Timing relief valve

The utility model discloses a timing relief valve, which comprises a pressure-reducing valve and a timer. The reducing valve comprises an air inlet and an air outlet, the timer adopts a timer with a cam oscillating rod mechanism and is fixed in a shell of the reducing valve, a pushing force mechanism is further arranged in the reducing valve, and the pushing force mechanism comprises a spring, a connecting rod and a pushing rod. One end of the connecting rod is vertically connected with one end of an oscillating rod of the timer, the other end of the connecting rod is connected with one end of the pushing rod arranged above the timer, the other end of the pushing rod is extended to the air outlet and provided with a head matched with the air outlet in a shape and a size, and central axes of the pushing rod and the air outlet are in a same direction. The spring is arranged between the connecting rod and an inner wall of an air inlet end. The timing relief valve can automatically close the air outlet of the red