| 摘要 |
PROBLEM TO BE SOLVED: To provide an electric-powered spot welding gun in which a rod is smoothly advanced/retracted by using a ball thread, and each path of circulation passages of a first ball group to transmit power and circulation passages of a second ball group to lock the constituents are adequately set. SOLUTION: In the electric-powered spot welding gun has a rod with a hollow part, a cylindrical rotation-preventive part 30a fixed to an end part of the rod, a ball spline shaft 32 having spline grooves 31a, 31b, and 31c, and a hollow rotor with a ball thread groove formed in the inner wall thereof, wherein the rotation preventive part 30a is provided with three first circulation passages 59a, 59b and 59c which are circulated with the first ball group inserted therein, and three second circulation passages 60a, 60b and 60c which are circulated with the second ball group inserted therein. The second circulation passages 60a, 60b and 60c are arranged so that the sections thereof are in radial shape around the axis of the rotation preventive part 30a. COPYRIGHT: (C)2005,JPO&NCIPI
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