| 摘要 |
An antifriction screw and nut construction wherein helical screw threads are engaged by antifriction mounted rollers carried by an annular nut body and extending radially inward into the bore of the nut body. Several embodiments of the invention are shown, directed to the object of preventing sliding friction between the roller surfaces and the engaged screw thread surfaces due to the distortions resulting from loading of the nut. In one embodiment the sidewalls of the screw thread are rounded or convex while the rollers have a straight taper, thereby to reduce the line area of contact and improve the frictional characteristics. In another embodiment of the invention the rollers are bulged or convex while the sidewalls of the threads are of flat characteristics to reduce sliding friction. In still another embodiment, the rollers have a straight taper and the thread walls a straight characteristic but the rollers are mounted intentionally with a slight misalignment which becomes remedied under normal loading to produce a true, nonsliding line contact with minimum friction. A novel screw construction comprises a double blunt thread having sloped, opposed helical faces the angles of which are related to the thread spacing and crest thickness.
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