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US3244459A - Pressure lubricated drill bit bearing - Google Patents

Pressure lubricated drill bit bearing Download PDF

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Publication number
US3244459A
US3244459A US292048A US29204863A US3244459A US 3244459 A US3244459 A US 3244459A US 292048 A US292048 A US 292048A US 29204863 A US29204863 A US 29204863A US 3244459 A US3244459 A US 3244459A
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journal
bearing
piston
clearance
roller cone
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US292048A
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John E Ortloff
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ExxonMobil Upstream Research Co
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Exxon Production Research Co
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    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B10/00—Drill bits
    • E21B10/08—Roller bits
    • E21B10/22—Roller bits characterised by bearing, lubrication or sealing details
    • E21B10/24—Roller bits characterised by bearing, lubrication or sealing details characterised by lubricating details
    • E21B10/246—Roller bits characterised by bearing, lubrication or sealing details characterised by lubricating details with pumping means for feeding lubricant

Definitions

  • This invention relates to the drilling of boreholes in the earth. It relates particularly to roller cone type bits for use in the drilling of such boreholes. It relates especially to a system for providing lubrication to such roller cone bits.
  • rotary drilling method In the art of drilling wells for the production of oil and gas, the most commonly used method is the so-called rotary drilling method.
  • a drill bit In the rotary drilling method, a drill bit is suspended at the lower end of a string of drill pipe which is supported from the surface of the earth.
  • the drill string is conveniently formed of many joints of drill pipe, each joint usually being about 30 feet long.
  • a drilling fluid under high pressure is forced down through the drill string, through the drill bit, and back up to the surface through the annulus between the drill pipe and the wall of the borehole. While the drilling fluid serves primarily to carry the rock cuttings from the drill bit to the surface, it also serves to cool the bit.
  • the drill bit/ obtains its rotary motion from the drill pipe which is rotated from the surface. It is known that the rate of penetration of a drill bit can be increased by increasing the force (commonly called bit weight) of the drill bit on the bottom of the borehole. The penetration of the drill bit is also influenced by the rate at which the drilling fluid is forced through the pipe and 'by the rate of rotation of the bit.
  • rock bit is normally composed of a shank member which threadedly connects into the lower end of a string of drill pipe.
  • a rock bit is normally composed of a shank member which threadedly connects into the lower end of a string of drill pipe.
  • three leg members extend downwardly from the shank.
  • the lower end of each leg member is sometimes called a shaft or pin which extends inwardly and downwardly toward the axis of the bit.
  • On the exterior of the shaft are inner bearing races.
  • Roller cone cutting elements or members are rotatably supported by roller and ball bearings from the shaft of each such leg.
  • the interior of the roller cone element contains the outer bearing races.
  • each individual cone rotates about the shaft of the leg member from which it is supported.
  • the cone also rotates about the bottom of the hole. Normally only the rolling cutting surfaces of the cone are exposed to the bottom of the hole.
  • the action of the rolling cutting surface on the bottom of the hole is a twisting, tearing or gouging action for softer formations, and an approximate chipping, crushing action on the harder formations.
  • a rock bit should be so designed that the teeth, that is, the roller cutting portions of the cone, and the bearings which support the roller cone from the leg members, should wear out at the same time. Due to recent developments in the manufacturing of the roller teeth, such as use of tungsten carbide compact bits, the cutting surface consistently outlasts the bearings by a large factor in hard formation drilling. The same is true in the case of soft formation bits where only light bit weights are required.
  • the major problems way 20 and about the cutters.
  • This invention relates to a lubricating system for extending the life of the bearings of a roller cone type bit. Sealing means are provided to effectively separate or close off the clearance between the journal of the leg and the bearing of the roller cone from the exterior of the bit. A special pump means is provided to circulate lubricating fluid under high pressure through this sealed off clearance space. The pumping means is actuated by the rotation of the roller cone element about the shaft. This system provides high lubricating characteristics.
  • FIG. 1 is a section view illustrating the best mode contemplated for practicing the invention.
  • leg member 12 Shown in the drawing is shank 10 from which extends leg member 12. In most cases there will be three such leg members; however, for the purposes of illustrating this invention, only one leg will be shown.
  • Leg member 12 has an integral shaft 14 forming a journal 1d.
  • the shaft 14 extends inwardly and downwardly toward the axis of the bit.
  • Shank It has an internal chamber 18 through which drilling fluid is conducted downwardly to passage- Roller cutter element 22 having teeth or cutting elements 24 is rotatably supported about shaft 14.
  • the internal surface of roller cone element 22 forms a bearing 26 which mates with journal 16.
  • a clearance 28 is provided between journal 16 and bearing 26. Clearance 28 is preferably about .0005 to .002 inch.
  • Roller cone 22 is rotatably supported from shaft 14 of the bit leg 12 by ball bearings 3d.
  • the inner race for ball bearings Si? is provided at 312 in shaft 14.
  • One-half of the outer race is provided at 34 in the inner portion of roller cone 22.
  • the other half of the outer race is provided at 36 in annular bearing retainer 38.
  • Sufiicient clearance is provided between face 37 of shirt tail 46 of leg 12 and retainer 38 to permit placing ball bearings 39 in their races after retainer 38 has been placed over shaft 14 and adjacent to face 37.
  • Seal means are provided between bearing retainer 38 and shirt tail 40 of bit leg 12.
  • Retaining ring 38 has an annular groove or cell 559 which is positioned just above outer race 36.
