| 摘要 |
PROBLEM TO BE SOLVED: To improve a rotational angle resolution of a valve element rotated by a motor to enhance resolution of a valve opening, in a rotary motor-driven valve rotating the valve element by a stepping motor so as to change a valve opening for a flow rate control. SOLUTION: Output of the stepping motor 2 of the rotary motor-driven valve 1 is transmitted from an output rotational shaft 12 to the valve element 4 as rotation decelerated through a planetary gear mechanism 3. If an angular resolution of the stepping motor 2 is not changed, the rotational angle resolution of the valve element 4 is increased by decelerating action of the planetary gear mechanism 3 to control the valve opening with high accuracy. A valve passage 40 is constituted of a passage wall part 42 having a spiral wall face 43 of the valve element 4 and a seat wall face 20 of a valve seat sheet 5. By rotation of the valve body 4, a sectional area of a passage connecting between valve holes 26, 27 through the valve passage 40 is changed so that the valve opening from a fully opened condition to a fully closed condition. COPYRIGHT: (C)2005,JPO&NCIPI
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