Abstract: A valve includes a valve body including a main passage defining a first volume and a second volume. The valve also includes a valve spool moveable relative to the valve body. The valve spool includes a central vent passage capable of fluid communication with each of the first volume and the second volume. Air flows between the first volume and the second volume through the central vent passage as the valve spool moves relative to the valve body and as the valve changes between an actuated position and a non-actuated position.

Abstract: A housing, mandrel and bearing assembly positionable in a wellbore includes a torque transmission member adapted to connect to a source of rotational torque (e.g. a downhole motor power output) and a tubular mandrel adapted to connect to a drill bit. A lower tubular housing is adapted to contain a lower bearing and catch sleeve assembly. The catch assembly is adapted to retain the mandrel in the lower housing if the mandrel breaks. An upper tubular housing contains an upper bearing and is adapted to connect to a housing of the downhole motor. A method of assembling the downhole housing, mandrel and bearing assembly is disclosed.

Abstract: A downhole housing, mandrel and bearing assembly 100 includes a flex shaft 20 adapted to connect to a downhole motor power output 309 and a tubular mandrel 30 adapted to connect to a drill bit 370. A lower tubular housing 60 is adapted to contain a lower bearing assembly 90 and catch sleeve assembly 110. The catch assembly 110 is adapted to retain the mandrel 30 in the lower housing if the mandrel breaks. An upper tubular housing 70 contains an upper bearing assembly 80 and is adapted to connect to a housing 302 of the downhole motor 301. A method of assembling the downhole housing, mandrel and bearing assembly 100 is disclosed.

Abstract: A seal alignment system includes an engine block, a cover component spaced apart from the engine block and defining a first bore therethrough, and a crankshaft protruding from the engine block and extending through the first bore, wherein the crankshaft is rotatable about a central longitudinal axis and has an outer surface. The seal alignment system also includes an annular seal spaced apart from the engine block and defining a second bore therethrough, and an alignment device configured for coaxially aligning the annular seal with the central longitudinal axis so that the crankshaft extends through the second bore and the annular seal abuts the outer surface.

Abstract: It is an object of the present invention to provide a resin composition whose flowability is secured when the resin composition is injection-molded into injection-molded articles such as a resin-made crown-shaped cage and a resin-made seal both for a rolling bearing and a resin-made sliding bearing and which is capable of enhancing the mechanical strengths and toughnesses of these injection-molded articles to such an extent that these injection-molded articles can be used as bearing members. The resin composition is formed into a molded article and used as a bearing member. The resin composition is composed of polyamide resin or polyester resin to which polycarbodiimide is added. The polyamide resin is at least one resin selected from among polyamide 66 resin and polyamide 11 resin. The polyester resin is polytrimethylene terephthalate resin. 0.5 to 6 wt % of the polycarbodiimide is contained in an entirety of the resin composition.

Abstract: A drill tool includes a cone mounted for rotation on a bearing shaft that extends from a bit head. The cone has a first planar base surface opposed to a second planar base surface of the bit head. A first annular groove is formed in the first planar base surface, and a second annular groove is formed in the second planar base surface. The first and second annular grooves are at least partially aligned with each other. The combination of the first and second annular grooves form a first annular gland. A protector ring is inserted into the first annular gland, and functions to divide a fluid path between the bearing shaft of the drill tool and an external environment into a plurality of parallel fluid paths that pass around the protector ring. Each parallel fluid path includes a convolution defined by a plurality of fluid direction changing corners.

Abstract: Surface texturing is employed to modify the topography of one or more surfaces (radial or cylindrical) of the sealing system for a roller cone rock bit. The surface texturing produces a regular or repeated patterned dimpled surface which retains additional lubricant helpful in reducing friction in the boundary and mixed lubrication regimes.

Abstract: The electronic device mounting apparatus 1 comprises: a first camera 123 for imaging a flexible board 74 of a base member 70 of a test carrier 60 to generate a first image information; an image processing apparatus 40 for detecting a position of an alignment mark 79 of the flexible board 74 from the first image information and calculating a print start position 782 of the first interconnect patterns 78 on the flexible board 74 on the basis of the position of the alignment mark 79; a printing head 122 for forming a first interconnect pattern 78 on the flexible board 74 from the print start position 782; and a second conveyor arm 21 for mounting a die 90 on the flexible board 74 on which the first interconnect pattern 78 is formed.

