Abstract:
Provided herein is an apparatus, including a stationary component and a rotatable component; a fluid between the stationary component and the rotatable component; a limiter shoulder of the stationary component; a flanged limiter bushing of the rotatable component; and a separating means for separating the limiter shoulder and the limiter bushing, wherein the separating means comprises the fluid.
Abstract:
Provided is a fluid dynamic bearing motor that can reduce vibration, oil deterioration, and power consumption by employing at least one pair of thrust bearings on upper and lower portions of a shaft. The fluid dynamic bearing motor includes: a housing to which a core with a coil wound around it, a sleeve having an axial hole at a central portion thereof, and a cover block supporting the sleeve are fixed; a shaft rotatably inserted into the axial hole to form an oil gap with the hole; a hub fixed to an upper end portion of the shaft and having a downwardly extending portion to an inner surface of which a magnet generating an electromagnetic force through an interaction with the core is attached; and circular thrust plates respectively fixed to upper and lower portions of the shaft, wherein receiving grooves are formed on an inner portion of the sleeve and accommodate the thrust plates to form fluid dynamic bearing surfaces. Since the fluid dynamic bearing motor employs the thrust fluid dynamic bearings on the upper and lower portions of the shaft, conical vibration of the shaft is prevented and heat generation and power consumption are reduced. Furthermore, since the fluid dynamic bearing motor employs the hydrodynamic pressure cover, oil leakage is prevented and an internal pressure of the fluid dynamic bearing is enhanced.
Abstract:
A fluid bearing design is provided which according to one aspect includes a shaft defining together with a surrounding sleeve an asymmetric journal bearing, and a thrust bearing at or near an end of the shaft towards which the asymmetric journal bearing is pumping, with that end of the shaft being closed off. The journal bearing asymmetry establishes a hydraulic pressure toward the closed end of the shaft. This pressure provides an axial thrust to set the bearing gap for the conical bearing. The conical bearing itself is a relatively balanced bearing, although it may have a bias pumping toward the shaft and the journal bearing. A pressure closed equalization path from the journal bearing through the conical bearing to the end of the shaft may be established to maintain a constant hydraulic force across the conical bearing, and which may also prevent any asymmetry in the conical bearing from affecting the net thrust force acting upon the end of the shaft where the conical bearing is located. Alternatively, in a fluid dynamic bearing design comprising a shaft and a thrust plate at or near an end of the shaft, asymmetry is again established along the journal bearing to establish a pressure gradient directed toward the thrust bearing.
Abstract:
The shaft may be supported for rotation by a conical bearing rotating within a sleeve. To prevent misalignment of the rotor and stator as the motor heats up and fluid viscosity changes, a magnetic preload is established; in a preferred embodiment, the magnetic preload is achieved using a magnetic back iron aligned with the stator magnet, the magnetic back iron being supported from the base. The shaft may further include a lower journal bearing for maintaining radial alignment and/or stiffness. A shaft may be supported for rotation relative to a sleeve by a combination of journal bearing and thrust bearing whose gaps are connected and grooved to cooperate. The bearing system includes a magnetic preload at the end of the shaft distal from the journal bearing/thrust bearing combination, the magnetic force balancing the spiral groove thrust bearing to maintain the bearing support for the shaft and the load (including hub and disc) that it supports. Further, the journal bearing balances against the thrust bearing so that as fluid is drawn further into the thrust bearing, it is withdrawn from the journal bearing to reduce the working area of the journal bearing. A reservoir terminating in a capillary seal also provided on the far side of the thrust bearing from the journal bearing. This design allows the journal bearing to drain itself as the thrust bearing spins up and its pressure increases so that the pressure of the journal bearing matches the thrust bearing.
Abstract:
A typical dynamic bearing design comprises a ring shaped or circular thrust plate mounted at or near the end of a shaft, the shaft defining together with a surrounding sleeve a journal bearing by providing grooves on only one of the two surfaces facing the gap between the shaft and sleeve. On the ring shaped thrust plate supported by the shaft, the traditional upward thrust bearing defined between the lower face of the thrust plate and the facing surface of the sleeve is maintained; but no grooves are on the surface of the thrust plate distant from the shaft and a facing counterplate surface. Further, the journal bearing is defined to have an asymmetry so that a bias force pressure along the surface of the shaft toward the thrust plate is established. The combination of the journal groove asymmetry pumping action toward the shoulder or thrust plate, together with the single grooved thrust bearing, is sufficient to establish a constant pressure between the distal surface of the thrust plate and the facing counterplate, as well as between the groove thrust plate and the facing shoulder surface.
Abstract:
A centrifugal (non-positive displacement) motor pump suitable for use in a small output area with extremely small water volume, rather simple in structure, and small in size, comprising a tubular motor stator (10), a motor rotor (20) having a permanent magnet (30), formed integral with an impeller (32), and disposed inside the motor stator (10), and a pump casing (44) fixed to the opening end part of a motor casing (12) so as to cover the impeller (32), wherein a dynamic pressure bearing (54) is formed between the front face of the impeller (32) and a spiral groove (52) provided in the internal surface of the pump casing (44) opposed to the front face of the impeller (32).
Abstract:
A thrust bearing having a radial taper in its top (land) surface provides improved load distribution when used in high-pressure positive displacement swashplate piston pumps. The thrust bearing includes a plurality of grooves in its land surface which carry and distribute fluid on the top surface during operation of the pump. The fluid is distributed so as to form a hydrodynamic fluid buffer between the thrust bearing and an adjacent pump cam surface, so that the thickness of the fluid buffer is larger in radial regions corresponding to regions of increased load and stress.