To enable pressure sensors to be protected even if the load level of a pressure to be detected becomes high.
A pressure detecting device is provided with a pressure passage part 8 to pass pressurized air, a cylinder part 30 connected to the pressure passage part 8 with a bottom surface 30b on the opposite side to a connecting part 30a, an action valve 1 with magnetism arranged in such a way as to be slidable in the cylinder part 30 by pressurized air, pressure sensors 3a, 3b, and 3c to detect the pressure of a first space Z formed of the action valve 1 and the cylinder part 30, and a second space Y to guide a part of the pressurized air to the outside of the cylinder part 30 at the time when the action valve 1 is slid by the pressurized air a predetermined amount or more. The pressure sensors 3a, 3b and 3c are constituted so that their detection levels may be different from one another.
SAITO YOSHINOBU
SUZUKI MINORU
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