Hydrostatic feed screw mechanism and movable body using the same

摘要

A feed screw mechanism includes a nut having a female thread, and a feed screw shaft having a male thread screw-engaged with the female thread. A thrust pocket is formed along a flank of the female thread of the nut, and pressurized fluid is supplied thereto. A plurality of separated radial pockets are formed on the crest surface of the female thread of the nut, and pressurized fluid is supplied thereto. The thrust pocket is a continuous spiral groove formed along the flank of the female thread of the nut. This structure provides sufficient rigidity in both the radial and thrust directions while reducing the size of the feed screw mechanism.