Abstract: A roller cutter for a drill head for raise boring. The roller cutter having a shaft with a longitudinal center line, a hub rotatably mounted on the shaft, and a seal retainer located between the axial ends of the hub and the shaft at least arranged at one end of the roller cutter. The seal retainer supports a primary cutter seal providing sealing between the shaft and the hub in both axial and radial directions. A secondary cutter seal is located between the seal retainer and the hub, such that the secondary cutter seal provides sealing in the axial direction.

Abstract: Rotary drill bits may include on or more cutting element assemblies which include a cutter and a mounting system. In one embodiment, the mounting system includes a housing, a first bearing component disposed within the housing, and a second bearing component associated with the cutting element. In certain embodiments, the bearing components may comprise a table of superhard material bonded with a substrate. In one or more embodiments, the bearing components may include bearing surfaces that are arcuate. For example, the bearing surfaces may be substantially spherical (a portion of a sphere). The bearing components may be arranged to act as a radial bearing as well as a thrust bearing for the cutting element, enabling the cutting element to rotate about a longitudinal axis of the cutter, relative to the housing, while also enabling the longitudinal axis of the cutter to be displaced (change angles) relative to the housing.

Abstract: An isolated lubrication system for a drill bit is disclosed. The system comprises a body having a cutting arm with a journal and a rotary cutter mounted on the journal. The system also comprises a reservoir in a body to contain a fluid lubricant that isolated from communication outside the body. The system also comprises multiple conduits in communication with the reservoir and with respect to each other. The multiple conduits facilitate lubrication between the journal and the rotary cutter, including the bearings, by means of a gravitational force and/or a centrifugal force acting of the fluid lubricant. Further, the system comprises a sealing system. The sealing system includes a sealing cap provided to the reservoir, a seal provided between the journal and the rotary cutter, and a stepped passageway provided in a clearance between the rotary cutter and a cutting arm of the body.

Abstract: An earth-boring tool includes a movable component and an additive manufacturing formed flow control device in fluid communication with the movable component and configured to control a flowrate of the hydraulic fluid through the additive manufacturing formed flow control device, wherein the additive manufacturing formed flow control device is configured to control a movement of the movable component via the flowrate of hydraulic fluid through the additive manufacturing formed flow control device. An earth-boring tool includes an additive manufacturing formed flow control device in fluid communication with one or more components of the earth-boring tool and configured to provide a cooling fluid to the one or more components of the earth-boring tool.

Abstract: A thrust bearing is equipped with a resin coating applied to the surface of a base material. Lattice-shaped discharge grooves are formed in the surface of the thrust bearing, and planer protrusions having a square shape or the like are formed at the adjacent positions thereof. Each corner part of each planer protrusion form a sliding surface that slides with respect to a counterpart member. Contaminants such as wear particles that have infiltrated between the counterpart member and the sliding surface fail into the discharge grooves and then are discharged outside of the sliding surface. The chamfering of each corner part to a rounded shape prevents the contaminants from accumulating in the discharge grooves, thus preventing the contaminants from biting into the planer protrusions.

Abstract: Bearings for downhole tools including a first bearing member and a second bearing member, at least one of the first and second bearing members having a channel formed therein. Methods of cooling bearings of downhole tools comprise flowing a fluid within a channel formed in at least one bearing member. Heat is transferred from at least the at least one bearing member to the fluid. The fluid is flowed away from the at least one bearing member.

Abstract: According to one embodiment, the disclosure relates to a roller cone drill bit including a bit body having at least one support arm extending therefrom, a cone assembly containing bearings or retaining balls and rotatably mounted on a journal extending from each support arm, a lubricant reservoir disposed in each support arm, a lubricant chamber disposed in each support arm and fluidly coupled to the bearings or retaining balls, a bore disposed in each support arm to communicate lubricant between the lubricant reservoir and the lubricant chamber, and a pressure release mechanism disposed within the bore. The pressure release mechanism may be operable to relieve lubricant from the lubricant reservoir into the lubricant chamber when lubricant pressure within the lubricant reservoir exceeds pressure of the lubricant in the lubricant chamber. According to another embodiment, the disclosure relates to methods of relieving lubricant in such a bit.

