| 摘要 |
PROBLEM TO BE SOLVED: To provide a gate valve having a cam mechanism being structurally simplified and miniaturized and inexpensive, moving smoothly, capable of operating at high speed, and having excellent silentness and high reliability. SOLUTION: A cam mechanism portion 31 includes a roller 35 serving as a rolling element; a roller retaining member 38 having a retaining surface 38a for retaining the rolling surface 35a of the roller in such a manner that the roller 35 is free to rotate, the roller retaining member serving as a rolling element retaining member driven by an air cylinder; a cam member 32 disposed oppositely to the roller retaining member 38 and having a cam face 32a on which the roller 35 tilts a rolling valve rod 6, the cam member 32 being connected to the valve rod 6; and a lubricant retaining member 91 having an opposite surface 91a opposite to part of the rolling surface 35a of the roller 35 freely rotationally retained on the roller retaining member 38, for retaining a lubricant G in a gap formed between the rolling surface 35a and the opposite surface 91a.
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