At least one labyrinth seal assembly is disposed within a roller cutter of a roller reamer. A first labyrinth seal assembly of a roller cutter is positioned toward a first pillow block of a cutter cartridge that includes the roller cutter. An optional second labyrinth seal assembly is disposed within the roller cutter and toward second pillow block of the cutter cartridge A bearing shaft of the cutter cartridge extends through an inner channel of the roller cutter. The cutter cartridge is retained in an axial recess of a tool body of the roller reamer via a compound and separate wedging of each of the two pillow blocks into a same axial recess. Each pillow block is rotatably coupled to the bearing shaft at an opposing end of the roller cutter.

At least one labyrinth seal assembly is disposed within a roller cutter of a roller reamer. A first labyrinth seal assembly of a roller cutter is positioned toward a first pillow block of a cutter cartridge that includes the roller cutter. An optional second labyrinth seal assembly is disposed within the roller cutter and toward second pillow block of the cutter cartridge A bearing shaft of the cutter cartridge extends through an inner channel of the roller cutter. The cutter cartridge is retained in an axial recess of a tool body of the roller reamer via a compound and separate wedging of each of the two pillow blocks into a same axial recess. Each pillow block is rotatably coupled to the bearing shaft at an opposing end of the roller cutter.

A cutting roller has an axle (2), on which a cutting ring (4) is rotatably guided by a bearing device (10, 12). The bearing device is sealed against the environment by a sealing device (28, 30). By a compensating device (40), any differential pressure between the bearing device (10, 12) and the environment is compensable.

A cutting roller has an axle (2), on which a cutting ring (4) is rotatably guided by a bearing device (10, 12). The bearing device is sealed against the environment by a sealing device (28, 30). By a compensating device (40), any differential pressure between the bearing device (10, 12) and the environment is compensable.

An earth-boring tool for removing subterranean formation material in a borehole comprises a tool body having a central axis defining an axial center thereof and a leg extending in an axial direction from the tool body. A bearing assembly is removably coupled to the leg and includes a bearing shaft and a base member. The base member encircles a portion of the bearing shaft and abuts against a surface of the leg. A roller cone is rotatably coupled to the bearing assembly and has a rotational axis about which the roller cone rotates on the bearing assembly when the roller cone removes subterranean formation material in the borehole. A method of assembling a rotatable cutting structure assembly including the bearing assembly includes coupling the bearing shaft to the leg by disposing a mechanical fastener through an aperture formed through the leg and into a cavity of the bearing shaft.

Hardfacing materials include a polymer matrix material and particles of hard material embedded within and dispersed throughout the polymer matrix material. Earth-boring tools include a tool body and a hardfacing material on at least a portion of a surface of the body, wherein the hardfacing material includes a polymer matrix material and particles of hard material embedded within and dispersed throughout the polymer matrix material. Methods of applying hardfacing material to an earth-boring tool comprise mixing hard particles with a polymer precursor material to form a paste, applying the paste to a surface of an earth-boring tool, and curing the polymer precursor material to form a hardfacing material on the surface of the earth-boring tool.

A roller cone drill bit includes a pressure equalization bore defined within the roller cone drill bit that includes a lubricant chamber portion and an open portion. The drill bit also includes a lubricant passage defined within the drill bit and fluidically coupled to a first end of the lubricant chamber portion. Additionally, the roller cone drill bit includes a floating plug positioned within the pressure equalization bore between the lubricant chamber portion and the open portion. The floating plug is slidable along the pressure equalization bore and configured to seal the lubricant chamber portion from the open portion. Moreover, the roller cone drill bit includes a stop positioned at least partially within the pressure equalization bore or the lubricant passage to restrain the floating plug from sliding into the lubricant passage through the first end of the lubricant chamber portion.

A seal assembly includes a seal groove defined at least partially between a first member and a second member rotatable relative to the first member, an annular sealing element positioned in the seal groove and providing a mud surface, a lubricant surface axially opposite the mud surface, an inner radial surface, and an outer radial surface radially opposite the inner radial surface. One of the inner and outer radial surfaces is a dynamic surface that seals against the first member when the sealing element rotates with the second member, or seals against the second member when the second member rotates relative to the sealing element. A lubricant channel is defined through the sealing element and extending between the lubricant surface and the dynamic surface to provide a lubricant to the dynamic surface.

A seal assembly includes a seal groove defined at least partially between a first member and a second member rotatable relative to the first member, an annular sealing element positioned in the seal groove and providing a mud surface, a lubricant surface axially opposite the mud surface, an inner radial surface, and an outer radial surface radially opposite the inner radial surface. One of the inner and outer radial surfaces is a dynamic surface that seals against the first member when the sealing element rotates with the second member, or seals against the second member when the second member rotates relative to the sealing element. A lubricant channel is defined through the sealing element and extending between the lubricant surface and the dynamic surface to provide a lubricant to the dynamic surface.

An integral pressure relief assembly is comprised within a roller assembly of a roller reamer. The integral pressure relief assembly extends through a pair of pillow blocks and a bearing shaft of a retention assembly of the roller assembly. A volume of lubricant is inserted under pressure through a relief valve into an interior channel of the bearing shaft. A spring element in combination with an elastomeric piston provides additional pressure to the pressurized volume of lubricant contained within the integral pressure relief assembly. The lubricant absorbs heat from motion of the bearing shaft and a cutter assembly. As the lubricant increases in pressure, the relief valve releases lubricant from the bearing shaft when a sufficient differential pressure between the contained lubricant and the outside environment is achieved.