Abstract: The roller cone is retained to the head with axial play taken out of the bearings with a tension rod that is tensioned from the rear of the head and away from the nose bearing region of the head allowing greater resistance to loading in the region of the nose bearing and a reduction in critical stresses. The tension rod has a flat and is oriented for tightening so that the flat faces grease passages to allow grease to gain access to the bearings through the bore for the tension rod and otherwise fill the bore so the tension rod actively supports loading in the head bearing. The nose bearing can be separately supported to the cone directly with a retainer threaded to the cone or a spacer between the bearings can be used so that tensioning of the rod takes out the axial play in both bearings with force transmitted to a retainer at the back of the cone.

Abstract: The roller cone is retained to the head with axial play taken out of the bearings with a tension rod tensioned from the rear of the head and away from the nose bearing region of the head allowing greater resistance to loading in the region of the nose bearing and a reduction in critical stresses. The tension rod has a flat oriented for tightening and facing grease passages to allow grease to gain access to the bearings through the bore for the tension rod and otherwise fill the bore so the tension rod actively supports loading in the head bearing. The nose bearing is separately directly cone supported with a retainer threaded to the cone or a spacer between bearings can be used so that tensioning of the rod takes out the axial play in both bearings with force transmitted to a retainer at the back of the cone.

Abstract: Bearings for downhole tools including a first bearing member and a second bearing member, at least one of the first and second bearing members having a channel formed therein. Methods of cooling bearings of downhole tools comprise flowing a fluid within a channel formed in at least one bearing member. Heat is transferred from at least the at least one bearing member to the fluid. The fluid is flowed away from the at least one bearing member.

Abstract: Bearing assemblies, apparatuses, and motor assemblies using the same are disclosed. In an embodiment, a bearing assembly includes a plurality of superhard bearing elements distributed circumferentially about an axis. At least some of the superhard bearing elements may include a first end surface, a second end surface generally opposite the first end surface, a first side surface extending between the first end surface and the second end surface, a second side surface generally opposite the first side surface, and a bearing surface extending between the first end surface, the second end surface, the first side surface and the second side surface. Such superhard bearing elements may also include a ramped feature negatively sloping away from the bearing surface. The bearing assembly may further include a support ring that carries the plurality of superhard bearing elements.

Abstract: A roller cone bit having a sealed lubricant reservoir between a roller cone and a head section. A journal sleeve is included on the head section that circumscribes the journal bearing surface of the head section. The sleeve can axially pivot on the head section, but does not rotate thereon. The reservoir is formed into a journal bearing surface of the head section body and may be sealed by placing a seal around its periphery that extends between the journal bearing surface and journal sleeve. Sealing the reservoir results in a hydrostatic condition therein and substantially equalized pressures.

Abstract: A drill bit for drilling a wellbore, the drill bit having a body and at least one bearing. A rotary cone is rotatably attached to the bit body at the bearing. A lubricant reservoir is located in an inner portion of the bit body and is in fluid communication with the bearing. A communication port leads from the inner portion of the bit body to the exterior of the bit body. A fiber reinforced elastomeric pressure compensator diaphragm separates lubricant in the lubricant reservoir from the communication port.

Abstract: The present disclosure includes a lubricant for use in a roller cone rock bit, where the lubricant comprises a non-grease formulation. The lubricant can comprise synthetic lubricating fluids and combinations thereof as well as combinations of synthetic fluid or fluids with mineral oil or oils. The lubricant can contain one or more additional ingredients and have a minimum viscosity of 100 centistokes at 212° F. The additional ingredients include fluid soluble or dispersed extreme pressure and antiwear additives, and solid lubricants.

Abstract: A texture pattern is applied to bearing surfaces of earth-boring bits, especially the bearings of earth boring bits of the roller cutter variety. The textured surface that may be applied to either or both sides of the thrust washer faces, bearing faces, inlays, or thrust shoulders, or a combination thereof.

