摘要 |
A guide rail has an axially extending recessed groove opening upwardly to guide a nut block to move rectilinearly along the recessed groove when a ball screw shaft is rotated. A pair of strip-shaped magnets are secured to upper surfaces of both side walls of the guide rail. A flexible seal plate made of steel sheet is fixed to the guide rail with its opposite ends fastened to opposite ends of the guide rail. The seal plate slidably engages a guide recess formed in the upper surface of the nut block and crosses axially over the nut block forming an expanded portion along the outer surface of the nut block. A seal pressing member is attached to the nut block to press the expanded portion of the seal plate downwardly, and also to guide the seal plate towards the belt-shaped magnets at front and rear portions of the expanded portion so that the seal plate is attracted by the magnets at portions located before and behind the expanded portion, i.e., the nut block, to cover the recessed groove of the guide rail.
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