| 摘要 |
PURPOSE:To feed a member to be fed axially precisely at intervals of fine distance by providing a piezoelectric element which vibrates a guide bar for guiding the feed member axially to one end of the guide bar. CONSTITUTION:The 2nd piezoelectric element 35 on a carriage side is driven before the 1st piezoelectric element 25 on a guide-bar side is driven, so that clamping pieces 31 and 32 are so displaced as to come closer to each other. Consequently, a carriage 20 moves by fine distance together with the guide bar which moves finely in a feed direction. Then, the pulse voltage of the 2nd piezoelectric element 35 is ceased, the guide bar 24 is displaced finely as the piezoelectric element 25 contracts. At this time, the clamping pieces 31 and 32 generate no clamping force to the guide bar 24, so the carriage 20 stops at its current position because of its inertia even when the guide bar 24 is displaced in the opposite direction from the feed direction, so that it moves forth on the whole. Further, the carriage is moved back by cutting off the pulse voltage to the 1st piezoelectric element 25 after a pulse voltage is applied to the 2nd piezoelectric element 35. |