Abstract: One aspect of the present invention relates to a spindle motor manufacturing method for forming an oil repellent film which prevents a lubricating oil from flowing out, on a predetermined area adjacent to a hydrodynamic bearing, the predetermined area being located on at least one of a stationary member and a rotating member. The spindle motor manufacturing method mentioned above comprises a step of supplying an oil repellent solution by a supplying portion onto a part of the predetermined area for forming the oil repellent film, a step of applying an air current to the part of the predetermined area on which the oil repellent solution is supplied so as to peel off an excess part of the oil repellent solution supplied onto the part of the predetermined area, and a step of making a relative movement of the predetermined area in which the oil repellent film is formed, the relative movement being made with respect to the supplying portion by which the oil repellent solution is supplied.

Abstract: An earth boring bit has thrust faces with one of the thrust faces being at least partially tilted relative to the other. The bit has a cone rotatably mounted to a bearing pin of the bit body. The thrust faces are in the cone and on an end of the bearing pin. One of the thrust faces is completely flat and perpendicular to the axis of the bearing pin. The other thrust face has a tilted portion that is at a skewed angle relative to the axis. The tilted portion creates converging and diverging zones between the thrust faces.

Abstract: The invention relates to a trench wall cutter comprising a bearing shield, on which at least one cutting wheel is supported in a rotatable manner. Between the cutting wheel and the bearing shield at least one sealing member is provided. For the lubrication of the sealing member a lubricating device is provided, which has a lubricant inlet port arranged above the cutting wheel.

Abstract: A spindle motor is formed so as to support a pivot of a rotor by a pair of open bearings. The open bearings thus constructed will be less expensive and simple structures, so that a manufacturing cost thereof is reduced compared to a conventional spindle motor using a pair of ball bearings with shields. Accordingly, a low-cost spindle motor can be provided.

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.

Abstract: A rotary cone rock bit, comprises a bit body including a plurality of legs extending therefrom, each of the legs having an outer surface that includes a leading surface and a trailing surface, a roller cone rotatably supported on each of the legs, a bearing system between each cone and the leg on which it is supported, and a lubricant reservoir in fluid communication with the bearing system. The reservoir can be provided with a wear resistant plug, if desired. In the present bit, the reservoir has at least one opening positioned in either the leg's leading surface, trailing surface, center surface, shoulder surface or some combination of these. Alternatively, the reservoir can be formed inside the bit body, preferably by a canister or the like, which can be provided with a venting as desired.

Abstract: A sealing structure for a rock drill bit includes an elastomeric diaphragm for installation in the drill bit so as to separate grease from drilling mud. The diaphragm has an aperture extending through it, and a plug is disposed in the aperture so as to form a mechanical seal with a wall of the aperture. The plug has a channel therethrough which is normally held sealed by a face of the aperture in the diaphragm. If the pressure of the grease exceeds pressure in mud on the other side of the diaphragm by more than a critical value, the diaphragm aperture deforms and allows grease to move through the plug channel and escape. The critical value can be varied by using, with the same diaphragm, plugs having different numbers, sizes and axial positions of plug channels.

Abstract: A load responsive hydrodynamic bearing is provided in the form of a thrust bearing or journal bearing for supporting, guiding and lubricating a relatively rotatable member to minimize wear thereof responsive to relative rotation under severe load. In the space between spaced relatively rotatable members and in the presence of a liquid or grease lubricant, one or more continuous ring shaped integral generally circular bearing bodies each define at least one dynamic surface and a plurality of support regions. Each of the support regions defines a static surface which is oriented in generally opposed relation with the dynamic surface for contact with one of the relatively rotatable members. A plurality of flexing regions are defined by the generally circular body of the bearing and are integral with and located between adjacent support regions.

Abstract: The retainer of the present invention is made of a composite material having a body made from a polymer, a layer of solid lubricant formed over the body by chemically coating the body with a porous layer of solid lubricant and impregnating the solid lubricant with another lubricant using conventional methods such as vacuum impregnation. The retainer is placed between an outer raceway and an inner raceway to form a self-lubricating bearing. The bearing made in this manner has high lubrication tolerance (i.e. it performs well in the absence of external lubrication). Because of its high lubrication tolerance, the bearing is suitable for use in various applications such as dental/medical hand pieces that are periodically sterilized and other applications which occasionally experience periods of lubrication starvation.

