A tool includes a device including a housing and a rotor, the rotor to rotate about a longitudinal axis, and an axial gap generator including a stator assembly positioned adjacent to the rotor. The axial gap generator generates a voltage signal as a function of a gap spacing between the stator assembly and the rotor, the gap spacing being parallel to the longitudinal axis.

A piston actuated drilling tool includes a casing and a guide sleeve disposed within the casing in proximity to the top end of the casing. A piston is slidably disposed within the casing for reciprocating movement therein. The piston has a nose end arranged to reciprocate within the guide sleeve, wherein a first wear area of the tool occurs between the piston nose end and the guide sleeve. A replaceable wear bushing assembly is located within the guide sleeve at the first wear area. The replaceable wear bushing assembly can include either a static wear bushing or a sliding wear bushing.

Systems and methods for cold-spraying coatings on rotors in motor assemblies for improving reliability of motor assembly use downhole in wellbores is provided. For example, a motor assembly can include a stator positioned downhole in a wellbore and rotor coupled to the wellbore. The rotor can include a base material and a first coating deposited onto the base material via cold spraying for reducing damage to the rotor. The first coating may include sprayed particles that have a melting point temperature that is higher than a temperature of a gas used in the cold spraying. In some examples, the rotor may include a second coating deposited onto the first coating via cold spraying, high velocity oxygen fuel coating, or high velocity air fuel. The first coating may have a first hardness that is less than a second hardness of the second coating.

An improved sealed bearing pack for a downhole mud motor is disclosed. More specifically, embodiments of the present invention relate to a mud motor for straight and directional drilling with a sealed bearing pack designed to withstand higher torques, loads, and pressure operations and with a reduced failure rate. In some embodiments, the sealed bearing pack has more lateral support for improved horizontal drilling and extended operational life. Thus, one embodiment includes an adapter housing extending the length of the outer housing and a bearing within the adapter housing for increased support. Additionally, some embodiments include two thrust bearing assemblies for improved operations and reduced failures. Various embodiments include a longer flow sleeve than prior art sealed bearing packs.

Embodiments disclosed herein relate to bearing assemblies and methods of manufacturing. In an embodiment, a bearing assembly includes a support ring and bearing elements. The bearing elements are mounted to and distributed circumferentially about an axis of the support ring. At least one of the bearing elements includes a polycrystalline diamond table, a substrate bonded to the polycrystalline diamond table, bonding region defined by the substrate and the polycrystalline diamond table, and a corrosion resistant region. The corrosion resistant region includes a corrosion resistant material that covers at least a portion of at least one lateral surface of the bonding region. The corrosion resistant region prevents corrosion of at least some material in the bonding region covered by the corrosion resistant region (e.g., during use). Other embodiments employ one or more sacrificial anodes as an alternative to or in combination with the corrosion resistant region.

The present invention relates to a downhole operational tool for moving a tool part between a retracted position and a projected position in a well. The downhole operational tool comprises a tool body having an axial extension; the tool part being movable perpendicularly to the axial extension between the retracted position and the projected position; a projection actuator configured to project the tool part from the tool body by means of hydraulics, the projection actuator comprising an actuator housing and a projection piston configured to slide inside the actuator housing, the tool part being connected with the projection piston; and a retraction actuator comprising a spring element configured to retract the tool part into the tool body, the retraction actuator being connected with the projection piston so that when the projection actuator projects the tool part, the spring element is compressed. The spring element is arranged outside the actuator housing.

A downhole-type device includes an electric machine. The electric machine includes an electrical rotor configured to couple with a device to drive or be driven by the electric machine. An electrical stator surrounds the electric rotor. The electric stator includes a seal configured to isolate stator windings from an outside, downhole environment. An inner surface of the seal and an outer surface of the electric rotor define an annulus exposed to the outside environment. A bearing couples the electric rotor to the electric stator. A lubrication system is fluidically coupled to the downhole-type device. The lubrication system includes a topside pressure pump and a downhole-type distribution manifold configured to be used within a wellbore. The distribution manifold is fluidically connected to the topside pressure pump and the bearing to receive a flow of lubricant from the topside pressure pump.

A sealing unit (115) for sealing an annular gap (109) formed between a seal wear ring (106) and a seal carrier (112) has a sealing ring holder (118) which is U-shaped in a receptacle region and which, together with the receptacle region, encloses a fixing region (209) of the sealing ring (121).

A downhole drilling motor, system, and method for using same are disclosed. A downhole drilling motor can include a power section stator having a first end, a second end, an internal cavity passing therethrough. The downhole drilling motor can further include a rotor assembly positioned and fully encased in the internal cavity. The rotor assembly includes a power section rotor, a drivetrain operably coupled to the power section rotor and a bearing set. The power section rotor is positioned at the first end within the internal cavity of the power section stator. The power section rotor, the drivetrain, and the bearing set are fully encased in the internal cavity of the power section stator. Additional apparatuses, systems, and methods are disclosed.

A drive shaft assembly includes a drive shaft that includes a first cylindrical end having a first diameter, a cylindrical portion having a second diameter, and a second cylindrical end having the first diameter. A first distal end of the drive shaft includes a first distal spherical indentation. A first adapter cap includes a first tapered inner aperture and a first seal disposed within a first groove formed in a circumference of the first tapered inner aperture. The first tapered inner aperture is configured to receive the first cylindrical end of the drive shaft and the first seal forms a seal with the cylindrical portion of the drive shaft having the second diameter. A first adapter includes a first distal spherical indentation. A first distal spherical ball is removably attached to the first distal spherical indentation.