Nissan Motor Company Limited

Kayaba Kogyo Kabushiki Kaisha

Satoshi Chikamatsu

Koji Morita

Yoshiyuki Eto

Noboru Kurita

This invention relates to a pressure reducing valve wherein a spool is driven axially by a first plunger which moves according to the magnetization state of a first solenoid, and a control port is connected to a supply port and a tank port according to the axial position of this spool. The pressure of the control port acts on the spool in the opposite direction to that of the plunger via a feedback passage, and the pressure increases or decreases according to the current flowing through the first solenoid. According to this invention, a second plunger is arranged in series with the first plunger, and a spring tends to push the second plunger toward the first plunger. A second magnetized solenoid however keeps the second plunger held back against the restoring force of the spring so that it is not in contact with the first plunger, and releases the second plunger so that it pushes the first plunger when the current fails. Hence, even if the current supplied to the first and second solenoids is cut off, the control port maintains the predetermined pressure, and a fail-safe mechanism is realized by means of a simple construction.

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Kani, Japan

Satoshi Chikamatsu