Abstract: A rolling cutter drill bit comprises a body and three legs, each leg having a cantilevered bearing spindle, a roll cutter rotatably mounted on the bearing spindle, a lubricating system within the spindle, and a tubular bearing element located radially between the spindle and the rolling cutter. The tubular bearing element is formed of a wrought alloy material consisting primarily of chromium carbide and cobalt and having a yield strength of less than 120,000 psi and a ductility greater than 4%, both at room temperature, and is of low wall thickness.

Abstract: A solid lubricant is added to the internal passages of an air cooled bit such that the air erodes, or ablates, the solid lubricant into the air stream. Compressed air travels down the drill stem to the bit. The air passes through an air tube into the main air passage where the solid lubricant has been placed. As the air passes the solid lubricant, it erodes the solid lubricant. The solid lubricant particles ablated into the air stream travel through the ball passage into the journal air passage and out to the bearing surfaces between the cutter and the journal. The air stream both cools the surfaces and deposits the solid lubricant to reduce the friction between the bearing surfaces.

Abstract: A ball screw is provided which makes it easy to determine the degree of deterioration of lubricating grease so that new lubricating grease can be supplied efficiently without loss. The ball screw includes a threaded shaft formed with a thread groove in its outer peripheral surface, a nut formed with a thread groove in its inner peripheral surface, and a plurality of balls rollably retained in a circulating passage comprising a helical passage formed between these thread grooves when the nut is fitted on the threaded shaft, and a passage connecting both ends of the helical passage. The balls and the circulating passage are lubricated by a lubricating grease which has a brightness of 1 or over and in which a base oil having a viscosity at 100° C. of 3.0-7.5 mm2/s is thickened by a urea-family thickener.

Abstract: A rotary cone rock bit, comprises a bit body including a plurality of legs extending therefrom, each of the legs having an outer surface that includes a leading surface and a trailing surface, a roller cone rotatably supported on each of the legs, a bearing system between each cone and the leg on which it is supported, and a lubricant reservoir in fluid communication with the bearing system. The reservoir can be provided with a wear resistant plug, if desired. In the present bit, the reservoir has at least one opening positioned in either the leg's leading surface, trailing surface, center surface, shoulder surface or some combination of these. Alternatively, the reservoir can be formed inside the bit body, preferably by means of a canister, which can be provided with venting means as desired.

Abstract: A pressure compensating assembly for use in roller cone drilling bits of the sealed bearing type. The compensating assembly includes a hollow body arranged to fit into a cavity in the bit connected with the lubrication system of the bit and the hollow body includes a normally open lubricant passageway extending therethrough. A seal encircles the body on one side of the lubricant passageway and is arranged to sealingly engage the bit and an elastomeric, cup-shaped diaphragm is located on the body and has a lip arranged to sealingly engage the bit on the other side of the lubricant passageway. The diaphragm having a protuberance on the side of the diaphragm facing the passageway and sized to enter and close the passageway. The body, seal, and diaphragm being assembled into a unitary cartridge for introduction into the bit as a unit.

Abstract: A rotary cone rock bit, comprises a bit body including a plurality of legs extending therefrom, each of the legs having an outer surface that includes a leading surface and a trailing surface, a roller cone rotatably supported on each of the legs, a bearing system between each cone and the leg on which it is supported, and a lubricant reservoir in fluid communication with the bearing system. The reservoir can be provided with a wear resistant plug, if desired. In the present bit, the reservoir can be pressured-balanced with fluid in the bit plenum or the borehole annulus, or maintained at some desired differential with respect to either of these. Alternatively, the reservoir can be formed inside the bit body, preferably by means of a canister, which can be provided with venting means as desired.

Abstract: In a drill bit which has a reservoir for storing a supply of lubricant, generally grease, a lubricant passage is formed for flow of lubricant from the reservoir to the bearing. A relief port is formed in the drill bit body to connect at least one of the reservoir and the lubricant passage with an outside surface of the drill bit body. A normally-closed relief valve is mounted in the relief port to selectively permit fluid flow through the relief port and protect the lubrication system against changes in pressure, especially increases in pressure on the grease side, such as might be caused by thermal expansion of the grease or the production of off-gases by the grease. The valve is provided in the form of a small screw-in unit capable of separate manufacture and testing and comprises a valve body carrying a flexible diaphragm element. Venting is provided via a puncture in the diaphragm element.

