| 摘要 |
PURPOSE:To reduce the size of a whole device, by a method wherein a first male screw body is threadedly joined with the first female screw body of a body to be driven, by pitch of a second female body situated coaxially with the first male screw body is set to a value lower than that of the first female screw body, and a second male screw body is threadedly joined with the female body. CONSTITUTION:When a table 22 is rapidly fed, a second motor 43 is driven to rotate a second male screw body 41, and a stem part 28 of a first male screw body 26 in which a second female screw 39 is formed is moved in a direction in which it is pulled off from the second male screw body 41. Thus, the first male body 26 is driven rightward through the second female screw 39, with which the second male screw body 41 is threadedly joined, together with a first drive mechanism, and the table 22 is rapidly fed over a base bed 21. Meanwhile, when the table 22 is fed finely, a second motor 44 is stopped, a first motor 34 is run, the first screw body 26 is rotated, and the table 22 is finely fed rightwardly according to a difference between the pitches of the first and second male screws 29 and 40. |