  • the seal means includes a seal element 42 which can be phenolic resin, impregnated hard carbon or bronze for example.
  • the seal element 42 is held against face 37 of shirt tail 4% by a conical disc spring 44.
  • One end of conical disc spring 44 is sealingly secured to bearing retainer 38 at 46.
  • roller cone element 22 is rotatably supported from shaft 14 of leg 12 by ball bearing means 3i? and its associated races. A sealing contact is made between the roller cone and the leg. Thus space or clearance 28 is effectively sealed and isolated from the exterior of roller cone 22.
  • a chamber 51 which is cylindrical and axially aligned with the axis of shaft 14 is provided.
  • a piston 52 is mounted in cylinder 51 and seals 54 provide the sealing contact between piston 52 and cylinder 51.
  • External splines 56 of piston 52 engage internal splines 58 of the cylinder; thus, piston 52 has longitudinal movement within cylinder 51 but does not have rotational movement therein.
  • a spring 60 which urges piston 52 outwardly in the direction of the splines or toward the apex of the shaft or cutting element.
  • piston 52 reciprocates within cylinder 51.
  • the upper or power end of cylinder 51 is connected through conduit 66 through check valve 68 to clearance 28 between the journal and the bearing.
  • Check valve 68 which includes spring member 69 held in place by screw-threaded plug 71, permits the flow of fluid only from the cylinder toward the clearance.
  • Shaft 14 has a flat surface 70 to aid in getting fluid into clearance 28.
  • a second conduit 72 connects a second portion of the clearance 23 with reservoir 78 which is in leg 12 and is connected by conduit 7 9 with the inlet to cylinder 51.
  • a check valve 74 which includes spring member 75 held in place by washer '76, is provided in the inlet permitting fluid to flow only inwardly toward the cylinder.
  • Seal 42 prevents this as long as it is working properly. To aid its proper functioning, the mini-mum pressure within the cone 22 is maintained slightly above that of the pressure of the mud in the borehole surrounding the bit. Then if the seal should develop a slight leak, lubricating fluid would escape due to the pressure being in excess of that of the drilling fluid. Conversely, the higher pressure inside the roller cone 22 would prevent drilling fluid from entering. Means are provided so that when this does occur, make-up lubricating fluid is supplied to the pumping means. Lubricating fluid reservoir 78, in bit leg 12, is in communication through conduit 79 with the inlet to cylinder 51 of the pump.
  • Fluid reservoir 78 is preferably cylindrical in shape and has a diameter d
  • Axially aligned with fluid reservoir 78 is a second cylinder 80 having a diameter d which is larger than d
  • Cylinder 80 extends or opens into the exterior of leg 12.
  • Mounted in cylinder 80 is a piston member having an upper portion 82 of diameter d which is essentially the diameter of cylinder 80.
  • Sealing rings 84 are provided to give it a sliding and sealing contact with the inner wall of cylinder 89.
  • a retaining ring 81 is provided in cylinder 80 to prevent the piston from being forced out the upper end of cylinder S0.
  • a piston extension 86 Extending downwardly from element 82 is a piston extension 86 which has a diameter d substantially the same as the diameter of fluid reservoir 78.
  • a seal ring 87 is provided about extension 86.
  • a passage 90 is provided through piston elements 82 and 86.
  • Fitting 88 can be a valve which can be opened when it is desired to pump fluid downwardly through passage 90 and can be closed at other times.
  • a conduit 91 extends from annular space 94 beneath piston element 82 to the exterior of the bit.
  • a valve such as a removable plug 92 is provided at the outer end of conduit 91. When it is desired to load fluid reservoir 78, valve 92 is opened and piston 82 ispushed or forced to its lowermost position in cylinder 80.
  • roller cutting elements rotate about the axis of shaft 14- of leg 12.
  • diagonal face 64 on the cone and diagonal face 62 on the lower end of piston 52 are changing their relative position.
  • This change coupled with the energy thus stored in the spring 60, produces a reciprocating motion of piston 52.
  • the movement of piston 52 causes the fluid in cylinder 51 to pass downwardly through conduit 66 and check valve 68 into clearance 28 under very high pressure.
  • the pressure is primarily dependent upon the design of diagonal faces 62 and 64 (which determines the stroke of piston 52) and the volume within cylinder 51 above piston 52.
  • a lubricating fluid under high pressure is forced into clearance 28 at the point of greatest force between the journal and the bearing. This causes a hydrostatic bearing and prevents contact between the journal 16 and bearing 26.
  • the fluid then flows through clearance 28 through conduit 72 and back to the inlet to the pump cylinder 51.
  • any make-up fluid needed for the system is provided from reservoir 78.
  • the fluid in reservoir 78 is maintained under relatively high pressure by the piston difierential arrangement of piston elements 82 and 86.
  • the pressure of the drilling fluid in the well bore acts on the upper surface of piston element 82, which is of greater area than the area of the lower end of piston element 86.
  • the pumping means is selected to have an output pressure substantially greater than that developed in the reservoir 78.
  • very high pressure from the pump output is required to force the fluid through clearance 28 (which is at a minimum at the bottom of journal 16) around the journal and back through conduit 72.
  • this pressure drop can be in the range of from about 10,000 to about 20,000 p.s.i.
