DRILL ROLLER BIT Russian patent published in 2007 - IPC E21B10/22 

FIELD: rock-cutting tools, particularly roller bits characterized by bearing or lubricating details.

SUBSTANCE: roller bit comprises body with inclined pins and cutters installed on the pins by means of retaining and combined end bearing assembly including conical roller and ball bearings. Ball bearing balls are arranged in races between the rollers. Drill bit is provided with additional ball bearing located in aligned end grooves of bit cutter and conical end pin part. Balls of additional bearing are in common plane with that of main bearing, wherein the plane passes through pin axis. End combined bearing assembly is provided with spacing units arranged between main and additional ball bearings and cooperating with them. Each spacing unit is made as thrust bearings connected with each other through spring and having depressions for main and additional ball bearing balls receiving.

EFFECT: increased drilling speed.

4 cl, 2 dwg