An electric submersible pump assembly with integral heat exchanger, high-speed self-aligning bearings, and dual bearing thrust chamber is described. The described pump assembly, modules, and components may be used for operating an electric submersible pump at high speeds as well as over a wide range of speeds and flowrates without replacing downhole equipment. The described pump assembly may be shorter than comparable pump assemblies and may be assembled offsite, thereby leading to faster and easier installation with less down time. By operating over a wide range of speeds, the disclosed pump assembly allows the operator to reduce overall inventory, reduce down time for the well, and avoid other complications associated with replacing a pump assembly or other downhole components.

An electric submersible pump assembly with integral heat exchanger, high-speed self-aligning bearings, and dual bearing thrust chamber is described. The described pump assembly, modules, and components may be used for operating an electric submersible pump at high speeds as well as over a wide range of speeds and flowrates without replacing downhole equipment. The described pump assembly may be shorter than comparable pump assemblies and may be assembled offsite, thereby leading to faster and easier installation with less down time. By operating over a wide range of speeds, the disclosed pump assembly allows the operator to reduce overall inventory, reduce down time for the well, and avoid other complications associated with replacing a pump assembly or other downhole components.

A vibration generation device includes a rotor rotatable about a rotation axis, the rotor including a weight having a center of gravity that is eccentric with respect to the rotation axis. A shaft is inserted into the rotor and rotatably supports the rotor. A restriction part is disposed further inward than the weight in a radial direction, the restriction part being attached to one end of the shaft for restricting movement of the rotor in an axial direction.

A hollow shaft includes a hollow portion extending in an axial direction from an opening that is open at one end of the hollow shaft in the axial direction. The hollow shaft further includes a first communicating hole establishing radial communication between the hollow portion and an axial space between an upper lubricating oil and a lower lubricating oil. The hollow shaft further includes a second communicating hole establishing radial communication between the hollow portion and an unsealed space inside the motor. The unsealed space is connected to an external space outside the motor. The hollow shaft further includes a sealing member closing the opening. The hollow shaft has, in an inner peripheral surface facing the hollow portion, a recess recessed radially outward. A part of the sealing member is fitted into the recess.

A gear device includes a housing, a cover, and a gear. The cover covers an opening of the housing. The gear is accommodated in the housing. One of the housing and the cover includes a projection projected toward the gear and having a center axis that extends along a rotation axis of the gear. The gear includes a recess that receives the projection.

A stator includes: a stator core in which a coil strand is wound around each of a plurality of teeth portions formed in an annular yoke portion; an annular plate that is disposed at a position overlapping an annular portion of the stator core in a direction along an axial center of the stator core; a plurality of terminals which are supported by the plate and to which end portions of a plurality of the coil strands drawn out from the stator core are respectively connected; and a resin that encloses the stator core and the plate in a state where a part of the plurality of terminals is exposed.

A fluid dynamic bearing device includes a shaft disposed along a center axis, a sleeve cylindrically extending around the shaft, a thruster that closes a lower end of the sleeve, dynamic pressure grooves in the shaft or the sleeve, and a lubricating oil present therebetween. The shaft includes a shaft main body and a shaft flange extending radially outward from a lower end of the shaft main body. An inner peripheral surface of the sleeve includes a first inner peripheral surface that faces an outer peripheral surface of the shaft main body in the radial direction and a second inner peripheral surface that faces an outer peripheral surface of the shaft flange in the radial direction. The sleeve includes a sleeve inner lower surface and a circulation hole.

A motor for a disk drive includes a stationary unit, a bearing mechanism attached to the stationary unit, and a rotation unit supported on the stationary unit rotatably around a central axis via the bearing mechanism. The stationary unit includes a base portion that is a part of a housing defining an internal space sealed in the disk drive and includes a recess portion recessed from a side of the internal space toward an outside of the housing and not penetrated. The bearing mechanism includes a shaft extending in a direction of the central axis and a sleeve surrounding at least a portion of an outer circumferential surface of the shaft. A lower end portion of the shaft is press-fit and glued into the recess portion, and a lower surface of the base portion including a base step portion extending toward an axially upper side.

An electrically driven pump is provided, which includes a rotor assembly. The rotor assembly includes an impeller, a rotor and a shaft sleeve assembly. The impeller is arranged on one end of a shaft sleeve, and the rotor is arranged on another end of the shaft sleeve away from the end on which the impeller is mounted. The rotor includes a rotor core, a permanent magnet and a shield. The permanent magnet is arranged around an outer peripheral surface of the rotor core and fits the outer peripheral surface of the rotor core. The shield is fixed to the shaft sleeve, and an accommodating portion configured to accommodate the rotor core and the permanent magnet is formed between the shield and the shaft sleeve. The electrically driven pump has a simple structure and is easy to manufacture.

An electric submersible pump assembly with integral heat exchanger, high-speed self-aligning bearings, and dual bearing thrust chamber is described. The described pump assembly, modules, and components may be used for operating an electric submersible pump at high speeds as well as over a wide range of speeds and flowrates without replacing downhole equipment. The described pump assembly may be shorter than comparable pump assemblies and may be assembled offsite, thereby leading to faster and easier installation with less down time. By operating over a wide range of speeds, the disclosed pump assembly allows the operator to reduce overall inventory, reduce down time for the well, and avoid other complications associated with replacing a pump assembly or other downhole components.