| 摘要 |
PURPOSE: A drum apparatus is provided to economically and simply apply a pre-load to a ball bearing by fitting an elastic ring to a shaft under a tension so that a frictional force for maintaining the pre-load is formed by contact between the elastic ring and the shaft. CONSTITUTION: Holding a second ball bearing(9) in a first direction (downward) in the axial direction is provided by an upper end face of an elastic ring which is in contact with a part of the second ball bearing(9) connected to a shaft(3). The interval between the elastic ring and a rotary drum(2) is reduced by fastening the second ball bearing upward by the elastic ring, and consequently ball bearings(8,9) are fixed inside an upper and a lower holes without play. Moreover, for avoiding rattling in the axial direction inside the ball bearings, the elastic ring and rotary drum(2) are respectively supported by parts of the ball bearings and fastened by a pre-load. The elastic ring is set to the shaft and brought into contact with the second bearing(9) upon receipt of the pre-load.
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