| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a rotary four-way valve capable of switching a passage with little deterioration of system efficiency. SOLUTION: In switching a passage, a cam 16 is rotated to move a pilot valve 17 from a pilot port 12, and high pressure is introduced into a back pressure chamber of a low pressure closing valve 7 so that the low pressure closing valve 7 closes a port C. High pressure of the back pressure chamber is introduced into a port A through a check valve 13 to compensate for pressure of the other high pressure port. The cam 16 locks one end of a torsional coil spring 15 and rotates. When the thus increased spring force overcomes the pressing force decreasing due to pressure equalization to sliding surface of a main valve 5, the torsion coil spring 15 rotates the main valve 5 so that the pilot port 12 moves to the position of the pilot valve 17 to be closed, and a low pressure closing valve 7 opens. Thus, the low pressure closing valve 7 switches the passage while keeping a differential pressure between low pressure and high pressure so that an influence on the system efficiency is small.</p> |
