Abstract: A liquid pump (100) includes a top cover (40), a back plate (50), and a spacing member (60). The spacing member is sandwiched between the top cover and the back plate, thereby dividing an interior of the liquid pump into a fluid chamber (14) and a receiving cavity (16) isolated and hermetical from the fluid chamber. The fluid chamber is disposed between the top cover and the spacing member for receiving therein a fluid dynamic bearing (70) and a rotor (20) which drives working fluid to enter and leave the liquid pump. The receiving cavity is disposed between the spacing member and the back plate for receiving therein a stator (30) which drives the rotor to rotate in respective to the bearing.

Abstract: An ultrasonic motor includes a rotor (70) and a piezoelectric driving unit (50) for driving the rotor to rotate. The driving unit includes a piezoelectric film (52) and a vibration film (54) contacting with the rotor at an outer-periphery thereof. The ultrasonic motor further includes covers (56, 58) having a plurality of poles (560, 580) extending therefrom. Free ends of the poles fixedly connect with top and bottom sides of the vibration film, respectively.

Abstract: A sensorless and brushless motor is disclosed including a stator, a rotor, a control circuit and an induction coil (50). The stator includes a stator core (30) and a stator coil (34) wound around the stator core. The rotor includes a rotor magnet (40). The control circuit is electrically connected with the stator coil for controlling a current energizing the stator coil. The induction coil is mounted to the stator and electrically connected with the control circuit. When the rotor rotates, the induction coil is capable of outputting a signal to the control circuit and in response to the signal, the control circuit is capable of changing a direction of the current flowing in the stator coil. Thus, the commutation control for the stator coil is performed by the induction coil and the conventional Hall sensor is eliminated.

Abstract: A manufacturing tool (20) for forming a dynamic pressure groove (52) in an inner peripheral surface of a bearing sleeve (50) includes a tool shaft (21) for being rotated in a bore of the bearing sleeve while being moved in an axial direction thereof. Protrusions (25) are integrally and circumferentially arranged on an outer periphery of the tool shaft near a leading end (22) thereof. Machining tips (26) are integrally formed on outmost ends of the protrusions for machining the inner peripheral surface of the bearing sleeve to form the dynamic pressure groove therein.

Abstract: A liquid pump (100) includes a top cover (40), a back plate (50), and a spacing member (60). The spacing member is sandwiched between the top cover and the back plate, thereby dividing an interior of the liquid pump into a fluid chamber (14) and a receiving cavity (16) isolated and hermetical from the fluid chamber. The fluid chamber is disposed between the top cover and the spacing member for receiving therein a fluid dynamic bearing (70) and a rotor (20) which drives working fluid to enter and leave the liquid pump. The receiving cavity is disposed between the spacing member and the back plate for receiving therein a stator (30) which drives the rotor to rotate in respective to the bearing.

Abstract: A hydrodynamic bearing assembly comprises a bearing (10) defining a bearing hole (12) therein, a shaft (20) rotatably received in the bearing hole with a bearing clearance formed between a bearing surface of the bearing and an outer surface of the shaft, and a cover (40) attached to a top end of the bearing. The bearing clearance is filled with lubricant. A locking groove (22) is formed in an outer periphery of the shaft. The cover defines a through hole (42) receiving the shaft at the locking groove. Interlocking devices are formed on the cover and the bearing to join the cover and the bearing.

Abstract: An ultrasonic motor includes a rotor (70) and a piezoelectric driving unit (50) for driving the rotor to rotate. The driving unit includes a piezoelectric film (52) and a vibration film (54) contacting with the rotor at an outer-periphery thereof. The ultrasonic motor further includes covers (56, 58) having a plurality of poles (560, 580) extending therefrom. Free ends of the poles fixedly connect with top and bottom sides of the vibration film, respectively.

Abstract: A sensorless and brushless motor is disclosed including a stator, a rotor, a control circuit and an induction coil (50). The stator includes a stator core (30) and a stator coil (34) wound around the stator core. The rotor includes a rotor magnet (40). The control circuit is electrically connected with the stator coil for controlling a current energizing the stator coil. The induction coil is mounted to the stator and electrically connected with the control circuit. When the rotor rotates, the induction coil is capable of outputting a signal to the control circuit and in response to the signal, the control circuit is capable of changing a direction of the current flowing in the stator coil. Thus, the commutation control for the stator coil is performed by the induction coil and the conventional Hall sensor is eliminated.

Abstract: A hydrodynamic bearing assembly comprises a bearing (10) defining a bearing hole (12) therein, a shaft (20) rotatably received in the bearing hole with a bearing clearance formed between a bearing surface of the bearing and an outer surface of the shaft, and a cover (40) attached to a top end of the bearing. The bearing clearance is filled with lubricant. A locking groove (22) is formed in an outer periphery of the shaft. The cover defines a through hole (42) receiving the shaft at the locking groove. Interlocking devices are formed on the cover and the bearing to join the cover and the bearing.

Abstract: A manufacturing tool (20) for forming a dynamic pressure groove (52) in an inner peripheral surface of a bearing sleeve (50) includes a tool shaft (21) for being rotated in a bore of the bearing sleeve while being moved in an axial direction thereof. Protrusions (25) are integrally and circumferentially arranged on an outer periphery of the tool shaft near a leading end (22) thereof. Machining tips (26) are integrally formed on outmost ends of the protrusions for machining the inner peripheral surface of the bearing sleeve to form the dynamic pressure groove therein.