Conformal bearing for rock drill bit

An earth boring bit, comprising:

• a bit body having at least one depending leg;
• a bearing pin extending from the leg and having an axis and a journal surface that is rotationally asymmetric about the axis, the journal surface comprises a main journal bearing surface on a proximal end of the bearing pin, and a pilot pin radial bearing surface on a distal end of the bearing pin, and both the main journal bearing surface and the pilot pin radial bearing surface are rotationally asymmetric about the axis;
• and
• a cone having a cylindrical cavity slidingly mounted to and engaging the journal surface of the bearing pin, the cone being rotatable relative to the bearing pin;
• and
• the journal surface comprises a direct contact surface formed at a first radius, a non-contact surface formed at a second radius that is selected from the group consisting of equal to, longer than, and shorter than the first radius, the cylindrical cavity defines a maximum potential contact area having an angular span of 180°, and the direct contact surface spans at least 130° of said maximum potential contact area.

An earth boring bit, comprising:

• a bit body having at least one depending leg;
• a bearing pin extending from the leg and having an axis and a journal surface that is rotationally asymmetric about the axis, the journal surface comprises a main journal bearing surface on a proximal end of the bearing pin, and a pilot pin radial bearing surface on a distal end of the bearing pin, and both the main journal bearing surface and the pilot pin radial bearing surface are rotationally asymmetric about the axis;
• and
• a cone having a cylindrical cavity that fits slidingly on and directly engages the journal surface of the bearing pin, and only a portion of the journal surface is formed at a radius that matches a radius of the cylindrical cavity, the cone being rotatable relative to the bearing pin.