| 摘要 |
PURPOSE:To change a feed pitch accurately and simply and to keep it by holding a friction roller at a holding body capable of turning in a direction where a load angle is changed with respect to a driving angle and providing an angle adjusting means, at the holding body, for turning said holding body according to the displacement of a piezoeletric element. CONSTITUTION:The lead angle of a friction roller is changed by an angle adjusting means 26 to make a feed motion. Namely, the voltage of negative polarity is added to piezoelectric elements 22, 23 from an operating device 25 to contract the element 22, meantime, to extend the element 23 to turn a holding body 21 for inclining the lead angle of the roller 24 at a state of A1 and also maintaining added voltage from the device 25 constant so as to keep the lead angle A1. Accordingly, the roller 24 is followed by the rotation of a driving shaft 11 to be turned its circumference to be moved in an axial direction by a feed pitch according to the lead angle and a table 20 is fed to a bed 10 at a high speed. Meantime, when the table is reached near an aimed position, the lead angle of the roller 24 is to be small A2 by the angle adjusting means 26 to perform a minute feed motion. |
