SPEED INCREASING GEAR INNER ROLLER BEARING FOR ROLLING MACHINE

PROBLEM TO BE SOLVED: To provide a speed increasing gear inner roller bearing for a rolling machine, capable of preventing the degradation of the bearing life resulting from fretting wear by reducing the fretting wear on a contact area between a bearing ring and a roller. SOLUTION: The speed increasing gear inner roller bearing 1 for the rolling machine comprises first and second bearing rings 2, 3 opposed to each other, and a roller 4 rollingly provided between the two bearing rings 2, 3. The contact area is lubricated by oil. On portions of the two bearing rings 2, 3 contacting the roller 4, protecting films 11 each having a diamond-like carbon layer on the outermost surface are formed at a raceway surface 6 (10) of at least one of the two bearing rings 2, 3 and at a greater-load collar face 7a out of the collar faces of the first bearing ring 2. COPYRIGHT: (C)2007,JPO&INPIT