Patent ID: 8746374

Claim:
A drill tool, comprising: a bit body; at least one bearing shaft extending from the bit body; a cone mounted for rotation on the bearing shaft; a radial thrust bearing from which cone pumping pressure pulsation originates; a lubricant sealing system comprising an annular seal gland and a seal ring retained within the annular seal gland; and a lubricant cone pumping pressure restrictor system comprising an annular gland separate from the annular seal gland and a pressure restricting ring retained within the annular gland, wherein the lubricant cone pumping pressure restrictor system is positioned along the bearing shaft between the radial thrust bearing system and the lubricant sealing system, wherein the lubricant cone pumping pressure restrictor system functions to attenuate cone pumping lubricant pressure pulsation from acting on the seal ring retained within the annular seal gland; and wherein the pressure restricting ring retained within the annular gland does not provide a seal with respect to a flow of lubricant both towards and away from the seal ring.