| 摘要 |
PURPOSE:To enable a device to be made into high accuracy for its performance even both stationary and rotary members differ in an expansion coefficient each, in case of a turning gear required to meet high positional accuracy especially in a thrust direction, like a rotary head assembly for a VTR by way of example. CONSTITUTION:In case of a rotary head assembly as a turning gear, each of radial bearings 16R and 17R is made up of lubricating oil filled up in space between shallow grooves 16Ra and 17Ra cut in a shaft member 2 and a hole part of a rotary auxiliary member 3 being slightly larger than the peripheral part of each of these shallow grooves. That is to say, when this rotary auxiliary member 3 rotates, the lubricating oil produces high pressure as being fed by pressure by these shallow grooves 16Ra and 17Ra whereby such force that can fulcrumedly support the auxiliary member 3 by means of noncontact to the shaft member 2 can be secured. On the other hand, a thrust bearing 16S is made up of a shallow groove cut in at least one side surface of these surfaces at the side where a pedestal 8 and the rotary auxiliary member 3 are opposed with each other and a lubricant filled up in space between these opposite surfaces. |
