| 摘要 |
PURPOSE:To reduce the thickness of a rotary head device, to improve the rotation precision at low cost, and to prevent the absence of a preload on a roller bearing due to fluctuations of temperature, by providing the roller bearing between the opposed surfaces of a rotary member and a fixed drum, and using a magnetic force holding means for the rotary member. CONSTITUTION:In the end surfaces 24 and 26 of an upper rotary drum 22 and a lower fixed drum 21, annular groove parts 25 and 27 are made. Then, steel balls 28 are interposed between the groove parts 25 and 27. Thus, a roller bearing 29 consists of the groove parts 25 and 27 and steel balls 28. Further, a rotary transformer, etc., is fitted to the opposed end surfaces of the drums 21 and 22. The attracting force of a preload magnet 34 for a preload adjusting screw 35 is adjusted by the screw-in extent of the screw 35, and consequently while the drum 22 is held, a preload on the bearing 29 and steel balls 28 is adjusted without contacting. A stator coil 32 is powered up to rotate the drum 22. A head 36 makes a rotary scan on a tape surface to perform recording or reproduction. |