Abstract: A bore hole rotary reamer includes a body having cutters rotatably mounted by one or more respective spindles. A bearing region is formed on the spindle. At least one annular seal prevents ingress of contaminant to the bearing region. A circumferential void is formed adjacent the seal. At least one passageway extends in an axial direction of the spindle to the circumferential void and a piston movable in the passageway in response to supply of pressure to an outer side of the piston from the environment which surrounds the reamer. The piston transfers pressure to fluid in the cylindrical passage on an inner side of the piston to supply pressure to the circumferential void and thereby to the seal. The pressure is substantially determined by the pressure of the environment surrounding the reamer.

Abstract: A bearing damper includes: (a) an annular sleeve having spaced-apart grooves formed in a radially-facing surface therein; (b) an annular bearing race received in the sleeve; and (c) a resilient seal ring disposed in each of the grooves, wherein the seal rings cooperate with the sleeve and a radially-facing surface of the bearing race to define a closed annular gap, and further wherein the seal rings are sized so as to urge the bearing race towards a coaxial position relative to the sleeve.

Abstract: A method for monitoring a bearing is disclosed. The method involves positioning a non-contacting bearing isolator adjacent a bearing on a piece of rotating equipment so that at least one operating parameter of said bearing is communicated to said bearing isolator; and, positioning an energy detector within range of said bearing isolator so that said energy detector is able to monitor said at least one operating parameter of said bearing by detecting at least one operating parameter of said bearing isolator.

Abstract: Surface texturing is employed to modify the topography of one or more surfaces (radial or cylindrical) of the sealing system for a roller cone rock bit. The surface texturing produces a regular or repeated patterned dimpled surface which retains additional lubricant helpful in reducing friction in the boundary and mixed lubrication regimes.

Abstract: An earth bit includes a cutting cone rotatably mounted to a lug with a journal. A sealing member is sealingly engaged with the cutting cone and a wear ring carried by the lug. The wear ring is dynamically engaged with the first sealing member and statically engaged with the lug.

Abstract: A roller cone bit having an elastomeric seal with a self break-in property is disclosed. The elastomeric seal includes abrasive material on a sliding surface for facilitating break-in. Examples of abrasive materials include ground rock, hard metals, tungsten, tungsten carbide, tantalum, tantalum carbide, titanium carbide, titanium nitride, and minerals, diamonds and nanomaterial enhanced diamond.

Abstract: A roller cone drill bit having a bit body with at least one support arm extending from the bit body. Each support arm may have an associated spindle extending inwardly. A respective cone assembly may be rotatably disposed on each spindle. At least one diverter plug may be disposed in a hole formed in each support arm. A void space may be formed between one end of each diverter plug and the bottom of the associated hole. At least one fluid flow passageway may extend from the surface of the associated support arm to the void space to allow communication of fluid containing debris with the void space. Rotating action of the roller cone drill bit and associated cone assemblies may force packing of debris into the void space which results in biasing the diverter plug outwardly from the associated hole to contact adjacent portions of the associated cone assembly.

Abstract: An apparatus for processing materials provides a material processing chamber, formed from an enclosure having a top and a bottom. The bottom has an opening therein, and a shaft extends through the opening and into the chamber. A bearing assembly may be arranged about a lower portion of the shaft, the bearing assembly including a bearing extension arranged about a portion of the shaft. The bearing extension has a portion thereof extending through the opening of the bottom of the chamber. A first seal assembly forms a first seal between the bearing extension and the bottom of the chamber, and a second seal assembly forms a second seal between the bearing assembly and the shaft.

Abstract: A dust proof assembly of a five communicated tube comprises a bearing; an inner edge of the bearing having an annular recess; a cover being a hollow annular ring; the cover having a buckle corresponding to the annular recess. By above mentioned components, the cover is buckled to the bearing; the buckle of the cover is buckled to the annular recess of the bearing. A seat has a receiving portion; a lower end of the seat being formed with a threaded portion. The bearing and cover is received in the receiving portion of the seat. The cover is a hollow annular ring. The receiving portion has a stepped structure.

