A system includes a shaft body defining a longitudinal axis. A first internal fluid channel extends axially within the shaft body and includes an inlet opening through the shaft body for fluid communication of external fluid into the first internal fluid channel and an outlet opening through the shaft body for fluid communication of fluid from the first internal fluid channel to an area external of the shaft body. A second internal fluid channel extends axially within the shaft body and includes an inlet opening through the shaft body for fluid communication of external fluid into the second internal fluid channel and an outlet opening through the shaft body for fluid communication of fluid from the second internal fluid channel to an area external of the shaft body. The first and second internal fluid channels are in fluid isolation from one another within the shaft body.

A combined electrical insulator and conductor assembly for a bearing disposable between a shaft and a housing includes an annular insulator disposable about the bearing outer ring and configured to prevent electric current flow between the outer ring and the housing and including projections extending axially along and spaced circumferentially about a centerline. A conductor preferably includes a conductive disk with an outer radial end engageable with the housing inner surface, an inner radial end defining a central opening for receiving the shaft and openings each receiving a separate one of the plurality of projections of the insulator such that the disk is axially fixed relative to the insulator. An annular conductive brush subassembly is coupled with the conductive disk and includes a plurality of electrically conductive fibers contactable with the shaft outer surface so as to provide a conductive path between the shaft and the disk.

A motor assembly has an enhanced retention system for minimizing axial and radial movement of the bearings and output shaft. A front endbell assembly is fixed to a front end of the motor, the front endbell assembly including a plastic front endbell and a front bearing assembly through which a driving end of the output shaft extends. The plastic front endbell is over-molded about the front bearing assembly and elasticity of the plastic front endbell operates to preload the front bearing assembly to restrict axial movement of the front bearing assembly. Similarly, a rear endbell assembly is fixed to a rear end of the motor opposite from the front end, the rear endbell assembly including a plastic rear endbell and a rear bearing assembly into which a rear end of the output shaft extends. The plastic rear endbell is over-molded about the rear bearing assembly and elasticity of the plastic rear endbell operates to preload the rear bearing assembly to restrict axial movement of the rear bearing assembly. A spring or an appropriately sized output shaft may be used to preload the bearing assemblies oppositely from the over-molded plastic endbells.

To provide a grease composition that is capable of effectively preventing an early-flaking caused by hydrogen embrittlement, and a grease-sealed bearing in which the grease composition is sealed. A grease composition 7 contains a base oil, a thickener, and an additive. The additive contains sodium molybdate, and zinc alkyldithiophosphate having a 1-30 C primary alkyl group. The grease composition contains 0.1-5 mass % of the sodium molybdate relative to the whole of the grease composition. The grease composition contains 0.1-5 mass % of the zinc alkyldithiophosphate relative to the whole of the grease composition.

An instrumented bearing comprising a stationary outer ring and a rotating inner ring is provided with an encoder, a sensor assembly comprising a read head positioned opposite and at a reading distance from the encoder, and a leakage current collector capable of coming into sliding contact with an annular contact which can be rigidly connected, directly or indirectly, to the inner ring. The encoder and the read head are positioned axially between the outer ring and the leakage current collector. A conductive electrical connection between the leakage current collector and the stationary outer ring also forms a magnetic shield of ferromagnetic material, extending from the outer ring to the leakage current collector by surrounding the encoder and the read head.

Disclosed is an electronic motor with two bearings. The motor is structured so that, when loaded, the majority of the load (e.g., a radial load) is borne by one of the bearings. The bearing that bears a greater load may be larger and, thus, better suited for a heavy load. In some embodiments, the larger bearing may include rolling elements that have respective radii larger than respective radii of rolling elements of the other bearing by a ratio of at least 1.5 (150%). In some embodiments, the larger bearing may have an outer race with a radius that is greater than a radius of the outer race of the smaller bearing by a ratio of at least 1.5. In some embodiments, the motors may include a third bearing between the two bearings. The third bearing may reduce vibration in the motor.

A magnetic actuator for a magnetic suspension system includes a core section having an annular yoke and radially directed teeth joining the yoke. The magnetic actuator includes coils surrounding the teeth and a mechanical structure having a first section and a second section. The first section is attached to the yoke and conducts magnetic flux axially. The second section joins the first section and conducts the magnetic flux radially in a direction opposite to a direction of the magnetic flux in the teeth. The magnetic actuator includes a mechanical safety bearing that is between the second section and the teeth. Thus, the safety bearing is in a room surrounded by a magnetic flux circulation path. Therefore, the safety bearing does not increase an axial length of the magnetic suspension system.

To provide a fluid dynamic bearing lubricating oil base oil which is within a suitable 40° C. and 100° C. kinematic viscosity range capable of achieving both energy saving and high bearing rigidity, and is excellent in viscosity index, heat resistance (evaporation resistance), and low temperature fluidity. Provided is a fluid dynamic bearing lubricating oil base oil containing a trimellitic acid triester compound represented by the following general formula (1)

##STR00001##

wherein R1 to R3 are the same or different and each represent a linear alkyl group having 6 to 10 carbon atoms.

To provide a fluid dynamic bearing lubricating oil base oil which is within a suitable 40° C. and 100° C. kinematic viscosity range capable of achieving both energy saving and high bearing rigidity, and is excellent in viscosity index, heat resistance (evaporation resistance), and low temperature fluidity. Provided is a fluid dynamic bearing lubricating oil base oil containing an isophthalic acid diester compound represented by the following general formula (1)

##STR00001## wherein R1 and R2 are the same or different and each represent a linear alkyl group having 6 to 10 carbon atoms.

The motor includes a shaft, a cartridge including a plurality of bearings that support the shaft, and a sleeve that surrounds the bearings, and a housing including a bottom portion for receiving an impact from outside and an attaching portion provided in the bottom portion. The bottom portion of the housing extends in a direction intersecting with respect to a longitudinal direction of the shaft, and the cartridge is removably attached to the attaching portion.