Abstract: A wheel mount for a wheel comprises a spindle, a hub for surrounding the spindle and a bearing assembly interposed between the spindle and the hub. The spindle extends from an end of an axle of a vehicle and has a generally decreasing diameter from its proximal end to its distal end. The spindle is provided with a pair of lands near the ends of the spindle for receiving bearings, and has bearing retainers near the respective ends also, the distal retainer being removably attached. These inboard and outboard bearing retainers define an axial bearing space. The hub has a central aperture with an inboard land and an outboard land provided on an internal surface of the central aperture, also for receiving bearings. The bearing assembly comprises an inboard bearing and an outboard bearing in spaced apart relationship within the axial bearing space. The inboard bearing has an internal diameter larger than the internal diameter of the outboard bearing.

Abstract: A rotary cone drill bit includes a drill bit body having two or more support spindles extending inward and downward toward a vertical axis of the drill bit body. Each support spindle of the drill bit includes a base pin and further includes a pilot pin extending from the base pin along a longitudinal axis of the support spindle. A conical-shaped thrust face forms the transition from the base pin to the pilot pin. A cutting cone is rotatably mounted on each support spindle and includes a conical internal surface to run in contact with the conical thrust face of the support spindle. Rotation of the cutting cone carries lubricant from the non-load side of the spindle to the contact surfaces on the load side of the spindle.

Abstract: A rolling cutter drill bit comprises a main body and three depending legs, each leg having a cantilevered bearing spindle on which a rolling cutter is rotatably mounted. Bearings located between the cutter and spindle include a radial bearing, and a thrust bearing configured to carry onward thrust loads from the cutter onto the spindle. A bearing seal defines an enclosed region between the cutter and the spindle in which the bearings are located, and a pressure balanced lubricant delivery system within the spindle delivers lubricant to the bearings. The lubricant delivery system includes a non-return valve to allow lubricant to flow into the area of the enclosed region containing the thrust bearing and the area is bounded by a tortuous flow path which allows a more restricted flow of lubricant out of the thrust bearing area and into another area of the enclosed region, without pressurizing the bearing seal.

Abstract: A first embodiment of a radially disposed thrust bearing assembly for rotary cone rock bits consists of a first non-rotating radially disposed steel thrust bearing disc and an adjacent, carbide thrust bearing disc. One of the thrust bearing discs is pressed into a disc retention socket formed in the end of a spindle bearing extending from the end of a main axially aligned bearing cantilevered from a leg of the bit and the other thrust bearing disc is pressed into a disc retention socket formed in the rotary cone. An edge of the carbide disc is formed with large valleys and peaks, the robust undulations resist cracking when the carbide thrust bearing disc is pressed into its respective socket. Unique air passages and channels are formed in the main and spindle bearings to direct cooling air to the thrust bearing discs.

Abstract: A rolling cutter drill bit comprises a body and three legs, each leg having a cantilevered bearing spindle, a rolling cutter rotatably mounted on the bearing spindle, lubricant delivering means within the beating spindle, and a floating thrust bearing element configured to carry onward thrust loads from the rolling cutter onto the bearing spindle. Each floating thrust bearing element is formed of a wrought alloy material consisting primarily of chromium carbide and cobalt and having a yield strength of less than 120,000 psi and a ductility of at least 4%, both at room temperature.

Abstract: A rolling cutter drill bit comprises a main body and three depending legs, each leg having a cantilevered bearing spindle on which a rolling cutter is rotatably mounted. Bearings located between the cutter and spindle include a radial bearing, and a thrust bearing configured to carry onward thrust loads from the cutter onto the spindle. A bearing seal defines an enclosed region between the cutter and the spindle in which the bearings are located, and a pressure balanced lubricant delivery system within the spindle delivers lubricant to the bearings. The lubricant delivery system includes a non-return valve to allow lubricant to flow into the area of the enclosed region containing the thrust bearing and the area is bounded by a tortuous flow path which allows a more restricted flow of lubricant out of the thrust bearing area and into another area of the enclosed region, without pressurizing the bearing seal.