Abstract: An energizer for a mechanical seal assembly for use in a drill bit is disclosed. The energizer is a composite of at least two resilient materials, one having a durometer hardness that is greater than the other. The material contacting a journal provides relatively high frictional forces so as to prevent the energizer from rotating in relation to adjacent components. The relatively softer resilient material provides the energizing force necessary to maintain a good dynamic seal between the metal seal rings. The energizer components may be separate components that engage one another upon assembly, or may be bonded together to form a ring prior to assembly into the drill bit.

Abstract: In a motor arranged to rotate a color wheel of a projector unit, a rotor yoke is fixed to a rotor hub by crimping the entire circumference thereof in order to prevent lubricating oil from leaking to the outside of the motor. A joint portion between the rotor yoke and the rotor hub is sealed with a sealant, such as an adhesive, to securely seal the joint portion.

Abstract: Methods and apparatus for maintaining lubrication of rolling cone cutters mounted on journal pins. Embodiments comprise a rotating cone disposed on a journal pin and forming a journal gap there between. A cylindrical journal sleeve is disposed in the journal gap. The journal sleeve has a longitudinal gap forming opposing end portions, which are continuously contoured. A lubrication port is disposed in the journal pin and in fluid communication with a lubrication supply. The lubrication port has an outlet located in a recess in the journal gap. Each end of the recess comprises a transitioning surface extending between the bottom of the recess and the outer surface of the journal pin to prevent sharp transitions. In certain embodiments, the journal pin may comprise two or more lubrication ports, each located in a recess with transitioning surfaces.

Abstract: Disclosed is a seal assembly for dynamically sealing between rotatable members, such as employed to seal the rolling cone of a rock bit. One preferred assembly includes an energizer, first and second seal rings, and a cushioning ring having an L-shaped cross-section disposed about portions of one of the seal rings to seal and absorb impact loads and thereby protect the more-rigid seal rings.

Abstract: A self-aligning apparatus comprising a ball bearing assembly mounted on a base plate and supporting an axle on which is mounted a video camera. In response to the force of gravity, the axle rotates such that the camera maintains a line-of-sight parallel to the cable of a crane or similar heavy equipment such that the video camera constantly views the work site of the hook element of the equipment. The equipment operator can view in real time images transmitted by the camera there reducing dependency on ground observers and improving safety.

Abstract: A seal assembly for a shaft supporting a rotary element comprises a sealing ring having an inner radial surface in contact with a seal surface of the shaft. The sealing ring comprising a disc shaped integral radial lip normal to the inner radial surface. A disc shaped seal shield is assembled in sealing contact with a first surface of the integral disc shaped radial lip and also in sealing contact with a first radial surface of an annular seal groove. An energizer positioned in the annular seal groove is in contact with the bottom surface of the groove and a second radial surface of the groove. The energizer exerts a radial force on the outer radial surface of the sealing ring and a lateral force on the integral radial lip of the sealing ring.

Abstract: A seal assembly for a shaft supporting a rotary element comprises a sealing ring having an inner radial surface in contact with a seal surface of the shaft. The sealing ring comprising a disc shaped integral radial lip normal to the inner radial surface. A disc shaped seal shield is assembled in sealing contact with a first surface of the integral disc shaped radial lip and also in sealing contact with a first radial surface of an annular seal groove. An energizer positioned in the annular seal groove is in contact with the bottom surface of the groove and a second radial surface of the groove. The energizer exerts a radial force on the outer radial surface of the sealing ring and a lateral force on the integral radial lip of the sealing ring.

Abstract: A downhole mud motor (100) is disclosed which has an improved bearing mandrel (107) and a bearing stop (105) to transfer a larger percentage of the weight of a drill string to the bit. Also improved sealing systems (113) (114) (220) (515(706) for the transmission section and bearing section (116) (310) (117) (118) (119) prevent drilling mud from entering critical components. A piston stop is provided to prevent the piston from damaging other parts as the piston moves under pressure. Compensating pressure assembly (204) preferably including a disk (1408) is placed in the lower housing (108) to prevent pressure from building up in the bearing section (308). A combination of grooved ball seats (130) and circumferentially spaced balls (127) are provided in the transmission section (200) (207) to allow for greater flow of lubricant around the ball bearings.

Abstract: The present invention relates to a spindle motor with a magnetic seal. A method and an apparatus are described for sealing spindle motors, preferably those used for disk storage units.