  • a hydrostatic squeeze film effect is also created by the pressure built up between bearing 26 and journal 16. As the bearing rotates with respect to the journal, hydrodynamic pressure is developed in the clearance 28 and contributes to the total load carrying capacity of this bearing. In addition to these improved results of lubricating, the lubricating fluid under pressure prevents any possibility of drilling mud particles entering clearance 28 and causing damage to the hearing or journal surfaces.
  • cylinder 51 and piston 52 can be positioned in shaft 14 in a non-axial manner. If piston 52 has a reciprocating motion which is at an angle to the axis of shaft '14, then face 62 of the piston can be perpendicular to the axis of piston 52 and face 64 of the cone member is diagonal, as illustrated in FIG. 1. This is also true if cylinder 51 and piston 52 are arranged such that their axis is parallel to the axis of shaft 14, or in this case the face of the piston can be round for better load distribution. It is thus desired that only such limitation be imposed on the appended claims as are stated therein.
  • a bit for drilling boreholes in the earth which comprises:
  • roller cone member a portion of said roller cone member shaped to define a bearing means mating with the journal of said leg member, said bearing means and said journal having a suflicient clearance therobetween to permit the circulation of a lubricating fluid
  • sealing means for preventing the escape of lubricating fluid from between said journal and said bearing;
  • An apparatus as defined in claim 1 including a reservoir means for supplying lubricating fluid to the input to said pump means.
  • leg member extended from said shank means, a portion of said leg member forming a journal, such journal of said leg member having an axis, said leg member having a flat surface on its lower side;
  • roller cone member a portion of said roller cone member shaped .to define a bearing means mating with the journal of said leg member and forming a clearance therebetween and also surrounding said flat surface; said leg member having a cylinder whose longitudinal axis coincides with the axis of the journal of said leg member;
  • a piston having a pressure end, said piston sealably, slidably, and nonrotatalbly mounted within said cylinder, said piston also having a face member opposite its pressure end which is nonperpendicular to its axis;
  • first conduit means connecting the pressure end of the cylinder to the flat surface of said journal
  • check valve means in said second conduit means permitting the flow of fluid only inwardly toward said cylinder; and sealing means between said roller cone member and said leg member to maintain said fluid Within the assembly.
  • An apparatus as defined in claim 3 including makeup reservoir means for supplying lubricating fluid to the power end of said cylinder.

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  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Mining & Mineral Resources (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
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  • Earth Drilling (AREA)

Description

April 5, 1966 J. E. ORTLOFF PRESSURE LUBRICATED DRILL BIT BEARING Filed July 1, 1963 ag UN John E. Oriloff INVENTOR BY%AM ATTORNEY United States Patent Ofilice 3,244,459- Patented Apr. 5, 1966 ton, Tern, a corporation of Delaware Filed July 1, 1963, Ser. No. 292,048 Claims. (Cl. 3088.2)
This invention relates to the drilling of boreholes in the earth. It relates particularly to roller cone type bits for use in the drilling of such boreholes. It relates especially to a system for providing lubrication to such roller cone bits.
In the art of drilling wells for the production of oil and gas, the most commonly used method is the so-called rotary drilling method. In the rotary drilling method, a drill bit is suspended at the lower end of a string of drill pipe which is supported from the surface of the earth. The drill string is conveniently formed of many joints of drill pipe, each joint usually being about 30 feet long. As the hole is deepened, additional joints of drill pipe as needed are connected into the string. A drilling fluid under high pressure is forced down through the drill string, through the drill bit, and back up to the surface through the annulus between the drill pipe and the wall of the borehole. While the drilling fluid serves primarily to carry the rock cuttings from the drill bit to the surface, it also serves to cool the bit. The drill bit/ obtains its rotary motion from the drill pipe which is rotated from the surface. It is known that the rate of penetration of a drill bit can be increased by increasing the force (commonly called bit weight) of the drill bit on the bottom of the borehole. The penetration of the drill bit is also influenced by the rate at which the drilling fluid is forced through the pipe and 'by the rate of rotation of the bit.
One of the most widely used types of bit at the lower end of a string of drill pipe is the so-called rock bit or roller cone bit. A rock bit is normally composed of a shank member which threadedly connects into the lower end of a string of drill pipe. Usually three leg members extend downwardly from the shank. The lower end of each leg member is sometimes called a shaft or pin which extends inwardly and downwardly toward the axis of the bit. On the exterior of the shaft are inner bearing races. Roller cone cutting elements or members are rotatably supported by roller and ball bearings from the shaft of each such leg. The interior of the roller cone element contains the outer bearing races. As the drill pipe is rotated, the bit is likewise rotated. As the bit is rotated, each individual cone rotates about the shaft of the leg member from which it is supported. The cone also rotates about the bottom of the hole. Normally only the rolling cutting surfaces of the cone are exposed to the bottom of the hole. The action of the rolling cutting surface on the bottom of the hole is a twisting, tearing or gouging action for softer formations, and an approximate chipping, crushing action on the harder formations.
To perform ideally, a rock bit should be so designed that the teeth, that is, the roller cutting portions of the cone, and the bearings which support the roller cone from the leg members, should wear out at the same time. Due to recent developments in the manufacturing of the roller teeth, such as use of tungsten carbide compact bits, the cutting surface consistently outlasts the bearings by a large factor in hard formation drilling. The same is true in the case of soft formation bits where only light bit weights are required. One of the major problems way 20 and about the cutters.
bearings particles of the rock or earth formation that has been drilled. These two factors cause a rapid deterioration or wearing away of the bearings and failure of the bit.