Abstract: A well drilling bit comprises a bit body with a centralized portion and a plurality of radially and circumferentially spaced legs depending longitudinally therefrom. A respective cutter body is rotatably mounted on the free end of each leg with bearing means. The bit body has a respective lubricant passage communicating with each bearing and a respective upwardly opening lubricant reservoir recess, the recess also communicating with a respective vent port opening downwardly through the bit body. A respective lubricating mechanism is disclosed in each lubricant reservoir recess, and each such mechanism comprises an elastomeric pressure compensating diaphragm extending across the recess and sealed with respect thereto, dividing the recess into a lower portion communicating with the vent port and an upper portion communicating with the lubricant passage.

Abstract: The use of a sintered compact of a copper base alloy, a transition metal, a metalloid and a strengthener for bearing surfaces formed between roller cutter cones of sealed bearing rock bits.

Abstract: A shaft boring bit has a bit body with at least one saddle member secured to the bit body. The saddle receives and supports the ends of a journal member. A cutter is mounted for rotation on the journal member and an anti-friction bearing is disposed between the cutter and the journal and secures the cutter on the journal member. Seal means are provided between the cutter and the journal member to retain lubricant in the anti-friction bearing. A bearing loading passage is formed in the journal member for loading at least a portion of the anti-friction bearing between the cutter and the journal member. A lubricant compensator assembly is removably disposed in a lubricant compensator recess formed at one end of the journal. The lubricant compensator is in fluid communication with the anti-friction bearing and includes a rigid ball plug member, which obstructs the bearing loading passage and abuts the portion of the anti-friction bearing to retain the bearing between the cutter and journal.

Abstract: A cutter mounted on a boring head includes a shaft and a roller body rotatably mounted thereon The greasing of bearings disposed between the roller body and shaft is achieved through an axial bore formed in the shaft and into which a filling plug is inserted. Grease is pumped through the filling plug and into channels in which the bearings are disposed. The filling plug is then removed, leaving the bore essentially grease-free. To prevent the escape of grease from the passage during a cutting operation, while accommodating thermal expansion of the grease, a grease retainer plug is secured in the passage. The retainer plug forms a space which communicates with the bearings for receiving thermally expanding grease. If the volume of expanded grease exceeds the volume of that space, the grease passes through a pressure relief valve and displaces a cover of the valve to create another space of gradually expanding volume for receiving the grease.

Abstract: A roller cone rock bit (10) is provided that has a sealing system with double elastomer seals. A first elastomer seal (30) is disposed between a cone (18) having a cavity (24) and a spindle (16). A second elastomer seal (32) is disposed between cone (18) and spindle (16) forming a seal-gap (33). A main lubricant reservoir (49) has a diaphragm (56) disposed between an inner chamber (53) and an outer chamber (60). Inner chamber (53) is in fluid communication with cavity (24), and outer chamber (60) is in fluid communication with external fluids. Cavity (24) and inner chamber (50) are substantially filled with a first lubricant forming a first volume of lubricant. Diaphragm (56) is operable to transmit a pressure of the external fluids to the first volume of lubricant. A seal-gap lubricant reservoir (70) has a diaphragm (78) disposed between an inner chamber (75) and an outer chamber (82).

Abstract: An earth-boring bit has a bit body and at least one saddle member secured to the bit body to receive and support each of a pair of ends of a journal member. A cutter is mounted for rotation on the journal member and a bearing is defined between the cutter and journal member. A lubricant reservoir is formed in the journal member to receive a quantity of lubricant and is in fluid communication with the bearing. A seal means is provided between the cutter and journal member to retain lubricant in the bearing. A hydrostatic-pressure compensator is disposed in the lubricant reservoir in communication with hydrostatic-pressure in the borehole in which the bit operates. The hydrostatic-pressure compensator responses to hydrostatic-pressure to equalize a pressure differential across the seal means. An internal-pressure compensator is disposed in the lubricant reservoir and is responsive to the internal pressure of the lubricant to prevent the lubricant from being extruded past the seal means.

Abstract: An earth boring bit having a body and a cantilevered bearing shaft extending inwardly and downwardly from the body. A rotatable cutter with an open end is assembled over the shaft, which has a radial bearing surface formed around a longitudinal axis. The cutter has a radial bearing surface sized to permit assembly over the journal surface of the shaft. The shaft and cutter have opposed thrust bearing surfaces, one of which has a gradually tapered outer region and a planar inner region to gradually reduce peak stress from a maximum to a minimum and avoid abrupt changes in stress from a high to a low value.

