


According to the balance between the acting force F1 of the pilot pressure (Port P1) on the upper side of the pressure regulating piston ③ and the acting force F2 of the pressure at Port 2(A) acting on the lower side of the piston through the feedback oil circuit, the poppet valve core ⑥ is closed. The pressure at Port 2(A) is set according to the pressure of P1, and the pressure at Port 2(A) forms a balanced structure, which slows down the pressure rise speed at the port (Figure [2]).
When the pressure at Port P1 rises and exceeds the pressure at Port 2(A), then F2 > F1, the pressure regulating piston moves upward, the upper poppet valve core opens, and exhausts from Port 2(A) to Port 3(P) (Figure [1]). The pressure at Port 2(A) drops to a certain value and returns to the state in Figure [2] again.
In addition, when the pressure at Port P1 is lower than the pressure at Port 2(A), then F1 > F2, the pressure regulating piston moves downward, the lower poppet valve core opens, and supplies air from Port 1(P) to Port 2(A) (see Figure [3]). When the pressure at Port 2(A) rises to a certain value, it returns to the state in Figure [2] again.