Abstract: In the seal gland in a rotating cone drill bit, the O-ring is initially compressed between the journal and a central portion of the gland which has a cross-section parallel to the journal. These two concentric surfaces provide a minimum amount of contact pressure for a given amount of squeeze than other configurations. Chamfers connect the central portion to the sidewalls of the gland, so that after the seal has worn in use, it will ride up onto the chamfers, where additional squeeze to the seal. This allows the seal to operate in a standard regime during the first part of its lifetime and to automatically shift to a more compressed mode as the seal wears.

Abstract: A drill bit for use in a borehole at least partially containing drilling fluid includes a bit body having at least two bit components, including at least one leg, the leg having a journal segment, and a roller cone rotatably mounted upon the journal segment and forming at least one bearing cavity therebetween. Also included is an annular primary seal disposed between the leg and the roller cone, an annular secondary seal disposed between the leg and the roller cone and between the annular primary seal and the borehole and an annular space disposed between the annular primary seal and the annular secondary seal, the annular space at least partially containing fluid and being in substantially absolute fluid isolation from the bearing cavity and a conduit for permitting the flow of fluid from the annular space to the borehole. The annular secondary seal may be primarily elastomeric and the means for permitting the flow of fluid may further permit the flow of fluid from the borehole to the annular space.

Abstract: An earth-boring bit has a mechanical face seal assembly with PCD faces. The bit has a bearing shaft with a cone rotatably mounted on the bearing shaft. The seal locates between the bearing shaft and the cone for sealing lubricant therein. The seal includes at least one rigid seal ring having a carbide body and an annular PCD face located on it. The mating face may also be of a PCD material.

Abstract: A drill bit for use in a borehole at least partially containing drilling fluid includes a bit body having at least two bit components, including at least one leg, the leg having a journal segment, and a roller cone rotatably mounted upon the journal segment and forming at least one bearing cavity therebetween. Also included is an annular primary seal disposed between the leg and the roller cone, an annular secondary seal disposed between the leg and the roller cone and between the annular primary seal and the borehole and an annular space disposed between the annular primary seal and the annular secondary seal, the annular space at least partially containing fluid and being in substantially absolute fluid isolation from the bearing cavity and a conduit for permitting the flow of fluid from the annular space to the borehole. The annular secondary seal may be primarily elastomeric and a passage for permitting the flow of fluid may further permit the flow of fluid from the borehole to the annular space.

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 drill bit for use in a borehole at least partially containing drilling fluid includes a bit body having at least two bit components, including at least one leg, the leg having a journal segment, and a roller cone rotatably mounted upon the journal segment and forming at least one bearing cavity therebetween. Also included is an annular primary seal disposed between the leg and the roller cone, an annular secondary seal disposed between the leg and the roller cone and between the annular primary seal and the borehole and an annular space disposed between the annular primary seal and the annular secondary seal, the annular space at least partially containing fluid and being in substantially absolute fluid isolation from the bearing cavity and means for permitting the flow of fluid from the annular space to the borehole. The annular secondary seal may be primarily elastomeric and the means for permitting the flow of fluid may further permit the flow of fluid from the borehole to the annular space.

Abstract: An improved modular, radially-compliant, redundantly-sealing journal-type bearing assembly comprising two bearing elements retained in a housing and positively loaded in opposing directions by a compression spring disposed therebetween. A shaft to be supported and sealed against leakage by the bearing, such as a valve pintle shaft, is disposed in an axial bore in each of the bearing elements, which bores are fitted as closely to the diameter of the shaft as is possible without causing the shaft to bind in the bores. Each of the radial bearing faces opposite the spring forms a seal with a corresponding internal surface of the housing, defining thereby a redundant sealing system. The bearings are radially compliant within the housing by a predetermined small distance to allow the shaft to be operatively self-centered, such as by an attached valve head mating into a valve seat.