Abstract: A radially disposed thrust bearing surface formed in a rotary cone is provided with at least a pair of grooves and a ramp surface on the trailing edge of the grooves. The groove provides a lubricant reservoir and the ramp serves to generate hydrodynamic pressures during rotation of the rotary cone on the thrust surface of a journal bearing thereby distributing a film of lubricant on the opposing thrust bearing surfaces.

Abstract: A modular drill bit mounts legs within recesses in a body which are parallel to the central axis of the body using threaded studs with tapered outer portions, in conjuction with an attached pin having recesses therein receiving the upper ends of the legs. The lower ends of the legs terminate in spindles of open face configuration rotatably receiving cones thereon for rotation via a arrangement of bushings, roller bearings and thrust bearings, and a plurality of seals which slide and therefore rotate relative to both the leg spindle and the cone with the help of pressure compensating apparatus. A bushing disposed in the cone-leg spindle interface has oil-lubricated rubber rods disposed in apertures therein to prevent lock-up on an adjacent bearing surface. The cone is held on the leg spindle by a lock nut forming one end of a race for receiving rollers of a roller bearing, in conjunction with a ring-nut secured to an extended portion of the cone protecting the leg from wear and damage.

Abstract: A radially disposed thrust bearing surface formed in a rotary cone is provided with at least a pair of grooves and a ramp surface on the trailing edge of the grooves. The groove provides a lubricant reservoir and the ramp serves to generate hydrodynamic pressures during rotation of the rotary cone on the thrust surface of a journal bearing thereby distributing a film of lubricant on the opposing thrust bearing surfaces.

Abstract: A modular drill bit mounts legs within recesses in a body which are parallel to the central axis of the body using threaded studs with tapered outer portions, in conjunction with an attached pin having recesses therein receiving the upper ends of the legs. The lower ends of the legs terminate in spindles of open face configuration rotatably receiving cones thereon for rotation via a arrangement of bushings, roller bearings and thrust bearings, and a plurality of seals which slide and therefore rotate relative to both the leg spindle and the cone with the help of pressure compensating apparatus. A bushing disposed in the cone-leg spindle interface has oil-lubricated rubber rods disposed in apertures therein to prevent lock-up on an adjacent bearing surface. The cone is held in the leg spindle by a lock nut forming one end of a race for receiving rollers of a roller bearing, in conjunction with a ring-nut secured to an extended portion of the cone protecting the leg from wear and damage.

Abstract: The present invention provides a lubricant circulation system for a rock drill bit which circulates a flow of lubricant over the bit bearing surfaces to keep the bearings optimally lubricated and free to particulate contaminants from the drilling process. A lubricant pumping assembly, including a pair of nested gerotor pump elements is attached to either the drill bit cutting element or support structures so that one of the gerotors is driven by rotation of the bit cutting element or related structures and the other gerotor rotates freely. The gerotors have a corresponding tooth and recess configuration that pulls lubricant from the lubricant supply under positive pressure into a variable sized cavity formed as the gerotors rotate relative to each other and then forces lubricant to the bearing surfaces. Lubricant may optionally be pumped back to the lubricant supply with continued rotation of the gerotors or out of the journal area with the drilling cuttings for return to the surface.

Abstract: A fluid pressure compensator for a lubrication system in a rotary drill bit includes a diaphragm (44) with an enlarged thickness central portion (62) having a generally hemispherically shaped deformation (72) at its center to form a minimal thickness thereat progressively increasing to the enlarged thickness. A self sealing puncture (74) is provided at the center of the diaphragm (44) to relieve excess pressure differentials in the lubrication system internally of the drill bit and excess pressure differentials in the drilling fluid externally of the drill bit. The diaphragm (44) has an enlarged protuberance (64) about its outer periphery which is secured in sealing relation within a groove formed by sealing surfaces (66, 68, 70) on a leg (10) of the rotary bit and associated securing cap (46). A protective cup (42) supports the diaphragm (44) in an extended position and has dimples (58) for supporting the diaphragm (46) on the bottom (40) of the lubricant reservoir (49).