This invention relates to a lubricating system for extending the life of the bearings of a roller cone type bit. Sealing means are provided to effectively separate or close off the clearance between the journal of the leg and the bearing of the roller cone from the exterior of the bit. A special pump means is provided to circulate lubricating fluid under high pressure through this sealed off clearance space. The pumping means is actuated by the rotation of the roller cone element about the shaft. This system provides high lubricating characteristics. (a) It provides a hydrostatic hearing by the pumping of lubricating fluid between the journal and the bearing; (b) a hydrostatic squeeze film is available as lubricating fluid is always present between the two surfaces; and (c) a third component of the film pressure is developed by the relative rotation of the bearing components and can be called hydrodynamic effect.
The objects and a complete understanding of the invention can be had from the following description taken in conjunction with the drawing in which:
FIG. 1 is a section view illustrating the best mode contemplated for practicing the invention.
Shown in the drawing is shank 10 from which extends leg member 12. In most cases there will be three such leg members; however, for the purposes of illustrating this invention, only one leg will be shown. Leg member 12 has an integral shaft 14 forming a journal 1d. The shaft 14 extends inwardly and downwardly toward the axis of the bit. Shank It) has an internal chamber 18 through which drilling fluid is conducted downwardly to passage- Roller cutter element 22 having teeth or cutting elements 24 is rotatably supported about shaft 14. The internal surface of roller cone element 22 forms a bearing 26 which mates with journal 16. A clearance 28 is provided between journal 16 and bearing 26. Clearance 28 is preferably about .0005 to .002 inch.
Roller cone 22 is rotatably supported from shaft 14 of the bit leg 12 by ball bearings 3d. The inner race for ball bearings Si? is provided at 312 in shaft 14. One-half of the outer race is provided at 34 in the inner portion of roller cone 22. The other half of the outer race is provided at 36 in annular bearing retainer 38. Sufiicient clearance is provided between face 37 of shirt tail 46 of leg 12 and retainer 38 to permit placing ball bearings 39 in their races after retainer 38 has been placed over shaft 14 and adjacent to face 37.
Seal means are provided between bearing retainer 38 and shirt tail 40 of bit leg 12. Retaining ring 38 has an annular groove or cell 559 which is positioned just above outer race 36. The seal means includes a seal element 42 which can be phenolic resin, impregnated hard carbon or bronze for example. The seal element 42 is held against face 37 of shirt tail 4% by a conical disc spring 44. One end of conical disc spring 44 is sealingly secured to bearing retainer 38 at 46.
As shown above, roller cone element 22 is rotatably supported from shaft 14 of leg 12 by ball bearing means 3i? and its associated races. A sealing contact is made between the roller cone and the leg. Thus space or clearance 28 is effectively sealed and isolated from the exterior of roller cone 22.
Attention is next directed toward that part of the systern for circulating lubricating fluid under high pressure through the clearance between the journal 16 and bearing 26. A chamber 51 which is cylindrical and axially aligned with the axis of shaft 14 is provided. A piston 52 is mounted in cylinder 51 and seals 54 provide the sealing contact between piston 52 and cylinder 51. External splines 56 of piston 52 engage internal splines 58 of the cylinder; thus, piston 52 has longitudinal movement within cylinder 51 but does not have rotational movement therein. Mounted between the upper end of cylinder 51 and piston 52 is a spring 60 which urges piston 52 outwardly in the direction of the splines or toward the apex of the shaft or cutting element. The outermost end of piston 52 is cut to form a diagonal face 62. A second diagonal face 64 is provided in roller cone 22. Thus, as roller cone 22 rotates about shaft 14 of leg 12 during drilling operations, piston 52 reciprocates within cylinder 51. The upper or power end of cylinder 51 is connected through conduit 66 through check valve 68 to clearance 28 between the journal and the bearing. Check valve 68, which includes spring member 69 held in place by screw-threaded plug 71, permits the flow of fluid only from the cylinder toward the clearance. Shaft 14 has a flat surface 70 to aid in getting fluid into clearance 28. A second conduit 72 connects a second portion of the clearance 23 with reservoir 78 which is in leg 12 and is connected by conduit 7 9 with the inlet to cylinder 51. A check valve 74, which includes spring member 75 held in place by washer '76, is provided in the inlet permitting fluid to flow only inwardly toward the cylinder.
In drilling the greatest force between journal 16 and bearing 26 is at the bottom. Thus high pressure lubricant is directed to flat surface 70 at the bottom of the shaft at this point or area of greatest force. In operation the lubricating fluid is pumped between the bearing and the journal and a hydrostatic bearing effect is obtained. By having a fluid between the bearing and the journal and a hydrostatic squeeze film lubrication is also effected. Thirdly by having a fluid contained in clearance 28, a hydrodynamic lubrication effect is developed when relative motion bet-ween the bearing components are achieved as in drilling. The outlet of the pumping means is connected through conduit 66, check valve 68 and flat surface 70 to a first portion of clearance 28 at the point of highest force. Inlet conduit 72 of the pumping means is connected to one portion of clearance 28 which is on the upper side of shaft 14 at the point of smallest force. Thus a circulating path of lubricating fluid is obtained.
