Hydrodynamic pump passages for rolling cone drill bit
AssigneeBaker Hughes Incorporated
InventorsAaron J. Dick, Chih C. Lin
Life of this patent
Estimating the term…
Abstract
An earth boring bit has rotating cones with two lubricant passages to increase bearing capacity and cause lubricant circulation. A lubricant reservoir in the body supplies lubricant to passages between the cone and bearing pin. A pressure compensator equalizes lubricant pressure to the exterior of the bit. A first passage leads from the reservoir to the upper side of the bearing pin. A second passage leads from the reservoir to the bearing pin at a point from 185 degrees to 225 degrees as seen from an inner end of the bearing pin. This point is located in a diverging region 51d of an annular clearance surrounding the bearing pin.
Claims23
In an earth boring bit having a bit body with at least one depending leg, a cylindrical bearing pin extending from the leg, a rotatable cone having a cylindrical cavity that fits slidingly on a journal surface of the bearing pin, the improvement comprising:
- a recess on an exterior portion of the journal surface tat is in the range from 185 to 225 degrees as seen from an inner end of the bearing pin, the recess being located between a seal and a locking element groove of the cylindrical bearing pin and the recess being hollow to trap lubricant therein.
An earth boring bit, comprising:
- a bit body having at least one depending leg;
- a cylindrical bearing pin extending from the leg along a bearing pin axis;
- a rotatable cone having a cylindrical cavity that fits slidingly on a journal surface of the bearing pin, defining an annular clearance between the cavity and the journal surface, wherein weight imposed on the bit during drilling causes the annular clearance to be greater on an upper portion of the journal surface than on a lower portion of the journal surface;
- a lubricant reservoir in the body;
- a pressure compensator mounted to the body for reducing pressure differential between hydrostatic drilling fluid pressure exterior of the bit and pressure in the lubricant reservoir;
- a recess on an exterior portion of the journal surface between inner and outer ends of the journal surface;
- and
- wherein during operation of the drill bit, a lubricant pressure profile measured circumferentially around the clearance has a maximum positive peak followed by an immediate reduction zone to substantially the pressure of the lubricant in the lubricant reservoir, and wherein the recess is located substantially at the occurrence of the immediate reduction zone.
An earth boring bit, comprising:
- a bit body having at least one depending leg;
- a cylindrical bearing pin having an outer end joined to the leg and an inner end, the bearing pin extending downward and inward relative to an axis of rotation of the bit;
- a rotatable cone having a cylindrical cavity that fits slidingly on a journal surface of the bearing pin,
- a lubricant reservoir in the body;
- a pressure compensator mounted to the body for reducing pressure differential between hydrostatic drilling fluid pressure exterior of the bit and pressure in the lubricant reservoir;
- wherein under operating loads, the cone becomes eccentric relative to the bearing pin, resulting in an annular clearance between the cone and the journal surface that has a converging zone leading to a minimum clearance point and a diverging zone leading from the minimum clearance point to an unloaded side of the journal surface;
- and
- a recess located on the journal surface in a central area between inner and outer ends of the journal surface in the diverging zone closer to the minimum clearance point than the maximum clearance point.
In an earth boring bit having a bit body with at least one depending leg, a cylindrical bearing pin extending from the leg, a rotatable cone having a cylindrical cavity that fits slidingly on a journal surface of the bearing pin, a lubricant reservoir in the body, and a first passage leading from the lubricant reservoir to an exterior portion of the bearing pin, the improvement comprising:
- a second passage leading from the reservoir to a port on an exterior portion of the journal surface that is in the range from 185 to 225 degrees as seen from an inner end of the bearing pin.
An earth boring bit, comprising:
- a bit body having at least one depending leg;
- a cylindrical bearing pin extending from the leg along a bearing pin axis;
- a rotatable cone having a cylindrical cavity that fits slidingly on a journal surface of the bearing pin, defining an annular clearance between the cavity and the journal surface, wherein weight imposed on the bit during drilling causes the annular clearance to be greater on an upper portion of the journal surface than on a lower portion of the journal surface;
- a lubricant reservoir in the body;
- a pressure compensator mounted to the body for reducing pressure differential between hydrostatic drilling fluid pressure exterior of the bit and pressure in the lubricant reservoir;
- a first passage leading from the reservoir to a port on an exterior portion of the bearing pin;
- a second passage separate from the first passage and leading from the reservoir to a port on an exterior portion of the journal surface for supplying lubricant from the reservoir to the annular clearance;
- and
- wherein during operation of the drill bit, a lubricant pressure profile measured circumferentially around the clearance has a maximum positive peak followed by an immediate reduction zone to substantially the pressure of the lubricant in the lubricant reservoir, and wherein the port of the second passage is located substantially at the occurrence of the immediate reduction zone.
An earth boring bit, comprising:
- a bit body having at least one depending leg;
- a cylindrical bearing pin having an outer end joined to the leg and an inner end, the bearing pin extending downward and inward relative to an axis of rotation of the bit;
- a rotatable cone having a cylindrical cavity that fits slidingly on a journal surface of the bearing pin,
- a lubricant reservoir in the body;
- a pressure compensator mounted to the body for reducing pressure differential between hydrostatic drilling fluid pressure exterior of the bit and pressure in the lubricant reservoir;
- a first passage leading from an exterior portion of the bearing pin to the reservoir, wherein
- under operating loads, the cone becomes eccentric relative to the bearing pin, resulting in an annular clearance between the cone and the journal surface that has a converging zone leading to a minimum clearance point and a diverging zone leading from the minimum clearance point to an unloaded side of the journal surface;
- a second passage leading from the reservoir to a portion of the journal surface in the diverging zone closer to the minimum clearance point than the maximum clearance point.
Dependencies are inferred from the claim text.