Abstract: A drill bit for use in a borehole at least partially containing drilling fluid includes a bit body having at least two bit components, including at least one leg, the leg having a journal segment, and a roller cone rotatably mounted upon the journal segment and forming at least one bearing cavity therebetween. Also included is an annular primary seal disposed between the leg and the roller cone and an annular secondary seal disposed between the leg and the roller cone and between the annular primary seal and the borehole. An annular space is defined between the annular primary seal and the annular secondary seal, the annular space at least partially containing fluid and being in substantially absolute fluid isolation from the bearing cavity. The seals are configured to allow the passage of a fluid from the annular space to the borehole. The annular secondary seal may be primarily elastomeric and a passage for fluid from the borehole to the annular space can be included.

Abstract: A drill bit having a canted or non-canted leg backface, a canted or non-canted seal in the interface between the cone backface and the shirttail, and a canted seal that can be semi-encapsulated so that there is no straight-line path across the seal.

Abstract: A sealed bearing for a drill bit including cutting cones and having metal sealing surfaces between the seal cup base and the rotating cone combined with a compressible neoprene or like material having an inner seal lip to seal in the prepacked bearing cavity and an outer seal lip nestled in a recess in the bearing skirt to protect it to keep out foreign matter.

Abstract: In the seal gland in a rotating cone drill bit, the O-ring is initially compressed between the journal and a central portion of the gland which has a cross-section parallel to the journal. These two concentric surfaces provide a minimum amount of contact pressure for a given amount of squeeze than other configurations. Chamfers connect the central portion to the sidewalls of the gland, so that after the seal has worn in use, it will ride up onto the chamfers, where additional squeeze to the seal. This allows the seal to operate in a standard regime during the first part of its lifetime and to automatically shift to a more compressed mode as the seal wears.

Abstract: A drill bit for use in an earthen annulus that contains loose particles is connected to a fluid supply source and includes a bit body having at least one journal segment and at least one fluid conduit in fluid communication with the fluid supply source. A roller cone is rotatably mounted upon the journal segment and forms at least one bearing cavity therebetween. Annular primary and secondary seals are disposed between the roller cone and the bit body and between the bearing cavity and the earthen annulus. An air groove is provided around at least a portion of the cone or leg between the primary seal and the earthen annulus. The groove circumscribes less than the entire circumference of the groove or leg, and in preferred embodiments includes an exit port and/or a diversion plug. Both the exit port and the diversion plug help prevent the groove from becoming plugged with debris.

Abstract: The present invention is a self adjusting, volume balanced, single energizer rigid face seal for rolling cutter drill bits with floating journal bearings. Volume balancing is accomplished by utilizing a floating static seal between the rigid face seal ring and the bearing shaft. This floating static seal ring is moved axially within a annular groove by the volume pulses caused by the axial play of the cutter when in operation. At one end of the annular groove the geometry of the rigid seal ring and bearing shaft are set such that the seal assembly achieves volume balance when the bearing is running on its OD. If the bearing is running on its OD, the floating static seal will move from where ever it is in the annular groove by the volume pulses until it reaches the balance volume position.

Abstract: A drill bit for use in a borehole at least partially containing drilling fluid includes a bit body having at least two bit components, including at least one leg, the leg having a journal segment, and a roller cone rotatably mounted upon the journal segment and forming at least one bearing cavity therebetween. Also included is an annular primary seal disposed between the leg and the roller cone and an annular secondary seal disposed between the leg and the roller cone and between the annular primary seal and the borehole. An annular space is defined between the annular primary seal and the annular secondary seal, the annular space at least partially containing fluid and being in substantially absolute fluid isolation from the bearing cavity. The seals are configured to allow the passage of a fluid from the annular space to the borehole. The annular secondary seal may be primarily elastomeric and a passage for fluid from the borehole to the annular space can be included.

Abstract: A bearing seal for earth boring bits is disclosed. A supporting ring is located in a groove formed in the earth boring bit. An annular cavity between the outer circumference of the supporting ring and the bottom of the groove is connected with the outside. An O-ring made of rubber is provided in an annular space defined by the sidewalls of the groove, the inner circumference of the supporting ring and the cylindrical surface of the bearing shaft of the head section to form a seal comprising a radial and axial seal. Compressive deformation of the O-ring does not depend on the eccentric rotation of the cone. Therefore, the working life of the seal is increased and the compressive deformation is decreased, thus facilitating use at high rotating speeds.