It is very important to prevent drilling fluid from entering clearance 28. Seal 42 prevents this as long as it is working properly. To aid its proper functioning, the mini-mum pressure within the cone 22 is maintained slightly above that of the pressure of the mud in the borehole surrounding the bit. Then if the seal should develop a slight leak, lubricating fluid would escape due to the pressure being in excess of that of the drilling fluid. Conversely, the higher pressure inside the roller cone 22 would prevent drilling fluid from entering. Means are provided so that when this does occur, make-up lubricating fluid is supplied to the pumping means. Lubricating fluid reservoir 78, in bit leg 12, is in communication through conduit 79 with the inlet to cylinder 51 of the pump. Fluid reservoir 78 is preferably cylindrical in shape and has a diameter d Axially aligned with fluid reservoir 78 is a second cylinder 80 having a diameter d which is larger than d Cylinder 80 extends or opens into the exterior of leg 12. Mounted in cylinder 80 is a piston member having an upper portion 82 of diameter d which is essentially the diameter of cylinder 80. Sealing rings 84 are provided to give it a sliding and sealing contact with the inner wall of cylinder 89. A retaining ring 81 is provided in cylinder 80 to prevent the piston from being forced out the upper end of cylinder S0.
Extending downwardly from element 82 is a piston extension 86 which has a diameter d substantially the same as the diameter of fluid reservoir 78. A seal ring 87 is provided about extension 86. A passage 90 is provided through piston elements 82 and 86. At the top of passage is a fitting 38 such as a Zerk. Fitting 88 can be a valve which can be opened when it is desired to pump fluid downwardly through passage 90 and can be closed at other times. A conduit 91 extends from annular space 94 beneath piston element 82 to the exterior of the bit. A valve such as a removable plug 92 is provided at the outer end of conduit 91. When it is desired to load fluid reservoir 78, valve 92 is opened and piston 82 ispushed or forced to its lowermost position in cylinder 80. This exhausts all the air or other fluid which is below piston element 82 in annular space 94. Plug 92 is then inserted, thus closing conduit 91. Thereafter a lubricating fluid is injected through fitting 88 and passageway 90 to fill reservoir 78 and the space between cone 22 and journal 16. As fluid is injected, it forces piston element 52 upwardly. As the piston goes up, a partial vacuum is created or occurs in annular space 94 After the reservoir 78 and the space between cone 22 and journal 16 has been filled with lubricating fluid as described in the immediately above paragraph, the bit is ready for attachment to a drill string and use in drilling a borehole. It is believed that the operation of the tool is now apparent. However, a few comments will be made thereon. When drilling operations are commenced, roller cutting elements rotate about the axis of shaft 14- of leg 12. When this occurs, diagonal face 64 on the cone and diagonal face 62 on the lower end of piston 52 are changing their relative position. This change, coupled with the energy thus stored in the spring 60, produces a reciprocating motion of piston 52. The movement of piston 52 causes the fluid in cylinder 51 to pass downwardly through conduit 66 and check valve 68 into clearance 28 under very high pressure. The pressure is primarily dependent upon the design of diagonal faces 62 and 64 (which determines the stroke of piston 52) and the volume within cylinder 51 above piston 52. Thus a lubricating fluid under high pressure is forced into clearance 28 at the point of greatest force between the journal and the bearing. This causes a hydrostatic bearing and prevents contact between the journal 16 and bearing 26. The fluid then flows through clearance 28 through conduit 72 and back to the inlet to the pump cylinder 51.
Any make-up fluid needed for the system is provided from reservoir 78. The fluid in reservoir 78 is maintained under relatively high pressure by the piston difierential arrangement of piston elements 82 and 86. The pressure of the drilling fluid in the well bore acts on the upper surface of piston element 82, which is of greater area than the area of the lower end of piston element 86. Thus the pressure of the make-up fluid in the fluid reservoir 78 is in excess of that of the drilling fluid exterior of the bit. The pumping means is selected to have an output pressure substantially greater than that developed in the reservoir 78. As the clearance is very small between journal 16 and bearing 26, very high pressure from the pump output is required to force the fluid through clearance 28 (which is at a minimum at the bottom of journal 16) around the journal and back through conduit 72. For example, for a 9 inch diameter bit having a clearance of about .001 inch, this pressure drop can be in the range of from about 10,000 to about 20,000 p.s.i.
A hydrostatic squeeze film effect is also created by the pressure built up between bearing 26 and journal 16. As the bearing rotates with respect to the journal, hydrodynamic pressure is developed in the clearance 28 and contributes to the total load carrying capacity of this bearing. In addition to these improved results of lubricating, the lubricating fluid under pressure prevents any possibility of drilling mud particles entering clearance 28 and causing damage to the hearing or journal surfaces.
It is possible to produce modifications from the embodiment disclosed herein Without departing from the inventive concept. For example, cylinder 51 and piston 52 can be positioned in shaft 14 in a non-axial manner. If piston 52 has a reciprocating motion which is at an angle to the axis of shaft '14, then face 62 of the piston can be perpendicular to the axis of piston 52 and face 64 of the cone member is diagonal, as illustrated in FIG. 1. This is also true if cylinder 51 and piston 52 are arranged such that their axis is parallel to the axis of shaft 14, or in this case the face of the piston can be round for better load distribution. It is thus desired that only such limitation be imposed on the appended claims as are stated therein.
What is claimed is:
1. A bit for drilling boreholes in the earth which comprises:
a shank means;
a leg member extending from said shank means, the
lower portion of said leg member forming a journal;
a roller cone member, a portion of said roller cone member shaped to define a bearing means mating with the journal of said leg member, said bearing means and said journal having a suflicient clearance therobetween to permit the circulation of a lubricating fluid;
means to rotatably support said roller cone member from said leg member;
sealing means for preventing the escape of lubricating fluid from between said journal and said bearing;
pump means within said leg member having an input and an output;
means to connect the output of said pump means with one portion of the clearance between the journal and the bearing;
means to connect the input to said pump means to another portion of such clearance;
means for driving said pump means from the relative movement between said leg member and said roller cone member.
