| 摘要 |
PROBLEM TO BE SOLVED: To generate a thrust in a high speed and low speed movement using one small-capacity servo motor to the extent comparable to a large-capacity servo motor. SOLUTION: On the body of the driving device 19, there is supported a nut/screw part 23 which is screwed on so that a screw shaft member 27 connected to a movable table 3 is vertically moved. A reduction output part 31 for transmitting rotation to the nut/screw part 23 is installed, as are an A-side reduction input part 33 and a B-side reduction input part 35 for transmitting the rotation of a driving rotary body 37 from a motor 43 to the reduction output part. With an A-side first gear 51 provided in the driving rotary body, an adjacent A-side second gear 57 having the same diameter and pitch as the first is installed in the A-side reduction input part. Meantime, in the rotary driving body, a B-side first gear 53 is installed having a different number of teeth from that of the A-side first gear 51, with an adjacent B-side second gear 63 having the same diameter and pitch as the first is installed in the B-side reduction input part. A clutch 69 is provided which makes gear engagement to one side, either an A-side engaging gear 85 to be meshed with the A-side first and second gears 51, 57 or a B-side engaging gear 89 to be meshed with the B-side first and second gears 53, 63. COPYRIGHT: (C)2004,JPO
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