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AssigneeHitachi-GE Nuclear Energy, Ltd.
InventorsYuuichi MATSUSHITA, Toshihiro KODAMA, Kiyoshi HARADA, Hirokazu Akatsuka, Takahiro TSUCHIYA
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It is an object of the present invention to provide a gap expanding method of a ball screw for preventing an increase in torque relative to an electric motor due to a protruding bulge caused by generation of a scar on the traveling side of the screw shaft of the ball screw, and to provide a control rod drive mechanism incorporating the gap expanded ball screw. In a ball screw disposed in a control rod drive mechanism, the ball screw has a screw shaft and a ball nut engaged with the screw shaft via travelling balls, and the balls are each configured to have a diameter smaller than that of the existing ball, thereby expanding a gap between a ball traveling side of the screw shaft and the ball and a gap between the ball and a ball traveling side of the ball nut.
A method for gap expanding in a ball screw, the ball screw disposed in a control rod drive mechanism, the ball screw being operative in an underwater environment to convert via a driving shaft rotational motion of an electric motor to vertical motion to thereby move a hollow piston up or down, wherein
A method for gap expanding in a ball screw, the ball screw disposed in a control rod drive mechanism, the ball screw being operative in an underwater environment to convert via a driving shaft rotational motion of an electric motor to vertical motion to thereby move a hollow piston up or down, wherein
A method for gap expanding in a ball screw, the ball screw disposed in a control rod drive mechanism, the ball screw being operative in an underwater environment to convert via a driving shaft rotational motion of an electric motor to vertical motion to thereby move a hollow piston up or down, wherein
Dependencies are inferred from the claim text.