2. An apparatus as defined in claim 1 including a reservoir means for supplying lubricating fluid to the input to said pump means.
3. A bit which comprises:
a shank means;
a leg member extended from said shank means, a portion of said leg member forming a journal, such journal of said leg member having an axis, said leg member having a flat surface on its lower side;
a roller cone member, a portion of said roller cone member shaped .to define a bearing means mating with the journal of said leg member and forming a clearance therebetween and also surrounding said flat surface; said leg member having a cylinder whose longitudinal axis coincides with the axis of the journal of said leg member;
a piston having a pressure end, said piston sealably, slidably, and nonrotatalbly mounted within said cylinder, said piston also having a face member opposite its pressure end which is nonperpendicular to its axis;
means urging said piston outwardly toward said roller cone member;
a second face member rigidly supported from said roller cone member opposite the outer end of said piston, such second face being nonperpendicular to the axis of said piston;
first conduit means connecting the pressure end of the cylinder to the flat surface of said journal;
a check valve in said first conduit means permitting the flow of fluid only from said cylinder toward said flat surface;
second conduit means connecting another portion of said clearance remote from said flat surface to the pressure end of said cylinder;
check valve means in said second conduit means permitting the flow of fluid only inwardly toward said cylinder; and sealing means between said roller cone member and said leg member to maintain said fluid Within the assembly.
4. An apparatus as defined in claim 3 in which said means urging said piston is a spring.
5. An apparatus as defined in claim 3 including makeup reservoir means for supplying lubricating fluid to the power end of said cylinder.
References Cited by the Examiner UNITED STATES PATENTS 1,635,592 7/1927 Wadsworth 175229 1,838,067 12/1931 Wadsworth l229 1,909,128 5/1933 Scott et al. 308-82 2,174,102 9/1939 Catland.
2,831,660 4/1958 Smieohinski --228 2,906,504 9/1959 Parks 175-228 ERNEST R. PURSER, Primary Examiner.
CHARLES E. OCONNELL, Examiner.
W. J. MALONEY, Assistant Examiner.

Claims (1)

1. A BIT FOR DRILLING BOREHOLES IN THE EARTH WHICH COMPRISES: A SHANK MEANS; A LEG MEMBER EXTENDING FROM SAID SHANK MEANS, THE LOWER PORTION OF SAID LEG MEMBER FORMING A JOURNAL; A ROLLER CONE MEMBER, A PORTION OF SAID ROLLER CONE MEMBER SHAPED TO DEFINE A BEARING MEANS MATING WITH THE JOURNAL OF SAID LEG MEMBER, SAID BEARING MEANS AND SAID JOURNAL HAVING A SUFFICIENT CLEARANCE THEREBETWEEN TO PERMIT THE CIRCULATION OF A LUBRICATING FLUID; MEANS TO ROTATABLY SUPPORT SAID ROLLER CONE MEMBER FROM SAID LEG MEMBER; SEALING MEANS FOR PREVENTING THE ESCAPE OF LUBRICATING FLUID FROM BETWEEN SAID JOURNAL AND SAID BEARING; PUMP MEANS WITHIN SAID LEG MEMBER HAVING AN INPUT AND AN OUTPUT; MEANS TO CONNECT THE OUTPUT OF SAID PUMP MEANS WITH ONE PORTION OF THE CLEARANCE BETWEEN THE JOURNAL AND THE BEARING; MEANS TO CONNECT THE INPUT TO SAID PUMP MEANS TO ANOTHER PORTION OF SUCH CLEARANCE; MEANS FOR DRIVING SAID PUMP MEANS FROM THE RELATIVE MOVEMENT BETWEEN SAID LEG MEMBER AND SAID ROLLER CONE MEMBER.