Abstract: The invention provides a mechanical face seal for rotary rock bits with a novel coil spring energization system that prevents yielding of the coil springs in extreme torque conditions. Within at least one of the coil springs is a cylindrical pin designed to co-act with the spring such that the combination becomes very stiff in the radial direction as the spring extends beyond a certain amount. This prevents the high torque from yielding the springs. When the spring returns to its normal extension, the pin does not interfere with the axial compression of the spring. This combination allows the coil spring energizers of a rotary rock bit mechanical face seal to survive the occasional extreme torque event.

Abstract: An earth-boring bit has a bit body and at least one bearing shaft depending inwardly and downwardly from the bit body. The bearing shaft has a base where it joins the bit body. At least one cutter is mounted for rotation on the bearing shaft and has radial and axial surfaces that cooperate with the base of the bearing shaft to define a bearing seal gland. A bearing is defined between the cutter and bearing shaft. A seal element is disposed in the seal gland. A secondary seal is disposed in the seal gland opposite the cutter axial surface and cooperates with the seal element to at least partially seal the gland against entry of debris from the exterior of the bit.

Abstract: A sealed-bearing drill bit for use in an earthen annulus is provided having a dual seal arrangement. The drill bit includes at least one leg having a journal segment, and a roller cone mounted upon the journal segment and forming at least one bearing cavity therebetween. An annular primary seal is disposed between the leg and roller cone and between the bearing cavity and the earthen annulus. An annular secondary seal is disposed between the annular primary seal and the earthen annulus and is capable of substantially preventing the ingress of debris from the earthen annulus to the annular primary seal.

Abstract: An earth-boring bit has a bit body and at least one bearing shaft depending inwardly and downwardly from the bit body. The bearing shaft has a base where it joins the bit body. At least one cutter is mounted for rotation on the bearing shaft and has radial and axial surfaces that cooperate with the base of the bearing shaft to define a bearing seal gland. A bearing is defined between the cutter and bearing shaft. A seal element is disposed in the seal gland. A secondary seal is disposed in the seal gland opposite the cutter axial surface and cooperates with the seal element to at least partially seal the gland against entry of debris from the exterior of the bit.

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: In a deflecting/scanning apparatus, a rotating polygon mirror is rotatably supported by an air bearing constituted by a stationary shaft and a rotating sleeve which are made of a ceramic material. An upper portion of an end face of the rotating sleeve is covered with a lid as a separate member. A vent hole formed in the lid is sealed with an adhesive to form an air damper chamber.

Abstract: A drill bit for use in an earthen annulus that contains loose particles is connected to a fluid supply source and includes a bit body having at least one journal segment and at least one fluid conduit in fluid communication with the fluid supply source. A roller cone is rotatably mounted upon the journal segment and forms at least one bearing cavity therebetween. An annular primary seal is disposed between the roller cone and the bit body and between the bearing cavity and the earthen annulus, and an annular gap is disposed between the annular primary seal and the earthen annulus. The annular gap is in fluid communication with the fluid conduit and the earthen annulus. An annular secondary seal is disposed between the annular primary seal and the earthen annulus and is capable of substantially preventing the ingress of debris from the earthen annulus to the annular primary seal.

Abstract: A rolling cutter drill bit has at least one roller cutter mounted on a cantilevered bearing shaft with a sealed bearing and lubrication system, lubricant pressure balancing means, lubricant pressure relief means, and a volume compensating rigid face seal assembly axially movable through an operating range. The face seal assembly comprises two cooperating face seal rings, one ring mounted on the bearing shaft and the other ring mounted in the cutter; a first energizer for the seal ring mounted on the bearing shaft, having a stiffness K1; and a second energizer for the seal ring mounted in the cutter, having a stiffness K2. In order to minimize the variation in the sealing face force as the assembly moves through its operating range, the stiffness K2 is less than half, and preferably less than 0.2, of the stiffness K1.

Abstract: An earth-boring bit has a bit body, at least one cantilevered bearing shaft, including a base and a cylindrical journal bearing surface extending inwardly and downwardly from the bit body, and at least one cutter mounted for rotation on the cylindrical journal bearing surface of the bearing shaft. A seal assembly is disposed between the cylindrical journal bearing surface and the cutter proximally to the base of the cantilevered bearing shaft. The seal assembly includes at least one resilient sealing ring which is formed of a carboxylated hydrogenated acrylonitrile butadiene rubber.