| 摘要 |
PURPOSE:To obtain control action in a wide range further with high accuracy, by driving a stepping motor to open and close an expansion valve in response to an external condition. CONSTITUTION:A nut member 10 is screwed to a screw part 15 threaded to a rotary shaft 14 of a stepping motor 13 and converted to the screw motion moving a driving metal fixture 9 in the direction of a shaft, and a valve body 2 is moved in the same direction to change a valve opening. To form an orifice 4 as a smooth flow path between the body 2 and a valve box member 1A, a valve seat 5 of almost spindle shape is provided and the orifice 4 is formed with a smooth surface, then a large flow coefficient can be always held despite a change of area of the orifice 4 to obtain high accurate control. |