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Cited By (36)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3365247A (en) * 1964-06-24 1968-01-23 Aquitaine Petrole Roller bits for borehole drilling
US3844363A (en) * 1973-06-11 1974-10-29 E Williams Drill tool
US3866695A (en) * 1974-07-01 1975-02-18 Dresser Ind Bearing Cavity Pressure Maintenance Device For Sealed Bearing Rock Bit
US4055338A (en) * 1976-02-17 1977-10-25 Hughes Tool Company Drill string shock absorbing apparatus
FR2362991A1 (en) * 1976-08-23 1978-03-24 Skf Ind Trading & Dev ROLLER TREPAN
US4102419A (en) * 1976-05-10 1978-07-25 Klima Frank J Rolling cutter drill bit with annular seal rings
US4167220A (en) * 1977-01-29 1979-09-11 Skf Kugellagerfabriken Gmbh System for lubricating the bearings of cutting rollers of a roller bit
US4167219A (en) * 1978-08-24 1979-09-11 Dresser Industries, Inc. Viscous pump rock bit lubrication system
US4183416A (en) * 1978-08-18 1980-01-15 Dresser Industries, Inc. Cutter actuated rock bit lubrication system
US4240674A (en) * 1979-11-19 1980-12-23 Evans Robert F Positive lubricating and indexing bearing assembly
US4254838A (en) * 1979-07-24 1981-03-10 Eduardo Barnetche Automatic depth compensating device
US4256190A (en) * 1979-04-06 1981-03-17 Bodine Albert G Sonically assisted lubrication of journal bearings
US4298079A (en) * 1979-03-28 1981-11-03 Sandvik Aktiebolag Rotary drill bit
EP0040847A2 (en) * 1980-05-27 1981-12-02 Eduardo Barnetche Gonzalez Pressure compensating device
US4375242A (en) * 1980-08-11 1983-03-01 Hughes Tool Company Sealed and lubricated rock bit with air protected seal ring
US4386668A (en) * 1980-09-19 1983-06-07 Hughes Tool Company Sealed lubricated and air cooled rock bit bearing
US4446933A (en) * 1982-03-29 1984-05-08 Bodine Albert G Rotary earth boring drill bit with centrifugal lubrication system
US4501338A (en) * 1983-08-08 1985-02-26 Smith International, Inc. Grease pump for sealed bearing rotary cone rock bits
US4657091A (en) * 1985-05-06 1987-04-14 Robert Higdon Drill bits with cone retention means
EP0289668A1 (en) * 1987-04-14 1988-11-09 Bob Higdon Roller drill bit with a cone-retaining means
US4825964A (en) * 1987-08-24 1989-05-02 Rives Allen K Arrangement for reducing seal damage between rotatable and stationary members
US4887675A (en) * 1987-01-08 1989-12-19 Hughes Tool Company Earth boring bit with pin mounted compensator
US4895215A (en) * 1988-12-05 1990-01-23 Rives Allen K Seal cage assembly for relatively movable members
US5099932A (en) * 1990-12-21 1992-03-31 Cummins Engine Company, Inc. Rock drill bit lubricant circulating system
US5137097A (en) * 1990-10-30 1992-08-11 Modular Engineering Modular drill bit
NL9300293A (en) * 1992-02-17 1993-09-16 Kverneland Klepp As GATOPENER FOR THE UPPER HOLE SECTION OF OIL / GASKETS.
EP0699816A2 (en) 1994-08-31 1996-03-06 Camco International Inc. Thrust face lubrication system for a rolling cutter drill bit
US5628375A (en) * 1995-08-29 1997-05-13 Camco International Inc. Thrust face lubrication system for a rolling cutter drill bit
US5839523A (en) * 1995-02-14 1998-11-24 Sandvik Ab Methods and apparatus for lubricating a rotary cutter
US20050045387A1 (en) * 2003-08-22 2005-03-03 Smith International, Inc. Lubricant pump and cone movement dampener
US20050183888A1 (en) * 2004-02-23 2005-08-25 Dick Aaron J. Hydrodynamic pump passages for rolling cone drill bit
US20060249311A1 (en) * 2002-03-20 2006-11-09 Atlas Copco Secoroc Ab Grease filling arrangement in a cutter for a boring head
EP2620584A1 (en) * 2012-01-26 2013-07-31 Hydro Leduc Hydraulic brake for a drilling bit
DE102016222411A1 (en) * 2016-11-15 2018-05-17 Schaeffler Technologies AG & Co. KG Schmiermittelzuführbauteil
US10392865B2 (en) * 2015-03-25 2019-08-27 Sandvik Intellectual Property Ab Cutter for boring head
US11585158B2 (en) * 2020-05-21 2023-02-21 Caterpillar Inc. Isolated lubrication system for drill bits

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US1635592A (en) * 1921-03-10 1927-07-12 Frank L O Wadsworth Rotary drilling tool
US1838067A (en) * 1921-03-10 1931-12-22 Frank L O Wadsworth Rotary drilling tool
US1909128A (en) * 1931-02-16 1933-05-16 Hughes Tool Co Roller cutter and lubricator therefor
US2174102A (en) * 1938-03-09 1939-09-26 Globe Oil Tools Co Lubricated cutter mounting
US2831660A (en) * 1956-04-16 1958-04-22 Nat Oil Tool Co Inc Lubricated well drill
US2906504A (en) * 1958-08-07 1959-09-29 Jersey Prod Res Co Lubrication of bearings

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US1635592A (en) * 1921-03-10 1927-07-12 Frank L O Wadsworth Rotary drilling tool
US1838067A (en) * 1921-03-10 1931-12-22 Frank L O Wadsworth Rotary drilling tool
US1909128A (en) * 1931-02-16 1933-05-16 Hughes Tool Co Roller cutter and lubricator therefor
US2174102A (en) * 1938-03-09 1939-09-26 Globe Oil Tools Co Lubricated cutter mounting
US2831660A (en) * 1956-04-16 1958-04-22 Nat Oil Tool Co Inc Lubricated well drill
US2906504A (en) * 1958-08-07 1959-09-29 Jersey Prod Res Co Lubrication of bearings

