| 摘要 |
The linear drive mechanism incorporates a nut (2) which moves along the axis of a threaded spindle when the spindle is rotated. The friction between the spindle and the nut is reduced by a large number of small balls (6) which engage the thread and recirculate through a groove (8) in the cylindrical casing (3) of the nut. The thread in the nut is formed by the inside surface of a coil spring (5), with adjacent turns touching, fitting snugly inside the casing of the nut. The nut has end caps (7) with projecting portions (10) designed to guide the balls round the ends of the spring and into the return groove. There is a countersunk portion (14) on the outside of each end cap, surrounding the bores through which the spindle passes, to accommodate seals for cleaning off excess oil and grease, dirt etc.
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