| 摘要 |
PROBLEM TO BE SOLVED: To suppress deformation of a needle valve caused by repetition of seating and separation of a valve body on and from a valve seat, and to appropriately maintain control timing and a controlled variable in fluid control. SOLUTION: A part serving as the valve seat in the valve body 10, which the needle valve 20 is moved and is seated on, is formed of a different valve seat member 15 formed of appropriate material having a lower Young's modulus than the needle valve 20 irrespective of material of the valve body 10. Thereby, because the Young's modulus of the valve seat member 15 is lower than the Young's modulus of a seat part 21 of the needle valve 20, the valve seat member 15 is elastically deformed in seating, and abrasion of the seat part 21 of the needle valve 20 is suppressed. Furthermore, since the Young's modulus of the valve seat member 15 joined to a tip end inner wall of the valve body 10 is low, a sealing property between the valve body 10 and the needle valve 20 is sufficiently secured.
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