Cited By (46)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3365247A (en) * 1964-06-24 1968-01-23 Aquitaine Petrole Roller bits for borehole drilling
US3844363A (en) * 1973-06-11 1974-10-29 E Williams Drill tool
US3866695A (en) * 1974-07-01 1975-02-18 Dresser Ind Bearing Cavity Pressure Maintenance Device For Sealed Bearing Rock Bit
US4055338A (en) * 1976-02-17 1977-10-25 Hughes Tool Company Drill string shock absorbing apparatus
US4102419A (en) * 1976-05-10 1978-07-25 Klima Frank J Rolling cutter drill bit with annular seal rings
FR2362991A1 (en) * 1976-08-23 1978-03-24 Skf Ind Trading & Dev ROLLER TREPAN
US4167220A (en) * 1977-01-29 1979-09-11 Skf Kugellagerfabriken Gmbh System for lubricating the bearings of cutting rollers of a roller bit
US4183416A (en) * 1978-08-18 1980-01-15 Dresser Industries, Inc. Cutter actuated rock bit lubrication system
FR2438737A1 (en) * 1978-08-18 1980-05-09 Dresser Ind DRILL BIT LUBRICATING DEVICE
US4167219A (en) * 1978-08-24 1979-09-11 Dresser Industries, Inc. Viscous pump rock bit lubrication system
US4298079A (en) * 1979-03-28 1981-11-03 Sandvik Aktiebolag Rotary drill bit
US4256190A (en) * 1979-04-06 1981-03-17 Bodine Albert G Sonically assisted lubrication of journal bearings
US4254838A (en) * 1979-07-24 1981-03-10 Eduardo Barnetche Automatic depth compensating device
US4240674A (en) * 1979-11-19 1980-12-23 Evans Robert F Positive lubricating and indexing bearing assembly
EP0040847A2 (en) * 1980-05-27 1981-12-02 Eduardo Barnetche Gonzalez Pressure compensating device
EP0040847A3 (en) * 1980-05-27 1982-01-20 Eduardo Barnetche Gonzalez An automatic depth compensating system
US4328873A (en) * 1980-05-27 1982-05-11 Gonzalez Eduardo B Automatic depth compensating system for drill bit lubrication
US4375242A (en) * 1980-08-11 1983-03-01 Hughes Tool Company Sealed and lubricated rock bit with air protected seal ring
US4386668A (en) * 1980-09-19 1983-06-07 Hughes Tool Company Sealed lubricated and air cooled rock bit bearing
US4446933A (en) * 1982-03-29 1984-05-08 Bodine Albert G Rotary earth boring drill bit with centrifugal lubrication system
US4501338A (en) * 1983-08-08 1985-02-26 Smith International, Inc. Grease pump for sealed bearing rotary cone rock bits
US4657091A (en) * 1985-05-06 1987-04-14 Robert Higdon Drill bits with cone retention means
US4887675A (en) * 1987-01-08 1989-12-19 Hughes Tool Company Earth boring bit with pin mounted compensator
EP0289668A1 (en) * 1987-04-14 1988-11-09 Bob Higdon Roller drill bit with a cone-retaining means
US4825964A (en) * 1987-08-24 1989-05-02 Rives Allen K Arrangement for reducing seal damage between rotatable and stationary members
US4895215A (en) * 1988-12-05 1990-01-23 Rives Allen K Seal cage assembly for relatively movable members
US5137097A (en) * 1990-10-30 1992-08-11 Modular Engineering Modular drill bit
US5099932A (en) * 1990-12-21 1992-03-31 Cummins Engine Company, Inc. Rock drill bit lubricant circulating system
NL9300293A (en) * 1992-02-17 1993-09-16 Kverneland Klepp As GATOPENER FOR THE UPPER HOLE SECTION OF OIL / GASKETS.
US5337843A (en) * 1992-02-17 1994-08-16 Kverneland Klepp As Hole opener for the top hole section of oil/gas wells
EP0699816A2 (en) 1994-08-31 1996-03-06 Camco International Inc. Thrust face lubrication system for a rolling cutter drill bit
EP0699816A3 (en) * 1994-08-31 1997-05-07 Camco Int Thrust face lubrication system for a rolling cutter drill bit
US5839523A (en) * 1995-02-14 1998-11-24 Sandvik Ab Methods and apparatus for lubricating a rotary cutter
US5931241A (en) * 1995-08-29 1999-08-03 Camco International Inc. Hydrostatic thrust face lubrication system
US5628375A (en) * 1995-08-29 1997-05-13 Camco International Inc. Thrust face lubrication system for a rolling cutter drill bit
US20060249311A1 (en) * 2002-03-20 2006-11-09 Atlas Copco Secoroc Ab Grease filling arrangement in a cutter for a boring head
US20080000695A1 (en) * 2002-03-20 2008-01-03 Atlas Copco Secoroc Ab Grease filling arrangement in a cutter for a boring head
US7445062B2 (en) 2002-03-20 2008-11-04 Atalas Copco Secoroc Ab Grease filling arrangement in a cutter for a boring head
US20050045387A1 (en) * 2003-08-22 2005-03-03 Smith International, Inc. Lubricant pump and cone movement dampener
US20050183888A1 (en) * 2004-02-23 2005-08-25 Dick Aaron J. Hydrodynamic pump passages for rolling cone drill bit
US7128171B2 (en) 2004-02-23 2006-10-31 Baker Hughes Incorporated Hydrodynamic pump passages for rolling cone drill bit
EP2620584A1 (en) * 2012-01-26 2013-07-31 Hydro Leduc Hydraulic brake for a drilling bit
FR2986260A1 (en) * 2012-01-26 2013-08-02 Hydro Leduc HYDRAULIC BRAKE FOR TREPAN
US10392865B2 (en) * 2015-03-25 2019-08-27 Sandvik Intellectual Property Ab Cutter for boring head
DE102016222411A1 (en) * 2016-11-15 2018-05-17 Schaeffler Technologies AG & Co. KG Schmiermittelzuführbauteil
US11585158B2 (en) * 2020-05-21 2023-02-21 Caterpillar Inc. Isolated lubrication system for drill bits

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