Abstract: A bearing structure/sealing configuration with asymmetric sealing and fluid recirculation allows the shaft to exit both ends of the spindle hub is used. Asymmetric sealing is used across the bearing section, with recirculation provided to ensure that the asymmetric seal predominates. A centrifugal capillary seal may be used on one end of the motor, while a grooved pumping seal may be used on the opposite end, providing asymmetric sealing.

Abstract: A fluid dynamic bearing includes a shaft rotating within a sleeve. The shaft and sleeve are supported for relative rotation by fluid in the gap between the shaft and sleeve. To prevent fluid from leaking out of the fluid dynamic bearing into the surrounding atmosphere, one end of the fluid is defined by a capillary seal.

Abstract: The counterplate and/or sleeve are modified to reduce or eliminate distortion in the counterplate in a laser welded fluid bearing design. It is known to directly weld the counterplate which lies across the end of the shaft and the thrust plate to a wall or shoulder of the sleeve in which the counterplate is fit. The radial stiffness of the sleeve is weakened by cutting grooves or the like at or near the interface between the sleeve wall and the counterplate, or on the outer diameter of the sleeve wall to essentially weaken the sleeve wall. This weakening of the sleeve wall prevents bowing or distortion of the counterplate being imposed by the sleeve.