In a first aspect, a roller pitch bearing for a wind turbine is provided. The roller pitch bearing comprises a first bearing component and a second bearing component, the first bearing component being configured to rotate with respect to the second bearing component; wherein one of the first and the second bearing components is configured to be coupled to a wind turbine blade and the other one of the first and the second bearing components is configured to be coupled to a rotor hub of a wind turbine. The roller pitch bearing further a limiting structure attached to the first bearing component, the limiting structure radially extending from the first bearing component towards the second bearing component to limit a radial movement between the bearing components. In further aspect, a rotor for a wind turbine comprising a roller pitch bearing is provided.

A system for an unmanned aerial vehicle can include an altitude control system, which further includes a compressor assembly, a valve assembly, and an electronics assembly. The compressor assembly may include a driveshaft and a bearing assembly configured to rotate the driveshaft. The driveshaft may be formed from a first material and a compressor housing may be formed from a second material. The first and second materials may have different rates of thermal expansion. A dynamic preloading mechanism, such as a flexible plate, may be provided within the compressor assembly to exert a preloading force on the bearing assembly. Throughout the duration of the flight of the unmanned aerial vehicle, the preloading mechanism can continually compensate for differences in rates of thermal expansion between the first and second materials throughout.

A system for an unmanned aerial vehicle can include an altitude control system, which further includes a compressor assembly, a valve assembly, and an electronics assembly. The compressor assembly may include a driveshaft and a bearing assembly configured to rotate the driveshaft. The driveshaft may be formed from a first material and a compressor housing may be formed from a second material. The first and second materials may have different rates of thermal expansion. A dynamic preloading mechanism, such as a flexible plate, may be provided within the compressor assembly to exert a preloading force on the bearing assembly. Throughout the duration of the flight of the unmanned aerial vehicle, the preloading mechanism can continually compensate for differences in rates of thermal expansion between the first and second materials throughout.

A parallel bearing includes a rotary shaft bearing and a stator bearing, wherein the rotary shaft bearing is a contact bearing, and the rotary shaft bearing is sleeved on a rotary shaft; and the stator bearing is a non-contact bearing, the stator bearing is sleeved on the rotary shaft bearing, and a clearance is provided between the stator bearing and the rotary shaft bearing. The parallel bearing is cost-effective, reduces the relative rotational speed of each stage of bearing, breaks through the limitation of the theoretical DN factor and has the low dependency on the lubricating oil. In the rotor system having the parallel bearing, rotational speeds of multiple parallel bearings on the same rotary shaft can be adaptively adjusted to achieve the synchronous rotation, and thus the rotor system has the desired stability in high-speed operation.

A parallel bearing includes a rotary shaft bearing and a stator bearing, wherein the rotary shaft bearing is a contact bearing, and the rotary shaft bearing is sleeved on a rotary shaft; and the stator bearing is a non-contact bearing, the stator bearing is sleeved on the rotary shaft bearing, and a clearance is provided between the stator bearing and the rotary shaft bearing. The parallel bearing is cost-effective, reduces the relative rotational speed of each stage of bearing, breaks through the limitation of the theoretical DN factor and has the low dependency on the lubricating oil. In the rotor system having the parallel bearing, rotational speeds of multiple parallel bearings on the same rotary shaft can be adaptively adjusted to achieve the synchronous rotation, and thus the rotor system has the desired stability in high-speed operation.

A bearing unit having a stationary radially outer ring, a radially inner ring, rotatable with respect to a rotation axis (X) and steadily connected to a rotating shaft, a row of rolling bodies interposed between the radially outer ring and the radially inner ring, a casing, inside which the rings of the bearing unit are housed, a sealing device, and a protection disk. The protection disk may be mounted in an axially external position to the sealing device and fixed to the radially inner ring. Additionally, the protection disk may have a shaped metallic screen, and an elastomer coating over-molded on part of the screen. The protection disk may further be in contact with an axially external surface of the radially outer ring through the elastomer coating, which is provided with two lips, a first lip, non-contacting or contacting and radially external, and a second lip, contacting and radially internal.

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.

A rotating shaft assembly comprising a rotating shaft 1 mounted within a casing, and a primary bearing assembly in bearing engagement with the shaft and the casing and positioned between the shaft and the casing; the assembly further comprising a secondary bearing assembly comprising a secondary bearing normally radially spaced from the shaft and arranged to engage with or contact the shaft in the event of failure of the primary bearing normally in contact with the shaft, and means for insertion and/or removal of an inspection member to provide an indication of frictional engagement of the secondary bearing with the shaft.

A compressor includes a housing, a shaft that is rotated relative to the housing to compress a working fluid, and a foil bearing that supports the shaft. The foil bearing includes a top foil. The foil bearing is a foil gas bearing that is backed up by a ball bearing, or a mesh foil bearing with an actuator to compress a wire mesh dampener. A heat transfer circuit includes a compressor and a working fluid. The compressor includes a shaft that is rotated to compress the working fluid, and a foil bearing for supporting the shaft as it rotates.

A surface of a bearing member on a flow passage forming chamber-side is disposed to be exposed to the chamber. The bearing member includes a contact part, with which a side surface of a butterfly valve that is opposed to the bearing member is in contact, on at least a part of the surface of the bearing member on the chamber-side. The bearing member is a radial ball bearing and includes an outer bearing ring that is fitted to an inner periphery of a shaft hole, so that its axial displacement relative to a body is restricted, an inner bearing ring that is fitted on an outer periphery of a rotation shaft radially inward of the outer bearing ring, and a rolling element disposed between the outer bearing ring and the inner bearing ring. The contact part is provided on a surface of the inner bearing ring on the chamber-side.