with the upper piston, the other end of the spring is connected with the lower piston, one end of each guide rod is connected with the lower piston, and the other end of each guide rod is fixed to the rotary mechanism. The double-valve automatic grinding device has the advantages that air inlet valves and exhaust valves of engines can be automatically and simultaneously ground by the double-valve automatic grinding device, accordingly, the valve grinding efficiency and the valve grinding quality can be greatly improved, and the engine repair cost can be reduced.